One of the most common myths in the entire fire protection industry is that because CPVC is made of a type of plastic, it will melt and fail in a serious fire hazard.
Using CPVC as a material for fire sprinkler systems has been tried and tested since the 1980s when BlazeMaster® CPVC piping gained a reputation as the first listed and approved non-metallic fire sprinkler system for NFPA light hazard occupancies.
What is the science behind the system enabling it to function reliably during fire hazards? Read on to find out why a CPVC fire sprinkler pipe will retain its integrity in a blaze, buying end users vital time to get to safety.
The test: can BlazeMaster CPVC take the heat?
The Underwriters Laboratories (UL), an essential guideline within the industry to test and certify fire protection products, conducted a study to see if BlazeMaster CPVC piping could take the heat.
The test involved a fire that reached a peak temperature of ~427°C that came in direct contact with the joint and fitting of BlazeMaster CPVC piping. After approximately 1 minute into the test, the sprinkler head was activated and continued to activate after a total test time of 40 minutes.
During the burning test, BlazeMaster CPVC piping formed a charred layer on the outside of the pipe, which functioned as a barrier that reduced heat conduction. This enables water to keep flowing through the pipe, retaining the smoothness of the inner walls while fighting off the source of the fire.
The water flowing through the pipe will also cool the pipe, reducing the rate of burning from the inside. Considering ready.gov claims that a residence can take as little as 5 minutes to be engulfed in flames, a fire sprinkler system with adequate defence, such as BlazeMaster Fire Protection Systems, is integral to stave off a fire until residents can escape.
How does the material work?
In the 1980s, a special compound formula was developed to suit the demands of a fire sprinkler system for life safety applications. This formula, known as CPVC (or chlorinated polyvinyl chloride) was created by reacting additional chlorine with the polyvinyl chloride (PVC) polymer. While PVC contains approximately 57% total chlorine, CPVC has approximately 67%. This additional chlorine is what gives CPVC such a unique performance against direct flame for long periods of time, without sustaining combustion or burning.
It is a common misconception that anything associated with the term ‘plastic’ will melt and burn easily and that all plastics have the same characteristics. If this were the case, not a single plastic would be considered for use on a construction site. Each construction material is rated on its flammability, including plastics, with CPVC being rated V-0 according to UL94 testing. A V-0 rating indicates that burning of the plastic stops within 10 seconds on a vertical specimen.
The material classifications of CPVC
Created by the Lubrizol Corporation, BlazeMaster CPVC piping has achieved the best possible classification that a non-metal material can achieve, which is Bs1d0. The breakdown of this classification is as follows:
- Fire behaviour: B = low flammability, no contribution to flashover
- Smoke development: s1 = low smoke development
- Flaming droplets: d0 = no burning drops
Together with a Limiting Oxygen Index (LOI) of 60, this means that CPVC requires an atmosphere containing 60% or more of oxygen in order to sustain a flame. With the earth’s atmosphere only containing 21% oxygen, the material shows self-extinguishing characteristics and will stop burning the moment the flame is removed.
The evidence
BlazeMaster CPVC has been designed and used in buildings such as hotels, care homes, offices, hospitals, schools and tower blocks. All of these buildings have benefitted from a sprinkler system that has been designed to for 50 years of service life. Here’s one example of how the system has already helped to save lives:
Apartment building, Norway
In 2006 a fire broke out in a 1920s apartment building in Bergen, Norway, which was caused by a burning cigarette that had ignited a sofa. There were 40 residents in the building at the time but nobody was harmed during the blaze. Thankfully a CPVC fire sprinkler had been retrofitted as part of a major modernisation project only three months earlier — this put out the fire and allowed all the residents to leave safely.
BlazeMaster CPVC plastic fire sprinklers have passed UL safety tests and standards to extinguish fears that they will melt on contact with a large fire. Instead, BlazeMaster pipes and fittings can provide safety in the most serious of blazes.
Although established for decades in the US, many in the UK and Europe are still learning about the benefits of installing a BlazeMaster CPVC fire sprinkler system.
