NFPA 25 2014 has major changes related to antifreeze systems in Section 5.3.4. In recent years there have been several incidents related to high concentrations of certain antifreeze solutions. Some antifreeze concentrations can lead to actually making the antifreeze flammable or pose a hazard for firefighters.
If the type of antifreeze in a system is no longer permitted, the entire system must be drained and replaced with an approved solution. If the type of antifreeze in a system cannot be determined, the entire system must be drained and replaced with an approved solution. Samples must be taken at specified points and if the concentration is too low or too high, the system must be emptied and replaced with an acceptable solution. If the new approved solution is not sufficient to prevent the system from freezing, alternative methods of keeping the pipe from freezing must be implemented.
For systems that were installed prior to September 30, 2012, listed antifreeze solutions shall not be required until September 30, 2022, where all of the following conditions are met:
- The concentration of the antifreeze solution shall be limited to 50 percent glycerine by volume or 40 percent propylene glycol by volume.
- Newly introduced solutions shall be factory premixed antifreeze solutions (chemically pure or United States Pharmacopeia 96.5 percent).
- Antifreeze systems with concentrations in excess of 30 percent propylene glycol and 38 percent glycerine shall be permitted based upon an approved deterministic risk assessment prepared by a qualified person approved by the AHJ.
- The use of factory premised solutions is required because solutions that are not mixed properly have a possibility of separating from the water, allowing the pure concentrate (which is heavier than water) to drop out of solution and collect in drops or low points of the system. Such concentrations are combustible and could present problems during fires.
All Antifreeze systems should use listed antifreeze solutions.
NFPA 25, Section 5.3.3* Antifreeze Systems
Annually, before the onset of freezing weather, the antifreeze solution shall be tested using the following procedure (2017 edition):
- Using the antifreeze information sign required by 4.1.10, installation records, maintenance records, information from the owner, chemical tests, or other reliable sources of information, the type of antifreeze in the system shall be determined and (a) or (b) implemented if necessary: (a) If the antifreeze is found to be a type that is no longer permitted, the system shall be drained completely and the antifreeze replaced with an acceptable solution. (b) If the type of antifreeze cannot be reliably determined, the system shall be drained completely and the antifreeze replaced with an acceptable solution in accordance with 220.127.116.11.
- If the antifreeze is not replaced in accordance with 5.3.3(1)(a) and 5.3.3(1)(b), test samples shall be taken at the top of each system and at the bottom of each system as follows: (a) If the most remote portion of the system is not near the top or the bottom of the system, an additional sample shall be taken at the most remote portion. (b) If the connection to the water supply piping is not near the top or the bottom of the system, an additional sample shall be taken at the connection to the water supply.
- The specific gravity of each solution shall be checked using a hydrometer with a suitable scale or a refractometer having a scale calibrated for the antifreeze solution.
- If any of the samples exhibits a concentration in excess of what is permitted by 18.104.22.168, the system shall be emptied and refilled with a new acceptable solution.
- If a concentration greater than what is currently permitted by 22.214.171.124 was necessary to keep the fluid from freezing, alternative methods for preventing the pipe from freezing shall be employed.