FIRE PERFORMANCE PROPERTIES OF FLOWGUARD™ CPVC

Chlorinated Polyvinyl Chloride, or CPVC, is a specialty thermoplastic material which has been used in hot and cold water plumbing applications for over 40 years.
CPVC's widespread use in plumbing, fire sprinkler, industrial piping and many other applications is due to its high heat distortion temperature, ease of installation, light weight and resistance to corrosion.

An additional characteristic of FlowGuard™ CPVC is its outstanding fire safety profile. Fire hazard depends on many factors, including resistance to ignition, rate of flame spread, contribution to fuel load, quantity of
smoke generated and toxicity of smoke and gases.
CPVC outperforms traditional building materials such as wood in each of these categories. Since the system is filled with water, its potential for contributing to fire is minimal.
CPVC's ignition resistance is demonstrated by its flash ignition temperature of 482¢XC which compares favorably with the flash ignition temperature for wood of 260¢XC.

Also, CPVC will not burn unless an external flame source is present and will not sustain ignition once the flame source is removed.
It must be forced to burn due to its very high Limiting Oxygen Index (LOI) of 60. LOI is the percentage of oxygen needed in an atmosphere to support combustion. Since the Earth's atmosphere is only 21% oxygen, CPVC will not burn unless a flame is constantly applied, and stops burning when the ignition source is removed.

Limiting Oxygen Index (LOI)

Oxygen content Earth's atmosphere - 21%

  • Material
    Cotton
    Polypropylene Polyethylene
    Birch
    CPVC
 LO1
16-17
18
20
60

Extensive testing in a Steiner Tunnel shows that CPVC's flame spread is less than 15, in comparison to 100 for red oak. Contribution to a fire's fuel load (heat of combustion) can be measured in J/g. CPVC contributes 18300 J/g, less than Douglas fir at 21500 J/g or Polypropylene at nearly 47000 J/g.

Southwest Research Institute conducted UL723 (modified ASTM E84) tests on both dry and waterfilled FlowGuard™ CPVC water distribution pipe.
Testing confirms that water-filled CPVC pipe in diameters 63 mm (2 inch) and below and empty CPVC pipe in sizes 40 mm (1¼  inch) and smaller meet the 25/50 flame spread / smoke development criteria as a limited combustible material for use in plenum areas.

InEurope, CPVC piping systems have fire ratings which also reflect their excellect  fire resistance proprites, e.g. rated M1 in France and F90/R90 in Germany.

Other important fire characteristics are smoke toxicity and density.  Extensive testing was completed at United States Testing Company, Inc. according to the National Bureau of Standards protocol for combustion product toxicity. This is currently the most definitive method of determining the relative toxicity of materials. All of this testing has shown that CPVC is not unusually toxic - or in the vernacular of the NBS test - CPVC is "as toxic as wood" (Douglas fir). CPVC emitted smoke levels are also exceptionally low.  Testing at Underwriters Labs in Canada has shown that CPVC produces only one-third the smoke of kilndried wood.

The results from testing to satisfy the requirements for the New York State Toxicity Data Bank are on page 41.

The qualitative term, fire safe material, must acknowledge a number of performance characteristics.  Considered together, such characteristics can create a composite picture of the relative safety of combustible materials. When evaluated in this manner, FlowGuard@ CPVC presents an outstanding fire safety profile. Its inherent fire performance properties
make it an ideal candidate for residential and commercial construction applications while its other performance properties make it the cost-effective choice as well.

For these reasons CPVC products have been selected for use in aircraft interiors.

  • High ignition temperature
  • High Limiting Oxygen Index
  • Low toxicity
  • Low heat of combustion
  • 25/50 flame smoke development rating

The capacity of CPVC to resist combustion has also led to its use in fire sprinkler systems, under the Blazemaster®  trade name and is approved in such systems by Underwriters Laboratories (UL) in the USA and the Loss Prevention Council (LPC) in the UK.

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