Antifreeze Solutions for Use in Fire Sprinkler Systems

This revision modifies the text in Section 15.2 to reference the ¾ inch size as representative for assessing antifreeze for compatibility with thermoplastic sprinkler pipe. The current text in UL 1821 requires the largest and smallest size of pipe to be tested for the Long-Term Hydrostatic Pressure Test. This is appropriate when evaluating the pipe and material itself for hydrostatic strength with water, however, it is not necessary to test the largest size when evaluating the pipe and material for compatibility with antifreeze. The representative size chosen of ¾ inch pipe would have a lesser wall thickness than the larger sizes of CPVC and PEX, and thus be more susceptible to showing degradation from incompatible materials. Therefore, it is unnecessary to also test the largest size with thicker walls since compatibility issues would be first exhibited with the smaller representative size of ¾ inch. The concept of using smaller size pipe as representative of larger size pipe has also been discussed and confirmed with the UL 1821B, Evaluating Compatibility of Products with CPVC Piping, Standards Technical Panel Task Group. The task group agreed that for pipe with the same ratings and SDR, a thinner wall pipe can be representative of thicker wall pipe for compatibility assessments.