(a) Unheated Crawl Space. A crawl space is considered unheated unless it is:
(1) Provided with a positive heat supply equivalent to at least ten percent of the total calculated heat loss of the living unit; or
(2) Contains uninsulated ducts or piping; or
(3) Is used as a supply or return plenum.
(b) Crawl Space Plenums. When a crawl space is used as a supply or return plenum, the perimeter walls shall be insulated with material providing R-values as follows:
Supply Plenum R-7; Return Plenum R-7.
(Ord. 2025-74. Passed 3-5-74.)