Where a building element is penetrated by a service, fire collars are installed around pipes and other penetrations so that it does not compromise the fire resistance level (FRL) of the building element (wall or floor) the pipes pass through.
These collars are made to be cast into a concrete slab or retro fitted to the outside of a wall or floor.
There are two tests for fire collars. The stack test and the floor waste test.
The important difference between these tests is:
The floor waste test has thermocouples placed on an open part of the grate.
Whereas, the stack test has 2 meters of pipe on the non-fire side and has thermocouples placed in an insulated position on the outside of the pipe, 25mm from the wall or floor.
Common sense tells you, having a thermocouple over an open grate in the fire and smoke stream will detect more heat in a shorter time than it will in the insulated position of the outside of the pipe.
This is why collars that pass the stack test may not pass the floor waste test.
Whereas collars that pass the floorwaste test will always pass the stack test.
Prior to the introduction of the SNAP spring and mesh systems five years ago, fire collars relied solely on an intumescent material, which, when exposed to heat, swelled around the heat softened plastic pipe, eventually closing the opening.
The Snap system ensures the pipe is closed very quickly, more definitely, and resists shock waves better than any intumescent only collar, yet is no more expensive than inferior intumescent only collars.