Plumbing Engineer February 2020/57
sion cycle for black steel piping before the system is put in service for the first time. Trip testing. Trip the dry system from the inspector's test connection, timing the valve trip and water flow. This test allows everyone to test the supervisory and fire alarm signals but also puts water in the black steel pipe system for a second time. Again, it must be drained thoroughly. Thorough Draining of New Dry Pipe Sprinkler Systems Dry pipe sprinkler systems require thorough draining after acceptance testing for two significant reasons. The first is the reason for a dry system: it will be installed in areas where temperatures cannot be maintained above 40 F (4 C). Dry systems must be kept dry. If not, and if the water and moisture from the acceptance testing are not thoroughly removed, the water can freeze and break fit- tings, sprinklers and pipes. See Figure 3 for examples of freeze failures in dry sprinkler systems. Second, when the oxygen in water comes in contact with black or galvanized steel pipe, the corrosion process begins. It is imperative that all the moisture is removed from the dry sprinkler system. NFPA 13 installation requirements such as pipe slope and low-point drains facilitate water removal. However, drains must be clearly identified by drawings and signs (NFPA 13 requirements) and the locations and instructions for use must be clearly communicated to the owner/managers. It is imperative that this is part of the acceptance test- ing procedures and the fire sprinkler contractors are the experts entrusted with this documentation and training. See Figure 4 for examples of corrosion in dry sprinkler systems that can be discovered in as few as seven to 10 years. This corrosion process shortens system life expectancy, often causing freeze failures, but also obstructs pipes and sprinklers. Obstructed pipe and sprinklers, during a rare fire event, do not allow the fire sprinkler system to control the fire as intended. Owner Orientation by Contractors Instructions to managers should be video recorded for the end-users and should include the following. How to operate the valves. Where all drains are located and how to operate the same. A copy of NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, the current applicable edition in the jurisdiction. The specific requirements from NFPA 25 the owner should contract out to trained contractors and the particular requirements from NFPA 25 the owner must perform itself. An annual visit by a sprinkler contractor does not include everything that the standard requires for inspec- tion, testing and maintenance (IT&M). Unless the sprin- kler contractor educates the owner, many of these require- ments are never understood or known to the owner/ manager. What failure modes can be expected if the owner doesn't contract for full IT&M inclusion by contractors. Lifetime IT&M Requirements Additional information the contractor can supply to the building owner/manager during acceptance testing includes: An explanation by the sprinkler contractor that NFPA 25 changes every three years and the owner needs to obtain an updated copy and follow the mini- mum requirements for their specific systems; Ownership changes need to hand off the sprinkler system design and maintenance information to new owners; and If the owner changes IT&M contractors, there needs to be system orientation between the owners and the new contractors. Acceptance testing of fire and life safety systems should be significantly more orchestrated and thorough than is the current practice. It should include detailed communications between fire alarm and fire sprinkler contractors and between those same contractors and indi- viduals responsible for the long-term inspection, testing and maintenance of these systems that provide fire, life safety, property and firefighter protection. l Scott A. Futrell, PE, FSFPE, CFPS, SET, CFEI, is a fire protection engineer with Futrell Fire Consult & Design Inc., in Osseo, Minn., and has more than 40 years' experience designing, specifying and investigating fire protection systems. He is a Fellow in the Society of Fire Protection Engineers and has provided fire sprinkler sys- tem education through the society for almost 20 years. He can be reached by e-mail at firstname.lastname@example.org or visit www.ffcdi.com. Fig. 3
A common mode of failure of dry sprinkler systems is the failure of the fire alarm con- tractor and fire sprinkler contractor to work together.
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