A building complies with this section by being designed with and constructed to meet all prescriptive requirements in Subsection (a) and the requirements of Subsection (c) and (d) where they apply.
- A minimum aged solar reflectance of 0.63 and a minimum thermal emittance of 0.75; or
- A minimum Solar Reflectance Index (SRI) of 75.
EXCEPTION 1 to Section 140.3(a)1Aia: Wood-framed roofs in Climate Zones 3 and 5 are exempt from the requirements of Section 140.3(a)1Aia if the roof assembly has a U-factor of 0.034 or lower.
EXCEPTION 2 to Section 140.3(a)1Aia: Roof constructions with a weight of at least 25 lb/ft² over the roof membrane are exempt from the requirements of Section 140.3(a)1Aia.
EXCEPTION 3 to Section 140.3(a)1Aia: An aged solar reflectance less than 0.63 is allowed provided the maximum roof/ceiling U-factor in TABLE 140.3 is not exceeded.
- In Climate Zones 1 and 3 shall have a minimum aged solar reflectance of 0.20 and a minimum thermal emittance of 0.75, or a minimum SRI of 16.
- In Climate Zones 2 and 4 through 16 shall have a minimum aged solar reflectance of 0.25 and a minimum thermal emittance of 0.80, or a minimum SRI of 23.
EXCEPTION to Section 140.3(a)1Aiia: Roof constructions with a weight of at least 25 lb/ft² over the roof membrane.
Aged Solar Reflectance | Metal Building Climate Zone 1-16 U-factor | Wood framed and Other Climate Zone 6 - 8 U-factor | Wood Framed and Other All Other Climate Zones U-factor |
0.62-0.56 | 0.038 | 0.045 | 0.032 |
0.55-0.46 | 0.035 | 0.042 | 0.030 |
0.45-0.36 | 0.033 | 0.039 | 0.029 |
0.35-0.25 | 0.031 | 0.037 | 0.028 |
EXCEPTION to Section 140.3(a)1A: Roof area covered by building integrated photovoltaic panels and building integrated solar thermal panels are not required to meet the minimum requirements for solar reflectance, thermal emittance, or SRI.
NOTE: Demising walls are not exterior walls, and therefore demising wall area is not part of the gross exterior wall area or display perimeter, and windows in demising walls are not part of the window area.
EXCEPTION to Section 140.3(a)5A: Conditioned greenhouses. The requirements of Section 120.6(h)4 apply.
EXCEPTION 1 to Section 140.3(a)5B: Conditioned greenhouses. The requirements of Section 120.6(h)4 apply.
EXCEPTION 2 to Section 140.3(a)5B: For vertical windows containing chromogenic type glazing:
For purposes of this paragraph, the Relative Solar Heat Gain Coefficient, RSHGC, of a vertical window is:
EXCEPTION 1 to Section 140.3(a)5C: An area-weighted average Relative Solar Heat Gain Coefficient of 0.56 or less shall be used for windows:
a. That are in the first story of exterior walls that form a display perimeter; and
b. For which codes restrict the use of overhangs to shade the windows.
EXCEPTION 2 to Section 140.3(a)5C: For vertical glazing containing chromogenic type glazing:
i. the lower-rate labeled RSHGC shall be used with automatic controls to modulate the amount of heat flow into the space in multiple steps in response to daylight levels or solar intensity; and
ii. chromogenic glazing shall be considered separately from other glazing; and
iii. area-weighted averaging with other glazing that is not chromogenic shall not be permitted.
EXCEPTION 3 to Section 140.3(a)5C: Conditioned greenhouses. The requirements of Section 120.6(h)4 apply.
NOTE: Demising walls are not exterior walls, and therefore windows in demising walls are not subject to SHGC requirements.
EXCEPTION 1 to Section 140.3(a)5D: When the window’s primary and secondary sidelit daylit zones are completely overlapped by one or more skylit daylit zones, then the window need not comply with Section 140.3(a)5D.
EXCEPTION 2 to Section 140.3(a)5D: If the window’s VT is not within the scope of NFRC 200, or ASTM E972, then the VT shall be calculated according to Reference Nonresidential Appendix NA6.
