Revised Ordinances of Honolulu
(Link to original Word Processing Version)
Article 8. Building Envelope
Sections:
32-8.1 Scope.
32-8.2 General.
32-8.3 Calculation procedures and basic requirements.
32-8.4 Prescriptive criteria.
32-8.5 Systems performance criteria.
(32-8.6 Notice to owner of cost of insulation or radiant barrier. Repealed by Ord.
01-46.)
32-8.6 Reserved.
Sec. 32-8.1 Scope.
(a) The requirements of this article apply to all buildings or portions of buildings
which provide shelter or facilities for human occupancy. The requirements apply to new
buildings and to additions which increase the floor space of existing buildings.
(b) Exception. Buildings or portions of buildings with open walls or other permanently open
elements of the building envelope.
(Added by Ord. 94-75)
Sec. 32-8.2 General.
(a) Compliance. The building envelope is in compliance with the requirements of this article
when all of the following conditions are met:
(1) The required calculation procedures of Section 32-8.3 are used, and the basic requirements
(air leakage and comfort ventilation) of Section 32-8.3 are satisfied;
(2) Opaque roof surfaces are in compliance with the prescriptive criteria, Section 32-8.4;
(3) Opaque wall surfaces are in compliance with the prescriptive criteria, Section 32-8.4 or,
alternatively, the entire wall (including glazing) is in compliance with the system performance
criteria, Section 32-8.5;
(4) Vertical glazing is in compliance with the prescriptive criteria, Section 32-8.4, or alternatively,
the entire wall (including opaque) is in compliance with the system performance criteria,
Section 32-8.5; and
(5) Horizontal glazing is in compliance with the prescriptive criteria, Section 32-8.4.
(b) Climate. If local building site climate data is not available, climate data from
a nearby location with a similar climate may be used.
(Added by Ord. 94-75)
Sec. 32-8.3 Calculation procedures and basic requirements.
(a) Overall Thermal Transmittance (Uo). The overall thermal transmittance of the opaque portion of
walls and roofs shall be calculated in accordance with Equation 8-1.
Equation 8-1
Σ UiAi U1A1 + U2A2 +...+ UnAn
Uo = ______ = _________________________
Ao Ao
where:
Uo = The area-weighted average thermal transmittance of the opaque wall or roof [Btu/h-ft2-ºF].
Ao = The gross area of the opaque elements of the wall or roof
[ft2]. (See subsection (c).)
Ui = The thermal transmittance of each individual element of the envelope assembly with
a unique U-value [Btu/h-ft2-ºF] (see subsection (b)). Equal to 1/Ri (where Ri is
the total resistance to heat flow of an individual path through an envelope
assembly).
Ai = The area of the element of the envelope assembly which has U-value,
Ui [ft2].
(b) Thermal Transmittance (Ui). The thermal transmittance of each individual element of the envelope
assembly shall be determined with due consideration of surface conductances and all major
series and parallel heat flow paths.
(c) Gross Area of Opaque Envelope Components.
(1) The gross area of an opaque roof surface consists of the total surface
of the roof assembly exposed to outside air or unconditioned spaces. The opaque
roof assembly shall exclude skylight surfaces, service openings, and overhangs.
(2) The gross area of opaque exterior wall surfaces is measured on the exterior
and includes between-floor spandrels, peripheral edges of flooring and door areas. The opaque
wall surface excludes vents, grilles, pipes and windows.
(d) Relative Solar Heat Gain (RSHG).
(1) The vertical fenestration solar heat gain limits are expressed in terms of maximum
relative solar heat gain (RSHG). Relative solar heat gain shall be calculated as
determined in this section. When a fenestration system includes an overhang or sidefins,
then the RSHG shall be calculated with either Equation 8-2 for an overhang
or Equation 8-3 for sidefins. For a single window, either the overhang multiplier,
OHM, or the sidefin multiplier, SFM, but not both, may be used for
shading credit.
or
Equation 8-2
RSHGi = SCglz,i x
OLE Object Here
x SCext,i x OHMi
Equation 8-3
RSHGi = SCglz,i x
OLE Object Here
x SCext,i x SFMi
where:
RSHGi = Relative solar heat gain.
SCglz,i = Shading coefficient of the glass alone taken from the manufacturer's literature.
ISprop = Interior and/or integral shade shading coefficient adjustment, based on the proposed type
of shade and the type of glass. Equal to the ratio of the
shading coefficient with shades to the shading coefficient of the glazing alone (SCglz).
As a default, ISprop. may be assumed to equal ISdef. (then ISprop./ISdef. =
1.0). (Unitless.)
ISdef=Default shading coefficient adjustment. For a medium-colored venetian blind with the proposed glazing.
Equal to the ratio of the shading coefficient of the fenestration with a
medium- colored venetian blind to the shading coefficient of the glazing alone. (Unitless.)
SCext = Shading coefficient of exterior shade screens or louvers. Default is 1.0. (Unitless.)
OHMi = Overhang Multiplier. Calculated as a function of Overhang Projection Factor, OPF. From
Equation 8-4 or Table 8-3.
SFMi = Sidefin Multiplier. Calculated as a function of the Sidefin Projection Factor,
SPF. From Equation 8-5 or Table 8-4.
The overhang and sidefin multipliers are calculated with the following equations.
Equation 8-4
OHMi = 1 + ai x OPFi + bi x OPFi2
where:
OHM = Overhang Multiplier.
OPF = Overhang Projection Factor. The maximum value allowed for credit is 1.5. From
Equation 8-6.
a, b = Coefficients which depend on orientation. From Table 8-1.
Equation 8-5
SFMi = 1 + ci x SPFi + di x SPFi2
where:
SFM = Sidefin Multiplier.
SPF = Sidefin Projection Factor. The maximum value allowed for credit is 1.5. From
Equation 8-7.
c, d = Coefficients which depend on orientation. From Table 8-2.
Table 8-1 -- Overhang Multiplier Coefficients
Orientation a b
North -0.440 0.123
East, West and South -0.840 0.245
Table 8-2 -- Sidefin Multiplier Coefficients
Orientation c d
North -0.81 0.27
East -0.51 0.13
South -0.65 0.16
West -0.61 0.16
The overhang and sidefin projection factors are calculated using the following equations.
where:
OPF = Overhang Projection Factor.
A = Horizontal projection of overhang.
B = Height of overhang. The vertical distance between the bottom of the overhang
and the bottom of the window.
Note: Overhangs shall extend the full width of the window to receive credit
for shading.
where:
SPF = Sidefin Projection Factor.
A = Sidefin depth, measured perpendicular to the window surface. If the left and
right sidefins have different depths, then A is the average of the two
depths.
B = Distance between sidefins. If the window width is less than the sidefin
spacing, then the average of the distance between the left sidefin and the
right edge of the window and the distance between the right sidefin and
the left edge of the window may be used. The average provides a
larger SPF and, therefore, a larger sidefin credit.
Note: Sidefins shall extend the full height of the window to receive credit
for shading.
A single sidefin shall receive shading credit if, for window orientations between true
north and either true east or west, the sidefin is on the south
side of the window. Similarly, for windows facing between true south and east
or west, a single sidefin is eligible for credit if it is on
the north side of the window.
Table 8-3 -- Overhang Multiplier, OHM
East, West
Overhang Projection Factor North and South
0.0 - 0.1 1.00 1.00
0.1 - 0.2 0.96 0.92
0.2 - 0.3 0.92 0.84
0.3 - 0.4 0.88 0.77
0.4 - 0.5 0.84 0.70
0.5 - 0.6 0.81 0.64
0.6 - 0.7 0.78 0.58
0.7 - 0.8 0.75 0.53
0.8 - 0.9 0.73 0.48
0.9 - 1.0 0.70 0.44
1.0 - 1.1 0.68 0.40
1.1 - 1.2 0.66 0.37
1.2 - 1.3 0.65 0.34
1.3 - 1.4 0.64 0.32
1.4 - 1.5 0.62 0.30
Note: Equation 8-4 for OHM may be used to provide slightly greater credit
for overhangs than the values in this table.
Table 8-4 -- Sidefin Multiplier, SFM
Sidefin Sidefin Multiplier
Projection
Factor North South East West
0.0 - 0.1 1.00 1.00 1.00 1.00
0.1 - 0.2 0.92 0.95 0.94 0.94
0.2 - 0.3 0.85 0.90 0.88 0.88
0.3 - 0.4 0.78 0.86 0.82 0.83
0.4 - 0.5 0.72 0.82 0.76 0.78
0.5 - 0.6 0.66 0.78 0.71 0.74
0.6 - 0.7 0.61 0.74 0.67 0.69
0.7 - 0.8 0.56 0.71 0.62 0.65
0.8 - 0.9 0.52 0.68 0.58 0.62
0.9 - 1.0 0.49 0.65 0.54 0.58
1.0 - 1.1 0.46 0.62 0.51 0.55
1.1 - 1.2 0.43 0.60 0.48 0.53
1.2 - 1.3 0.41 0.57 0.45 0.50
1.3 - 1.4 0.40 0.56 0.43 0.48
1.4 - 1.5 0.39 0.54 0.40 0.47
Note: Equation 8-5 for SFM may be used to provide slightly greater credit
for sidefins than the values in this table.
(2) Exterior Shading Devices. Exterior louvers or exterior sunscreens shall be allowed for compliance
in the RSHG calculations in subsection (d). In Equation 8-2 or Equation 8-3
an exterior shading device shall be described either by its shading coefficient (SCext)
or by its overhang multiplier (OHM) or sidefin multiplier (SFM). Automatic or manually
operable louvers shall be assumed to have an Overhang Projection Factor (for horizontal
louvers) or Sidefin Projection Factor (for vertical louvers) of 1.0. Projection factors for
fixed louvers and sunscreens shall be calculated as the ratio of louver width
to louver spacing (see Equations 8-6 and 8-7).
(3) Interior Shading Devices. Interior shading devices shall be allowed for compliance with the
RSHG requirements in accordance with Equations 8-2 or 8-3.
(e) Air Leakage and Comfort Ventilation. All residential buildings including hotel and motel guest
rooms shall meet the requirements of subdivision (1) for comfort ventilation. In addition,
conditioned spaces in residential buildings and hotel and motel guest rooms shall meet
the requirements of subdivision (1) and the air leakage requirements of subdivision (2).
Conditioned spaces in commercial buildings shall comply with subdivision (2). Unconditioned spaces in
commercial buildings shall comply with either subdivision (1) or subdivision (2).
(1) Comfort Ventilation.
(A) When compliance with this section is required under subsection (e), then habitable spaces
and working spaces shall meet the following requirements. Kitchens are exempt from this
section.
(i) Louvers or door catches which allow doors to be held open shall be
provided for interior doors. This requirement does not apply to hotel and motel
guest room entry doors;
(ii) A minimum of two operable openings to outside shall be provided on opposite
or adjacent walls. Operable openings include operable windows, sliding glass doors, louvers and
entry screen doors (if entry door is provided with door catches). For spaces
with only one external wall, two windows on either side of a wing
wall may be used; and
(iii) The minimum total free area for ventilation in each space shall be equal
to 12 percent of floor area. No more than 70 percent of the
total free area may be placed on one wall. For spaces employing a
wing wall, no more than 70 percent of the total free area may
be placed on one side of the wing wall.
(B) Exceptions.
(i) Spaces with wiring provided for ceiling fans. In each space, a minimum of
one ceiling fan outlet shall be provided for each 400 ft2 of floor
area. When more than one outlet is required within a space, the outlets
shall be uniformly distributed throughout the room. Wiring shall enable wall-mounted fan controls;
(ii) Hotel/motel guest rooms that are air- conditioned;
(iii) Spaces employing innovative natural ventilation designs which do not comply with this section,
but which can be shown through analysis or demonstration to provide adequate air
movement or temperature and humidity conditions for human comfort.
(2) Air Leakage. Conditioned spaces shall meet the following criteria for minimizing air leakage.
(A) The conditioned space shall be enclosed. Conditioning of unenclosed spaces is allowed only
under the provisions of Section 32-9.3(j);
(B) Fenestration and doors enclosing conditioned space shall be weatherstripped or otherwise tightly sealed
to minimize air leakage. Operable windows shall be capable of being tightly closed.
Openings which may be closed but not tightly sealed, such as jalousie windows
or louvers, may account for up to 2 percent of the wall area
enclosing the space;
(C) Commercial entrances enclosing conditioned space shall be revolving or self-closing doors to minimize
air leakage; and
(D) Exterior joints, cracks and holes in building envelope components enclosing conditioned space shall
be caulked, gasketed, weatherstripped or otherwise sealed to prevent air leakage.
(f) Roof Heat Gain Factor (RHGF). The solar heat gain limits for opaque roof
constructions are expressed in terms of the roof heat gain factor (RHGF) which
is described in Equation 8-8. The maximum allowed limits are listed in Section
32-8.4(a).
Equation 8-8
RHGF= Ur x α x RB
where:
RHGF = Roof Heat Gain Factor. [Btu/ft2-h-ºF].
Ur = overall thermal transmittance value for the gross area of opaque roof surfaces,
as defined in subsection (c). [Btu/ft2-h-ºF].
α = roof surface absorptivity. Between 0.3 and 1.0 [unitless].
RB = Radiant Barrier credit. Equals 0.33 if a radiant barrier is installed and
1.00 otherwise [unitless]. Radiant barrier installation shall comply with subsection (g) to qualify
for credit.
(g) Radiant Barrier Eligibility. To qualify for the radiant barrier credit (RB) described in
subsection (f), the installation of the radiant barrier shall meet the following criteria:
(1) The emissivity of the radiant barrier shall be less than or equal to
0.10. The manufacturer shall provide test data or documentation of the emissivity using
ASTM E-408, Test Method for Total Normal Emittances of Surfaces Using Inspection Meter
Techniques, ASTM Philadelphia, PA 19103.
(2) The radiant barrier shall be securely installed in a permanent manner using one
of the following five installation methods.
(A) Draped with the shiny side facing down over the top cord of the
truss before the roof deck is installed. A minimum air gap of 3/4
inch shall be provided between the radiant barrier and the roof deck above
at the center of the span. A minimum 3/4-inch air gap shall also
be provided between the radiant barrier and the ceiling or insulation below.
(B) Stretched with the shiny side facing down between the top cords of the
truss and stapled or otherwise secured at each side. A minimum air space
of 3/4 inch above and below is required.
(C) Stapled or otherwise secured to the bottom surface of the top cord of
the truss and draped below with the shiny side facing down. For attic
installations only. A minimum air space of 3/4 inch above and below is
required.
(D) Laid on top of the roof deck with the shiny side facing up
and a minimum 3/4-inch air gap between the radiant barrier and the roofing
material above. For open beam ceiling construction only. The roof slope shall be
greater than or equal to 14 degrees from horizontal.
(E) Laminated to the underside of the roof sheathing with at least 3/4-inch air
space below.
(3) At least one square foot of free area for ventilation shall be provided
per 150 square feet of attic floor area, or in the case of
vaulted or open beam ceilings, per 150 square feet of ceiling area. In
vaulted or open beam ceilings, the air space shall be vented with vent
area approximately evenly distributed between the top and the bottom. In vaulted ceilings,
vents shall be provided for each air space between rafters.
(Added by Ord. 94-75; Am. Ord. 01-47)
Sec. 32-8.4 Prescriptive criteria.
(a) Opaque Roof Surfaces.
(1) The roof heat gain factor (RHGF) for opaque roofs shall be less than
0.05 when calculated as described in Section 32-8.3(f).
(2) Exception. Roofs which are completely shaded from direct sunlight or attics with one
square foot of free area for ventilation per ten square feet of attic
floor area shall be exempt from the requirement in subsection (a).
(b) Opaque Wall Surfaces.
(1) The overall thermal transmittance value (Uo) for the gross area of opaque wall
surfaces, as defined in Section 32-8.3, shall be less than or equal to
0.15 for metal framed walls and 0.10 for all others. Alternatively, the R-value
of insulation shall be greater than or equal to R-11.
(2) Exceptions.
(A) Walls with a heat capacity greater than 7.5 Btu/ºF-ft2 of wall surface area;
(B) Portions of opaque walls completely shaded from direct sunlight by an overhang, adjacent
building or feature of the landscape such as a hill or cliff. The
wall must be shaded all day, throughout the year;
(C) Walls shaded by overhangs with a projection factor greater than or equal to
0.2 on north facing walls or 0.3 on all other orientations. The projection
factor equals the ratio of the horizontal projection of the overhang to the
height of the wall (measured as the vertical distance from the bottom of
the wall to the bottom outer edge of the overhang);
(D) Walls enclosing spaces which are not air-conditioned.
(c) Vertical Glazing.
(1) The relative solar heat gain (RSHG) of vertical fenestration, as defined in Section
32-8.3(d), shall be less than or equal to the appropriate value in Table
8-6. The maximum RSHG for north orientations shall be based on the window-to-wall
ratio (WWR) for north-facing walls. The maximum RSHG for all other orientations shall
be based on the combined WWR for east, west and south walls. Linear
interpolation may be used to determine the maximum allowed RSHG for WWR's which
lie within one of the ranges.
(2) Exceptions.
(A) A window area of up to 2 percent of gross exterior wall area
may exceed the RSHG limits for any given orientation;
(B) Individual windows may exceed the maximum RSHG limit as long as the area-weighted
average RSHG's for both the north orientation and the combined east, west and
south orientations are less than or equal to the maximum limit.
