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NFPA issues new safety alert on antifreeze in sprinklers (4/6)

April 6, 2011
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Concerns about the combustibility of antifreeze in sprinkler solutions has led The National Fire Protection Association‘s (NFPA) Standard Council to issued four Tentative Interim Amendments (TIAs) that address the issue. The TIAs provide new requirements in NFPA standards for the use of antifreeze in both new and existing sprinkler systems. NFPA has also issued a new safety alert regarding the use of antifreeze in sprinkler systems. These actions come after extensive research and standards development activities, according to an NFPA press release.

TIAs and Safety Alert replace previous ones issued in August 2010. The entire NFPA Safety Alert and more information can be found at

The four new TIAs apply to:
  • NFPA 13, Standard for the Installation of Sprinkler Systems (2010 edition)
  • NFPA 13R, Standard for the Installation of Sprinkler Systems in Residential Occupancies up to and Including Four Stories in Height (2010 edition)
  • NFPA 13D, Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes (2010 edition)
  • NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems (2011 edition) A general summary of the main new antifreeze requirements is below.

New Sprinkler Systems Containing Antifreeze – NFPA 13, NFPA 13D and NFPA 13R Sprinkler Systems

  • New systems are required to use only factory premixed antifreeze solutions. The maximum allowable concentration of glycerin for a new system is 48% by volume.
  • The maximum allowable concentration of propylene glycol for a new system is 38% by volume.
  • All factory premixed antifreeze solutions used in NFPA 13 and 13R systems must be provided with a certificate indicating the type of antifreeze, the concentration and the freezing point. Factory premixed antifreeze solutions of propylene glycol in excess of 40% by volume are permitted in ESFR (Early Suppression Fast Response) systems where the sprinklers are listed for such use in a specific application.
  • Factory premixed antifreeze solutions other than propylene glycol and glycerin are permitted only where they are specifically listed for use in sprinkler systems.
  • New systems, once installed, must be annually tested in the manner required for existing systems, summarized below.

Existing Sprinkler Systems Containing Antifreeze

Existing NFPA 13D Sprinkler Systems

  • NFPA13D systems must be tested annually by a qualified individual. NFPA 13D provides two alternative test procedures. In the first alternative, the system is drained and two solution samples are taken, one near the beginning and one near the end of the draining process. In the second alternative, the system is not drained and two solution samples are taken, one at the highest practical elevation and one at the lowest practical elevation of the system.
  • The two samples collected using either alternative procedure are then tested to verify that the specific gravity of both samples is similar. If the specific gravity of both samples is similar and if the system is found to contain factory premixed antifreeze solutions of either glycerin at a maximum concentration of 50% by volume or propylene glycol at a maximum concentration of 40% by volume (or other solutions listed specifically for use in fire protection systems), then the existing solution is allowed to remain in service. If these conditions are not met, the existing solution must be replaced with a premixed antifreeze solution of either glycerin at a maximum concentration of 50% by volume or propylene glycol at a maximum concentration of 40% by volume (or other solutions listed specifically for use in fire protection systems).
  • The concentration of antifreeze solutions shall be limited to the minimum necessary for the anticipated minimum temperature.
  • Following the annual test, a tag must be attached to the riser indicating the date of the last test, the type and concentration of antifreeze solution, the date the antifreeze was replaced (if applicable), the name and license number of the contractor that tested and/or replaced the antifreeze solution, a statement indicating if the entire system was drained and replaced with antifreeze and a warning to test the concentration of the solution at yearly intervals per NFPA 13D.
Existing NFPA 13 and NFPA 13R Sprinkler Systems
  • Antifreeze solutions systems must be tested annually, prior to the onset of freezing weather.
  • If it is determined that the solution found in the system is no longer permitted or if the type of anti-freeze cannot be reliably determined, the system must be drained and replaced with an acceptable factory premixed solution.
  • If the initial tests indicate that the solution type is acceptable, test samples must be taken at the top and bottom of each system (in some cases an additional sample must be taken).
  • If all the test samples indicate a concentration of glycerin not greater than 50% by volume or propylene glycol not greater than 40% by volume, then the solution is permitted and may remain in the system.
  • If any of the samples indicate a concentration in excess of the permissible maximum concentrations (i.e. 50% glycerin/40% propylene glycol), the system must be emptied and refilled with a factory premixed solution):
  • For newly introduced glycerin solutions, the solutions must be factory premixed solutions with a concentration not exceeding 48% by volume.
  • For newly introduced propylene glycol solutions, the solutions must be factory premixed solutions with a concentration not exceeding 38% by volume.

NFPA makes further recommendations on sprinklers

Consider alternatives to antifreeze. It is important to remember that, while the TIAs to the NFPA sprinkler standards allow the limited use of antifreeze as an option to address freeze potential, they do not require the use of antifreeze in sprinkler systems. Both in designing new systems and evaluating existing systems, owners and contractors are encouraged to investigate other methods of maintaining wet pipe systems in environments where freezing of pipes may be a concern. Several alternative design options exist including the use of insulation, heating areas where sprinkler piping is run, or use of dry pipe and preaction systems in areas subject to freezing.

Use the minimum necessary concentration. Where antifreeze is used in sprinkler systems, the concentration of antifreeze solution used in the system should be limited to the minimum concentration necessary for the lowest anticipated temperatures. Of course, in no event should the minimum concentration ever exceed the concentrations permitted by the applicable NFPA sprinkler standard.

Initial testing. If not already completed, the testing required by the TIAs should be initiated as soon as possible and be conducted by a qualified individual. NFPA recommends that homeowners with residential sprinkler systems contact a local sprinkler contractor for assistance.

About the National Fire Protection Association (NFPA) NFPA is a worldwide leader in fire, electrical, building, and life safety. The mission of the international nonprofit organization founded in 1896 is to reduce the worldwide burden of fire and other hazards on the quality of life by providing and advocating consensus codes and standards, research, training, and education. Visit NFPA’s website at for more information.

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