Fire Protection of Services Openings ~ penetration of compartment
walls and floors (zones of restricted fire spread, e.g. flats in one
building), by service pipes and conduits is very difficult to avoid.
An exception is where purpose built service ducts can be
accommodated. The Building Regulations, Approved Document B3:
Sections 7 [Vol. 1] and 10 [Vol. 2] determines that where a pipe
passes through a compartment interface, it must be provided with
a proprietary seal. Seals are collars of intumescent material which
expands rapidly when subjected to heat, to form a carbonaceous
charring. The expansion is sufficient to compress warm plastic and
successfully close a pipe void for up to 4 hours.In some circumstances fire stopping around the pipe will be
acceptable, provided the gap around the pipe and hole through the
structure are filled with non-combustible material. Various
materials are acceptable, including reinforced mineral fibre, cement
and plasters, asbestos rope and intumescent mastics.Pipes of low heat resistance, such as PVC, lead, aluminium alloys
and fibre cement may have a protective sleeve of non-combustible
material extending at least 1 m either side of the structure.Services---Fire Stops and Seals