The use of CPVC (chlorinated polyvinyl chloride - a polymer) fire protection pipes and systems is becoming more and more the standard. Over 2 billion feet of BlazeMaster® CPVC fire sprinkler pipes alone have been installed in more than 60 countries worldwide, including the UK.
While CPVC stands up to its reputation of having a lower cost of install compared to steel, the integrity and safety that the system provides are sometimes misunderstood within the industry. In this article, we take a deeper look at the safety of CPVC fire sprinkler pipes and the UK approvals it has achieved to rival steel as the product of choice.
What is CPVC Pipe and how does it work?
BlazeMaster pipe and fittings compounds are made from chlorinated polyvinyl chloride, which is formed by reacting additional chlorine upon the polyvinyl chloride (PVC) polymer. While PVC contains approximately 57% total chlorine by mass, CPVC has approximately 67%.
This additional chlorine content imparts unique performance attributes such as the ability to withstand a direct flame for long periods of time without sustaining combustion or continuing to burn. Instead, the CPVC pipe will:
- Char only on the pipe's outside wall when exposed to direct flame, while the structural integrity of the pipe remains essentially in tact and the interior remains smooth.
- CPVC will not burn by itself and will self-extinguish the moment the flame is removed.
- The charred layer functions as a thermal barrier and reduces the conduction of heat into the pipe.
- The moment a sprinkler head activates, the water flow will carry away the heat and thus cool the pipe from the inside, which further reduces the rate of deterioration from burning.
UK Approvals
Submitted to the flammability rating as per EN 13501, the Lubrizol Advanced Materials CPVC has achieved the best possible classification that a non-metal material can achieve, which is Bs1d0:
- Fire behaviour: B = low flammability, no contribution to flashover
- Smoke development: s1 = low smoke development
- Flaming droplets: d0 = no burning drops
CPVC fire protection systems have also had UK approvals from the Loss Prevention Certification Board (LPCB) and listed on their Red Book as an approved fire and security product.
More recently, CPVC fire sprinkler pipes have been made eligible for use in residential and domestic occupancies in Wales following the Welsh Government's decision to agree regulation that all new and converted housing from 2016 onwards should include a fire protection system.
Reliability. For Life.
As well as being able to work in temperatures up to 65°C and have a working pressure of 12 bar, CPVC fire sprinkler pipes offer advantages long after installation, in particular with regards to the impact of corrosion on long-term service life and water quality too.
Corrosion
Any steel product is synonymous with corrosion and fire protection systems are no different. As you will already understand, the higher the corrosion levels inside the pipe, the more friction is created which decreases the flow of water in the event of an emergency - potentially stopping the system from working altogether.
Using the Hazen-Williams formula to calculate friction and roughness inside the pipe, steel's performance dropped by over 50% for pipes that were in service for between 4 and 40 years. Meanwhile, CPVC continued to protect lives and property at the same level as the day it was installed.
Water quality
Tested and listed CPVC pipes and fittings should be Water Regulations Advisory Scheme (WRAS) approved for use with potable water. Water quality after being in the fire protection system, however, has been put to the test to see how CPVC performs compared to steel and copper.
While steel contained high turbidity, particulate solids and high levels of Legionella bacteria in the 14-week study, the water in CPVC pipes "did not show any deterioration - and in fact had a lower turbidity than the initial water. The study by the KIWA Institute in the Netherlands also found that Legionella bacteria in CPVC pipes was significantly lower too.
Lower cost of install
Aside from the health and safety benefits that CPVC fire sprinkler pipes can provide compared to steel, it also has a significantly lower cost of installation. A 40-bed care home that requires a retrofit, for example, would require over 1,300 hours to install steel (screwed), where as CPVC would take only 640 hours - more than a 50% reduction in time.
Of course, with a lower installation time means a lower cost of install, and this, combined with the reliability and compliance to UK approvals make CPVC a favourable alternative to steel.