(C) Individual windows completely shaded from the sun are exempt from the RSHG limits
and shall be excluded from the window area calculation.
Table 8-6 -- Maximum Relative Solar Heat Gain (RSHG)
for High-Rise Residential and Nonresidential Buildings
East, West
North and South
WWR Range Max. RSHG Max. RSHG
0 - 0.15 0.85 0.65
0.15 - 0.30 0.85 0.45
0.30 - 0.45 0.65 0.30
0.45 - 0.60 0.50 0.25
0.60 - 0.75 0.40 0.20
0.75 - 1.00 0.40 0.20
(d) Horizontal Glazing (Skylights). The horizontal projection of skylight area shall be limited to
a maximum fraction of the horizontal projection of roof area which is specified
by the following equation:
Equation 8-9
A = 0.025 / SC
where:
A = Maximum allowed skylight area measured as the skylight's horizontal projection. Expressed as
a fraction of the horizontal projection of roof area. Shall be less than
or equal to 0.15.
SC = Shading coefficient of skylight; may be from manufacturer's literature.
(Added by Ord. 94-75; Am. Ord. 01-47)
Sec. 32-8.5 Systems performance criteria.
(a) Purpose. This section provides a systems approach to compliance with the wall and
window requirements of this code. This section may be used instead of Sections
32-8.3(b) and 32-8.3(c).
(b) Compliance.
(1) Walls of the building envelope are in compliance with this subsection when the
annual cooling energy flux (ACEF) attributable to transmission and solar gain for the
proposed design is less than the ACEF of the reference design. The ACEF
shall be calculated using the methods of subsection (c).
(2) The reference building and proposed design are defined as follows:
Surface Areas and Orientation. Walls of the reference building shall have the same
gross surface areas and orientations as walls in the proposed design. Glazing area
and orientation of the reference building shall be identical to the proposed design.
Shading Coefficients (SCx). The shading coefficient of glazing in the reference building shall
be equal to the relative solar heat gain requirements of Section 32-8.4(c) for
each window orientation.
Projection Factor (PF). The projection factor of the reference building shall be zero
(no overhangs) for all window orientations.
Visible Transmittance (VT). The visible transmittance of glazing in the reference building shall
be equal to the RSHG requirement of Section 32-8.4(c) for each orientation minus
0.25. The visible transmittance shall not be less than zero.
Glazing Thermal Transmittance (Uof). The glazing thermal transmittance in the reference building shall
be equal to 1.21 Btu/h-ft2-ºF.
Opaque Wall Thermal Transmittance (Wall Uo). The thermal transmittance of opaque wall surfaces
in the reference building shall be equal to the requirement specified in Section
32-8.4(b) for all orientations.
Wall Heat Capacity (HC). Wall heat capacity in the reference design shall be
equal to 1.0.
Equipment Power Density (EQUIP). The equipment power density in W/ft2 of the reference
building shall be equal to that in the proposed design. The equipment power
density in the proposed design is the average receptacle power density in W/ft2,
considering diversity, in the activity areas within 15 feet of each exterior wall.
If the equipment power density is not known for the proposed design, use
a value from Table 13-2 for both the reference building and the proposed
design. If the building occupancy is not known, use 0.5 W/ft2 for both
the reference design and the proposed design.
Lighting Power Density (LIGHTS). The lighting power density in W/ft2 of the reference
building shall be equal to that in the proposed design. The lighting power
density in the proposed design is the average for activity areas within 15
feet of each exterior wall.
If the lighting power density is not known for the proposed design, select
a value from Table 6-5 for both the reference building and the proposed
design. If the building occupancy is not known, use 1.5 W/ft2 for both
the reference building and the proposed design.
Daylighting Control Factor (DLCF). The daylighting control factor (DLCF) for the reference design
shall be determined from Equation 8-10 for each orientation. The DLCF for the
reference design shall not be greater than 1.0.
Equation 8-10
DLCFref = WWRprop x 1.67
where:
DLCFref = The daylighting control factor (DLCF) for the reference building.
WWRprop = The window wall ratio of the proposed design for each orientation.
The daylighting control factor (DLCF) for the proposed design shall be equal to
the ratio of daylighted perimeter to total perimeter and shall be calculated separately
for each orientation. The daylighted perimeter includes the width of windows and as
much as three feet of wall to the left and right of windows.
This may be determined from Equation 8-11. The DLCF for the proposed design
shall not be greater than 1.0.
Equation 8-11
DLCFprop = Σ (Pw + Pwr + Pwl) / Pt
where:
DLCFprop = Daylighting control factor for the proposed design for each orientation.
Pw = Width of each window on each orientation.
Pwr = Daylighted area to the right of each window on each orientation. This
shall be the lesser of three feet, half the distance to the next
window or the distance to a wall in the room or space that
is perpendicular to the building perimeter.
Pwl = Daylighted area to the left of each window on each orientation. Similar
to Pwr.
Pt = The total perimeter on each orientation.
Loads from Occupants. Sensible load from occupants in the reference building shall be
equal to that of the proposed design. The default is 0.6 W/ft2.
(c) Equation for Annual Cooling Energy Flux (ACEF). This section contains the external wall
equation for use in determining external wall cumulative annual cooling energy flux and
for determining compliance with the systems performance method of this section.
Seven individual terms are identified that correlate variables with physical meaning such as
U-values, internal gains, and weather-related variables.
CLU,
CLUO,
CLXUO: Terms that correlate the cumulative annual cooling loads with the thermal transmittance of
the wall.
CLM: Term that correlates the cumulative annual cooling loads with the heat capacity of
the wall.
CLG: Term that correlates the cumulative annual cooling loads with the internal gains from
occupant light and equipment.
CLS: Term that correlates the cumulative annual cooling loads with the incident solar gains.
CLC: Term that correlates the cumulative annual cooling loads with the climate variables for
a specific location.
(1) Cooling Equation.
Equation 8-12
WCc or Cl = Σ [CLUOi + CLXUOi
+ CLGi + CLSi + CLCi + Σ(CLUi,j + CLMi,j )]
If WC c or C 1 < 0.0, then WC c or C 1 is set equal
to 0.0.
where:
Subscripts
i = matrix consideration for each given orientation.
j = matrix consideration for each wall mass construction type for the given
orientation.
Indices
m = number of wall construction types per orientation.
n = number of wall orientations.
Variables
CLUOi = FCi x UOCi[CUO1i x EAi x VSi x CDD50 + CUO2i x
Gi + CUO3i x Gi2 x EAi2 x VSi x CDD50 + CUO4i
x Gi2 x EAi2 x VSi x CDD65]
CLXUOi = FCi(1/UOCi)[CXUO1i x EAi x VSi x CDD50 + CXUO2i x EAi(VSi x
CDD50)2 + CXUO3i x Gi x CDD50 + CXUO4i x Gi2 x EAi2
x VSi x CDD50 + CXUO5i x Gi2 x CDD65]
CLGi = FCi{Gi[CG1i + CG2i x CDD50 + CG3i x EAi(VSi x CDD50)2 +
CG4i x EAi2 x VSi x CDD50 + CG5i x CDD65 + CG6i
x CDD503 + CG7i x CDD653] + Gi2[CG8i x EAi x VSi x
CDD50 + CG9i x EAi2 x VSi x CDD50]}
CLSi = FCi{EAi[CS1i + CS2i x VSi x CDD50 + CS3i(VSi x CDD50)2 +
CS4i x VSi x CDD65 + CS5i(VSi x CDD65)2] + EAi2[CS6i + CS7i(VSi
x CDD65)2]}
CLCi = FCi[CC1i x CDD50 + CC2i x CDD502 + CC3i x CDH80 +
CC4i x CDH802 + CC5i x CDD65 + CC6i(VSi x CDD65)2 + CC7i
x VSi x CDD50 + CC8i(VSi x CDD50)2 + CC9i(VSi x CDH80)2 +
CC10i x VSi + CC11i x DR + CC12i x DR2 + CC13i]
CLUi,j = FOi,j x Uow,i[CU1i x CDH80 + CU2i x CDH802 + CU3i(VSi x
CDH80)2 + CU4i x DR]
CLMi,j = FOi,j x CMCi,j[CM1i + CM2i x EAi x VSi x CDD50
+ CM3i x EAi x VSi x CDD65 + CM4i x EAi2 x
VSi x CDD50 + CM5i x Gi2 x CDD65 + CM6i x Gi
x CDD50 + CM7i x Gi x CDD65 + CM8i x Gi x
EAi x VSi x CDD50]
Note: The coefficients for various orientations in the above equations are shown in Table
8-8.
Climate data
CDD50 = Cooling degree-days base 50ºF.
CDD65 = Cooling degree-days base 65ºF.
CDH80 = Cooling degree-hours base 80ºF.
DR = average daily temperature range for warmest month.
VSi = annual average daily incident solar energy on facade under consideration, Btu/(ft2-day).
Building Data
FCi = ratio, wall area (opaque and glazed) of zone under consideration divided by
total wall area (opaque and glazed) of all zones.
FOi,j = ratio, opaque wall area of zone under consideration divided by total wall
area (opaque and glazed) of all zones. If multiple mass constructions are present,
the FOi,j is calculated for each construction j and used to form the
area weighted mass correction.
Uow,i = area average U-value of opaque walls (including those of mass construction) in
zone under consideration, Btu/(h-ft2-ºF).
UOCi = area average U-value of wall (opaque and glazed, evaluated under cooling conditions)
in zone under consideration, Btu/(h-ft2-ºF).
WWRi = window wall ratio for zone under consideration; defined as fenestration area divided
by total wall area (opaque and glazed).
EAi = effective aperture fraction for zone under consideration, where:
Equation 8-13
EAi = WWRi x RSHGi
and
RSHGi = the relative solar heat gain for the fenestration in a given orientation,
as determined from Section 32-8.3(d).
Internal Load
Equation 8-14
Gi = Ep,i + Lp,i (1 - Rc,i x Kd,i ) + Ol,i
where:
Gi = effective internal gain (W/ft2) for zone under consideration.
Ep,i = equipment power, from subsection (b).
Lp,i = lighting power, from subsection (b).
Ol,i = occupant load adjustment, from subsection (b).
Rc,i = for a specified orientation, the ratio of the daylighting area of the
space to the total area of the space.
Equation 8-15
Kd,i = 5.871(WWRi x VLTi x OHMi ) - 13.311(WWRi x VLTi x
OHMi )2
If WWR i x VLT i x OHM i is greater than 0.22, then K d,i is
set equal to 0.647.
where:
WWRi = as defined above under Building Data.
VLTi = visible light transmittance of the glazing material, as defined in subsection (b).
OHMi = Overhang multiplier, from Section 32-8.3(d).
CMCi,j = mass correction from Eq 8-16. If multiple mass constructions are present, then
each CMCi,j is evaluated separately and combined by area weighting. If the U-value
of the mass wall is greater than 0.40, then Uow = 0.4 shall
be used to calculate the CMCi,j. If the value of HC is greater
than 20, then HC = 20 shall be used to calculate the CMCi,j.
(2) Cooling Delta Load Factor Equations. Equation 8-16 is used to predict the Cooling
Delta Load Factor values.
Equation 8-16
CMC = Cooling Delta Load Factor =
[1 - e-CP1(HC-1)]
x
OLE Object Here
x
where:
HC = Wall Heat Capacity (Btu/ft2-ºF).
U = Wall U-Value (Btu/h-ft2-ºF).
A = (Cooling degree-hours base 80ºF)/10,000 + 2 (ºF-h).
B = (Daily Range)/10 + 1(ºF).
CP1 = C5
CP2 = C15/B3 + C16/(A2B2) + C17
CP3 = C1/A3 + C2B3 + C3/(A2B) + C4
CP4 = C12/(A2B2) + C13/B3 + C14
CP5 = C18
CP6 = C6B LN(A) + C7
LN = Natural Logarithm
CP7 = C19/(A2B2) + C20/(AB) + C21A2/B + C22
CP8 = C8/(A2B2) + C9/(AB) + C10/(A2B) + C11
The coefficients C1 through C22 are taken from Table 8-7.
Table 8-7 -- Cooling Delta Load Coefficients
Insulation Position
Coefficient Exterior Integral Interior
C 1 220.724503 139.105667 181.616776
C 2 -.056589 -.033991 -.055196
C 3 -118.835388 -10.326704 -34.158966
C 4 -13.674420 -20.867386 -25.591934
C 5 .236381 .283882 .081029
C 6 .959588 .305851 1.418998
C 7 -.255004 .022622 .432421
C 8 -905.677979 -307.943848 -1882.926758
C 9 425.191895 80.209610 443.195801
C 10 -2.510600 .049955 .430200
C 11 -43.387955 -5.989545 -28.285065
C 12 -259.723389 -11.396114 -63.562256
C 13 -33.975525 .366851 20.844650
C 14 20.488235 30.253494 9.817521
C 15 -26.209152 8.833706 24.459824
C 16 -241.173386 -22.254623 -70.337494
C 17 18.897781 29.329697 9.884280
C 18 -.353790 -.023878 -.114646
C 19 156.305634 63.322754 326.344727
C 20 -74.098999 -16.334656 -77.635498
C 21 .445363 -.011114 -.074788
C 22 7.496696 1.295576 5.204088
Table 8-8
Cooling
Coefficients North East South West
CU1 0.001539 0.003315 0.003153 0.00321
CU2 -0.308548E-07 -0.896618E-07 -0.712993E-07 -0.810530E-07
CU3 0.799493E-13 0.379280E-13 0.183083E-13 0.339810E-13
CU4 -0.079647 0.163114 0.286458 0.11178
CM1 0.32314 0.515262 0.71477 0.752643
CM2 0.153060E-05 0.138197E-05 0.161630E-05 0.142228E-05
CM3 -0.204322E-05 -0.160240E-05 -0.211063E-05 -0.197938E-05
CM4 -0.753665E-06 -0.767849E-06 -0.664430E-06 -0.740067E-06
CM5 -0.100472E-05 0 0.801057E-05 0.315193E-05
CM6 0.366708E-04 0.356503E-04 0.448106E-04 0.296012E-04
CM7 -0.673045E-04 -0.640938E-04 -0.000119 -0.766719E-04
CM8 -0.238335E-07 -0.472534E-07 -0.497469E-07 0
CUO1 -0.651094E-05 -0.838669E-05 -0.888996E-05 -0.756465E-05
CUO2 -1.040207 -1.507235 -1.512625 -1.238545
CUO3 -0.438254E-05 -0.278828E-05 -0.231352E-05 -0.412567E-05
CUO4 0.126580E-04 0.809874E-05 0.736219E-05 0.106712E-04
CXUO1 0.103744E-05 0.119338E-05 0.118588E-05 0.123251E-05
CXUO2 -0.132180E-12 -0.134656E-12 -0.116252E-12 -0.130002E-12
CXUO3 0.275554E-04 0.202621E-04 0.202365E-04 0.236964E-04
CXUO4 0.974090E-07 0.117514E-06 0.939207E-07 0.136276E-06
CXUO5 -0.118247E-04 -0.909694E-05 -0.909192E-05 -0.111077E-04
CG1 0.891286 0.583388 0.393756 0.948654
CG2 0.001479 0.001931 0.002081 0.001662
CG3 -0.552042E-12 -0.282139E-12 -0.284766E-12 -0.455720E-12
CG4 0.252311E-05 0.370821E-05 0.430536E-05 0.591511E-05
CG5 -0.001151 -0.001745 -0.001864 -0.00153
CG6 0.195243E-11 0 -0.296055E-11 0.316358E-11
CG7 -0.835805E-11 0.101089E-10 0.330027E-10 0
CG8 0.141022E-05 0.753875E-06 0.713300E-06 0.970752E-06
CG9 -0.238887E-05 -0.164961E-05 -0.163927E-05 -0.197363E-05
CS1 46.9871 33.9683 18.32016 29.3089
CS2 0.348091E-04 0.374118E-04 0.340490E-04 0.502498E-04
CS3 0 0 0.271313E-11 0
CS4 -0.166409E-04 0.694779E-05 -0.282181E-04 -0.277158E-04
CS5 0.842765E-11 0 -0.304677E-11 0.291137E-11
CS6 -56.5446 0 26.9954 14.9771
CS7 -0.134764E-10 -0.588097E-11 -0.650089E-11 -0.789218E-11
CC1 0.002747 0 0.010349 0.001865
CC2 0 0.318928E-06 -0.304413E-06 0
CC3 -0.000348 0.000319 0.00024 0.000565
CC4 0.122123E-07 -0.775318E-07 -0.271443E-07 -0.544380E-07
CC5 0.012112 0.011894 0.013248 0.009236
CC6 0.104027E-11 -0.622661E-12 -0.205178E-11 0
CC7 -0.124013E-04 -0.706280E-05 -0.165377E-04 -0.602685E-05
CC8 0 0 0.820869E-12 0
CC9 -0.375797E-13 0.606235E-13 0.197598E-13 0.389425E-13
CC10 0.030056 0.023121 0.0265 0.01704
CC11 0 0 -0.271026 -0.244274
CC12 0.002138 0.001103 0.006368 0.007323
CC13 -12.8674 -13.16522 -18.271 -10.1285
(Sec. 32-8.6 Notice to owner of cost of insulation or radiant barrier. Repealed by
Ord. 01-46.)
