32a8_14.htm - Revised Ordinances of Honolulu

Revised Ordinances of Honolulu

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     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 Repealed by Ord. 01-46.)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 (U_o). 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 U_iA_i        U₁A₁ + U₂A₂ +...+ U_nA_n
U_o =    ______    =    _________________________
A_o              A_o

where:

U_o = The area-weighted average thermal transmittance of the opaque wall or roof [Btu/h-ft²-ºF].

A_o = The gross area of the opaque elements of the wall or roof [ft²]. (See subsection (c).)

U_i = 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/R_i (where R_i is the total resistance to heat flow of an individual path through an envelope assembly).

A_i = The area of the element of the envelope assembly which has U-value, U_i [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

RSHG_i = SC_glz,i x

OLE Object Here

x SC_ext,i x OHM_i

Equation 8-3

RSHG_i = SC_glz,i x

OLE Object Here

x SC_ext,i x SFM_i

where:

RSHG_i = Relative solar heat gain.

SC_glz,i= Shading coefficient of the glass alone taken from the manufacturer's literature.

IS_prop = 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 (SC_glz). As a default, IS_prop. may be assumed to equal IS_def. (then IS_prop./IS_def. = 1.0). (Unitless.)

IS_def=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.)

SC_ext = Shading coefficient of exterior shade screens or louvers. Default is 1.0. (Unitless.)

OHM_i = Overhang Multiplier. Calculated as a function of Overhang Projection Factor, OPF. From Equation 8-4 or Table 8-3.

SFM_i = 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

OHM_i = 1 + a_i x OPF_i + b_i x OPF_i²

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

SFM_i = 1 + c_i x SPF_i + d_i x SPF_i²

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.

Equation 8-6

OPF = A / B

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.

Equation 8-7

SPF = A / B

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 (SC_ext) 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= U_r x α x RB

where:

RHGF = Roof Heat Gain Factor. [Btu/ft²-h-ºF].

U_r = 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 (U_o) 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 (SC_x). 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 (U_of). The glazing thermal transmittance in the reference building shall be equal to 1.21 Btu/h-ft²-ºF.
Opaque Wall Thermal Transmittance (Wall U_o). 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

DLCF_ref = WWR_prop x 1.67

where:

DLCF_ref = The daylighting control factor (DLCF) for the reference building.

WWR_prop = 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

DLCF_prop = Σ (P_w + P_wr + P_wl) / P_t

where:

DLCF_prop = Daylighting control factor for the proposed design for each orientation.

P_w = Width of each window on each orientation.

P_wr = 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.

P_wl = Daylighted area to the left of each window on each orientation. Similar to P_wr.

P_t = 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

WC_c or C_l = Σ [CLUO_i + CLXUO_i
+ CLG_i + CLS_i + CLC_i + Σ(CLU_i,j + CLM_i,j )]

If WC_c or C₁ < 0.0, then WC_c or C₁ 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

CLUO_i = FC_i x UOC_i[CUO1_i x EA_i x VS_i x CDD50 + CUO2_i x G_i + CUO3_i x G_i² x EA_i² x VS_i x CDD50 + CUO4_i x G_i² x EA_i² x VS_i x CDD65]

CLXUO_i = FC_i(1/UOC_i)[CXUO1_i x EA_i x VS_i x CDD50 + CXUO2_i x EA_i(VS_i x CDD50)² + CXUO3_i x G_i x CDD50 + CXUO4_i x G_i² x EA_i² x VS_i x CDD50 + CXUO5_i x G_i² x CDD65]

CLG_i = FC_i{G_i[CG1_i + CG2_i x CDD50 + CG3_i x EA_i(VS_i x CDD50)² + CG4_i x EA_i² x VS_i x CDD50 + CG5_i x CDD65 + CG6_i x CDD50³ + CG7_i x CDD65³] + G_i²[CG8_i x EA_i x VS_i x CDD50 + CG9_i x EA_i² x VS_i x CDD50]}

CLS_i = FC_i{EA_i[CS1_i + CS2_i x VS_i x CDD50 + CS3_i(VS_i x CDD50)² + CS4_i x VS_i x CDD65 + CS5_i(VS_i x CDD65)²] + EA_i²[CS6_i + CS7_i(VS_i x CDD65)2]}

CLC_i = FC_i[CC1_i x CDD50 + CC2_i x CDD50² + CC3_i x CDH80 + CC4_i x CDH80² + CC5_i x CDD65 + CC6_i(VS_i x CDD65)² + CC7_i x VS_i x CDD50 + CC8_i(VS_i x CDD50)² + CC9_i(VS_i x CDH80)² + CC10_i x VS_i + CC11_i x DR + CC12_i x DR² + CC13_i]

CLU_i,j = FO_i,j x U_ow,i[CU1_i x CDH80 + CU2_i x CDH80² + CU3_i(VS_i x CDH80)² + CU4_i x DR]

CLM_i,j = FO_i,j x CMC_i,j[CM1_i + CM2_i x EA_i x VS_i x CDD50 + CM3_i x EA_i x VSi x CDD65 + CM4_i x EA_i² x VS_i x CDD50 + CM5_i x G_i² x CDD65 + CM6_i x G_i x CDD50 + CM7_i x G_i x CDD65 + CM8_i x G_i x EA_i x VS_i 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.