EXCEPTION 3 to Section 140.3(a)5D: For vertical windows containing chromogenic type glazing:
i. The higher-rate labeled VT shall be used with automatic controls to modulate the amount of light transmitted into the space in multiple steps in response to daylight levels or solar intensity; and
ii. Chromogenic glazing shall be considered separately from other glazing; and
iii. Area-weighted averaging with other glazing that is not chromogenic shall not be permitted.
EXCEPTION 4 to Section 140.3(a)5D: Conditioned greenhouses. The requirements of Section 120.6(h)4 apply.
NOTE: Demising walls are not exterior walls, and therefore windows in demising walls are not subject to VT requirements.
RSHGC = SHGC × [1 + a × (2.72-PF – 1) × (sin(b × Az) + c]
WHERE:
a | b | c | |
Overhang | 0.150 | 0.130 | 5.67 |
Exterior Horizontal Slat | 0.144 | 0.133 | 5.13 |
RSHGC = Relative Solar Heat Gain Coefficient.
SHGC = Solar Heat Gain Coefficient of the vertical fenestration.
Az = Azimuth of the vertical fenestration in degrees.
PF = Projection factor as calculated by Equation 140.3-C.
VT ≥ 0.11/ WWR
WHERE:
WWR = Window Wall Ratio, the ratio of (i) the total window area of the entire building to (ii) the total gross exterior wall area of the entire building. If the WWR is greater than 0.40, then 0.40 shall be used as the value for WWR in EQUATION 140.3-B.
VT = Visible Transmittance of framed window.
EXCEPTION 1 to Section 140.3(a)6A: Buildings with an atria over 55 feet high shall have a skylight area no greater than 10 percent of the gross exterior roof area.
EXCEPTION 2 to Section 140.3(a)6A: Conditioned greenhouses. The requirements of Section 120.6(h)4 apply.
EXCEPTION 1 to Section 140.3(a)6B: For skylights containing chromogenic type glazing:
i. the lower-rate labeled U-factor shall be used with automatic controls to modulate the amount of heat flow into the space in multiple steps in response to daylight levels or solar intensity; and
ii. chromogenic glazing shall be considered separately from other glazing; and
iii. area-weighted averaging with other glazing that is not chromogenic shall not be permitted.
EXCEPTION 2 to Section 140.3(a)6B: Conditioned greenhouses. The requirements of Section 120.6(h)4 apply.
EXCEPTION 1 to Section 140.3(a)6C: For skylights containing chromogenic type glazing:
i. the lower-rated labeled SHGC shall be used to demonstrate compliance with this section; and
ii. chromogenic glazing shall be considered separately from other glazing; and
iii. area-weighted averaging with other glazing that is not chromogenic shall not be permitted.
EXCEPTION 2 to Section 140.3(a)6C: Conditioned greenhouses. The requirements of Section 120.6(h)4 apply.
EXCEPTION 1 to Section 140.3(a)6D: For skylights containing chromogenic type glazing:
i. the higher-rated labeled VT shall be used with automatic controls to modulate the amount of light transmitted into the space in multiple steps in response to daylight levels or solar intensity and;
ii. chromogenic glazing shall be considered separately from other glazing; and
iii. area-weighted averaging with other glazing that is not chromogenic shall not be permitted.
EXCEPTION 2 to Section 140.3(a)6D: Conditioned greenhouses. The requirements of Section 120.6(h)4 apply.
EXCEPTION 1 to Section 140.3(a)6E: Skylights designed and installed to exclude direct sunlight entering the occupied space by the use of fixed or automated baffles or the geometry of the skylight and light well.
EXCEPTION 2 to Section 140.3(a)6E: Conditioned greenhouses. The requirements of Section 120.6(h)4 apply.
EXCEPTION to Section 140.3(a)9: Relocatable Public School Buildings.
EXCEPTION to Section 140.3(a)9Bi: Materials in TABLE 140.3-A shall be deemed to comply with Section 140.3(a)9B provided that all joints are sealed and all of the materials are installed as air barriers in accordance with the manufacturer's instructions.
EXCEPTION to Section 140.3(a)9Bii: The following materials shall be deemed to comply with Section 140.3(a)9B if all joints are sealed and all of the materials are installed as air barriers in accordance with the manufacturer's instructions:
a. Concrete masonry walls that have at least two coatings of paint or at least two coatings of sealer coating.
b. Concrete masonry walls with integral rigid board insulation.
c. Structurally insulated panels.
d. Portland cement or Portland sand parge, or stucco, or a gypsum plaster, each with minimum 1/2 inch thickness.