Sec. 32-8.6 Reserved.
Article 9. Heating, Ventilating and Air Conditioning
(HVAC) Systems
Sections:
32-9.1 Scope.
32-9.2 General.
32-9.3 Basic requirements.
32-9.4 Prescriptive criteria.
Sec. 32-9.1 Scope.
(a) The requirements of this article apply to all new HVAC systems or system
components in both new and existing buildings.
(b) Exception. This article does not apply to the maintenance and repair of existing
systems.
(Added by Ord. 94-75)
Sec. 32-9.2 General.
The requirements in this article represent minimum design criteria. Where applicable, the state
department of health (DOH) Administrative Rules, Title 11, Chapter 39, enforced by the
DOH, shall apply to ventilation and air conditioning. (Added by Ord. 94-75)
Sec. 32-9.3 Basic requirements.
(a) Load Calculations.
(1) Calculation Procedures. Cooling system design loads for the purpose of sizing systems and
equipment shall be determined in accordance with the procedures described in the ASHRAE
Handbook, 1989 Fundamentals or a similar computation procedure. For those design parameters addressed
in (2) through (9), the values specified shall be used.
(2) Indoor Design Conditions. Indoor design temperature and humidity conditions for general comfort applications
shall be in accordance with the comfort criteria established in ANSI/ASHRAE Standard 55-1981
Thermal Environmental Conditions for Human Occupancy, or Chapter 8 of the ASHRAE Handbook,
1989 Fundamentals, or both, except that winter humidification and summer dehumidification are not
required.
(3) Outdoor Design Conditions. Outdoor design conditions shall be selected from "Climatic Data for
Region X Arizona, California, Hawaii, Nevada," Golden Gate and Southern California Chapters, ASHRAE,
Fifth Edition, May 1982, or from data obtained from the National Climatic Center
or a similar recognized weather data source. Cooling design temperatures shall be no
greater than the 0.5 percent annualized value.
(4) Ventilation. Outdoor air ventilation loads shall be based on ventilation rates specified in
subsection (f).
(5) Envelope. Envelope cooling loads shall be based on envelope characteristics, such as thermal
conductance, shading coefficient, and air leakage, consistent with the values used to demonstrate
compliance with Article 8.
(6) Lighting. Lighting loads shall be based on actual design lighting levels or power
budgets consistent with Article 6.
(7) Other Loads. Other HVAC system loads, such as those due to people and
equipment, shall be based on design data compiled from one or more of
the following sources:
(A) Actual information based on the intended use of the building;
(B) Published data from manufacturers' technical publications;
(C) Technical society publications such as the ASHRAE Handbooks, 1991 HVAC Applications and 1992
HVAC Systems and Equipment;
(D) Alereza, "Estimates of recommended heat gains due to commercial appliances and equipment," ASHRAE
Transactions, Vol. 90, Pt 2A, pp. 25-58, 1984.
(E) Default values to be used in determining the design energy budget in Article
13 are taken from Tables 13-1, 13-2, and 13-4;
(F) Other data based on designer's experience of loads and occupancy patterns.
(8) Safety Factor. Design loads may, at the designer's option, be increased by as
much as 10 percent to account for unexpected loads or changes in space
usage.
(9) Pickup Loads. Transient loads such as cool-down loads which occur after off-hour setback
or shutoff, may be calculated from basic principles, based on the heat capacity
of the building and its contents, the level of setback, and desired recovery
time, or may be assumed to be up to l0 percent of the
steady-state cooling design loads. The steady-state load may include a safety factor in
accordance with subdivision (8).
(b) Separate Air Distribution Systems.
(1) Zones with special process temperature requirements, humidity requirements, or both, shall be served
by separate air distribution systems from those serving zones requiring only comfort conditions,
or shall include supplementary provisions so that the primary systems may be specifically
controlled for comfort purposes only.
(2) Exception. Zones that require only comfort cooling and are served by a system
primarily used for process temperature and humidity control, need not be served by
a separate system if the total supply air to these comfort zones is
no more than 25 percent of the total system supply air, or the
total conditioned floor area of the zones is less than 1,000 ft2.
(c) Temperature Controls.
(1) System Control. Each HVAC system shall include at least one temperature control device.
(2) Zone Controls.
(A) The supply of cooling energy to each zone shall be controlled by individual
thermostatic controls responding to temperature within the zone.
(B) Exceptions.
(i) Independent perimeter systems that are designed to offset only envelope heat gains may
serve one or more zones also served by an interior system, with the
following limitations:
1. The perimeter system shall include at least one thermostatic control zone for each
building exposure having exterior walls facing only one orientation for 50 contiguous feet
or more;
2. The perimeter system cooling supply shall be controlled by thermostat located within the
zone served by the system.
(ii) A dwelling unit may be considered a single zone.
(3) Thermostats shall be shaded from direct solar radiation and shall be isolated from
heat gain due to large equipment and machinery.
(4) Where used to control comfort cooling, zone thermostatic controls shall be capable of
being set, locally or remotely, by adjustment or selection of sensors, up to
85 degrees Fahrenheit or higher.
(d) Off-hour and Interlock Controls.
(1) Off-hour Controls.
(A) HVAC systems shall be equipped with automatic controls capable of accomplishing a reduction
of energy use through control setback or equipment shutdown during periods of nonuse
or alternate use of the spaces served by the system.
(B) Exceptions.
(i) Systems serving areas expected to operate continuously;
(ii) Where it can be shown that setback or shutdown will not result in
a decrease in overall building energy costs;
(iii) Equipment with full load demands of 2 kW (6826 Btu/hr) or less may
be controlled by readily accessible manual off-hour controls;
(iv) Where process conditioning is required on a 24-hour basis.
(2) Systems that serve zones which can be expected to operate non-simultaneously for more
than 750 hours per year shall include isolation devices and controls to shut
off or set back the supply of cooling to each zone independently. Isolation
is not required for zones expected to operate continuously or expected to be
inoperative only when all other zones are inoperative.
For buildings where occupancy patterns are not known at the time of system
design, such as speculative buildings, isolation areas may be predesignated.
Zones may be grouped into a single isolation area provided that the total
conditioned floor area does not exceed 25,000 ft2 per group nor include more
than one floor.
(3) Operable doors leading from a conditioned space to a balcony or patio in
hotel or motel guest rooms shall be provided with interlock controls to disable
cooling of the space while the door is open.
(e) Dehumidification. Where a humidistat is used for comfort dehumidification, it shall be capable
of being set to prevent the use of fossil fuel or electricity to
reduce relative humidities below 60 percent.
(f) Ventilation.
(1) Outdoor air ventilation rates shall not exceed the minimum rates required by ASHRAE
Standard 62-1989 by more than 10 percent.
(2) Exception. Outdoor air quantities may be greater if required because of special occupancy
or process requirements, source control of air contamination or local codes, or if
it can be shown that the additional outside air does not increase overall
building energy costs.
(g) Materials and Construction.
(1) Insulation required by subdivisions (2) and (3) shall be suitably protected from damage.
Insulation should be installed in accordance with MICA Commercial and Industrial Insulation Standards,
1983.
(2) Piping Insulation.
(A) All HVAC system piping shall be thermally insulated in accordance with Table 9-1.
(B) Exceptions. Piping insulation shall not be required in any of the following cases:
(i) Factory installed piping within HVAC equipment tested and rated in accordance with Section
32-10.3;
(ii) Piping that conveys fluids which have a design operating temperature range between 55
degrees Fahrenheit and 105 degrees Fahrenheit;
(iii) Piping that conveys fluids which have not been heated or cooled through the
use of fossil fuels or electricity;
(iv) Where it can be shown that the heat gain and/or heat loss to
or from piping without insulation will not increase building energy costs.
Table 9-1 -- Minimum Pipe Insulation (Inches) a
Insulation
Conductivity
Fluid Nominal Pipe Diameter (in)
Design Cond. Mean
Operating Range, Rating
Temp., Btu·in/ Temp., Runouts b 1 and 1.25 2.5 5 8
Range °F h·ft 3 °F °F up to 2 less to 2 to 4
& 6 and up
Heating Systems (Steam, Steam Condensate, and Hot Water)
Above 350 0.32-0.34 250 1.5 2.5 2.5 3.0 3.5 3.5
251-350 0.29-0.31 200 1.5 2.0 2.5 2.5 3.5 3.5
201-250 0.27-0.30 150 1.0 1.5 1.5 2.0 2.0 3.5
141-200 0.25-0.29 125 0.5 1.5 1.5 1.5 1.5 1.5
105-140 0.24-0.28 100 0.5 1.0 1.0 1.0 1.5 1.5
Domestic and Service Hot Water c
105 and 0.24-0.28 100 0.5 1.0 1.0 1.5 1.5 1.5
Greater
Cooling Systems (Chilled Water, Brine & Refrigerant)d
40-55 0.23-0.27 75 0.5 0.5 0.75 1.0 1.0 1.0
Below 40 0.23-0.27 75 1.0 1.0 1.5 1.5 1.5 1.5
a. For minimum thicknesses of alternative insulation types, see Section 32-9.3(g)(2).
b. Runouts to individual terminal units not exceeding 12 feet in length.
c. Applies to recirculation sections of service or domestic hot water systems and first
8 feet from storage tank for nonrecirculating systems.
d. The required minimum thicknesses do not consider water vapor transmission and condensation. Additional
insulation and/or vapor retarders may be required to limit water vapor transmission and
condensation.
Alternative Insulation Types. Insulation thicknesses in Table 9-1 are based on insulation with
thermal conductivities within the range listed in Table 9-l for each fluid operating
temperature range, rated in accordance with ASTM C 335-84 at the mean temperature
listed in the table. For insulation that has a conductivity outside the range
shown in Table 9-l, for the applicable fluid operating temperature range at the
mean rating temperature shown, when rounded to the nearest 1/100th Btu·inch/h·°F·ft2, the minimum
thicknesses shall be determined in accordance with Equation 9-1:
Equation 9-1
T = PR [(1 + t / PR)K/k - 1]
where:
T = minimum insulation thickness for material with conductivity K, inches.
PR = pipe actual outside radius, in.
t = insulation thickness from Table 9-1, in.
K = conductivity of alternate material at the mean rating temperature indicated in Table
9-1 for the applicable fluid temperature range, Btu·in/h·°F·ft2.
k = the lower value of the conductivity range listed in Table 9-1 for
the applicable fluid temperature range, Btu·in/h·°F·ft2.
(3) Air Handling System Insulation.
(A) All air handling ducts and plenums installed as part of an HVAC air
distribution system shall be thermally insulated in accordance with Table 9-2.
(B) Exceptions.
(i) Factory installed plenums, casings, or ductwork furnished as a part of HVAC equipment
tested and rated in accordance with Section 32-10.3.
(ii) Where it can be shown that the heat gain to or heat loss
from ducts without insulation will not increase building energy costs.
Table 9-2 -- Minimum Duct Insulation a
Temperature Insulation
Differenceb R-valuec
°F ft 2 ·h·°F/Btu
Exterior of Building all 8.0
Inside of building envelope in < 15 Not Required
conditioned or unconditioned > 15 to < 40 3.3
spacese > 40 5.0d
a. Insulation R-values shown are for the insulation as installed and do not include
film resistance. The required minimum thicknesses do not consider water vapor transmission and
condensation. Additional insulation and/or vapor retarders may be required to limit vapor transmission
and condensation. Where exterior walls are used as plenum walls, wall insulation shall
be as required by the most restrictive conditions of this article or Article
8.
b. Temperature difference is at design conditions (see Section 32-9.3(a)) between the space within
which the duct is located and the design air temperature in the duct.
c. Insulation resistance measured on a horizontal plane in accordance with ASTM C518-85 at
a mean temperature of 75 degrees Fahrenheit at the installed insulation thickness.
d. Insulation resistance for runouts to terminal devices less than 10 feet in length
need not exceed 3.3 ft2·h·°F/Btu.
e. Unconditioned spaces include crawl spaces and attics.
(4) Duct Construction.
(A) All air handling ductwork and plenums shall be constructed and erected in accordance
with the following SMACNA publications:
(i) HVAC Duct Construction Standards -- Metal and Flexible, 1985;
(ii) HVAC Duct Leakage Test Manual, 1985;
(iii) TIMA Fibrous Glass Duct Construction Standards, 1989.
(B) In addition to the above-referenced standards, the following are required:
(i) Leakage Tests. Ductwork which is intended to operate at static pressures in excess
of 3 in. wc shall be leak-tested and be in conformance with sections
of the HVAC Duct Leakage Test Manual, as follows: Test procedures shall be
in accordance with those outlined in Section 5 of the manual, or equivalent;
test reports shall be provided in accordance with Section 6 of the manual,
or equivalent; the tested duct leakage class at a test pressure equal to
the design duct pressure class rating shall be equal to or less than
Leakage Class 6 as defined in Section 4.l of the manual. Leakage testing
may be limited to representative sections of the duct system, but in no
case shall such tested sections include less than 25 percent of the total
installed duct area for the designated pressure class.
(ii) Additional Sealing. Where supply ductwork and plenums that are intended to operate
at static pressures from l/4 in. to 2 in. wc inclusive, are located
outside of the conditioned space or in return plenums, joints shall be sealed
in accordance with Seal Class C, as defined in the SMACNA manuals referenced
above. Pressure- sensitive tape shall not be used as the primary sealant where
such ducts are intended to operate at static pressures of 1 in. wc
or greater.
(h) Energy Recovery. Condenser heat recovery from air conditioning or refrigeration equipment is required
for any single cooling system larger than 10 tons of cooling capacity or
compressor size of greater than 15 hp for buildings with service hot water
heaters with more than 75,000 Btu/h or 12 kW input rating, unless an
alternative system can be shown to have a lower life-cycle cost as determined
in accordance with procedures defined by the National Institute of Standards and Technology
(NIST) Life-Cycle Costing Manual for the Federal Energy Management Program, NIST Handbook 135,
and its supplement, Energy Price Indices and Discount Factors for Life-Cycle Cost Analysis.
Assumptions used in any calculation should use the latest price indices and discount
factors available at the time the calculation is submitted to the city.
(i) Completion Requirements.
(1) Operating and Maintenance Manual. An operating and maintenance manual shall be provided to
the building owner. The manual shall include basic data relating to the operation
and maintenance of HVAC systems and equipment. Required routine maintenance actions shall be
clearly identified. Where applicable, HVAC control information such as diagrams, schematics, control sequence
descriptions, and maintenance and calibration information shall be included.
(2) Air System Balancing.
(A) Air system balancing shall be accomplished in a manner to first minimize throttling
losses, then fan speed shall be adjusted to meet design flow conditions. Balancing
procedures shall be in accordance with those established by the National Environmental Balancing
Bureau (NEBB) Procedural Standards (1983), the Association of Air Balancing Council (AABC) National
Standards (1982), or equivalent procedures.
(B) Exception. Damper throttling may be used for air system balancing with fan motors
of 1 hp or less, or if throttling results in no greater than
1/3 hp fan horsepower draw above that required if the fan speed were
adjusted.
(3) Hydronic System Balancing.
(A) Hydronic system balancing shall be accomplished in a manner to first minimize throttling
losses, then the pump impeller shall be trimmed or pump speed shall be
adjusted to meet flow conditions.
(B) Exceptions. Valve throttling may be used for hydronic system balancing under any of
the following conditions:
(i) Pumps with pump motors of 10 hp or less;
(ii) If throttling results in no greater than three (3) pump horsepower draw above
that required if the impeller were trimmed;
(iii) To reserve additional pump pressure capability in open-circuit piping systems subject to fouling.
Valve throttling pressure drop shall not exceed that expected for future fouling;
(iv) Where it can be shown that throttling will not increase overall building energy
costs.
(j) Cooling of Unenclosed Spaces.
(1) Cooling systems for unenclosed spaces shall meet the following requirements:
(A) Cooling system capacity shall be no greater than 20 Btu/hr per ft2 of
floor area or 400 Btu/hr per occupant, whichever is greater. The estimated number
of occupants shall be based on the intended average occupancy and shall not
exceed the Estimated Maximum Occupancy listed in Table 2 of ASHRAE Standard 62-1989.
(B) The floor area used to calculate the allowed cooling capacity shall be limited
by a perimeter defined as follows:
(i) The perimeter shall not extend beyond the location of the ceiling air supply
diffusers or the throw of the side wall diffusers.
(ii) The perimeter shall be set back at least 10 feet from the opening
to the outside, which is defined by the outer edge of the ceiling
or overhanging roof.
(iii) The perimeter shall be bounded on at least one side by a permanent,
ceiling-height physical obstruction such as a wall or fixed window.
(k) System Commissioning.
(1) HVAC control systems shall be tested to assure that control elements are calibrated,
adjusted, and in proper working condition.
(2) For projects larger than 50,000 ft2 (4600 m2) conditioned area, detailed instructions for
commissioning HVAC systems shall be provided by the designer in plans and specifications.
(Added by Ord. 94-75; Am. Ord. 01-47)
Sec. 32-9.4 Prescriptive criteria.
(a) System and Equipment Sizing.
(1) HVAC systems and equipment shall be sized to provide no more than the
space and system loads calculated in accordance with Section 32-9.3(a).
(2) Exceptions.
(A) Equipment capacity may exceed the design load, provided the equipment selected is the
smallest size needed to meet the load within available options of the desired
equipment line.
