Avoid the hassle and expense of antifreeze for fire sprinklers

All new and existing antifreeze systems must utilise a premixed specified antifreeze as of September 30, 2022, per NFPA requirements. To prevent the water in wet pipe systems from freezing, antifreeze is a solution of water and an active ingredient. Typically, these antifreeze solutions are made up of a specified ratio of water and propylene glycol or glycerin. Glycerin and propylene glycol are combustible materials that can catch fire when their concentration is high enough. Gravity causes the active ingredient (antifreeze being heavier) and water to naturally separate over time because of their distinct densities. When the proportion of the active ingredient relative to water becomes too high near the sprinkler head, it can serve as fuel for a fire when the sprinkler discharges.

Premixed antifreeze can cost up to $84 per gallon, which makes antifreeze systems prohibitively expensive. In addition to being more expensive, antifreeze is known to undergo chemical breakdown at high temperatures, which causes sprinkler piping to internally corrode. In less than five years, leaks can also occur in wet systems that feed antifreeze loops.


Fire sprinklers using antifreeze are subject to complex maintenance and inspection requirements:

  1. It is necessary to conduct annual testing that measures the specific gravity and concentration of several system samples.
  2. They might necessitate the installation of an extra control/test valve, which is typically placed at the system's highest feasible position. Additionally, the system needs to be fully emptied and refilled with the correct solution if any sample during a test exhibits a mixture at a concentration that exceeds what is permitted.
  3. Specific signage describing the location of antifreeze systems away from the riser and the characteristics of the antifreeze used in them is required for sprinklers that utilise antifreeze. The supplier, together with the volume and concentration of the antifreeze used, must be listed on the signs.
  4. Propylene glycol-based antifreeze is not recommended for use in systems with CPVC sprinkler pipe since it absorbs into the pipe and results in "environmental stress cracking." CPVC can only be used with antifreeze solutions that contain glycerin.
  5. Expansion chambers in certain antifreeze systems enable the water and antifreeze mix to expand without rupturing the sprinkler pipe. The NFPA provides a set of calculations (NFPA 13) for figuring out how big an expansion chamber should be. Backflow preventers are also necessary for antifreeze systems to prevent antifreeze from leaking back into the water supply.

Given these complex requirements, it’s not hard to see why the use of antifreeze is falling out of favor.                   


Automist a dry pipe fire protection for homes susceptible to freezing

Automist prevents freezing without the mess and hassle of antifreeze. It is a completely dry system until use. In the event of a fire, the system is triggered automatically by a ceiling-mounted detector. Automist’s sprayheads will scan the room to look for temperature changes indicating a fire. If danger is detected, the sprayhead best positioned to tackle it targets it with watermist. Only then does a pump activate and the system floods the hoses with a maximum water demand of only 2.4 gallons per minute. Watermist removes heat, suppressing the fire while minimising water damage. Plumis are building a network of authorised reseller installers across the US, fill out the application form below to become a Plumis partner:

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