I. The entire floor area of all stories that have any spaces directly under a roof.
II. The entire floor area of all stories that have a building entrance or loading dock.
III. Representative above grade wall sections of the building totaling at least 25% of the wall area enclosing the remaining conditioned space. Floor areas in parts a. and b. above shall not be included in the 25%.
MATERIALS | MINIMUM THICKNESS | |
1 | Plywood | Minimum 3/8inches thickness |
2 | Oriented strand board | Minimum 3/8 inches thickness |
3 | Extruded polystyrene insulation board | Minimum 1/2 inches thickness |
4 | Foil-backed polyisocyanurate insulation board | Minimum 1/2 inches thickness |
5 | Closed cell spray foam with a minimum density of 2.0 pcf | Minimum 2 inches thickness |
6 | Open cell spray foam with a density no less than 0.4 pcf and no greater than 1.5 pcf | Minimum 5-1/2 inches thickness |
7 | Exterior and interior gypsum board | Minimum 1/2 inches thickness |
8 | Cement board | Minimum 1/2 inches thickness |
9 | Built up roofing membrane | No minimum thickness |
10 | Modified bituminous roof membrane | No minimum thickness |
11 | Fully adhered single-ply roof membrane | No minimum thickness |
12 | A Portland cement or Portland sand parge, or a gypsum plaster | Each with Minimum 5/8 inches thickness |
13 | Cast-in-place concrete, or precast concrete | No minimum thickness |
14 | Fully grouted concrete block masonry | No minimum thickness |
15 | Sheet steel or sheet aluminum | No minimum thickness |
Climate Zone | ||||||||||||||||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | |||||
Maximum U-factor | Roofs/ Ceilings | Metal Building | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | ||
Wood Framed and Other | 0.034 | 0.034 | 0.034 | 0.034 | 0.034 | 0.049 | 0.049 | 0.049 | 0.034 | 0.034 | 0.034 | 0.034 | 0.034 | 0.034 | 0.034 | 0.034 | ||||
Walls | Metal Building | 0.113 | 0.061 | 0.113 | 0.061 | 0.061 | 0.113 | 0.113 | 0.061 | 0.061 | 0.061 | 0.061 | 0.061 | 0.061 | 0.061 | 0.057 | 0.061 | |||
Metal-framed | 0.060 | 0.055 | 0.071 | 0.055 | 0.055 | 0.060 | 0.060 | 0.055 | 0.055 | 0.055 | 0.055 | 0.055 | 0.055 | 0.055 | 0.055 | 0.055 | ||||
Mass Light1 | 0.196 | 0.170 | 0.278 | 0.227 | 0.440 | 0.440 | 0.440 | 0.440 | 0.440 | 0.170 | 0.170 | 0.170 | 0.170 | 0.170 | 0.170 | 0.170 | ||||
Mass Heavy1 | 0.253 | 0.650 | 0.650 | 0.650 | 0.650 | 0.690 | 0.690 | 0.690 | 0.690 | 0.650 | 0.184 | 0.253 | 0.211 | 0.184 | 0.184 | 0.160 | ||||
Wood-framed and Other | 0.095 | 0.059 | 0.110 | 0.059 | 0.102 | 0.110 | 0.110 | 0.102 | 0.059 | 0.059 | 0.045 | 0.059 | 0.059 | 0.059 | 0.042 | 0.059 | ||||
Floors/ Soffits | Raised Mass | 0.092 | 0.092 | 0.269 | 0.269 | 0.269 | 0.269 | 0.269 | 0.269 | 0.269 | 0.269 | 0.092 | 0.092 | 0.092 | 0.092 | 0.092 | 0.058 | |||
Other | 0.048 | 0.039 | 0.071 | 0.071 | 0.071 | 0.071 | 0.071 | 0.071 | 0.071 | 0.071 | 0.039 | 0.071 | 0.071 | 0.039 | 0.039 | 0.039 | ||||
Roofing Products | Low-sloped | Aged Solar Reflectance | 0.63 | 0.63 | 0.63 | 0.63 | 0.63 | 0.63 | 0.63 | 0.63 | 0.63 | 0.63 | 0.63 | 0.63 | 0.63 | 0.63 | 0.63 | 0.63 | ||
Thermal Emittance | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | ||||
Steep Sloped | Aged Solar Reflectance | 0.20 | 0.25 | 0.20 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | |||
Thermal Emittance | 0.75 | 0.80 | 0.75 | 0.80 | 0.80 | 0.80 | 0.80 | 0.80 | 0.80 | 0.80 | 0.80 | 0.80 | 0.80 | 0.80 | 0.80 | 0.80 | ||||