(B) Equipment whose capacity exceeds the design load may be specified if oversizing the
equipment can be shown to not increase the overall annual energy costs.
(C) Standby equipment may be installed if controls and devices are provided which allow
standby equipment to operate automatically only when the primary equipment is not operating.
(D) Multiple units of the same equipment type, such as multiple chillers and boilers,
with combined capacities exceeding the design load may be specified to operate concurrently
only if controls are provided that sequence or otherwise optimally control the operation
of each unit based on load.
(E) For a single piece of equipment which has both heating and cooling capability,
only the cooling function need meet the requirements of this section. Capacity for
the heating function shall be, within available equipment options, the smallest size necessary
to meet the load.
(b) Zone Controls.
(1) Zone thermostatic and humidistatic controls shall prevent:
(A) Reheating;
(B) Recooling;
(C) Mixing or simultaneous supply of air that has been previously mechanically heated and
air that has been previously cooled;
(D) Other simultaneous operation of heating and cooling systems to the same zone.
(2) Exceptions.
(A) Variable air volume systems which, during periods of occupancy, are designed to reduce
the air supply to each zone to a minimum before reheating, recooling, or
mixing takes place. This minimum volume shall be no greater than the largest
of the following:
(i) 30 percent of the peak supply volume;
(ii) The minimum allowed to meet ventilation requirements of Section 32-9.3(f);
(iii) 0.4 cfm/ft2 of zone conditioned floor area;
(B) Zones where special pressurization relationships or cross-contamination requirements are such that variable air
volume systems are impractical, such as some areas of hospitals and laboratories;
(C) At least 75 percent of the energy for reheating or for providing warm
air in mixing systems is provided from a site-recovered or site-solar energy source;
(D) Zones where specified humidity levels are required to satisfy process needs, such as
computer rooms and museums. See Section 32-9.3(b);
(E) Zones with a peak supply air quantity of 300 cfm or less.
(c) Fan System Design Criteria.
(1) General.
(A) The following design criteria apply to all HVAC fan systems used for comfort
ventilating and/or air conditioning. For the purposes of this section, the energy demand
of a fan system is the sum of the demand of all fans
which are required to operate at design conditions to supply air from the
cooling source to the conditioned space(s) and return it to the source or
exhaust it to the outdoors.
(B) Exceptions.
(i) Systems with total fan system motor power of l0 hp or less;
(ii) Unitary equipment for which the energy used by the fan is considered in
the efficiency ratings of Section 32-10.3;
(iii) For the purposes of subsection (c), total fan energy demand need not include
the additional power required by air treatment or filtering systems with final pressure
drops in excess of 1.0 in. wc.
(2) Constant Volume Fan Systems. For fan systems which provide a constant air volume
whenever the fans are operating, the power required by the motors for the
combined fan system at design conditions shall not exceed 0.8 W/cfm of supply
air.
(3) Variable Air Volume (VAV) Fan Systems.
(A) For fan systems which are able to vary system air volume automatically as
a function of load, the power required by the motors for the combined
fan system shall not exceed l.25 W/cfm of supply air at design conditions.
(B) Individual VAV fans with motors 25 hp and larger shall include controls and
devices necessary for the fan motor to demand no more than 50 percent
of design wattage at 50 percent of design air volume, based on manufacturer's
test data.
(d) Pumping System Design Criteria.
(1) General.
(A) The following design criteria apply to all HVAC pumping systems used for comfort
air conditioning. For the purposes of subsection (d), the energy demand of a
pumping system is the sum of the demand of all pumps which are
required to operate at design conditions to supply fluid from the cooling source
to the conditioned space(s) or heat transfer devices(s) and return it to the
source.
(B) Exception. Systems with total pump system motor power of 10 hp or less.
(2) Friction Rate. Piping systems should be designed at a friction pressure loss rate
of no more than 4 feet of water per 100 equivalent feet of
pipe. Note: Lower friction rates may be required for proper noise or corrosion
control.
(3) Variable Flow.
(A) Pumping systems which serve control valves designed to modulate or step open and
closed as a function of load, shall be designed for variable fluid flow.
The system shall be capable of reducing system flow to 50 percent of
design flow or less. Flow may be varied with variable speed driven pumps
or staged multiple pumps.
(B) Exceptions.
(i) Dedicated equipment pumps separated from modulation control valves in a primary/secondary loop arrangement.
Secondary pumps shall comply with (A);
(ii) Systems that serve no more than one control valve;
(iii) Systems that include supply temperature reset controls in accordance with subsection (e)(2) without
exception;
(iv) Where the overall building energy costs resulting from an alternative design can be
shown to be no more than those from a variable flow system.
(e) System Temperature Reset Controls.
(1) Air Systems.
(A) Systems supplying cooled air to multiple zones shall include controls which automatically reset
supply air temperatures by representative building loads or by outside air temperature. Temperature
shall be reset by at least 25 percent of the design supply-air-to-room-air temperature
difference. Zones which are expected to experience relatively constant loads, such as interior
zones, shall be designed for the fully reset supply temperature.
(B) Exceptions.
(i) Systems which comply with subsection (b) without using exceptions (2)(A) or (2)(B);
(ii) Where it can be shown that supply air temperature reset increases overall building
annual energy costs.
(2) Hydronic Systems.
(A) Systems supplying chilled water to comfort air conditioning systems shall include controls which
automatically reset supply water temperatures by representative building loads (including return water temperature)
or by outside air temperature. Temperature shall be reset by at least 25
percent of the design supply-to-return water temperature difference.
(B) Exceptions.
(i) Systems that comply with subsection (d)(3) without exception;
(ii) Where it can be shown that supply temperature reset increases overall building annual
energy costs;
(iii) Systems for which supply temperature reset controls cannot be implemented without causing improper
operation of heating, cooling, humidification, or dehumidification systems;
(iv) Systems with less than 600,000 Btu/hr design capacity.
(f) Kitchen Hoods.
(1) Individual kitchen exhaust hoods larger than 5000 cfm (2500 L/s) shall be provided
with make-up air sized for at least 50 per cent of exhaust air
volume that is uncooled or cooled without the use of mechanical cooling.
(2) Exceptions:
(A) Where hoods are used to exhaust ventilation air which would otherwise exfiltrate or
be exhausted by other fan systems.
(B) Certified grease extractor hoods that require a face velocity no greater than 60
fpm (18 m/s).
(Added by Ord. 94-75; Am. Ord. 01-47)
Article 10. Heating, Ventilating and Air
Conditioning (HVAC) Equipment
Sections:
32-10.1 Scope.
32-10.2 General.
32-10.3 Basic requirements.
Sec. 32-10.1 Scope.
(a) The requirements of this article apply to new HVAC equipment installed in new
or existing buildings.
(b) Exception. This article does not apply to the maintenance or repair of existing
HVAC equipment.
(Added by Ord. 94-75)
Sec. 32-10.2 General.
HVAC equipment shall be supplied with the information necessary to make the analysis
required to determine compliance with this code.
(Added by Ord. 94-75)
Sec. 32-10.3 Basic requirements.
(a) Mechanical Equipment Efficiency.
(1) Equipment shown in Tables 10.1A through 10.1G shall have a minimum performance at
the specified rating conditions when tested in accordance with the specified test procedure.
Omission of minimum performance requirements for equipment not listed in Tables 10.1A through
10.1G does not preclude use of such equipment. Equipment not listed in Tables
10.1A through 10.1G has no minimum performance requirements. Where multiple rating conditions or
performance requirements are provided, the equipment shall satisfy all stated requirements, unless otherwise
exempted by footnotes in the table. However, equipment covered under the Federal Energy
Policy Act of 1992 (EPACT) shall have no minimum efficiency requirements for operation
at minimum capacity or other than standard rating conditions. Equipment used to provide
water heating functions as part of a combination system shall satisfy all stated
requirements for the appropriate space heating or cooling category.
(2) If a certification program exists for a product covered in Tables 10.1A through
10.1G, and it includes provisions for verification and challenge of equipment efficiency ratings,
then the product shall be either listed in the certification program or, alternatively,
the ratings shall be verified by an independent laboratory test report. If no
certification program exists for a product covered in Tables 10.1A through 10.1G, the
equipment efficiency ratings shall be supported by data furnished by the manufacturer. Where
components such as indoor or outdoor coils from different manufacturers are used, the
system designer shall specify component efficiencies whose combined efficiency meets the minimum equipment
efficiency requirements in this section.
(3) Tables 10.1A through 10.1G contain the minimum efficiency requirements for equipment covered by
this section of the standard. The tables are organized to cover the following
types of equipment:
(A) Table 10.1A Air Conditioners and Condensing Units;
(B) Table 10.1B Heat Pumps;
(C) Table 10.1C Water Chilling Packages;
(D) Table 10.1D Packaged Terminal and Room Air Conditioners and Heat Pumps;
(E) Table 10.1E Furnaces, Duct Furnaces and Unit Heaters;
(F) Table 10.1F Boilers; and
(G) Table 10.1G Heat Rejection Equipment.
(4) Gas-fired and oil-fired forced air furnaces with input ratings $ 225,000 Btu/h (65
kW) shall also have an intermittent ignition or interrupted device (IID), and have
either power venting or a flue damper. A vent damper is an acceptable
alternative to a flue damper for furnaces where combustion air is drawn from
the conditioned space. All furnaces with input ratings $ 225,000 Btu/h (65 kW),
including electric furnaces, that are not located within the conditioned space shall have
jacket losses not exceeding 0.75% of the input rating.
(5) Exceptions:
(A) Water-cooled centrifugal water-chilling packages that are not designed for operation at ARI Standard
550 test conditions (and thus cannot be tested to meet the requirements of
Table 10.1C) of 44°F leaving chilled water temperature and 85°F entering condenser water
temperature shall have a minimum full load COP and IPLV rating as shown
in Tables 10.1H, I, and J. The table values are only applicable over
the following full load design ranges:
(i) Leaving Chiller Water Temperature: 40 to 48°F;
(ii) Entering Condenser Water Temperature: 75 to 85°F; and
(iii) Condensing Water Temperature Rise: 5 to 15°F.
(B) Chillers designed to operate outside of these ranges are not covered by this
standard.
(b) Maintenance. Operation and maintenance information shall be provided with the equipment by the
equipment supplier.
Table 10.1A (I-P Units)
Unitary Air Conditioners and Condensing Units, Electrically Operated,
Minimum Efficienc y Requirements
Equipment Type
|
Size Category
|
Sub-Category or Rating Condition
|
Minimum Efficiencyb
|
Test Procedure
|
Air Conditioners,
Air Cooled
|
< 65,000 Btu/hd
|
Split System
|
10.0 SEER
|
ARI 210/240
|
|
|
|
Single Package
|
9.7 SEER
|
|
|
|
e65,000 Btu/h and
< 135,000 Btu/h
|
Split System and
Single Package
|
10.3 EERc
10.6 IPLVc
|
|
|
|
e135,000 Btu/h and
< 240,000 Btu/h
|
Split System and
Single Package
|
9.7 EERc
9.9 IPLVc
|
ARI 340/360
|
|
|
e 240,000 Btu/h and
<760,000 Btu/h
|
Split System and
Single Package
|
9.5 EERc
9.7 IPLVc
|
|
|
|
e760,000 Btu/h
|
Split System and
Single Package
|
9.2 EERc
9.4 IPLVc
|
|
Air Conditioners, Water and Evaporatively Cooled
|
< 65,000 Btu/h
|
Split System and
Single Package
|
12.1 EER
11.2 IPLV
|
ARI 210/240
|
|
|
e 65,000 Btu/h and
< 135,000 Btu/h
|
Split System and
Single Package
|
11.5 EERc
10.6 IPLVc
|
|
|
|
e135,000 Btu/h and
d240,000 Btu/h
|
Split System and
Single Package
|
11.0 EERc
10.3 IPLVc
|
ARI 340/360
|
|
|
> 240,000 Btu/h
|
Split System and
Single Package
|
11.0 EERc
10.3 IPLVc
|
|
Condensing Units,
Air Cooled
|
e135,000 Btu/h
|
|
10.1 EER
11.2 IPLV
|
ARI 365
|
Condensing Units,
Water or Evaporatively Cooled
|
e135,000 Btu/h
|
|
13.1 EER
13.1 IPLV
|
|
b IPLVs are only applicable to equipment with capacity modulation.
c Deduct 0.2 from the required EERs and IPLVs for units with a
heating section other than electric resistance heat.
d Single-phase air-cooled air-conditioners < 65,000 Btu/h are regulated by NAECA. SEER values
are those set by NAECA.
|
Table 10.1B (I-P Units)
Unitary and Applied Heat Pumps, Electrically Operated, Minimum Efficiency Requirements
Equipment Type
|
Size Category
|
Sub-Category or Rating Condition
|
Minimum Efficiencyb
|
Test Procedure
|
Air Cooled, (Cooling Mode)
|
< 65,000 Btu/hd
|
Split System
|
10.0 SEER
|
ARI 210/240
|
|
|
|
Single Package
|
9.7 SEER
|
|
|
|
e65,000 Btu/h and
< 135,000 Btu/h
|
Split System and
Single Package
|
10.1 EERc
10.4 IPLVc
|
|
|
|
e135,000 Btu/h and
<240,000 Btu/h
|
Split System and
Single Package
|
9.3 EERc
9.5 IPLVc
|
ARI 340/360
|
|
|
e240,000 Btu/h
|
Split System and
Single Package
|
9.0 EERc
9.2 IPLVc
|
|
Water-Source
(Cooling Mode)
|
< 17,000 Btu/h
|
85°F Entering Water
|
|
ARI 320
|
|
|
|
86°F Entering Water
|
11.2 EER
|
ARI/ISO-13256-1
|
|
|
e 17,000 Btu/h and
<65,000 Btu/h
|
85°F Entering Water
|
|
ARI 320
|
|
|
|
86°F Entering Water
|
12.0 EER
|
ARI/ISO-13256-1
|
|
|
e65,000 Btu/h and
< 135,000 Btu/h
|
85°F Entering Water
|
|
ARI 320
|
|
|
|
86°F Entering Water
|
12.0 EER
|
ARI/ISO-13256-1
|
Groundwater-Source
(Cooling Mode)
|
< 135,000 Btu/h
|
70°F Entering Water
50EF Entering Water
|
|
ARI 325
|
|
|
|
59°F Entering Water
|
16.2 EER
|
ARI/ISO-13256-1
|
Ground Source
(Cooling Mode)
|
< 135,000 Btu/h
|
77°F Entering Brine
70EF Entering Brine
|
|
ARI 330
|
|
|
|
77°F Entering Water
|
13.4 EER
|
ARI/ISO-13256-1
|
Air Cooled
(Heating Mode)
|
< 65,000 Btu/hd
(Cooling Capacity)
|
Split System
|
6.8 HSPF
|
ARI 210/240
|
|
|
|
Single Package
|
6.6 HSPF
|
|
|
|
e65,000 Btu/h and
< 135,000 Btu/h
(Cooling Capacity)
|
47°F db/43°F wb Outdoor Air
17°F db/15°F wb Outdoor Air
|
|
|
|
|
e135,000 Btu/h
(Cooling Capacity)
|
47°F db/43°F wb Outdoor Air
17°F db/15°F wb Outdoor Air
|
|
ARI 340/360
|
Water-Source
(Heating Mode)
|
< 135,000 Btu/h
(Cooling Capacity)
|
70°F Entering Water
|
|
ARI 320
|
|
|
|
68°F Entering Water
|
4.2 COP
|
ARI/ISO-13256-1
|
Groundwater-Source
(Heating Mode)
|
< 135,000 Btu/h
(Cooling Capacity)
|
70°F Entering Water
50EF Entering Water
|
|
ARI 325
|
|
|
|
50°F Entering Water
|
3.6 COP
|
ARI/ISO-13256-1
|
Ground Source
(Heating Mode)
|
< 135,000 Btu/h
(Cooling Capacity)
|
32°F Entering Brine
|
|
ARI 330
|
|
|
|
32°F Entering Water
|
3.1 COP
|
ARI/ISO-13256-1
|
b IPLVs and Part load rating conditions are only applicable to equipment with
capacity modulation.
c Deduct 0.2 from the required EERs and IPLVs for units with a
heating section other than electric resistance heat.
d Single-phase air-cooled heat pumps < 65,000 Btu/h are regulated by NAECA. SEER
and HSPF values are those set by NAECA.
