CPVC – A MATERIAL SUSCEPTIBLE TO FAILURE IN SPRINKLER SYSTEMS

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Chlorinated polyvinyl chloride ("CPVC") has been used in potable water distribution systems since the 1960s. More recently, CPVC has been used in high rise fire suppression piping systems.  Within the last decade, failures in these systems have been identified raising questions as to (1) the appropriateness of CPVC and (2) the suitability of CPVC when mated with steel piping. 

When mated with steel piping, CPVC piping is placed under a static and pressurized environment.  These conditions make CPVC susceptible to failure due to stress and chemical attack. Often, a definitive cause of such a failure cannot be specifically identified, however, the following should be considered in deciding whether to pursue a CPVC fire suppression system claim:

 

1. Manufacturing Process Errors: Extrusion or molten processes used in CPVC manufacturing can cause stress in the product.  The molding process may also expose the part to chemical attack from other environmental contaminants. This can cause stress cracking, referred to as environmental stress cracking or ESC. 

 

2. Installation Errors: The installation method can adversely impact the performance of CPVC piping. For example if the part is manipulated to provide an offset between floors, or clamped in place, stress can be introduced.  The installation method can also allow for the introduction of contaminants into the piping.  The most common contaminates are (1) glue used to assemble the CPVC; cutting oils used to thread/cut steel pipe; antimicrobial coatings used to prevent corrosion; and pipe thread sealants containing chlorine and hydrocarbons.  These contaminants has been shown to cause degradation or chemical attack of the CPVC, which can cause ESC. 

 

Efforts are underway to develop testing protocols through entities such as the NFPA Committee of Sprinkler Installation Criteria, as well as the NFSA, Underwriter Laboratories ("UL"), and Factory Mutual ("FM") advisory committees.  In December 2008, FM issued an alert regarding incidents of failure regarding potential incompatibility of CPVC with certain coated steel piping.  FM testing discussed in a March 30, 2010 release noted that in certain instances CPVC failures were seen within a thirty day period.  As a result, FM Approval Standards 1630 and 1635 are being considered for revision so as to test the tensile strength of CPVC when in contact with antimicrobial films or coatings.  This concern has also caused certain manufacturers to advise against the use of coated steel piping with CPVC, or others, to being offering non coated steel piping.   

 

Given these complicated loss scenarios, in addition to traditional fire and mechanical engineers, experts in the fields of polymers, chemistry and codes should be considered for CPVC losses.  Through early identification and coordination, your next CPVC sprinkler loss may result in a recovery.

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