VS_i = annual average daily incident solar energy on facade under consideration, Btu/(ft²-day).

Building Data

FC_i = ratio, wall area (opaque and glazed) of zone under consideration divided by total wall area (opaque and glazed) of all zones.

FO_i,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 FO_i,j is calculated for each construction j and used to form the area weighted mass correction.

U_ow,i = area average U-value of opaque walls (including those of mass construction) in zone under consideration, Btu/(h-ft²-ºF).

UOC_i = area average U-value of wall (opaque and glazed, evaluated under cooling conditions) in zone under consideration, Btu/(h-ft²-ºF).

WWR_i = window wall ratio for zone under consideration; defined as fenestration area divided by total wall area (opaque and glazed).

EA_i = effective aperture fraction for zone under consideration, where:

Equation 8-13

EA_i = WWR_i x RSHG_i

and

RSHG_i = 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

G_i = E_p,i + L_p,i (1 - R_c,i x K_d,i ) + O_l,i

where:

G_i = effective internal gain (W/ft2) for zone under consideration.

E_p,i = equipment power, from subsection (b).

L_p,i = lighting power, from subsection (b).

O_l,i = occupant load adjustment, from subsection (b).

R_c,i = for a specified orientation, the ratio of the daylighting area of the space to the total area of the space.

Equation 8-15

K_d,i = 5.871(WWR_i x VLT_i x OHM_i ) - 13.311(WWR_i x VLT_i x OHM_i )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:

WWR_i = as defined above under Building Data.

VLT_i = visible light transmittance of the glazing material, as defined in subsection (b).

OHM_i = Overhang multiplier, from Section 32-8.3(d).

CMC_i,j = mass correction from Eq 8-16. If multiple mass constructions are present, then each CMC_i,j is evaluated separately and combined by area weighting. If the U-value of the mass wall is greater than 0.40, then U_ow = 0.4 shall be used to calculate the CMC_i,j. If the value of HC is greater than 20, then HC = 20 shall be used to calculate the CMC_i,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)]

OLE Object Here

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

C₁    220.724503    139.105667    181.616776
C₂    -.056589    -.033991    -.055196
C₃    -118.835388    -10.326704    -34.158966
C₄    -13.674420    -20.867386    -25.591934
C₅    .236381    .283882    .081029
C₆    .959588    .305851    1.418998
C₇    -.255004    .022622    .432421
C₈    -905.677979    -307.943848    -1882.926758
C₉    425.191895    80.209610    443.195801
C₁₀    -2.510600    .049955    .430200
C₁₁    -43.387955    -5.989545    -28.285065
C₁₂    -259.723389    -11.396114    -63.562256
C₁₃    -33.975525    .366851    20.844650
C₁₄    20.488235    30.253494    9.817521
C₁₅    -26.209152    8.833706    24.459824
C₁₆    -241.173386    -22.254623    -70.337494
C₁₇    18.897781    29.329697    9.884280
C₁₈    -.353790    -.023878    -.114646
C₁₉    156.305634    63.322754    326.344727
C₂₀    -74.098999    -16.334656    -77.635498
C₂₁    .445363    -.011114    -.074788
C₂₂    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·ft³ °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
Difference^b          R-value^c
°F            ft² ·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
spaces^e                         > 40         5.0^d

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 Efficiency^b

Test Procedure

Air Conditioners, Air Cooled	< 65,000 Btu/h^d	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 EER^c 10.6 IPLV^c
	e135,000 Btu/h and < 240,000 Btu/h	Split System and Single Package	9.7 EER^c 9.9 IPLV^c	ARI 340/360
	e 240,000 Btu/h and <760,000 Btu/h	Split System and Single Package	9.5 EER^c 9.7 IPLV^c
	e760,000 Btu/h	Split System and Single Package	9.2 EER^c 9.4 IPLV^c
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 EER^c 10.6 IPLV^c
	e135,000 Btu/h and d240,000 Btu/h	Split System and Single Package	11.0 EER^c 10.3 IPLV^c	ARI 340/360
	> 240,000 Btu/h	Split System and Single Package	11.0 EER^c 10.3 IPLV^c
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 Efficiency^b	Test Procedure
Air Cooled, (Cooling Mode)	< 65,000 Btu/h^d	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 EER^c 10.4 IPLV^c
	e135,000 Btu/h and <240,000 Btu/h	Split System and Single Package	9.3 EER^c 9.5 IPLV^c	ARI 340/360
	e240,000 Btu/h	Split System and Single Package	9.0 EER^c 9.2 IPLV^c
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/h^d (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	3.2 COP 2.2 COP
	e135,000 Btu/h (Cooling Capacity)