|
Table 10.1C (I-P Units)
Water Chilling Packages, Minimum Efficiency Requirements
Equipment Type
|
Size Category
|
Sub-Category or Rating Condition
|
Minimum Efficiencyb
|
Test Procedure
|
Air Cooled, With Condenser,
Electrically Operated
|
< 150 Tons
|
|
2.80 COP
2.80 IPLV
|
ARI 550
or
ARI 590
as appropriate
|
|
|
e150 Tons
|
|
|
|
Air Cooled,
Without Condenser,
Electrically Operated
|
All Capacities
|
|
3.10 COP
3.10 IPLV
|
|
Water Cooled,
Electrically Operated,
Positive Displacement
(Reciprocating)
|
All Capacities
|
|
4.20 COP
4.65 IPLV
|
ARI 590
|
Water Cooled,
Electrically Operated,
Positive Displacement
(Rotary Screw and Scroll)
|
< 150 Tons
|
|
4.45 COP
4.50 IPLV
|
ARI 550
or
ARI 590
as appropriate
|
|
|
e150 Tons and
< 300 Tons
|
|
4.90 COP
4.95 IPLV
|
|
|
|
e300 Tons
|
|
5.50 COP
5.60 IPLV
|
|
Water Cooled,
Electrically Operated, Centrifugal
|
< 150 Tons
|
|
5.00 COP
5.00 IPLV
|
ARI 550
|
|
|
e150 Tons and
< 300 Tons
|
|
5.55 COP
5.55 IPLV
|
|
|
|
e300 Tons
|
|
6.10 COP
6.10 IPLV
|
|
Air Cooled Absorption
Single Effect
|
All Capacities
|
|
0.60 COP
|
|
Water Cooled Absorption
Single Effect
|
All Capacities
|
|
0.70 COP
|
|
Absorption Double Effect,
Indirect-Fired
|
All Capacities
|
|
1.00 COP
1.05 IPLV
|
|
Absorption Double Effect,
Direct-Fired
|
All Capacities
|
|
1.00 COP
1.00 IPLV
|
|
b The chiller equipment requirements do not apply for chillers used in low temperature
applications where the design leaving fluid temperature is less than or equal to
40°F.
|
Table 10.1D (I-P Units)
Packaged Terminal Air Conditioners, Packaged Terminal Heat Pumps, Room Air Conditioners, and Room Air
Conditioner Heat Pumps, Electrically Operated, Minimum Efficiency Requirements
Equipment Type
|
Size Category (Input)
|
Sub-Category or Rating Condition
|
Minimum Efficiency
|
Test Procedure
|
PTAC (Cooling Mode)
New Construction
|
All Capacities
|
95°F db Outdoor Air
|
12.5 - (0.213 x Cap/1000)b EER
|
|
|
|
|
82°F db Outdoor Air
|
14.7 - (0.213 x Cap/1000)b EER
|
|
PTAC (Cooling Mode) Replacementsc
|
All Capacities
|
95°F db Outdoor Air
|
10.9 - (0.213 x Cap/1000)b EER
|
|
|
|
|
82°F db Outdoor Air
|
13.1 - (0.213 x Cap/1000)b EER
|
|
PTHP (Cooling Mode)
New Construction
|
All Capacities
|
95°F db Outdoor Air
|
12.3 - (0.213 x Cap/1000)b EER
|
|
|
|
|
82°F db Outdoor Air
|
14.5 - (0.213 x Cap/1000)b EER
|
|
PTHP (Cooling Mode)
Replacementsc
|
All Capacities
|
95°F db Outdoor Air
|
10.8 - (0.213 x Cap/1000)b EER
|
|
|
|
|
82°F db Outdoor Air
|
13.0 - (0.213 x Cap/1000)b EER
|
|
PTHP (Heating Mode)
New Construction
|
All Capacities
|
|
3.2 - (0.026 x Cap/1000)b COP
|
|
PTHP (Heating Mode)
Replacementsc
|
All Capacities
|
|
2.9 - (0.026 x Cap/1000)b COP
|
|
Room Air Conditioners, with Louvered Sides
|
< 6,000 Btu/h
|
|
9.7 EER
|
ANSI/AHAM
RAC-1
|
|
|
e6,000 Btu/h and
< 8,000 Btu/h
|
|
9.7 EER
|
|
|
|
e 8,000 Btu/h and
< 14,000 Btu/h
|
|
9.8 EER
|
|
|
|
e14,000 Btu/h and
< 20,000 Btu/h
|
|
9.7 EER
|
|
|
|
e20,000 Btu/h
|
|
8.5 EER
|
|
Room Air Conditioners, without Louvered Sides
|
< 8,000 Btu/h
|
|
9.0 EER
|
|
|
|
e8,000 Btu/h and
< 20,000 Btu/h
|
|
8.5 EER
|
|
|
|
e20,000 Btu/h
|
|
8.5 EER
|
|
Room Air Conditioner Heat Pumps with Louvered Sides
|
< 20,000 Btu/h
|
|
9.0 EER
|
|
|
|
e 20,000 Btu/h
|
|
8.5 EER
|
|
Room Air Conditioner Heat Pumps without Louvered Sides
|
< 14,000 Btu/h
|
|
8.5 EER
|
|
|
|
e 14,000 Btu/h
|
|
8.0 EER
|
|
Room Air Conditioner, Casement Only
Room Air Conditioner, Casement --Slider
|
All Capacities
|
|
8.7 EER
|
|
|
|
|
|
|
|
|
|
All Capacities
|
|
9.5 EER
|
|
|
|
|
|
|
|
b Cap means the rated cooling capacity of the product in Btu/h. If
the unit's capacity is less than 7000 Btu/h, use 7000 Btu/h in the
calculation. If the unit's capacity is greater than 15,000 Btu/h, use 15,000 Btu/h
in the calculation.
c Replacement units must be factory labeled as follows: "MANUFACTURED FOR REPLACEMENT APPLICATIONS
ONLY; NOT TO BE INSTALLED IN NEW CONSTRUCTION PROJECTS." Replacement efficiencies apply only
to units with existing sleeves less than 16 in. high and less than
42 in. wide.
|
Table 10.1E (I-P and SI Units)
Warm Air Furnaces and Combination Warm Air Furnaces/Air-Conditioning Units,
Warm Air Duct Furnaces and Unit Heaters, Minimum Efficiency Requirements
Equipment Type
|
Size Category (Input)
|
Sub-Category or Rating Condition
|
Minimum Efficiencyd
|
Test Procedure
|
Warm Air Furnace,
Gas-Fired
|
< 225,000 Btu/h
(66 kW)
|
|
78% AFUE
or
80% Etc
|
DOE 10 CFR
Part 430 or
ANSI Z21.47
|
|
|
e225,000 Btu/h
(66 kW)
|
Maximum Capacityc
|
80% Ecf
|
ANSI Z21.47
|
Warm Air Furnace,
Oil-Fired
|
< 225,000 Btu/h
(66 kW)
|
|
78% AFUE
or
80% Etc
|
DOE 10 CFR
Part 430 or
UL 727
|
|
|
e225,000 Btu/h
(66 kW)
|
Maximum Capacityb
|
81% Etg
|
UL 727
|
Warm Air
Duct Furnaces,
Gas-Fired
|
All Capacities
|
Maximum Capacityb
|
80% Ece
|
ANSI Z83.9
|
Warm Air
Unit Heaters,
Gas-Fired
|
All Capacities
|
Maximum Capacityb
|
80% Ece
|
ANSI Z83.8
|
Warm Air
Unit Heaters,
Oil-Fired
|
All Capacities
|
Maximum Capacityb
|
80% Ece
|
UL 731
|
b Maximum rating as provided for and allowed by the unit's controls.
c Combination units not covered by NAECA (3-phase power or cooling capacity greater
than or equal to 65,000 Btu/h [19 kW]) may comply with either rating.
d Et = Thermal efficiency. See test procedure for detailed discussion.
e Ec = Combustion efficiency (100% less flue losses). See test procedure for
detailed discussion.
f Ec = Combustion efficiency. Units must also include an IID, have jacket
losses not exceeding 0.75% of the input rating, and have either power venting
or a flue damper. A vent damper is an acceptable alternative to a
flue damper for those furnaces where combustion air is drawn from the conditioned
space.
g Et = Thermal efficiency. Units must also include an IID, have jacket
losses not exceeding 0.75% of the input rating, and have either power venting
or a flue damper. A vent damper is an acceptable alternative to a
flue damper for those furnaces where combustion air is drawn from the conditioned
space.
|
Table 10.1F (I-P Units)
Boilers, Gas- and Oil-Fired, Minimum Efficiency Requirements
Equipment Typef
|
Size Category
|
Sub-Category or
Rating Condition
|
Minimum Efficiencyd
|
Test Procedure
|
Boilers, Gas-Fired
|
< 300,000 Btu/h
|
Hot Water
|
80% AFUE
|
DOE 10 CFR
Part 430
|
|
|
|
Steam
|
75% AFUE
|
|
|
|
e300,000 Btu/h and d 2,500,000 Btu/h
|
Maximum Capacityb
|
75% Et
|
H.I. Htg Boiler Std
|
|
|
> 2,500,000 Btu/hf
|
Hot Water
|
80% Ec
|
|
|
|
> 2,500,000 Btu/hf
|
Steam
|
80% Ec
|
|
Boilers, Oil-Fired
|
< 300,000 Btu/h
|
|
80% AFUE
|
DOE 10 CFR
Part 430
|
|
|
e300,000 Btu/h and d 2,500,000 Btu/h
|
Maximum Capacityb
|
78% Et
|
H.I. Htg Boiler Std
|
|
|
> 2,500,000 Btu/hf
|
Hot Water
|
83% Ec
|
|
|
|
> 2,500,000 Btu/hf
|
Steam
|
83% Ec
|
|
Oil-Fired (Residual)
|
e300,000 Btu/h and
d2,500,000 Btu/h
|
Maximum Capacityb
|
78% Et
|
H.I. Htg Boiler Std
|
|
|
> 2,500,000 Btu/hf
|
Hot Water
|
83% Ec
|
|
|
|
> 2,500,000 Btu/hf
|
Steam
|
83% Ec
|
|
b Maximum rating as provided for and allowed by the unit's controls.
d Et = Thermal efficiency. See reference document for detailed information.
f These requirements apply to boilers with rated input of 8,000,000 Btu/h or
less that are not packaged boilers, and to all packaged boilers. Minimum efficiency
requirements for boilers cover all capacities of packaged boilers.
|
Table 10.1G (I-P and SI Units)
Performance Requirements for Heat Rejection Equipment
Equipment Type
|
Total System Heat Rejection Capacity at Rated Conditions
|
Sub-Category or
Rating Condition
|
Required Performancea,b
|
Test Procedure
|
Propeller or Axial Fan Cooling Towers
|
All
|
95°F (35°C) Entering Water
85°F (29°C) Leaving Water
75°F (24°C) wb Outdoor Air
|
e38.2 gpm/hp
(3.23 L/s kW)
|
CTI ATC-105
and
CTI STD-201
|
Centrifugal Fan
Cooling Towers
|
All
|
95°F (35°C) Entering Water
85°F (29°C) Leaving Water
75°F (24°C) wb Outdoor Air
|
e 20.0 gpm/hp
(1.7 L/s kW)
|
CTI ATC-105
and
CTI STD-201
|
Air Cooled Condensers
|
All
|
125°F (52°C) Condensing Temperature
R22 Test Fluid
190°F (88°C) Entering Gas Temperature
15°F (8°C) Subcooling
95°F (35°C) Entering Drybulb
|
e176,000 Btu/h hp
(69 COP)
|
ARI 460
|
a For purposes of this table, cooling tower performance is defined as the
maximum flow rating of the tower divided by the fan nameplate rated motor
power.
b For purposes of this table air-cooled condenser performance is defined as
the heat rejected from the refrigerant divided by the fan nameplate rated motor
power.
|
Table 10.1H (I-P Units)
COPs and IPLVs for Non-Standard Centrifugal Chillers d 150 Tons
Centrifugal Chillers d 150 Tons
COPstd = 5.4
|
|
2 gpm/ton
|
2.5 gpm/ton
|
3 gpm/ton
|
4 gpm/ton
|
5 gpm/ton
|
6 gpm/ton
|
Leaving Chilled Water Temperature (°F)
|
Entering Condenser Water Temperature (°F)
|
LIFTa
(°F)
|
|
46
|
75
|
29
|
6.00
|
6.27
|
6.48
|
6.80
|
7.03
|
7.20
|
|
45
|
75
|
30
|
5.92
|
6.17
|
6.37
|
6.66
|
6.87
|
7.02
|
|
44
|
75
|
31
|
5.84
|
6.08
|
6.26
|
6.53
|
6.71
|
6.86
|
|
43
|
75
|
32
|
5.75
|
5.99
|
6.16
|
6.40
|
6.58
|
6.71
|
|
42
|
75
|
33
|
5.67
|
5.90
|
6.06
|
6.29
|
6.45
|
6.57
|
|
41
|
75
|
34
|
5.59
|
5.82
|
5.98
|
6.19
|
6.34
|
6.44
|
|
46
|
80
|
34
|
5.59
|
5.82
|
5.98
|
6.19
|
6.34
|
6.44
|
|
40
|
75
|
35
|
5.50
|
5.74
|
5.89
|
6.10
|
6.23
|
6.33
|
|
45
|
80
|
35
|
5.50
|
5.74
|
5.89
|
6.10
|
6.23
|
6.33
|
|
44
|
80
|
36
|
5.41
|
5.66
|
5.81
|
6.01
|
6.13
|
6.22
|
|
43
|
80
|
37
|
5.31
|
5.57
|
5.73
|
5.92
|
6.04
|
6.13
|
|
42
|
80
|
38
|
5.21
|
5.48
|
5.64
|
5.84
|
5.95
|
6.04
|
|
41
|
80
|
39
|
5.09
|
5.39
|
5.56
|
5.76
|
5.87
|
5.95
|
|
46
|
85
|
39
|
5.09
|
5.39
|
5.56
|
5.76
|
5.87
|
5.95
|
|
40
|
80
|
40
|
4.96
|
5.29
|
5.47
|
5.67
|
5.79
|
5.86
|
|
45
|
85
|
40
|
4.96
|
5.29
|
5.47
|
5.67
|
5.79
|
5.86
|
|
44
|
85
|
41
|
4.83
|
5.18
|
5.40
|
5.59
|
5.71
|
5.78
|
|
43
|
85
|
42
|
4.68
|
5.07
|
5.28
|
5.50
|
5.62
|
5.70
|
|
42
|
85
|
43
|
4.51
|
4.94
|
5.17
|
5.41
|
5.54
|
5.62
|
|
41
|
85
|
44
|
4.33
|
4.80
|
5.05
|
5.31
|
5.45
|
5.53
|
|
40
|
85
|
45
|
4.13
|
4.65
|
4.92
|
5.21
|
5.35
|
5.44
|
Condenser DTb
|
14.04
|
11.23
|
9.36
|
7.02
|
5.62
|
4.68
|
a LIFT = Entering Condenser Water Temperature -- Leaving Chilled Water Temperature
b Condenser DT = Leaving Condenser Water Temperature (F) -- Entering Condenser Water
Temperature (F)
Kadj = 6.1507 - 0.30244(X) + 0.0062692(X)2 - 0.000045595(X)3
where X = Condenser DT + LIFT
COPadj = Kadj * COPstd
|
Table 10.1I (I-P Units)
COPs and IPLVs for Non-Standard Centrifugal Chillers
> 150 Tons, d 300 Tons
Centrifugal Chillers > 150 Tons, d 300 Tons
COPstd = 5.55
|
|
2 gpm/ton
|
2.5 gpm/ton
|
3 gpm/ton
|
4 gpm/ton
|
5 gpm/ton
|
6 gpm/ton
|
Leaving Chilled Water Temperature ( F)
|
Entering Condenser Water Temperature (°F)
|
LIFTa
(°F)
|
|
|
|
|
|
|
46
|
75
|
29
|
6.17
|
6.44
|
6.66
|
6.99
|
7.23
|
7.40
|
|
45
|
75
|
30
|
6.08
|
6.34
|
6.54
|
6.84
|
7.06
|
7.22
|
|
44
|
75
|
31
|
6.00
|
6.24
|
6.43
|
6.71
|
6.90
|
7.05
|
|
43
|
75
|
32
|
5.91
|
6.15
|
6.33
|
6.58
|
6.76
|
6.89
|
|
42
|
75
|
33
|
5.83
|
6.07
|
6.23
|
6.47
|
6.63
|
6.75
|
|
41
|
75
|
34
|
5.74
|
5.98
|
6.14
|
6.36
|
6.51
|
6.62
|
|
46
|
80
|
34
|
5.74
|
5.98
|
6.14
|
6.36
|
6.51
|
6.62
|
|
40
|
75
|
35
|
5.65
|
5.90
|
6.05
|
6.26
|
6.40
|
6.51
|
|
45
|
80
|
35
|
5.65
|
5.90
|
6.05
|
6.26
|
6.40
|
6.51
|
|
44
|
80
|
36
|
5.56
|
5.81
|
5.97
|
6.17
|
6.30
|
6.40
|
|
43
|
80
|
37
|
5.46
|
5.73
|
5.89
|
6.08
|
6.21
|
6.30
|
|
42
|
80
|
38
|
5.35
|
5.64
|
5.80
|
6.00
|
6.12
|
6.20
|
|
41
|
80
|
39
|
5.23
|
5.54
|
5.71
|
5.91
|
6.03
|
6.11
|
|
46
|
85
|
39
|
5.23
|
5.54
|
5.71
|
5.91
|
6.03
|
6.11
|
|
40
|
80
|
40
|
5.10
|
5.44
|
5.62
|
5.83
|
5.95
|
6.03
|
|
45
|
85
|
40
|
5.10
|
5.44
|
5.62
|
5.83
|
5.95
|
6.03
|
|
44
|
85
|
41
|
4.96
|
5.33
|
5.55
|
5.74
|
5.86
|
5.94
|
|
43
|
85
|
42
|
4.81
|
5.21
|
5.42
|
5.66
|
5.78
|
5.86
|
|
42
|
85
|
43
|
4.63
|
5.08
|
5.31
|
5.56
|
5.69
|
5.77
|
|
41
|
85
|
44
|
4.45
|
4.93
|
5.19
|
5.46
|
5.60
|
5.69
|
|
40
|
85
|
45
|
4.24
|
4.77
|
5.06
|
5.35
|
5.50
|
5.59
|
Condenser DTb
|
14.04
|
11.23
|
9.36
|
7.02
|
5.62
|
4.68
|
a LIFT = Entering Condenser Water Temperature -- Leaving Chilled Water Temperature
b Condenser DT = Leaving Condenser Water Temperature (F) - Entering Condenser Water
Temperature (F)
Kadj = 6.1507 - 0.30244(X) + 0.0062692(X)2 - 0.000045595(X)3
where X = Condenser DT + LIFT
COPadj = Kadj * COPstd
|
Table 10.1J (I-P Units)
COPs and IPLVs for Non-Standard Centrifugal Chillers > 300 Tons
Centrifugal Chillers > 300 Tons
COPstd = 6.1
|
|
2 gpm/ton
|
2.5 gpm/ton
|
3 gpm/ton
|
4 gpm/ton
|
5 gpm/ton
|
6 gpm/ton
|
Leaving Chilled Water Temperature (°F)
|
Entering Condenser Water Temperature (°F)
|
LIFTa
(°F)
|
|
46
|
75
|
29
|
6.80
|
7.11
|
7.35
|
7.71
|
7.97
|
8.16
|
|
45
|
75
|
30
|
6.71
|
6.99
|
7.21
|
7.55
|
7.78
|
7.96
|
|
44
|
75
|
31
|
6.61
|
6.89
|
7.09
|
7.40
|
7.61
|
7.77
|
|
43
|
75
|
32
|
6.52
|
6.79
|
6.98
|
7.26
|
7.45
|
7.60
|
|
42
|
75
|
33
|
6.43
|
6.69
|
6.87
|
7.13
|
7.31
|
7.44
|
|
41
|
75
|
34
|
6.33
|
6.60
|
6.77
|
7.02
|
7.18
|
7.30
|
|
46
|
80
|
34
|
6.33
|
6.60
|
6.77
|
7.02
|
7.18
|
7.30
|
|
40
|
75
|
35
|
6.23
|
6.50
|
6.68
|
6.91
|
7.06
|
7.17
|
|
45
|
80
|
35
|
6.23
|
6.50
|
6.68
|
6.91
|
7.06
|
7.17
|
|
44
|
80
|
36
|
6.13
|
6.41
|
6.58
|
6.81
|
6.95
|
7.05
|
|
43
|
80
|
37
|
6.02
|
6.31
|
6.49
|
6.71
|
6.85
|
6.94
|
|
42
|
80
|
38
|
5.90
|
6.21
|
6.40
|
6.61
|
6.75
|
6.84
|
|
41
|
80
|
39
|
5.77
|
6.11
|
6.30
|
6.52
|
6.65
|
6.74
|
|
46
|
85
|
39
|
5.77
|
6.11
|
6.30
|
6.52
|
6.65
|
6.74
|
|
40
|
80
|
40
|
5.63
|
6.00
|
6.20
|
6.43
|
6.56
|
6.65
|
|
45
|
85
|
40
|
5.63
|
6.00
|
6.20
|
6.43
|
6.56
|
6.65
|
|
44
|
85
|
41
|
5.47
|
5.87
|
6.10
|
6.33
|
6.47
|
6.55
|
|
43
|
85
|
42
|
5.30
|
5.74
|
5.98
|
6.24
|
6.37
|
6.46
|
|
42
|
85
|
43
|
5.11
|
5.60
|
5.86
|
6.13
|
6.28
|
6.37
|
|
41
|
85
|
44
|
4.90
|
5.44
|
5.72
|
6.02
|
6.17
|
6.27
|
|
40
|
85
|
45
|
4.68
|
5.26
|
5.58
|
5.90
|
6.07
|
6.17
|
Condenser DTb
|
14.04
|
11.23
|
9.36
|
7.02
|
5.62
|
4.68
|
a LIFT = Entering Condenser Water Temperature -- Leaving Chilled Water Temperature
b Condenser DT = Leaving Condenser Water Temperature (F) - Entering Condenser Water
Temperature (F)
Kadj = 6.1507 - 0.30244(X) + 0.0062692(X)2 - 0.000045595(X)3
where X = Condenser DT + LIFT
COPadj = Kadj * COPstd
|
(Added by Ord. 94-75; Am. Ord. 01-47)
Article 11. Service Water Heating Systems
and Equipment
Sections:
32-11.1 Scope.
