BCAB #1016 - Firestopping & Blocking, Articles 18.104.22.168., 22.214.171.124. and 126.96.36.199.
August 19, 1988
Re: Firestopping & Blocking, Articles 188.8.131.52., 184.108.40.206. and 220.127.116.11.
With reference to your letter of June 15, 1988 requesting interpretations of the Building Code.
Our decisions on the three questions raised are as follows:
Article 18.104.22.168. makes firestops in drop ceilings mandatory, where the exposed construction material within the concealed space has a flame-spread rating greater than 25. Wood frame construction would fall within this category.
While Article 22.214.171.124. is not specific on firestopping joist openings from a dwelling unit into a garage, we agree with the inspector on this issue. The principle in Article 126.96.36.199. supports his interpretation, and justifies firestops.
We find nothing to support a general requirement for intermediate blocking in loadbearing wood stud walls. While this is undoubtedly beneficial, it is not mandatory. It is stated that the blocking reduces twisting and bowing as the studs dry out, and we have no dispute with this statement, but must assume that if the moisture content of the studs complies with the limit of 19 per cent in Article 188.8.131.52. at the time of installation, then the Code considers subsequent distortion to fall within acceptable tolerances.
J.C. Currie, Chair