REQ | REQ | REQ | REQ | REQ | REQ | REQ | REQ | REQ | REQ | REQ | REQ | REQ | REQ | REQ | REQ | |||||
Exterior Doors, Maximum U-factor | Non-Swinging | 0.50 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 0.50 | |||
Swinging | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 |
Fenestration | Climate Zone | ||||||||||||||||||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | ||||||||
Vertical | Fixed Window | ||||||||||||||||||||||
Area-weighted Performance Rating | Max U-factor | 0.36 | 0.36 | 0.36 | 0.36 | 0.36 | 0.36 | 0.36 | 0.36 | 0.34 | 0.36 | 0.34 | 0.34 | 0.34 | 0.34 | 0.34 | 0.36 | ||||||
Max RSHGC | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.22 | 0.25 | 0.22 | 0.22 | 0.22 | 0.22 | 0.22 | 0.25 | |||||||
Min VT | 0.42 | ||||||||||||||||||||||
Curtainwall or Storefront | |||||||||||||||||||||||
Max U-factor | 0.38 | 0.41 | 0.41 | 0.41 | 0.41 | 0.41 | 0.38 | 0.41 | 0.41 | 0.41 | 0.41 | 0.41 | 0.41 | 0.41 | 0.41 | 0.41 | |||||||
Max RSHGC | 0.25 | 0.26 | 0.26 | 0.26 | 0.26 | 0.26 | 0.25 | 0.26 | 0.26 | 0.26 | 0.26 | 0.26 | 0.26 | 0.26 | 0.26 | 0.26 | |||||||
Min VT | 0.46 | ||||||||||||||||||||||
Operable Window | |||||||||||||||||||||||
Max U-factor | 0.46 | ||||||||||||||||||||||
Max RSHGC | 0.22 | ||||||||||||||||||||||
Min VT | 0.32 | ||||||||||||||||||||||
Glazed Doors | |||||||||||||||||||||||
Max U-factor | 0.45 | ||||||||||||||||||||||
Max RSHGC | 0.23 | ||||||||||||||||||||||
Min VT | 0.17 | ||||||||||||||||||||||
Max WWR% | 40% | ||||||||||||||||||||||
All Climate Zones | |||||||||||||||||||||||
Skylights | Glass, Curb Mounted | Glass, Deck Mounted | Plastic, Curb Mounted | Tubular Daylighting Devices (TDDs) | |||||||||||||||||||
Area-Weighted | Max U-factor | 0.58 | 0.46 | 0.88 | 0.88 | ||||||||||||||||||
Max SHGC | 0.25 | 0.25 | NR | NR | |||||||||||||||||||
Min VT (Min VTannual for TDDs) | 0.49 | 0.49 | 0.64 | 0.38 | |||||||||||||||||||
Maximum SRR% | 5% |
Climate Zone | |||||||||||||||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | ||||
Maximum U-factor | Roofs / Ceilings | Metal Building | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | 0.041 | |
Wood Framed and Other | 0.028 | 0.028 | 0.034 | 0.028 | 0.034 | 0.034 | 0.039 | 0.028 | 0.028 | 0.028 | 0.028 | 0.028 | 0.028 | 0.028 | 0.028 | 0.028 | |||
Walls | Metal Building | 0.061 | 0.061 | 0.061 | 0.061 | 0.061 | 0.061 | 0.061 | 0.061 | 0.061 | 0.061 | 0.057 | 0.057 | 0.057 | 0.057 | 0.057 | 0.057 | ||
Metal-framed | 0.069 | 0.069 | 0.069 | 0.069 | 0.069 | 0.069 | 0.105 | 0.069 | 0.069 | 0.069 | 0.069 | 0.069 | 0.069 | 0.069 | 0.048 | 0.069 | |||
Mass, Light1 | 0.170 | 0.170 | 0.170 | 0.170 | 0.170 | 0.227 | 0.227 | 0.227 | 0.196 | 0.170 | 0.170 | 0.170 | 0.170 | 0.170 | 0.170 | 0.170 | |||
Mass, Heavy1 | 0.160 | 0.160 | 0.160 | 0.184 | 0.211 | 0.690 | 0.690 | 0.690 | 0.690 | 0.690 | 0.184 | 0.253 | 0.211 | 0.184 | 0.184 | 0.160 | |||
Wood-framed and Other | 0.059 | 0.059 | 0.059 | 0.059 | 0.059 | 0.059 | 0.059 | 0.059 | 0.059 | 0.059 | 0.042 | 0.059 | 0.059 | 0.042 | 0.042 | 0.042 | |||
Floors / Soffits | Raised Mass1 | 0.045 | 0.045 | 0.058 | 0.058 | 0.058 | 0.069 | 0.092 | 0.092 | 0.092 | 0.069 | 0.058 | 0.058 | 0.058 | 0.045 | 0.058 | 0.037 | ||
Other | 0.034 | 0.034 | 0.039 | 0.039 | 0.039 | 0.039 | 0.071 | 0.039 | 0.039 | 0.039 | 0.039 | 0.039 | 0.039 | 0.034 | 0.039 | 0.034 | |||
