NFPA Safety Alert

Published:  03 May, 2011

NFPA issues updated Safety Alert regarding antifreeze in sprinkler systems.

Following reports of a fire incident involving a sprinkler system that contained a high concentration antifreeze solution, research and standards development activities were begun to address concerns raised by the combustibility of antifreeze solutions in residential sprinkler systems. As information became available, NFPA published two successive Safety Alerts providing guidance from NFPA in its role as a safety advocate and announcing Tentative Interim Amendments (TIAs) to NFPA sprinkler standards that were issued by the NFPA Standards Council. The TIAs and the additional NFPA guidance offered in those Safety Alerts were interim actions while the responsible standards development Technical Committees reviewed the results of the research and reached consensus on further amendments to the NFPA sprinkler standards. 

The sprinkler committees have now completed the review and consideration of the issues related to the use of antifreeze in sprinkler systems and, based on the available information, have reached consensus on four TIAs that were issued by the NFPA Standards Council (PDF, 81 KB) on March 1, 2011. The four TIAs achieve a more comprehensive approach to the treatment of antifreeze in NFPA sprinkler standards, and provide new requirements for the use of antifreeze in both new and existing residential occupancies and in non-residential occupancies as well. 

New Requirements for Sprinkler Systems Containing Antifreeze – A Summary

The four new TIAs apply, respectively, to:

The previous TIAs that were issued by the Standards Council in August 2010 are no longer in effect.

What follows is a general summary of the main new antifreeze requirements that the TIAs have added to the NFPA sprinkler standards. This summary does not describe all the details or all of the provisions; the applicable sprinkler standard, as amended by the new TIAs, should be directly consulted for a complete and accurate understanding of the requirements related to the use of antifreeze. 

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.

 For more information, click here.

  • Operation Florian

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