ASHRAE-90.1-2022- - Page 060

Extracted Content

2. For semiheated spaces, nonswinging doors that are horizontally hinged sectional doors with a single row of fenestration shall have an assembly U-factor less than or equal to 0.440 in Climate Zones 3 through 6 and less than or equal to 0.360 in Climate Zones 7 and 8, provided the fenes- tration area is at least 14% and no more than 25% of the total door area .

5.5.4 Fenestration 5.5.4.1 General. Compliance with U-factors, SHGC, and VT / SHGC shall be demonstrated for the overall fenestration product. Gross wall areas and gross roof areas shall be calculated separately for each space conditioning category for the purposes of determining compliance.

Exceptions to 5.5.4.1:

1. If there are multiple assemblies within a single class of construction for a single space condition- ing category, it shall be permitted to demonstrate compliance based on a n area-weighted average U-factor, SHGC, VT / SHGC, or LSG . The area-weighted average across multiple classes of con- struction or multiple space conditioning categories shall not be permitted for use to demonstrate compliance.
2. Vertical fenestration shall be permitted to demonstrate compliance based on an area-weighted average U-factor, SHGC, VT / SHGC, or LSG across multiple classes of construction for a single space conditioning category, but not across multiple space conditioning categories .

Exception to 5.5.4.2.1: Vertical fenestration complying with Section 5.5.4.4.1, Exception 3.

5.5.4.2.2 Maximum Skylight Fenestration Area. The total skylight area shall not be greater than that specified in Tables 5.5-0 through 5.5-8.

Exception to 5.5.4.2.2: The total skylight area is permitted to be increased to no greater than 6% of the

gross roof area, provided the skylights meet all of the criteria in Section 5.5.4.4.2, Exception 1 and the total daylight area under skylights is a minimum of half the floor area of the space .

5.5.4.2.3 Minimum Skylight Fenestration Area. In any enclosed space in a building that is

a. 2500 ft [2] and greater; b. directly under a roof with ceiling heights greater than 15 ft; and c. one of the following space types: office, lobby, atrium, concourse, corridor, storage (including nonrefriger ated warehouse), gymnasium, fitness/exercise area, playing area, gymnasium seating area, convention exhibit/event space, courtroom, automotive service, fire station engine room, manufacturing corridor/ transition and bay areas, retail, library reading and stack areas, distribution/sorting area, transportation baggage and seating areas, or workshop, the total daylight area under skylights shall be a minimum of half the floor area and either

1. provide a minimum skylight area to daylight area under skylights of 3% with a skylight VT of at least 0.40 or
2. provide a minimum skylight effective aperture of at least 1%.

These skylights shall have a glazing material or diffuser with a measured haze value greater than 90% when tested according to ASTM D1003. General lighting in the daylight area shall be controlled as described in Section 9.4.1.1(f).

Exceptions to 5.5.4.2.3:

1. Enclosed spaces in Climate Zones 6 through 8.
2. Enclosed spaces where it is documented that existing structures or natural objects block directbeam 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.
3. Enclosed spaces where the daylight area under roof monitors is greater than 50% of the enclosed space floor area.
4. Enclosed spaces where it is documented that 90% of the skylight area is shaded on June 21 in the Northern Hemisphere (December 21 in the Southern Hemisphere) at noon by permanent architectural features of the building.
5. Enclosed spaces where the total area minus the primary sidelighted area and secondary side- lighted area is less than 2500 ft [2] and where the lighting is controlled according to sidelighting requirements described in Section 9.4.1.1(e).

58 ANSI/ASHRAE/IES Standard 90.1-2022 (I-P)