Roofing | Low-sloped | Aged Solar Reflectance | NR | NR | NR | NR | NR | NR | NR | NR | 0.55 | 0.55 | 0.55 | NR | 0.55 | 0.55 | 0.55 | NR | |
Thermal Emittance | NR | NR | NR | NR | NR | NR | NR | NR | 0.75 | 0.75 | 0.75 | NR | 0.75 | 0.75 | 0.75 | NR | |||
Steep- Sloped | Aged Solar Reflectance | NR | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | NR | ||
Thermal Emittance | NR | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0. 75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | NR | |||
REQ | REQ | REQ | REQ | REQ | REQ | NR | REQ | REQ | REQ | REQ | REQ | REQ | REQ | REQ | REQ | ||||
Exterior Doors, Maximum U-factor | Non-Swinging | 0.50 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 1.45 | 0.50 | ||
Swinging | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 |
Fenestration | All Climate Zones | |||||||
Fixed | Operable | Curtainwall/ | Glazed | |||||
Vertical | Area-Weighted Performance Rating | Max | 0.36 | 0.46 | 0.41 | 0.45 | ||
Max RSHGC | 0.25 | 0.22 | 0.26 | 0.23 | ||||
Area-Weighted Performance Rating | Min VT | 0.42 | 0.32 | 0.46 | 0.17 | |||
Maximum WWR% | 40% | |||||||
Skylights | Glass, Curb Mounted | Glass, Deck Mounted | Plastic, Curb Mounted | |||||
Area-Weighted Performance Rating | Max | 0.58 | 0.46 | 0.88 | ||||
Max SHGC | 0.25 | 0.25 | NR | |||||
Area-Weighted Performance Rating | Min VT | 0.49 | 0.49 | 0.64 | ||||
Maximum SRR% | 5% | |||||||
Notes: 1. As defined in Section 100.1, light mass walls are walls with a heat capacity of at least 7.0 Btu/ft²-oF and less than 15.0 Btu/ft²-oF. Heavy mass walls are walls with a heat capacity of at least 15.0 Btu/ft²-oF. 2. Glazed Doors applies to both site-built and to factory-assembled glazed doors. |
Roofs/ Ceilings | Metal Buildings | Maximum U-factor | 0.041 |
Roofs/ Ceilings | Non-Metal Buildings | Maximum U-factor | 0.034 |
Walls | Wood frame buildings | Maximum U-factor | 0.042 |
Walls | Metal frame buildings | Maximum U-factor | 0.057 |
Walls | Metal buildings | Maximum U-factor | 0.057 |
Walls | Mass/7.0≤ HC | Maximum U-factor | 0.170 |
Walls | All Other Walls | Maximum U-factor | 0.059 |
Floors and Soffits | Floors and Soffits | Maximum U-factor | 0.048 |
Roofing Products | Low-Sloped | Aged Solar Reflectance | 0.63 |
Roofing Products | Low-Sloped | Thermal Emittance | 0.75 |
Roofing Products | Steep-Sloped | Aged Solar Reflectance | 0.25 |
Roofing Products | Steep-Sloped | Thermal Emittance | 0.80 |
Fenestration | Windows | Maximum U-factor | 0.47 |
Fenestration | Windows | Maximum SHGC | 0.26 |
Fenestration | Glazed Doors(Site-Built and Factory Assembled) | Maximum U-factor | 0.45 |
Fenestration | Glazed Doors(Site-Built and Factory Assembled) | Maximum SHGC | 0.23 |
Fenestration | Skylights | Glass with Curb Maximum U-factor | 0.99 |
Fenestration | Skylights | Glass without Curb Maximum U-factor | 0.57 |
Fenestration | Skylights | Plastic with Curb Maximum U-factor | 0.87 |
Fenestration | Skylights | Glass Type 0-2% SRR Maximum SHGC | 0.46 |
Fenestration | Skylights | Glass Type 2.1-5% SRR Maximum SHGC | 0.36 |
Fenestration | Skylights | Plastic Type 0-2% SRR Maximum SHGC | 0.69 |
Fenestration | Skylights | Plastic Type 2.1-5% SRR Maximum SHGC | 0.57 |
Exterior Doors | Non-Swinging doors | Maximum U-factor | 0.50 |
Exterior Doors | Swinging doors | Maximum U-factor | 0.70 |
EXCEPTION 1 to Section 140.3(c): Auditoriums, churches, movie theaters, museums and refrigerated warehouses.
