Information Notice No. 89-52: Potential Fire Damper Operational Problems
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555
June 8, 1989
Information Notice No. 89-52: POTENTIAL FIRE DAMPER OPERATIONAL PROBLEMS
All holders of operating licenses or construction permits for nuclear power
This information notice is being provided to alert addressees to potential
problems affecting the closing reliability of curtain-type fire dampers under
ventilation system operational air flow conditions. 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 do not constitute NRC
requirements; therefore, no specific action or written response is required.
Description of Circumstances:
On November 6, 1984, Ruskin Manufacturing transmitted a 10 CFR Part 21 notifi-
cation to the NRC regarding seven of its curtain-type fire dampers that failed
to close during ventilation duct air flow tests. The tests were performed at
the Palo Verde nuclear plant and were conducted to determine the ability of
the curtain-type fire dampers to close under operational air flow conditions,
On January 18, 1985, Northern States Power Company (NSP) notified the NRC of
several curtain-type fire dampers that failed to fully close under ventilation
system air flow conditions during ventilation duct system operability tests
performed by NSP. The fire damper testing method used remote trip wires in
place of the thermal links and the ventilation ducts were fully closed with no
open duct access panels, thus representing the actual air flow and pressures
that would be present during operating conditions.
On May 14, 1986, Wisconsin Public Service Corporation (WPSC) notified the NRC
of two curtain-type fire dampers manufactured by Action Air that were tested
and that failed to close completely under normal air flow conditions.
On December 27, 1987, Alabama Power Company notified the NRC that control room
fire dampers at Farley Unit 1 were inoperable because of failure to close
during testing under air flow conditions.
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June 8, 1989
Page 2 of 3
On February 23, 1988, Alabama Power Company reported to NRC that a number of
fire dampers at Farley Unit 2 failed to close when tested under air flow.
Until quite recently, the only industry standard governing the design, fabri-
cation, and testing of fire dampers was Underwriters Laboratories, Inc. (UL)
Standard 555, "Fire Dampers and Ceiling Dampers." The 1979 edition states in
part that "the closing reliability of fire dampers...is evaluated on the basis
that...ventilating systems are automatically shut down when a fire occurs...
therefore, the UL ratings are applicable to fire dampers...installed in
systems where air movement is effectively stopped at the start of a fire...."
The standard does not evaluate whether or not fire dampers will close under
air flow conditions. Therefore, the UL fire damper rating only indicates
whether a fire damper in the closed position will main-tain its integrity under
fire conditions for a specific time period, typically rated for 1� or 3 hours.
NRC requirements and guidelines for fire damper configurations are contained
in various documents, including Appendix A to the Branch Technical Position
(BTP) APCSB 9.5-1, "Guidelines for Fire Protection for Nuclear Power Plants
Docketed Prior to July 1, 1976," (NUREG-75/087; NUREG-0800) and Standard
Review Plan (SRP) 9.5.1, "Fire Protection Program" (NUREG-0800). The extent
to which these guidelines apply to a specific plant depends on licensee
commitments and license requirements that are applicable to the fire
protection program. The objective of these guidelines is to provide a fire
damper that will close and latch as required to ensure that those systems and
components important to safe shutdown will be capable of performing their
Licensees should be aware that fire damper testing methods that do not
simulate the actual total differential pressure at the damper (i.e., visual
inspection or drop testing with duct access panels open) may not show
operability under air flow conditions. If licensees depend on the UL product
listing and do not sufficiently model air flow during surveillance testing,
they cannot be sure that the dampers will close fully when called upon to do
so unless air flow is stopped first.
Licensees who have adequately addressed this issue have either (1) type tested
"worse-case" air flow conditions of plant-specific fire damper configurations;
(2) tested all dampers installed in required fire barriers; or (3) administra-
tively shut down the ventilation systems to an area upon confirmation of a
fire. The last approach has been incorporated into plant emergency
Because all curtain-type fire dampers currently installed at nuclear power
stations are of a similar design, all stations having these fire dampers
should consider the 10 CFR Part 21 report, which specifically references
Ruskin dampers, to be applicable to curtain-type fire dampers manufactured by
other companies. This type of fire damper, as installed in nuclear power
stations, is typically used to protect redundant trains of safe shutdown
systems and should be capable of closing and latching under anticipated air
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June 8, 1989
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No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact one of the techni-
cal contacts listed below or the Regional Administrator of the appropriate
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contacts: Dennis J. Kubicki, NRR
Joseph J. Petrosino, NRR
Joseph M. Ulie, Region III
Attachment: List of Recently Issued NRC Information Notices
June 8, 1989
Page 1 of 1
LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information Date of
Notice No._____Subject_______________________Issuance_______Issued to________
89-51 Potential Loss of Required 5/31/89 All holders of OLs
Shutdown Margin During or CPs for nuclear
Refueling Operations power reactors.
88-88, Degradation of Westinghouse 5/31/89 All holders of OLs
Supp. 1 ARD Relays or CPs for nuclear
89-50 Inadequate Emergency 5/30/89 All holders of OLs
Diesel Generator Fuel or CPs for nuclear
Supply power reactors.
89-49 Failure to Close Service 5/22/89 All holders of OLs
Water Cross-Connect or CPs for nuclear
Isolation Valves power reactors.
89-48 Design Deficiency in the 5/22/89 All holders of OLs
Turbine-Driven Auxiliary or CPs for nuclear
Feedwater Pump Cooling power reactors.
89-47 Potential Problems With 5/18/89 All holders of OLs
Worn or Distorted Hose or CPs for nuclear
Clamps on Self-Contained power reactors and
Breathing Apparatus fuel facilities.
89-46 Confidentiality of 5/11/89 All holders of
Exercise Scenarios licenses for fuel
having an approved
89-45 Metalclad, Low-Voltage 5/8/89 All holders of OLs
Power Circuit Breakers or CPs for nuclear
Refurbished with Sub- power reactors.
89-44 Hydrogen Storage on the 4/27/89 All holders of OLs
Roof of the Control Room or CPs for nuclear
OL = Operating License
CP = Construction Permit
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