United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 97-72: Potential for Failure of the Omega Series Sprinkler Heads

UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS
WASHINGTON, D.C.  20555-0001

                                             September 22, 1997

NRC INFORMATION NOTICE 97-72:  POTENTIAL FOR FAILURE OF THE OMEGA SERIES
                               SPRINKLER HEADS

Addressees

All holders of operating licenses or construction permits for nuclear power
reactors and fuel cycle facilities. 

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to alert addressees to a potential for failure of the Omega Series
sprinkler heads manufactured by Central Sprinkler Company of Lansdale,
Pennsylvania.  It is expected that recipients will review the information for
applicability to their facilities and consider actions, as appropriate, to
avoid similar problems.  However, suggestions contained in this information
notice are not NRC requirements; therefore, no specific action or written
response is required.

Description of Circumstances

Documents issued by state and local fire protection authorities state that
independent laboratory testing of samples of certain Omega Series sprinkler
heads demonstrated that water pressure necessary for sprinkler activation may
exceed available system pressure (Maryland State Fire Marshall News Release,
April 28, 1997, and Fairfax County, Virginia,  Fire and Rescue Department, May
16, 1997, NRC Accession No. 9708140231).  In the event of a fire, this
situation could render sprinkler systems relied upon for the protection of
structures, systems, or components important to safety inoperable.  

The sprinkler heads of concern were manufactured between 1983 and June 1996
and include Models C-1, C-1A, R-1, R-1A, R-1M, EC-20, EC-20A, Model M Upright,
Model M Pendent, Model M Sidewall, HEC-12, HEC-20, Prohibitor C-1A, Prohibitor
EC-20A, Prohibitor HEC-12, Flow Control Pendent Flush, and Flow Control
Pendent sprinkler heads.  These sprinkler heads contain an EPDM rubber O-ring. 
The manufacturer has stated that contamination of the piping system from
hydrocarbons or leak sealants may result in O-ring swell which increases the
operating pressure of the sprinkler head above the listing requirement of 
7 psig.  State and local fire protection authorities report failure rates up
to 45 percent and failures have been reported with specimens taken from stocks
of spare sprinklers that had never been installed.  In sprinkler heads
manufactured after June 1996, the manufacturer has replaced the EPDM O-ring
with a silicone O-ring.  In a letter of comment on a draft version of this
information notice, the manufacturer states that the silicone seal "...will
prevent any excessive hydrocarbon based contamination concerns with...the
sprinklers" (letter to  Alfred E. Chaffee, NRC from Carmine Schiavone, Central
Sprinkler Co., July 17, 1997, NRC 


9709220048.                                                                                    IN 97-72
                                                                                    September 22, 1997
                                                                                    Page 2 of 2


Accession No. 9708140231).  Although the NRC has not verified the
manufacturer�s claims, the staff is not aware of any reported failures of the
sprinkler heads that contain the silicone O-ring.

This information notice requires no specific action or written response.  If
you have any questions about the information in this notice, please contact
the technical contacts listed below or the appropriate Office of Nuclear
Reactor Regulation (NRR) or Office of Nuclear Material Safety and Safeguards
(NMSS) project manager.


     signed by                                    signed by D.B. Matthews for

Elizabeth Q. Ten Eyck, Director                   Jack W. Roe, Acting Director
Division of Fuel Cycle Safety                     Division of Reactor Program Management
  and Safeguards                                  Office of Nuclear Reactor Regulation
Office of Nuclear Material Safety
  and Safeguards

Technical contacts:  E. A. Connell, NRR
                     301-415-2838
                     E-mail:  eac@nrc.gov

                     P. W.  Lain, NMSS
                     301-415-6317
                     E-mail:  pwl@nrc.gov

Attachments:  
1.  List of Recently Issued NMSS Information Notices
2.  List of Recently Issued NRR Information Notices


Page Last Reviewed/Updated Tuesday, December 03, 2013