There are many types of plastic pipes in the construction industry. UPVC, CPVC, HDPE, PEX, PEX-AL-PEX, PP, PP-R to name a few. They are all acronyms for different types of combustible plastic pipe used to carry different water or gas supply around buildings. There are so many that one could forgive you for not knowing the ins and outs of each different type of plastic. There is one type of plastic used for pipes that does need some extra consideration when it comes to having other materials come into contact with the plastic.

The particular one we’re referring to is the orange CPVC pipe found often in sprinkler systems. Commonly known brands within the industry such as FlowGuard Gold, BlazeMaster and Corzan or FlameGuard, LabWaste and EverTuff, are all made from CPVC.

There are many benefits to using the chlorinated polyvinyl chloride (CPVC) pipe and fittings according to the manufacturers of these piping systems. Some of these claimed benefits include:

• Better durability and long service life due to the ability to avoid corrosion and scale build-up over traditional steel pipes.
• Superior flow due to the pipe's ability to reduce loss of pressure which typically increases over time in steel pipes with scale and corrosion build up.
• Chlorine Resistance — water treatment processes commonly use chlorine to treat drinking water which can be detrimental to the inside of steel pipes, which over time can cause the pipes to become thinner and as the material loses strength is more susceptible to leaks.
• Easier to install and handle on site due to the pipes being lightweight and not requiring heavy equipment to join the pipes due to the CPVC systems using a low VOC solvent cement.
• Ability to save costs due to installation efficiencies and a more stable material cost than the ever-fluctuating steel prices.

Whilst there are many considerations to whether steel or CPVC sprinkler systems are most suitable to your project, there is another factor that needs to be considered when using a CPVC sprinkler system, and it relates to the chemical compatibility of materials that may come in contact with the CPVC pipe.

So, where would you see materials come onto contact with the pipe, you may ask? Treatment of the pipes where they pass through fire rated walls is a common area for the pipe to need a specific firestopping treatment to re-instate the fire compartment once a service has penetrated it. This often involves a fire rated sealant coming in direct contact with the pipe.

Degradation can occur in CPVC pipe materials when the compounding ingredients used to manufacture the pipe are altered or destroyed. Degradation can occur due to prolonged exposure to conditions in excess of the recommended temperature, pressure and chemical concentration of the pipe which harm the base compounding additives in the pipe. Using a non-compatible sealant or silicone to fill the gap around the pipe can cause what is known to be Environmental Stress Cracking (ESC). ESC is an issue from which a chemical (possibly a weak solvent or even a non-solvent) achieves an extremely localised weakening at the surface of the material which permits propagation of a crack commonly causing the system to leak and be ineffective.

Therefore it is critical that any firestopping sealant that is used on CPVC products is checked for both chemical compatibility, and of course like all firestopping products, evidence that the product has been tested in accordance with AS1530.4:2014 & AS4072.1-2005 that it meets the required fire resistance level for the desired application.

BOSS FireMastic-HPE is a graphite-based, high pressure exerting fire rated sealant used to reinstate the fire resistance performance of wall, floor and ceiling systems treating a variety of plumbing, electrical and HVAC services. BOSS Fire have undergone a rigorous testing regime on CPVC pipe systems in a number of fire rated wall substrates. In a fire scenario FireMastic-HPE will expand with enough pressure to close combustible pipes and provide a high performance firestopping method of up to FRR -/120/120.

To avoid any issues with the CPVC Sprinkler Systems, manufacturers of CPVC piping systems have developed their own scheme and testing facilities which allow sealant manufacturers to send their products off to be tested for chemical compatibility with the CPVC manufacturers piping products. Once a product has been tested and is found to be suitable for use with the manufacturers CPVC piping system is gets added by the pipe manufacturer to their list of approved compatible products.

The two major manufacturers of CPVC piping systems have both approved BOSS FireMastic-HPE as being chemically compatible with their associated brands of piping.

FBC System Compatible:

FBC System Compatible indicates that this product has been tested, and is monitored on an ongoing basis, to assure its chemical compatibility with FlowGuard Gold, BlazeMaster and Corzan piping systems and products made with TempRite Technology*. 

BOSS FireMastic-HPE is FBC system compatible.

Spears System Compatible

Spears laboratory testing has shown FireMastic-HPE to be compatible with satisfactory performance in normal installation of CPVC products. FireMastic-HPE has been tested and has shown no adverse CPVC compatibility issues when installed and utilised as intended with Spears systems known as FlameGuard, LabWaste, EverTuff and CTS.

BOSS FireMastic-HPE is proudly distributed by Potter Interior Systems throughout New Zealand.