United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 86-103: Respirator Coupling Nut Assembly Failures

                                                            SSINS No.:  6835
                                                            IN 86-103 

                                UNITED STATES
                           WASHINGTON, D.C. 20555

                              December 16, 1986



All nuclear power reactor facilities holding an operating license or a 
construction permit and fuel fabrication facilities. 


This information notice is being issued for two reasons. This notice is 
primarily provided to alert recipients to a mechanical failure of coupling 
nut assemblies used with Mine Safety Appliance (MSA) respirators. This 
notice also corrects erroneous statements contained in IN 86-46. Recipients 
are expected to review the information for applicability to their 
respiratory protection program and consider actions, if appropriate, to 
preclude similar problems it their facilities. However, suggestions 
contained in this notice do not constitute NRC requirements; therefore, no 
specific action or written response is required. 

Description of Circumstances: 

Information Notice No. 86-46, "Improper Cleaning and Decontamination of 
Respirator Protection Equipment," issued June 12, 1986, discusses how 
exposure to organic solvents produces cracking in plastic coupling nut 
assemblies on MSA respirators. This office has received several comments 
that IN 86-46 incorrectly stated that the coupling nuts are used with the 
Ultra-Twin respirators. A check with MSA indicated that the coupling nut 
assembly (MSA Part #96547) is used with the ULTRA-VUE face piece, not the 

MSA redesigned the coupling nut assemblies discussed in IN 86-46. This new 
simplified design (supplied by MSA under the same part number as the old 
design) has not been completely successful. The Pilgrim Station recently has 
reported that several of the new design coupling nut assemblies have failed 
during mask removal. When the mask is removed by grasping the filter 
housing, the new design appears to concentrate the force onto the coupling 
assembly sealing flange. This leads to mechanical failure of the sealing 
flange which causes the filter (with the nut attached) to separate from the 
mask. As stated in IN 86-46, this coupling nut is also used to connect the 
Ultra-Vue face piece to the air supply hose of an MSA self-contained 
breathing apparatus (SCBA). It is unclear whether the SCBA hose connection 
can produce the mechanical leverage necessary to break the coupling assembly 
seal flange; however, a damaged coupling assembly failing under use could 
lead to a life-threatening situation for the wearer. 



                                                       IN 86-103 
                                                       December 16, 1986 
                                                       Page 2 of 2 

MSA is currently reevaluating the coupling nut assembly to eliminate the 
failure mechanism noted by Pilgrim. In the interim, they have replaced the 
faulty coupling nuts from Pilgrim with the original designed style. 
Licensees experiencing problems with these coupling nuts should contact Eric 
Beck, Product-line Manager, MSA, Pittsburgh, PA, on (412) 273-5194. 

No specific action or written response is required by this information 
notice. If you have any questions about this matter, please contact the 
Regional Administrator of the appropriate regional office or this office. 

                                   Edward L. Jordan, Director 
                                   Division of Emergency Preparedness 
                                     and Engineering Response 
                                   Office of Inspection and Enforcement 

Technical Contacts:  Roger L. Pedersen, IE 
                     (301) 492-9425 

                     James E. Wigginton, IE 
                     (301) 492-4967 

Attachment:  List of Recently Issued IE Information Notices
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