BCAB #1055A - Ventilation in Crawl Space

July 21, 1989

BCAB #1055A

Re: Ventilation in Crawl Space

With reference to your letter of April 17, 1989 dealing further with our decision #1055.

As we indicated previously, if a crawl space is treated as part of the heated enclosure, and ventilated to the same extent as is required for occupied spaces, then this would be acceptable. We do not include design checks within our functions, but will make a suggestion to resolve your problems. From your letter it would appear that you may be having difficulty with the provisions of Article 9.33.3.5., which requires control by a centrally located dehumidistat. We do not take this to mean a location centrally in the building, but a location central to the operational needs of the system, from which it can respond reasonably effectively to conditions throughout the area covered by the system. In your situation this includes the crawl space.

To avoid further correspondence on this matter, which has now included three appeals, we recommend that the problem be discussed jointly with technical staff from the Building Standards Branch and the authority having jurisdiction in your particular area of concern.