It’s been 10 years since NFPA guidelines specified that site-mixed, unlisted antifreeze was no longer an approved option for wet systems. Because a listed alternative wasn’t yet widely available, new systems were almost exclusively designed as a dry system.
Because the primary purpose of antifreeze is to protect sprinkler systems from cold, contractors tend to only consider the minimum use temperature when selecting a listed antifreeze.
When installing listed antifreeze, the manufacturer’s installation guide is the final word. But talking with installers who have already started switching their clients to a listed product has revealed three installation tips that you won’t find in the official installation guide.
A UL-listed, factory-premixed antifreeze – like freezemaster™ antifreeze – will soon be the new normal for sprinkler systems needing seasonal freeze protection. This new normal requires different installation and maintenance than building owners and ITM contractors are used to with traditional antifreezes. Not taking these differences into account significantly shortens the life of listed antifreeze.
Before July 2021, a listed antifreeze approved for use in Ordinary Hazard 1 & 2 sprinkler systems larger than 40 gallons did not exist, even though many of these buildings require a system with significantly more antifreeze. This limitation made it difficult and expensive for antifreeze-based fire sprinkler systems in larger applications to maintain compliance with NFPA requirements.
Planning for freezing temperatures during the sweltering summer might not be the first thing on anyone’s to-do list in the fire sector. But in the case of sprinkler system freeze protection, 2021 is the year it should be. Advance planning, insights from the field and a broad perspective on where winterizing is needed will be useful to prepare for safe, effective freeze protection in sprinklered applications this winter and next.
Fire sprinkler systems can be prone to a specific category of corrosion plaguing the industry known as microbiologically influenced corrosion, or MIC. According to the FM Global report “Corrosion and Corrosion Mitigation in Fire Protection Systems,” MIC is responsible for 10-30% of corrosion in all piping systems in the U.S.
During the years when there were no listed antifreezes to protect fire sprinklers from freezing in severely cold weather, dry pipe systems were often chosen to fill the void after NPFA put into place new regulations requiring listed antifreezes for new systems. The most common applications affected by this included attics, unheated warehouses, commercial freezers, overhead canopies, loading docks and parking garages. Now that listed antifreezes are commercially available, however, it’s worth evaluating experiences from the field where dry system use increased in situations where it might not have been best suited. While these systems can be the right solution in some scenarios, they can have significant drawbacks in others.