- Q. When we build homes, we drill numerous holes through wall plates and subfloor assemblies for wiring, plumbing, and hvac ducts. Are there any code requirements for sealing the gaps around these penetrations?
A.Redwood Kardon responds: The model codes are clear about sealing pipe and cable penetrations through draft stops or fire-rated assemblies. The two codes I am familiar with, theUniform Building Code(1994 UBC, sections 708 & 709) and CABO’s One and Two Family Dwelling Code (section 602.7), state that fire-rated assemblies must be sealed with a noncombustible material. One such material is Flame-X (Firestops Systems, 12187 Industrial Rd., Surrey, BC V3V 3S1, Canada; 604/580-1788), a gunnable one-component sealant that meets code requirements.
This provision is intended to prevent fire-carrying drafts from communicating between floors, under stairs, or through large concealed spaces. In practice, however, many jurisdictions do not enforce this regulation when the wall cavities are sufficiently insulated to retard drafts between fire stops ( UBC , section 708.3.1) or fire-rated assemblies ( UBC , Table 7-B).
In many areas, local energy efficiency requirements stipulate that conditioned spaces be sealed from nonconditioned spaces. Standard sealant can be used if the penetrations are not located within a fire stop or a fire-rated assembly.
Redwood Kardon is a building inspector for the City of Oakland, Calif., and author of Code Check , a field guide to building a safe home. An online version of Code Check can be found on the Web at www.codecheck.com.