Page 487 - 2018_IRC

ENERGY EFFICIENCY

VENTILATION. The natural or mechanical process of sup- N1101.7 (R301.1) Climate zones. Climate zones from Fig-
plying conditioned or unconditioned air to, or removing such ure N1101.7 or Table N1101.7 shall be used for determining
air from, any space. the applicable requirements in Sections N1101 through
VENTILATION AIR. That portion of supply air that comes N1111. Locations not indicated in Table N1101.7 shall be
from outside (outdoors) plus any recirculated air that has been assigned a climate zone in accordance with Section
treated to maintain the desired quality of air within a designated N1101.7.2.
space. N1101.7.1 (R301.2) Warm humid counties. In Table
VISIBLE TRANSMITTANCE [VT]. The ratio of visible N1101.7 warm humid counties are identified by an aster-
light entering the space through the fenestration product isk.
assembly to the incident visible light, Visible Transmittance, N1101.7.2 (R301.3) International climate zones. The
includes the effects of glazing material and frame and is climate zone for any location outside the United States
expressed as a number between 0 and 1. shall be determined by applying Table N1101.7.2(1) and
WHOLE HOUSE MECHANICAL VENTILATION SYS- then Table N1101.7.2(2).
TEM. An exhaust system, supply system, or combination N1101.8 (R301.4) Tropical climate zone. The tropical cli-
thereof that is designed to mechanically exchange indoor air mate zone shall be defined as:
with outdoor air when operating continuously or through a 1. Hawaii, Puerto Rico, Guam, American Samoa, US Vir-
programmed intermittent schedule to satisfy the whole house gin Islands, Commonwealth of Northern Mariana
ventilation rates. Islands; and
ZONE. A space or group of spaces within a building with heat- 2. Islands in the area between the Tropic of Cancer and
ing or cooling requirements that are sufficiently similar so that the Tropic of Capricorn.
desired conditions can be maintained throughout using a single
controlling device.

462 2018 INTERNATIONAL RESIDENTIAL CODE ®
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