32-11.2 General.
32-11.3 Basic requirements.
Sec. 32-11.1 Scope.
The requirements of this article apply to new water heating systems and equipment
installed in new buildings, major additions to buildings or portions of buildings undergoing
major alterations or repair. Emergency replacements of water heating equipment need not comply
with this article. (Added by Ord. 94-75)
Sec. 32-11.2 General.
(a) Information. Service water heating equipment shall be supplied with the information needed to
make the analysis required to determine compliance with this code.
(b) Compliance. The water heating system and equipment are in compliance with the requirements
of this article when the basic requirements of Section 32-11.3 are satisfied.
(Added by Ord. 94-75)
Sec. 32-11.3 Basic requirements.
(a) Sizing of Systems. Service water heating system design loads for the purpose of
sizing and selecting systems shall be determined in accordance with the procedures described
in Chapter 44 of ASHRAE Handbook, 1991 HVAC Applications, or a similar computation
procedure. Table 11-2 may be used for sizing residential water heating systems.
(b) Equipment Efficiency.
(1) Minimum Equipment Efficiency.
(A) All water heaters and hot water storage tanks shall meet the criteria of
Table 11-1. Where multiple criteria are listed, all criteria shall be met. Where
no criteria are provided, no requirements need be met.
(B) Exception. Storage water heaters and hot water storage tanks having more than 140
gallons of storage capacity need not meet the standby loss (SL) or heat
loss (HL) requirements of Table 11-1 if the tank surface area is thermally
insulated to R-12.5 and if a standing pilot light is not used.
(2) Data furnished by the equipment manufacturer or certified under a nationally recognized certification
program or rating procedure shall be acceptable to satisfy these requirements.
(3) Omissions. Omission of minimum performance requirements for certain classes of equipment does not
preclude use of such equipment when appropriate.
(c) Piping Insulation.
(1) Circulating Systems and Systems with Pipes Heated by Heat Tape or Similar Means.
Piping insulation shall conform to the requirements of Table 9-1 or an equivalent
level as calculated in accordance with Equation 9-1.
(2) Noncirculating Systems. The first eight feet of piping from a storage system that
is maintained at a constant temperature shall be insulated as provided in Table
9-1 or to an equivalent level as calculated in accordance with Equation 9-1.
(d) Temperature Controls.
(1) Service water heating systems shall be equipped with temperature controls capable of adjusting
storage temperatures from 90 degrees Fahrenheit to a temperature setting compatible with the
intended use. Some representative hot water utilization temperatures are listed in the ASHRAE
Handbook, 1991 HVAC Applications, Chapter 44, Table 3.
(2) Exception. Service water heating systems serving residential dwelling units may be equipped with
controls capable of adjustment down to 110 degrees Fahrenheit only.
(e) Remote or Booster Heaters.
(1) Where temperatures higher than 130 degrees Fahrenheit are required at certain outlets for
a particular intended use, separate remote heaters or booster heaters shall be installed
for those outlets.
(2) Exception. Where it can be shown that either energy cost is not reduced
by the application of this requirement or that the total installed cost of
the equipment, maintenance and energy used over the life of the equipment is
not reduced.
(f) Circulating Hot Water Systems and Heated Pipes.
(1) Systems designed to maintain temperatures in hot water pipes, including circulating hot water
systems and heat tape on water pipes, shall be equipped with automatic time
switches or other controls that can be set to turn off the system
when availability of hot water is not required.
(2) Exception. When the need for hot water is continuous.
Table 11-1 -- Minimum Performance of Water Heating Equipment
Category Type Fuel Input Rating Vol. Input to Test Energy Et g Standby
Vol. Ratio Method Factor c % Loss d
(Btuh/gal) %/hr
NAECA all electricf <12kW all DOE Test >0.93-0.00132V
Covered storage gas <75,000 Btuh all Proc. 10 >0.62-0.0019V
Water instantaneous gas <200,000 Btuh all CFR, Part >0.62-0.0019V
Heating storage oil <105,000 Btuh all 430 >0.59-0.0019V
Equipmenta instantaneous oil <210,000 Btuh all >0.59-0.0019V
pool heater gas/oil all all ANSI >78%
Z21.56-1989
Other Water storage electric all all ANSI <0.30+27/VT
Heating Z21.10.3,
Equipmentb storage/ gas/oil <155,000 Btuh all <4,000 1990 >78% <1.3+114/VT
instantaneous >155,000 Btuh all <4,000 >78% <1.3+95/VT
<10 >4,000 >80% -
e 10 >4,000 >77% <2.3+67/VT
air-source electric >24A all >3.0
heat pumph
Unfired all <6.5Btuh/ft2e
Storage
Tanks
a. Consistent with National Appliance Energy Conservation Act (NAECA) of 1987.
b. All except those water heaters covered by NAECA.
c. V is the rated storage volume as specified by the manufacturer.
d. VT is the storage volume in gallons as measured during the test to
determine the standby loss. VT may differ from V, but it is within
the tolerances allowed by the applicable Z21 and UL standards. Accordingly, for the
purpose of estimating the standby loss requirement using the rated volume shown on
the rating plate VT should be considered as no less than 0.95V for
gas and oil water heaters and no less than 0.90V for electric water
heaters.
e. Heat loss of tank surface area (Btuh/ft2) based on 80°F water-air temperature difference.
f. Electric water heaters covered by NAECA include heat pumps with maximum current ratings
of 24 A at a voltage no greater than 250 V.
g. Et = thermal efficiency. C.O.P. for heat pumps.
h. Heat pump C.O.P. minimum requirements based on 75°F DB, 63°F WB, 70°F inlet
and 130°F leaving water temperature (heat pumps rated for a maximum leaving water
temperature of 120°F shall have a minimum C.O.P. of 3.7).
(g) Swimming Pools, Hot Tubs and Spas.
(1) Swimming Pool, Hot Tub and Spa Heaters. All water heaters for swimming pools,
hot tubs and spas shall meet the criteria of Table 11-1 and shall
be equipped with a readily accessible switch to allow shutting off the heater
without adjusting the thermostat setting and to allow restarting without manually relighting a
pilot light.
(2) Pool Heating Systems.
(A) Active solar or heat pump heating systems shall be used for swimming pool
heating.
(B) Exception. Alternative systems may be used if it can be shown that they
are more cost-effective as determined by life-cycle cost analysis as performed in accordance
with procedures defined by the National Institute of Standards and Technology (NIST) Life-Cycle
Costing Manual for the Federal Energy Management Program, NIST Handbook 135, and its
supplement, Energy Price Indices and Discount Factors for Life-Cycle Cost Analysis. Assumptions used
in any calculation should use the latest price indices and discount factors available
at the time the calculation is submitted to the city.
(3) Time Switches.
(A) Time switches shall be installed so that the pump can be set to
run in the off-peak electric demand period and can be set for the
minimum time necessary to maintain the water in a clear and sanitary condition
in keeping with applicable health standards.
(B) Exception. Pumps required to operate solar or waste-heat recovery pool heating systems need
not use time switches.
Table 11-2 -- Residential Hot Water Consumption for Sizing
Water Heating Systems
Residential Hot Water
Dwelling Consumption
Unit Size (ft 2 ) a (gal/day)
< 1,000 30
> 1,000 and < 1,400 40
> 1,400 and < 1,800 60
> 1,800 80
a Excluding garage area.
(h) Heat Traps. Vertical pipe risers serving storage water heaters and storage tanks not
having integral heat traps and serving a nonrecirculating system shall have heat traps
on both the inlet and outlet piping as close as practical to the
storage tank. A heat trap is a means to counteract the natural convection
of heated water in a vertical pipe run. The means is either a
device specifically designed for the purpose or an arrangement of tubing that forms
a loop of 360 degrees or piping that from the point of connection
to the water heater (inlet or outlet) includes a length of piping directed
downwards before connection to the vertical piping of the supply water or hot
water distribution system, as applicable.
(Added by Ord. 94-75; Am. Ord. 01-47)
Article 12. Energy Management
Sections:
32-12.1 General
32-12.2 Other specific control requirements.
32-12.3 General requirements.
Sec. 32-12.1 General.
This article describes the minimum measurement, control, testing and documentation features that shall
be provided for the building. The intent is to provide design data along
with a means of testing the facility in its completed form so that
the facility can be operated in an energy-efficient manner as intended by this
code. (Added by Ord. 94-75)
Sec. 32-12.2 Other specific control requirements.
See the following articles for specific control requirements for specific systems and equipment:
Article 5 - electric power and distribution systems
Article 6 - lighting systems
Article 9 - HVAC systems
Article 10 - HVAC equipment
Article 11 - service water heating systems and equipment
(Added by Ord. 94-75)
Sec. 32-12.3 General requirements.
(a) Public Utility Meter. Each public utility energy service meter provided shall be located
or arranged so that the meter can be monitored. Monitoring of utility company
meters and the installation of submetering or checkmetering shall be in compliance with
the utility company regulations.
(b) Building Energy Measurement System.
(1) Each distinct building energy service shall have a measurement system provided to accumulate
a record or indicator reading of the overall amounts of the energy being
delivered.
(2) Exception. A building of 5,000 ft2 gross floor area or less in a
complex of buildings may have its measurement system included with another building in
the same complex.
(c) Equipment Energy Measurement. All equipment used for heating or cooling and HVAC delivery
systems of greater than 20 kVA or 60,000 Btu/h energy input shall be
arranged so that the inputs and outputs such as flow, temperature and pressure
can be individually measured to determine the equipment energy consumption, the installed performance
capabilities and efficiencies, or both. The intent of this requirement is to provide
physical access or other provisions in the equipment or layout that will allow
these measurements in the future if so desired. Installation of the measurement equipment
is not required for compliance with this code.
(Added by Ord. 94-75)
Article 13. Building Energy Cost Budget Method
Sections:
32-13.1 Purpose.
32-13.2 Scope.
32-13.3 General
32-13.4 Determination of the annual energy cost budget.
32-13.5 Design energy consumption (DECON) and design energy cost (DECOS).
32-13.6 Compliance.
32-13.7 Standard calculation procedure.
32-13.8 The simulation tool.
Sec. 32-13.1 Purpose.
This article provides criteria for the design of energy- efficient buildings that allow
greater design flexibility than the other compliance paths of this code, while providing
building energy efficiency levels consistent with the other paths. This path provides an
opportunity for the building designer to evaluate and take credit for innovative energy
efficiency designs, materials, and equipment such as daylighting, heat recovery, better zonal temperature
control, and thermal storage, as well as other applications of "off peak" electrical
energy that cannot be accounted for in the prescriptive or system performance paths.
Designers are encouraged to employ the building energy cost budget method set forth
in this article for evaluating proposed design alternatives in preference to using the
prescriptive or system performance methods. (Added by Ord. 94-75)
Sec. 32-13.2 Scope.
The building energy cost budget method may be used when designs fail to
meet either the prescriptive or system performance criteria of this code. It may
be employed for evaluating the compliance of all proposed designs (except shell buildings).
(Added by Ord. 94-75)
Sec. 32-13.3 General.
Compliance is achieved when the estimated design energy cost (DECOS) is not greater
than the energy cost budget (ECB). (Added by Ord. 94-75)
Sec. 32-13.4 Determination of the annual energy cost budget.
The energy cost budget (ECB) is the summation of the 12 monthly energy
cost budgets (ECBm). Each ECBm is the product of the monthly budget energy
consumption (BECONm) of each type of energy used multiplied by that monthly energy
cost (ECOSm) per unit of energy for each type of energy used. The
ECB shall be determined in accordance with Equation 13-1 as follows:
Equation 13-1
ECB = ECBjan + ...ECBm + ... + ECBdec
Based on Equation l3-2:
Equation 13-2
ECBm = (BECONm1) x (ECOSm1) + .. + (BECONmi) x (ECOSmi)
where:
ECB = The annual Energy Cost Budget
ECBm = The monthly Energy Cost Budget
BECONmi = The monthly Budget Energy Consumption of the ith type of energy
ECOSmi = The monthly Energy Cost, per unit of the ith type of energy
The ECOSmi shall be determined using current rate schedules or contract prices available
at the building site for all types of energy purchased. These costs shall
include demand charges, rate blocks, time of use rates, interruptable service rates, delivery
charges, fuel adjustment factors, taxes, and all other charges applicable for the type,
location, operation, and size of the proposed building. The BECONmi shall be calculated
from the first day through the last day of each month, inclusive.
(a) Reference Building. Each floor shall be oriented exactly as in the proposed design.
The form, gross and conditioned floor area of each floor and the number
of floors shall be as in the proposed design. All other characteristics such
as lighting, envelope and HVAC system shall meet the requirements of Articles 5
through 12.
(b) Calculation Procedure and Simulation Tool. The reference building shall be modeled using the
criteria of Sections 32-13.7 and 32-13.8. The modeling shall use a climate data
set appropriate for both the site and the complexity of the energy conserving
features of the design. ASHRAE WYEC weather tapes or bin weather data shall
be a default choice.