EXCEPTION 2 to Section 140.3(c): In buildings with unfinished interiors, future enclosed spaces for which there are plans to have:
- A floor area of less than or equal to 5,000 square feet, or
- Ceiling heights of less than or equal to 15 feet.
This exception shall not be used for S-1 or S-2 (storage), or for F-1 or F-2 (factory) occupancies.
EXCEPTION 3 to Section 140.3(c): Enclosed spaces having a designed general lighting system with a lighting power density less than 0.5 watts per square foot.
EXCEPTION 4 to Section 140.3(c): Enclosed spaces where it is documented that permanent architectural features of the building, existing structures or natural objects block direct beam sunlight on at least half of the roof over the enclosed space for more than 1500 daytime hours per year between 8 a.m. and 4 p.m.
EXCEPTION to Section 140.3(d)2D: Where it is documented that existing adjacent structures or natural objects within view of the vertical fenestration block direct sunlight onto the vertical fenestration between 8 a.m. and 5 p.m. for less than 500 daytime hours per year.
EXCEPTION to Section 140.3(d)2F: Horizontal slats with a Visible Transmittance of 0.03 or less when tested as specified in ASTM E1175.
EXCEPTION to Section 140.3(d)2H: Where the slats are located entirely within the vertical fenestration’s rough opening or a fin is located at the window jambs and extends vertically the entire height of the window jamb and extends horizontally the entire depth of the projection.
EXCEPTION to Section 140.3(d)3E: Where it is documented that existing adjacent structures or natural objects within view of the vertical fenestration block direct sunlight onto the vertical fenestration between 8 a.m. and 5 p.m. for less than 750 daytime hours per year.
EXCEPTION to Section 140.3(d)3F: Where an exterior light shelf is installed greater than two feet below the clerestory sill.
Daylighting Device
|
Orientation of the Vertical Fenestration
|
Projection Factor
|
Horizontal Slats
|
East or West
|
2.0 to 3.0
|
Interior Light Shelf
|
South
|
1.0 to 2.0
|
Exterior Light Shelf
|
South |
0.25 to 1.25
|
Projection Factor = | Projection / Spacing |
Distance Factor = | D / (HAS × Projection Factor) |
WHERE : | |
Projection = | The horizontal distance between the base edge and the projected edge of the overhang, slat, or light shelf. |
Spacing = | For overhangs, the vertical distance between the projected edge of the overhang and sill of the vertical fenestration below it. For horizontal slats, the vertical distance between the projected edge of a slat to the base edge of the slat below it. For interior light shelves, the vertical distance between the projected edge of the light shelf and head of the clerestory fenestration above it. For exterior light shelves, the vertical distance between the projected edge of the light shelf and sill of the vertical fenestration below it. |
D = | Distance between the existing structure or nature object and the fenestration |
HAS = | Height difference between the top of the existing structure or nature object and the bottom of the fenestration |
NOTE: | The base edge is the edge of an overhang, slat, or light shelf that is adjacent to the vertical fenestration. The projected edge is the opposite edge from the base edge. |
NOTE: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code. Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8, and 25943, Public Resources Code.