12 . PERFORMANCE OF CONSTRUCTION MATERIALS UNDER FIRE
12.1 Mineral wool versus other types of insulation
Mineral wool is an insulation that has low thermal conductivity , minimizes heat conduction and is a key component used in many firestop systems as a backing material for the firestop sealant to be installed against when you have larger annular space .
The reason for its popularity as an ideal firestop backing material is that it does not conduct heat and can resist temperatures over 1,000 ° C . Since its density is over three times more than fiberglass insulation , mineral wool also offers better accoustic insulation properties . Other materials used on site for insulation purposes like foam , fiberglass insulation , backer rods , etc ., usually burn easily and quickly in the event of a fire , thus are not suitable alternatives to mineral wool . When inspecting firestopping applications , it is imperative that the proper backing material is installed , including the proper orientation and compression , per the listed firestop system .
12.2 Combustible and non-combustible pipes
Combustible and non-combustible pipes differ when exposed to fire due to the difference in their flammable properties .
Combustible pipes like plastic pipes ( PVC ) burn away creating a hole / opening in place of the pipe . Combustible pipe penetrations generally require intumescent materials to properly firestop around the penetration . These could be an intumescent sealant or intumescent device such as a firestop collar or firestop cast-in device . Intumescent products consist of materials which rapidly expands when exposed to fire and seals or closes the annular space around the combustible pipe as it burns away .
Non-combustible pipes like metallic pipes does not burn . They melt leaving a char or residue behind . For non-combustible pipes , non-intumescent products such as flexible or elastomeric firestop sealants are generally sufficient to properly firestop a non-combustible pipe penetration . Always refer to a tested UL firestop system or engineering judgment which will identify the appropriate firestopping products to be installed for the specific application .
12.3 Compatibility with CPVC pipes
Chlorinated polyvinyl chloride ( CPVC ) is a thermoplastic produced by chlorination of polyvinyl chloride ( PVC ) resin . CPVC is significantly more flexible than PVC , has greater insulating properties than copper and can also withstand higher temperatures .
CPVC is easy to work with , including machining , welding and forming processes . It offers high corrosion resistance at elevated temperatures and it can be bent , shaped and welded , making it a better choice for wide variety of processes and applications . It also has fire-retardant properties .
When firestopping CPVC pipes , care must be taken not to allow the pipe to be exposed to any material that may result in a failure . Some sealant may contain phthalates and phosphate esters which can have an interaction with the CPVC pipe , which can then cause it to weaken , split or crack . Therefore , it is important that the products that are used in conjunction with these CPVC piping systems do not contain any of these components and are chemically compatible .
Inspection Guidebook 26 / 28