It is and has been surprising to me when fire protection contractors ask the pipe freezing question or when they ask piping support questions in context with approval by local AHJ of any kind. The reason for the surprise is because contractors have ready access to materials, labor and space to conduct their own very convincing freeze tests or load tests. The pipe freezing question is often asked. The mechanics of why piping systems fail due to freezing is documented to be the result of excessive water pressure in the unfrozen part of a water piping system. Pipe failure is not due to the conventional wisdom idea that ice expands against the piping. The frozen part is a solid ice plug that occupies more volume than the original liquid water volume that has frozen. Since the unfrozen water is not compressible that increase volume change of the now frozen water results in excessive pressure in the remaining piping. Notice where an antifreeze hose cock fails that has frozen because the outside hose was never removed for the winter trapping water within the assembly. It fails at the assembly part farthest into the building where the assembly was the warmest, not at the colder section closer to the building exterior. Ask some of your plumber friends, perhaps the older ones, if they have ever seen dry ice packed around a water service line as a way to shutoff the water when the service tap valve cannot be found or is not functioning. This method works well as long as the excess down stream pressure is monitored and is periodically removed by cracking a valve open. A simple experiment demonstrates the freezing mechanics. Here is a link to one performed at a university in Wisconsin. https://www.madisongroup.com/publications/StudyofFreezing.pdf <https://www.madisongroup.com/publications/StudyofFreezing.pdf> Another information source is here from Illinois: https://www.ideals.illinois.edu/handle/2142/54757 <https://www.ideals.illinois.edu/handle/2142/54757> A fire protection contractor with any doubts (I would have doubts and I would want to see it myself.) could easily fabricate a small jungle gym of scrap piping, fittings and used sprinklers to setup outside the shop for testing the condition of residual water freezing in sprinkler drops. Regarding load testing, it was common practice many years ago to build a small structural part of a building and then load it up with tons of whatever material was on hand to prove strength beyond that required for the structure. There is not much tech required to tally up the weights applied. Load tests for fire protection components would be much less elaborate. For a very simple example, if an AHJ questions how strong some twisted wire bracing is, then mock up a simple seat suspended by the practice for the AHJ to sit on. Contractors also have the means they did not have tears ago to use smart phones to record their testing methods.
Allan Seidel St. Louis, MO _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
