Existing Firewall

[dooleybob41]

I’m reviewing firewall requirements for an existing hospital building. There is a 4-hour rated wall that was created as part of an addition where the addition abuts an existing building. The addition was done in 1981 under the 1979 UBC, and is noted as being of construction Type I. The existing building is identified as being of Type II 1-Hour. Since these two are of different construction types, both IBC and NFPA require a firewall be provided between them (IBC Table 707.3.10 calls for 3-hour firewall). The nature of a firewall as identified in both the IBC and NFPA requires that it be self-supporting. The 4-hour wall that was created as part of the addition is 8” CMU, and is not self-supporting. I don’t have a copy of the 1979 UBC, but am wondering if at that time the 4-hour wall provided met the requirements for a firewall.

 

[RLGA]

The UBC did not have fire walls--they used the term "area separation walls" and the requirements were very minimal. There was no requirement for structural stability in the UBC like there is now in the IBC.