(Added by Ord. 94-75)
Sec. 32-13.5 Design energy consumption (DECON) and design energy cost (DECOS).
The DECON shall be calculated by modeling the proposed design using the same
methods, assumptions, climate data, and simulation tool as were used to establish the
ECB, except as explicitly provided in Section 32-13.7. The DECOS shall be calculated
as provided in Equation 13-3 using the same rate schedules or contract prices
as were used to establish the ECB. If the proposed design includes cogeneration
or renewable energy sources designed for the sale of energy off site, the
energy cost and income resulting from outside sales shall not be included in
the calculation of DECOS. Such systems shall be modeled as operating to supply
energy needs of the proposed design only.
Equation 13-3
DECOS = DECOSjan + ...DECOSm .... + DECOSdec
Equation 13-4
DECOSm = (DECONm1) x (ECOSm1) + ...+ (DECONmi) x (ECOSmi)
where:
DECOS = The annual Design Energy Cost
DECOSm = The monthly Design Energy Cost
DECONmi = The monthly Design Energy Consumption of the ith type of energy
ECOSmi = The monthly Energy Cost per unit of the ith type of energy
(See Section 32-13.4 for ECOSmi definitions)
The DECONmi shall be calculated from the first day through the last day
of the month, inclusive.
(Added by Ord. 94-75)
Sec. 32-13.6 Compliance.
The proposed design complies with this code when the design energy cost (DECOS)
is not greater than the energy cost budget (ECB) as provided in Equation
13-5, and all of the basic requirements of Sections 32-5.3, 32-6.3, 32-8.3, 32-9.3,
32-10.3, 32-11.3, and 32-12.3 are met.
Equation 13-5
DECOS < ECB
(Added by Ord. 94-75)
Sec. 32-13.7 Standard calculation procedure.
The standard calculation procedure consists of methods and assumptions for calculating the ECB
for the reference building and the DECON and DECOS of the proposed design.
In order to maintain consistency between the ECB and the DECOS, the input
assumptions in this section shall be used.
"Prescribed" assumptions shall be used without variation. "Default" assumptions shall be used unless
the designer can demonstrate that a different assumption better characterizes the building's use
over its expected life. Any modification of a default assumption shall be used
in modeling both the reference building and the proposed design unless the designer
demonstrates a clear cause to do otherwise. Special procedures necessary for speculative buildings
are discussed in subsection (g).
(a) Orientation and Shape. The reference building shall consist of the same number of
stories and gross floor area for each story as the proposed design. Each
floor shall be oriented exactly as the proposed design. The geometric form shall
be the same as the proposed design. Glass area and orientation shall be
exactly as the proposed design.
(b) Internal Loads. Internal loads shall be modeled as noted in the following subdivisions
(1) through (3).
(1) Occupancy. Occupancy schedules shall be default assumptions. The same assumptions shall be made
in computing design energy consumption as are used in calculating the energy cost
budget.
Occupancy levels vary by building type and time of day. Table 13-1, Occupancy
Density, establishes the density presented as ft2/person of conditioned floor area that will
be used by each building type. Table 13-5, Building Schedule Percentage Multipliers, establishes
the percentage of the people that are in the building by hours of
the day for each building type.
(2) Lighting. Interior lighting power allowance (ILPA), for calculating the ECB shall be determined
from Article 6. The lighting power used to calculate the DECOS shall be
the actual adjusted power of the proposed lighting design. If the lighting controls
in the proposed design are more effective at saving energy than those required
by Section 32-6.3, the actual installed lighting power shall be used along with
the schedules reflecting the action of the controls to calculate the DECOS. This
"actual installed lighting power" shall not be adjusted by the power adjustment factors
listed in Table 6-4.
Lighting levels in buildings vary based on the type of uses within buildings,
by area and by time of day. Table 13-5 contains the lighting energy
profiles which establish the percentage of the lighting load that is ON in
each reference building by hour of the day. These profiles are default assumptions
and can be changed if required when calculating the ECB to provide, for
example, a 12-hour rather than an eight-hour workday.
(3) Receptacle. Receptacle loads and profiles are default assumptions. The same assumptions shall be
made in calculating design energy consumption as were used in calculating the energy
cost budget.
Receptacle loads include all general service loads that are typical in a building.
These loads should include additional process electrical usage, but exclude HVAC primary or
auxiliary electrical usage. Table 13-2, Receptacle Power Densities, establishes the density in W/ft2
to be used. The receptacle energy profiles shall be the same as the
lighting energy profiles in Table 13-5. This profile establishes the percentage of the
receptacle load that is ON by hour of the day and by building
type.
(c) Envelope.
(1) Insulation and Glazing. The insulation and glazing characteristics of the reference building envelope
shall be determined from Section 32-8.4. In the calculation of the DECON of
the proposed design, the envelope characteristics of the proposed design shall be used.
The reference building shall not have an overhang. The reference building shall be
modeled with a glazing material with a constant shading coefficient equal to the
relative solar heat gain requirements in Section 32-8.4(c).
(2) Infiltration.
(A) For reference buildings, infiltration assumptions shall use the prescribed assumptions for calculating the
ECB and default assumptions for the DECON. Infiltration shall impact only perimeter zones.
When the HVAC system is ON, no infiltration shall be assumed to occur.
When the HVAC system is OFF, the infiltration rate for buildings with or
without operable windows shall be assumed to be 0.038 cfm/ft2 of the gross
exterior wall.
(B) Exception. Hotels/motels and residential buildings shall have infiltration rates of 0.038 cfm/ft2 of
gross exterior wall area at all times.
(3) Envelope and Ground Absorptivities. Absorptivity assumptions shall be prescribed assumptions for the reference
building and default assumptions for the proposed design. The solar absorptivity of opaque
elements of the building envelope shall be assumed to be 70 percent. The
solar absorptivity of ground surfaces shall be assumed to be 80 percent (20
percent reflectivity).
(4) Window Management. If the plans and specifications show interior shading devices which perform
better than a medium-colored venetian blind, then those shading devices may be modeled
in the proposed design, and the reference building shall be modeled with medium-colored
venetian blinds. Otherwise, interior shading shall be modeled identically in the proposed and
reference buildings, either with medium-colored venetian blinds or without interior shades.
If the simulation tool has a window management algorithm, then manually operated shades
shall be assumed to close when solar gain exceeds 30 Btu/h-ft2. Otherwise, assume
that half the blinds are closed continuously. If the proposed design includes special
controls for interior shading devices, then they may be modeled, and the blinds
in the reference building shall be assumed to close when solar gain exceeds
30 Btu/h-ft2.
(5) Shading. For reference buildings and the proposed design, shading by permanent structures, terrain,
and vegetation may be taken into account for computing energy consumption, whether or
not these features are located on the building site. A permanent fixture is
one that is likely to remain for the life of the proposed design.
(d) HVAC Systems and Equipment. The HVAC system and equipment type in the reference
building shall be the same as the proposed design, but the system and
equipment in the reference building shall exactly meet the requirements of Articles 9
and 10. Special energy cost-reducing features of the proposed design need not be
included in the reference building if they are not required in Articles 9
and 10. If the HVAC system type in the proposed design is not
allowed under the requirements of Section 32-9.4, then a reasonably similar complying system
shall be modeled in the reference building.
(1) HVAC Zones. For multi-family buildings, the reference building shall have one zone per
dwelling unit. The proposed design shall have one zone per unit unless zonal
thermostatic controls are provided within units; in this case, two zones per unit
shall be modeled.
In all other building types, HVAC zones for calculating the ECB and the
DECOS shall be exactly the same. The zones in the simulation shall correspond
to the zones provided by the controls in the proposed design.
Building types such as assembly or warehouse may be modeled as a single
zone if there is only one space.
Thermally similar zones, such as those facing one orientation on different floors, may
be grouped together for the purposes of either the DECOS or ECB simulation.
(2) Equipment Sizing and Redundant Equipment. Process loads should be modeled in calculating both
the ECB and the DECOS. If process loads are modeled, the equipment shall
be sized in accordance with the methods of Article 9 to include the
capacity to meet the process loads. The designer shall document the installation of
process equipment and the size of process loads.
If process loads are not modeled, then for calculating the ECB of reference
buildings HVAC equipment shall be sized to meet the requirements of Section 32-9.4(a)
without utilizing any of the exceptions.
For calculating the DECOS, actual air flow rates and installed equipment size shall
be used in the simulation, except that excess capacity provided to meet process
loads need not be modeled if the process load was not modeled in
setting the ECB. Equipment sizing in the simulation of the proposed design shall
correspond to the equipment actually selected for the design, and the designer shall
not use equipment sized automatically by the simulation tool.
Redundant and/or emergency equipment need not be simulated if it is controlled such
that it will not be operated during normal operations of the building.
(e) Service Water Heating. The service water heating loads for reference buildings are defined
in terms of Btu/person-hours in Table 13-3. The service water heating loads from
Table 13-3 are prescribed for multi-family buildings and default for all other buildings.
The same service water heating load assumptions shall be made in calculating DECOS
as were used in calculating the ECB.
The service water heating system, including piping losses, for the reference building shall
be modeled using the methods of the ASHRAE Handbook, 1991 HVAC Applications, using
a system that meets all requirements of Article 11.
The service water heating equipment type for the reference building shall be an
electric resistance storage water heater if the proposed building uses electric water heating
or shall be a utility gas storage water heater if the proposed building
uses gas water heating.
(f) Controls.
(1) Conditioned and Unconditioned Spaces.
(A) All occupied spaces in the reference and proposed buildings shall be simulated as
being air- conditioned. When no cooling system is shown on the plans for
the proposed design, reasonable assumptions shall be made about the HVAC system type,
and the same assumptions shall be made for the proposed and reference buildings.
(B) Exception. Unconditioned spaces which meet the envelope requirements of Sections 32-8.4 or 32-8.5
may be omitted from the thermal model in the proposed and reference designs.
(2) Space Temperature Controls.
(A) Space temperature controls for the reference building except multi-family shall be set at
75 degrees Fahrenheit for space cooling. The system shall be OFF during off-hours
according to the appropriate schedule in Table 13-3.
(B) Exceptions. Setback shall not be modeled in determining either the ECB or DECOS
if setback is not realistic for the proposed design such as a facility
being operated 24 hours per day.
(3) For multi-family buildings, the thermostat schedule for the dwelling units shall be as
in Table 13-4. The reference building shall use the single zone schedule. The
proposed design shall use the two-zone schedule only if zonal thermostatic controls are
provided. The thermostat assumptions for multi-family buildings are prescribed assumptions.
(4) When providing for outdoor air ventilation when calculating the ECB, controls shall be
assumed to close the outside air intake to reduce the flow of outside
air to zero cfm during "setback" and "unoccupied" periods. Ventilation using inside air
may still be required to maintain scheduled setback temperature. Outside air ventilation, during
occupied periods, shall be as required by ASHRAE Standard 62-1989 or the proposed
design, whichever is greater.
(5) If dehumidification requires subcooling of supply air, then reheat for the reference building
shall be from recovered waste heat such as condenser waste heat.
(g) Speculative Buildings.
(1) Lighting. The interior lighting power allowance (ILPA) for calculating the ECB shall be
determined from Table 6-5. The DECOS may be based on an assumed adjusted
lighting power for future lighting improvements.
The assumption about future lighting power used to calculate the DECOS shall be
documented so that the future installed lighting systems may be in compliance with
this assumption. Documentation shall be provided to enable future lighting systems to use
either the prescriptive method of Section 32-6.4 or the systems performance method of
Section 32-6.5. Documentation for future lighting systems that use the prescriptive method of
Section 32-6.4 shall be stated as a maximum adjusted lighting power for the
tenant spaces. The adjusted lighting power allowance for tenant spaces shall account for
the lighting power provided for the common areas of the building.
Documentation for future lighting systems that use the systems performance method of Section
32-6.5 shall be stated as a required lighting adjustment. The required lighting adjustment
is the whole building lighting power assumed in order to calculate the DECOS
minus the ILPA value from Table 6-5 that was used to calculate the
ECB. When the required lighting adjustment is less than zero, a complete lighting
design shall be developed for one or more representative tenant spaces, demonstrating acceptable
lighting within the limits of the assumed lighting power limit.
(2) HVAC Systems and Equipment. If the HVAC system is not completely specified in
the plans, the DECOS shall be based on reasonable assumptions about the construction
of future HVAC systems and equipment. These assumptions shall be documented so that
future HVAC systems and equipment may be in compliance with this assumption.
(Added by Ord. 94-75)
Sec. 32-13.8 The simulation tool.
(a) Annual energy consumption should be simulated with a multizone, 8,760 hours per year
building energy program. The tool should account for:
(1) The dynamic heat transfer of the building envelope, including the effects of solar
and internal gains;
(2) Equipment efficiencies as a function of load and climate;
(3) Lighting and HVAC system controls and distribution systems by simulating the whole building;
(4) The operating schedule of the building including night setback during various times of
the year;
(5) Energy consumption information at a level necessary to determine the ECB and DECOS
via the appropriate utility rate schedules.
(b) While analysis tools should simulate an entire year on an hour-by-hour basis (8,760
hours per year), tools that approximate this dynamic analysis procedure or provide equivalent
results are acceptable.
(Added by Ord. 94-75)
Table 13-1 -- Occupancy Density
Conditioned Floor Area
Building Type Sq ft/Person
1. Assembly 50
2. Office 275
3. Retail 300
4. Warehouse 15,000
5. School 75
6. Hotel/Motel 250
7. Restaurant 100
8. Health/Institutional 200
9. Multi-family 0 a
10. Light Manufacturing 750
Heat generation: Btu/person-hour: 230 sensible and 190 latent
a. See notes for multi-family high-rise in Table 13-5.
Table 13-2 -- Receptacle Power Densities
Building Type Watts/ft 2 of
Conditioned Floor Area
1. Assembly 0.25
2. Office 0.75
3. Retail 0.25
4. Warehouse 0.1
5. School 0.5
6. Hotel/Motel 0.25
7. Restaurant 0.1
8. Health 1.0
9. Multi-family 0 a
10. Light Manufacturing 0.2 b
a. See notes for multi-family high-rise in Table 13-5.
b. Non-process load.
Table 13-3 -- Service Hot Water Quantities
Building Type Btu/Person-hour a
1. Assembly 215
2. Office 175
3. Retail 135
4. Warehouse 225
5. School 215
6. Hotel/Motel 1,110
7. Restaurant 390
8. Health 135
9. Multi-family 1,700 b
10. Light Manufacturing 225 c
a. This value is the number to be multiplied by the percentage multipliers of
the building profile schedules in Table 13-5. See Table 13-1 for occupancy levels.
b. Total hot water use per dwelling unit for each hour shall be 3,400
Btu/h times the multi-family Service Water Heating (SWH) system multiplier from Table 13-5.
c. Non-process load.
