[Federal Register Volume 73, Number 17 (Friday, January 25, 2008)]
[Pages 4578-4579]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-1273]



Centers for Disease Control and Prevention

[Docket Number NIOSH-123]

Notice of Opportunity for Public to Provide NIOSH with Comment: 
Positive-Pressure Closed-Circuit Self-Contained Breathing Apparatus

AGENCY: The National Institute for Occupational Safety and Health 
(NIOSH) of the Centers for Disease Control and Prevention (CDC), 
Department of Health and Human Services.

ACTION: (1) Notice of opportunity for public to provide NIOSH with 
comment on the public's reevaluation of NIOSH limitations on and 
precaution for safe use of positive-pressure closed-circuit self-
contained breathing apparatus, Authority: Public Law 91-596. (2) Notice 
of opportunity for manufacturers and stakeholders to provide NIOSH with 
input on the NIOSH prohibition against using a respirator which uses a 
breathing gas of pure oxygen during direct exposure to open flames and/
or high radiant heat.


SUMMARY: The NIOSH, National Personal Protective Technology Laboratory 
(NPPTL), is currently reevaluating its limitations on and precaution 
for safe use of positive-pressure closed-circuit self-contained 
breathing apparatus. As stated in the Federal Register (Vol. 50, No. 
222, pages 47456-47457 dated Monday, November 18, 1985) NIOSH's 
position on this topic is that:

    Available information does not demonstrate to the satisfaction 
of NIOSH that positive-pressure closed-circuit self-contained 
breathing apparatus which use a breathing gas of pure oxygen can be 
used during direct exposure to open flames and/or high radiant heat 
and assure the wearer's safety. Therefore, NIOSH has determined that 
until it has been demonstrated to the satisfaction of NIOSH that 
those devices can be worn under such conditions, it is prudent to 
presently limit the use of positive-pressure closed-circuit self-
contained breathing apparatus which use pure oxygen breathing gas to 
mines and mining atmospheres which do not involve exposure to open 
flames or high radiant heat.

    Background: NIOSH/NPPTL is currently developing performance 
concepts as part of the rulemaking process to develop a Closed-Circuit 
Self-Contained Breathing Apparatus (CC-SCBA) Module. This process has 
identified that flame and heat durability requirements need to be 
considered as part of the module. On possible inclusion to the 
requirements is the National Fire Protection Agency (NFPA) Heat and 
Flame Test, NFPA 1981, Section 8.11. NIOSH has conducted laboratory 
testing on two (2) different manufacturer's apparatus. In the initial 
testing, NFPA testing procedures were followed with the exception that 
a ``dummy'' cylinder was used in lieu of the oxygen cylinder. Test 
results were encouraging and were presented at NIOSH/NPPTL public 
meetings held on July 19, 2005 and on October 12, 2006. Arrangements 
are being made to conduct the same tests with full oxygen cylinders.
    Additional research was garnered through testing conducted at a 
second laboratory. NPPTL personnel witnessed a Flame Engulfment Test. 
In Germany, Department 8 of the Association for the Promotion of German 
Fire Safety (VFDB) has included in its Guideline 0802 the same 
requirements for Close-Circuit Breathing Apparatus that has been 
written into the draft European Standard EN137 for Open-circuit 
Compressed Air Breathing Apparatus for flame engulfment. In this 
Directive, if special thermal loads for protective equipment cannot be 
excluded during tactical operation, the device must pass the flame 
engulfment test which is described in Appendix D. Their flame 
engulfment test is similar to NFPA's. In addition, this directive 
requires that when using closed-circuit compressed air breathing 
apparatus, type positive pressure with mixed gas supply (N2, 
O2) with an oxygen content of >= 30% by volume in the 
breathing circuit risks by oxygen emerging from a leakage in the mask 
cannot be excluded. These devices must pass the oxygen flame engulfment 
test procedure described in appendix G as follows:

     Simulate possible oxygen enrichment under a firefighter 
helmet according to EN 443 through a defined leakage in the respiratory 
protective mask (2.5 mm, 10 mm above the right temple strap). The test 
set-up simulates real conditions by equipping the test head with real 
hair, a flame protection hood and the respective neck curtains.
     Flame engulfment test is in accordance with Appendix D

    [cir] Device is attached to a test dummy and preheated in an oven 
at 90  5[deg] C for 15 minutes
    [cir] Complete unit is then exposed to direct flames for 10 seconds
    [cir] Test dummy with the apparatus is then lifted to 150  5/0 mm and dropped
    [cir] During the entire test, the device is connected to a 
breathing machine. The pass/fail criteria are:

[[Page 4579]]

     Device must not continue to burn for more than 5 seconds
     No component that secures the device to the user's body or 
that secures the cylinder must come off or be displaced
     Breathing resistance as per EN 137 are met
     The test head must not continue to burn for more than 5 

    The closed-circuit self-contained breathing apparatus used in the 
test witnessed by NIOSH/NPPTL personnel successfully passed all of the 
listed criteria.
    Additionally, the National Institute of Standards and Technology 
(NIST), Building and Fire Research Laboratory, Fire Research Division 
has provided a computational fluid dynamic (CFD) study of oxygen 
dissipation into the environment surrounding a respirator facepiece. 
For this study, 3-dimensional scans were taken of actual heads and 
masks for use in the CFD software. Leak geometries representing an 
imperfect seal were defined. Other variables included oxygen 
concentration fields and flow streamlines for multiple combinations of 
fuel and air in the surrounding environment, content of the leak, 
various breathing patterns, etc. Conclusions reached during the study 
     Oxygen expelled through leak in respirator is propelled 
away from head region through advection and dissipates through 
     Risk of flammable mixture near head is observed in 10% 
propane environment.
     This is an extreme environment (fuel-rich, near flammable 
     In case of flammable environment, oxygen leak results in 
small, fuel-lean region near head.
     In fuel-lean environment, oxygen further decreases fuel 
    NIST Technical Note 1484 titled, ``A Computational Model of 
Dissipation of Oxygen from an Outward Leak of a Closed-Circuit 
Breathing Device'' available through the internet at this link, http://fire.nist.gov/bfrlpubs/fire07/PDF/f07024.pdf chronicles the research 
work completed by NIST.
    Through this announcement, NIOSH/NPPTL is seeking input from 
stakeholders and manufacturers to determine the following:

    1. Opinion on the current prohibition.
    2. Provide supporting data to maintain, modify, or rescind the 
current prohibition.
    3. If additional research is needed to support rescinding the 
prohibition, what would it entail?
    4. Willingness to participate in a collaborative agreement with 
NIOSH/NPPTL to conduct research on this topic and support willing to 
    5. Other comments on the subject.
    Public Comment Period: Submit input to the NIOSH Docket Office 
within 60 days after the date of publication of this notice in the 
Federal Register. Reference Docket Number NIOSH-123 in comments.

ADDRESSES: Input can be submitted by:
     Mail: NIOSH Docket Office, Robert A. Taft Laboratories, M/
S C 34, CC SCBA O2 Prohibition--NIOSH Docket Number 123, 
4676 Columbia Parkway, Cincinnati, OH 45226.
     E-mail: [email protected].
     Fax: (513) 533-8285.
     Phone: (513) 533-8303.
     NPPTL Web Site: http://www.cdc.gov/niosh/npptl.
    Contact Person for Technical Information: Timothy R. Rehak at 412-
386-6866 or e-mail: [email protected].

    Dated: January 16, 2008.
James D. Seligman,
Chief Information Officer, Centers for Disease Control and Prevention.
 [FR Doc. E8-1273 Filed 1-24-08; 8:45 am]