Table 13-4 -- Building Cooling Thermostat Setpoint Schedule
Hour of Day
1 2 3 4 5 6 7 8 9 10 11 12
13 14 15 16 17 18 19 20 21 22 23 24
Assembly
Weekday OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75 75 75 75
75 75 75 75 75 75 OFF
Weekend OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75 75 75 75
75 75 75 75 75 OFF
Office
Weekday OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75 75 75 75
75 75 75 75 OFF OFF
Sat. OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75 75 75 75 OFF OFF OFF OFF OFF OFF
Sun. OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF
Retail
Weekday OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75 75 75 75
75 75 75 OFF OFF OFF
Sat. OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75 75 75 75
75 75 75 75 OFF OFF
Sun. OFF OFF OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75 OFF OFF OFF OFF OFF OFF OFF
Warehouse
Weekday OFF OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75 75 OFF OFF OFF OFF OFF OFF OFF
Sat. OFF OFF OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 OFF OFF OFF OFF OFF OFF OFF OFF
Sun. OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF
School
Weekday OFF OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75 75 75 75
75 75 75 OFF OFF
Sat. OFF OFF OFF OFF OFF OFF OFF OFF 75 75 75 75 75 OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF
Sun. OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF
Hotel
All Days 75 75 75 75 75 75 75 75 75 75 75
75 75 75 75 75 75 75 75 75 75 75 75 75
Restaurant
Weekday 75 75 75 OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75
75 75 75 75 75 75 75 75
Sat. 75 75 75 OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75
75 75 75 75 75 75
Sun. 75 75 75 OFF OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75
75 75 75 75 75
Health
All Days 75 75 75 75 75 75 75 75 75 75 75
75 75 75 75 75 75 75 75 75 75 75 75 75
Multi-family
One-Zone
All Days 78 78 78 78 78 78 78 78 78 78 78
78 78 78 78 78 78 78 78 78 78 78 78 78
Two-Zone
Bedrooms
& Bathrooms
All Days 78 78 78 78 78 78 78 78 78 85 85
85 85 85 85 85 85 78 78 78 78 78 78 78
Other Rooms
All Days 85 85 85 85 85 85 78 78 78 78 78
78 78 78 78 78 78 78 78 78 78 78 78 78
Light Manufacturing
Weekday OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75 75 75 75
75 75 75 75 OFF OFF
Sat. OFF OFF OFF OFF OFF OFF 75 75 75 75 75 75 75 75 75 75 75 75 OFF OFF OFF OFF OFF OFF
Sun. OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF
Table 13-5 -- Building Schedule Percentage Multipliers a,b,c
Hour of Day
1 2 3 4 5 6 7 8 9 10 11 12
13 14 15 16 17 18 19 20 21 22 23 24
Assembly
Occupancy
Weekday 0 0 0 0 0 0 0 0 20 20 20 80
80 80 80 80 80 80 20 20 20 20 10 0
Sat 0 0 0 0 0 0 0 0 20 20 20 60
60 60 60 60 60 60 60 60 60 80 10 0
Sun 0 0 0 0 0 0 0 0 10 10 10 10
10 70 70 70 70 70 70 70 70 70 20 0
Lighting
Weekday 0 0 0 0 0 0 40 40 40 75 75 75
75 75 75 75 75 75 75 75 75 75 25 0
Sat 0 0 0 0 0 0 0 30 30 50 50 50
50 50 50 50 50 50 50 50 50 50 0 0
Sun 0 0 0 0 0 0 0 30 30 30 30 30
65 65 65 65 65 65 65 65 65 65 0 0
HVAC
Weekday OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON OFF
Sat OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON OFF
Sun OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON OFF
Service Hot Water
Weekday 0 0 0 0 0 0 0 0 0 5 5 35
5 5 5 5 5 0 0 0 0 0 0 0
Sat 0 0 0 0 0 0 0 0 0 5 5 20
0 0 0 0 0 0 0 65 30 0 0 0
Sun 0 0 0 0 0 0 0 0 0 5 5 10
0 0 0 0 0 0 0 65 30 0 0 0
Office
Occupancy
Weekday 0 0 0 0 0 0 0 10 20 95 95 45
45 95 95 95 95 95 30 10 10 10 0 0
Sat 0 0 0 0 0 0 0 10 10 30 30 30
30 10 10 10 10 10 0 0 0 0 0 0
Sun 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
Lighting
Weekday 0 0 0 0 0 0 10 30 90 90 90 90
80 90 90 90 90 90 30 30 20 20 0 0
Sat 0 0 0 0 0 0 10 10 30 30 30 30
15 15 15 15 15 15 0 0 0 0 0 0
Sun 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
HVAC
Weekday OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON OFF OFF
Sat OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON ON OFF OFF OFF OFF OFF OFF
Sun OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF
Service Hot Water
Weekday 0 0 0 0 0 0 0 15 30 35 35 45
55 50 30 30 40 20 20 10 15 5 0 0
Sat 0 0 0 0 0 0 0 10 10 20 15 20
15 15 10 10 10 0 0 0 0 0 0 0
Sun 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
Retail
Occupancy
Weekday 0 0 0 0 0 0 0 10 20 50 50 70
70 70 70 80 70 50 50 30 30 0 0 0
Sat 0 0 0 0 0 0 0 10 20 50 60 80
80 80 80 80 80 60 20 20 20 10 0 0
Sun 0 0 0 0 0 0 0 0 0 10 20 20
40 40 40 40 40 20 10 0 0 0 0 0
Lighting
Weekday 0 0 0 0 0 0 0 20 50 90 90 90
90 90 90 90 90 90 60 60 50 0 0 0
Sat 0 0 0 0 0 0 0 10 30 60 90 90
90 90 90 90 90 90 50 30 30 10 0 0
Sun 0 0 0 0 0 0 0 0 0 10 40 40
60 60 60 60 60 40 20 0 0 0 0 0
HVAC
Weekday OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON OFF OFF OFF
Sat OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON OFF OFF
Sun OFF OFF OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON OFF OFF OFF OFF OFF
Service Hot Water
Weekday 0 0 0 0 0 0 0 10 20 30 40 55
60 60 45 40 45 45 40 30 30 0 0 0
Sat 0 0 0 0 0 0 0 15 20 25 40 50
55 55 45 45 45 45 40 35 25 20 0 0
Sun 0 0 0 0 0 0 0 0 0 10 25 30
35 35 30 30 35 30 20 0 0 0 0 0
Table 13-5 -- Building Schedule Percentage Multipliers
(continued)
Hour of Day
1 2 3 4 5 6 7 8 9 10 11 12
13 14 15 16 17 18 19 20 21 22 23 24
Warehouse
Occupancy
Weekday 0 0 0 0 0 0 0 15 70 90 90 90
50 85 85 85 20 0 0 0 0 0 0 0
Sat 0 0 0 0 0 0 0 0 20 20 20 20
10 10 10 10 0 0 0 0 0 0 0 0
Sun 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
Lighting
Weekday 0 0 0 0 0 0 0 40 70 90 90 90
90 90 90 90 90 0 0 0 0 0 0 0
Sat 0 0 0 0 0 0 0 0 10 25 25 25
10 10 10 10 0 0 0 0 0 0 0 0
Sun 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
HVAC
Weekday OFF OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON OFF OFF OFF OFF OFF OFF OFF
Sat OFF OFF OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON OFF OFF OFF OFF OFF OFF OFF OFF
Sun OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF
Service Hot Water
Weekday 0 0 0 0 0 0 0 5 25 35 35 45
55 40 35 40 15 0 0 0 0 0 0 0
Sat 0 0 0 0 0 0 0 0 0 10 10 15
0 0 0 0 0 0 0 0 0 0 0 0
Sun 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
School
Occupancy
Weekday 0 0 0 0 0 0 0 5 75 90 90 80
80 80 80 45 15 5 15 20 20 10 0 0
Sat 0 0 0 0 0 0 0 0 10 10 10 10
10 0 0 0 0 0 0 0 0 0 0 0
Sun 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
Lighting
Weekday 0 0 0 0 0 0 0 30 85 95 95 95
80 80 80 70 50 50 35 35 35 30 0 0
Sat 0 0 0 0 0 0 0 0 15 15 15 15
15 0 0 0 0 0 0 0 0 0 0 0
Sun 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
HVAC
Weekday OFF OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON OFF OFF
Sat OFF OFF OFF OFF OFF OFF OFF OFF ON ON ON ON ON OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF
Sun OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF
Service Hot Water
Weekday 0 0 0 0 0 0 0 5 30 55 60 70
75 80 60 60 5 5 15 20 20 20 0 0
Sat 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
Sun 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
Hotel
Occupancy
Weekday 90 90 90 90 90 90 70 40 40 20 20 20
20 20 20 30 50 50 50 70 70 80 90 90
Sat 90 90 90 90 90 90 70 50 50 30 30 30
30 30 30 30 30 50 60 60 60 70 70 70
Sun 70 70 70 70 70 70 70 70 50 50 50 30
30 20 20 20 30 40 40 60 60 80 80 80
Lighting
Weekday 20 15 10 10 10 20 40 50 40 40 25 25
25 25 25 25 25 25 60 80 90 80 60 30
Sat 20 20 10 10 10 10 30 30 40 40 30 25
25 25 25 25 25 25 60 70 70 70 60 30
Sun 30 30 20 20 20 20 30 40 40 30 30 30
30 20 20 20 20 20 50 70 80 60 50 30
HVAC
Weekday ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON
Sat ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON
Sun ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON
Service Hot Water
Weekday 20 15 15 15 20 25 50 60 55 45 40 45
40 35 30 30 30 40 55 60 50 55 45 25
Sat 20 15 15 15 20 25 40 50 50 50 45 50
50 45 40 40 35 40 55 55 50 55 40 30
Sun 25 20 20 20 20 30 50 50 50 55 50 50
40 40 30 30 30 40 50 50 40 50 40 20
Table 13-5 -- Building Schedule Percentage Multipliers
(continued)
Hour of Day
1 2 3 4 5 6 7 8 9 10 11 12
13 14 15 16 17 18 19 20 21 22 23 24
Restaurant
Occupancy
Weekday 15 15 5 0 0 0 0 5 5 5 20 50
80 70 40 20 25 50 80 80 80 50 35 20
Sat 30 25 5 0 0 0 0 0 0 5 20 45
50 50 35 30 30 30 70 90 70 65 55 35
Sun 20 20 5 0 0 0 0 0 0 0 10 20
25 25 15 20 25 35 55 65 70 35 20 20
Lighting
Weekday 15 15 15 15 15 20 40 40 60 60 90 90
90 90 90 90 90 90 90 90 90 90 50 30
Sat 20 15 15 15 15 15 30 30 60 60 80 80
80 80 80 80 80 90 90 90 90 90 50 30
Sun 20 15 15 15 15 15 30 30 50 50 70 70
70 70 70 70 60 60 60 60 60 60 50 30
HVAC
Weekday ON ON ON OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON
Sat ON ON ON OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON
Sun ON ON ON OFF OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON ON ON ON
Service Hot Water
Weekday 20 15 15 0 0 0 0 60 55 45 40 45
40 35 30 30 30 40 55 60 50 55 45 25
Sat 20 15 15 0 0 0 0 0 0 50 45 50
50 45 40 40 35 40 55 55 50 55 40 30
Sun 25 20 20 0 0 0 0 0 0 0 50 50
40 40 30 30 30 40 50 50 40 50 40 20
Health
Occupancy
Weekday 0 0 0 0 0 0 0 10 50 80 80 80
80 80 80 80 80 50 30 30 20 20 0 0
Sat 0 0 0 0 0 0 0 10 30 40 40 40
40 40 40 40 40 10 10 0 0 0 0 0
Sun 0 0 0 0 0 0 0 0 5 5 5 5
5 5 5 5 0 0 0 0 0 0 0 0
Lighting
Weekday 0 0 0 0 0 0 0 50 90 90 90 90
90 90 90 90 90 30 30 30 30 30 0 0
Sat 0 0 0 0 0 0 0 20 40 40 40 40
40 40 40 40 40 40 10 0 0 0 0 0
Sun 0 0 0 0 0 0 0 0 10 10 10 10
10 10 10 10 0 0 0 0 0 0 0 0
HVAC
Weekday ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON
Sat ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON
Sun ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON
Service Hot Water
Weekday 0 0 0 0 0 0 0 15 55 65 75 80
70 80 75 70 60 40 15 15 15 5 0 0
Sat 0 0 0 0 0 0 0 0 15 25 25 25
20 20 20 20 20 5 0 0 0 0 0 0
Sun 0 0 0 0 0 0 0 0 0 15 15 15
15 15 15 0 0 0 0 0 0 0 0 0
Table 13-5 -- Building Schedule Percentage Multipliers
(continued)
Hour of Day
1 2 3 4 5 6 7 8 9 10 11 12
13 14 15 16 17 18 19 20 21 22 23 24
Multi-Family
Service Hot Water
Weekday 0 0 0 5 5 5 80 70 50 40 20 20
25 25 50 50 70 70 35 20 15 15 5 0
Sat 0 0 0 0 0 0 20 45 50 50 35 30
30 30 70 90 70 65 55 35 30 25 5 0
Sun 0 0 0 0 0 0 0 20 25 25 15 20
25 35 55 65 70 35 20 20 20 20 5 0
HVAC Systems
Weekday ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON
Sat ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON
Sun ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON
One-zone Dwelling Unit
Occupancyd
All Days 67 67 67 67 67 67 67 49 21 21 21
21 21 21 21 21 21 67 67 67 67 67 67 67
Lightinge
All Days 0 0 0 0 0 0 95 85 0 0 0
0 0 0 0 0 0 0 0 90 90 90 90 90
Equipmentf
All Days 22 22 22 22 22 22 36 76 34 36 36
64 64 36 36 36 36 87 97 43 43 43 31 31
Two-zone Dwelling Unit
Bedrooms and Bathrooms
Occupancyd
All Days 67 67 67 67 67 67 45 27 0 0 0
0 0 0 0 0 0 0 0 21 21 33 67 67
Lightinge
All Days 0 0 0 0 0 0 66 23 0 0 0
0 0 0 0 0 0 0 0 31 31 47 63 63
Equipmentf
All Days 3 3 3 3 3 3 6 6 3 3 3
3 3 3 3 3 3 3 3 9 9 20 12 12
Other Rooms
Occupancyd
All Days 0 0 0 0 0 0 21 21 21 21 21
21 21 21 21 21 21 67 67 45 45 33 0 0
Lightinge
All Days 0 0 0 0 0 0 29 59 0 0 0
0 0 0 0 0 0 0 0 63 63 47 31 31
Equipmentf
All Days 19 19 19 19 19 19 30 70 34 34 34
61 61 34 34 34 34 84 94 34 34 23 19 19
Notes for Table 13-5:
(a) Reference: Recommendations for Energy Conservation Standards and Guidelines for New Commercial Buildings,
Vol. III, App. A. Pacific Northwest Laboratory, PNL-4870-8, 1983.
(b) Table 13-5 contains multipliers for converting the nominal values for building occupancy
(Table 13-1), receptacle power density (Table 13-2), service hot water (Table 13-3), and
lighting energy (Article 6) into time series data for estimating building loads under
the Standard Calculation Procedure. For each standard building profile, there are three series--one
each for weekdays, Saturday, and Sunday. There are 24 hours per series. These
represent the multiplier that should be used to estimate building loads from 12
a.m. to 1 a.m. (hour No. 1) through 11 p.m. to 12 a.m.
(hour No. 24). The estimated load for any hour is simply the multiplier
from the appropriate standard profile multiplied by the appropriate value from the tables
cited above.
(c) The building HVAC system schedule listed in Table 13-5 lists the hours
when the HVAC system shall be considered ON or OFF in accordance with
Section 32-13.7(c)(2).
(d) People. Assumes two people per dwelling unit. Maximum heat generation per person
= 420 Btu/h (230 Btu/h sensible, 190 Btu/h latent heat).
(e) Lighting. Maximum Installed = 300 Watts.
(f) Equipment. Sensible Heat Gain = [(833 Btu/unit*Number of Living Units) + (0.625
Btu/h-ft2 * Floor Area
of Zone)].
Latent Heat Gain = (0.2 * Sensible Heat Gain).
(Added by Ord. 94-75)
Article 14. Low-rise Residential Roof Heat Gain Requirements
Sections:
32-14.1 Scope.
32-14.2 Low-rise residential roof heat gain requirements.
Sec. 32-14.1 Scope.
(a) Notwithstanding Section 32-2.1, the requirements of this article shall apply to low-rise residential
buildings and cover new construction and enclosed, habitable additions to existing buildings where
the additions are 100 square feet or larger.
(b) "Roofs" shall mean the same as is defined in Section 32-3.1.
(Added by Ord. 01-46)
Sec. 32-14.2 Low-rise residential roof heat gain requirements.
(a) The opaque portions of roof assemblies shall include at least one of the
following:
(1) R-19 insulation between roof or ceiling framing members;
(2) Two inches of foam board insulation;
(3) A radiant barrier, as provided in subsection (d) and ventilation as provided in
subsection (c);
(4) A cool roof as provided in subsection (e) and a radiant barrier as
provided in subsection (d); or
(5) Any construction that meets the opaque roof heat gain requirements of Section 32-8.4(a).
(b) Plans shall indicate insulation type, thickness, and location; ventilation opening types, sizes and
locations; radiant barrier location; and roof surface type as appropriate, depending on the
compliance option selected from subsection (a).
(c) Additional ventilation of the space containing a radiant barrier for compliance with subsection
(a)(3) shall be provided by at least one of the following:
(1) A baffled ridge vent installed in accordance with the manufacturer's instructions in addition
to lower inlet openings to provide a total of no less than one
square foot of net free vent area for each 300 square feet of
roof area. No less than 30 percent of the total vent area shall
be in either the ridge vent or the lower half of the ventilated
space.
(2) A solar-powered exhaust fan that provides at least one cubic foot per minute
of airflow for each square foot of roof area.
(3) Upper and lower vents with total net free vent area of at least
one square foot for each 150 square feet of roof area. At least
30 percent of the total vent area shall be in the upper half
of the ventilated space and at least 30 percent of the total vent
area shall be in the lower half of the ventilated space.
(d) A radiant barrier used for compliance with subsection (a)(3) or (a)(4) shall have
an emissivity of no greater than 0.05 as tested per ASTM E-408, Test
Method for Total Normal Emittances of Surfaces Using Inspection Meter Techniques (manufacturer's test
results are acceptable). The radiant barrier shall be installed with the shiny side
facing down and with a minimum air gap thickness of 0.75 inches below.
The radiant barrier may be securely attached to the roof framing or may
be laminated to the bottom of the roof sheathing.
A radiant barrier is a sheet of material with a low emissivity on
at least one side that is used to reduce radiant heat transfer. Radiant
barriers typically have a shiny metallic appearance.
(e) A cool roof for purposes of compliance with subsection (a)(4) shall have a
total solar reflectance when tested according to ASTM E-903 of no less than
0.70. The infrared emittance using ASTM E-408 shall be no less than 0.75.
The manufacturer's test results shall be acceptable for compliance.
A cool roof has both a light color (high solar reflectance) and a
high emittance (can reject heat back to the environment). White painted surfaces and
other smooth white coatings typically meet these requirements. Surfaces that do not meet
the requirements include unpainted metal and most metalized roof coatings (silver appearance).
(f) At building sites higher than a 2,400-foot elevation, only subsection (a)(1) or subsection
(a)(2) shall be acceptable for compliance.
(g) For the purpose of this section, "net free vent area" means the total
area through which air can pass in a screen, grille face or register.
(h) For the purpose of this section, "roof area" means attic floor area; or,
if there is no attic, "roof area" means the horizontal projection of roof
area measured from the outside surface of the exterior walls.
(Added by Ord. 01-46; Am. Ord. 02-34)
Revised Ordinances
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