Respirators are complex devices; the SCBA is arguably the most complex of them all. That's why thehas dedicated a lab to its study.
The National Personal Protective Technology Laboratory located in Pittsburgh focuses on respiratory protective equipment and other personal protective technology. Its Technology Evaluation Branch certifies respirators. More than half of the branch's approvals are in air-purifying respirators and more than half of tests are related to respirators for chemical, biological, radiological or nuclear incidents.
Approval testing is based on a system approach; the respirator is tested as a complete system, not as component parts. Although some specific tests are done on individual components, the tested components often are returned to the complete respirator to ensure the system still functions.
CBRN SCBA approvals are based on three levels of approval. The entire respirator must pass the standard industrial SCBA requirements of 42 CFR 84, which predate the original edition of NFPA 1981, Open-Circuit Self-Contained Breathing Apparatus for Fire Service.
Subpart H of Part 84 consists of 42 CFR 84.70 through 84.104. Over 25 of those requirements apply to open-circuit pressure demand or positive-pressure SCBA. The others apply to closed-circuit breathing apparatus. Important tests include:
84.83: Remaining service life indicator. This section requires an indicator that warns when 25% of the cylinder gas is remaining. This requirement will be reviewed this year and may be changed to allow individual departments to set the indicator between 25% and 50%.
84.87: Compressed-gas filter check.
84.89: Weight requirement. This is currently set at 16 kg (35 pounds) but this does not include accessories.
84.90: Breathing-resistance inhalation. Using a breathing machine at 120 liters per minute, resistance must not exceed 32-mm water column height.
84.91(c)(d): Exhalation resistance. Continuous flow at 85 lpm must not exceed 51 mm of water or 38-mm water column height at zero flow.
84.92: Exhalation valve leakage. Must not exceed 30 mm per minute at a 25-mm water column height suction
84.93: Gas flow. The flow is measured at zero gage pressure in the facepiece and with 500-psig cylinder pressure applied.
84.95: Service time, open-circuit apparatus.
84.97: Test for carbon dioxide in inspired gas. This is the CO2 deadspace test to ensure that carbon dioxide is not building up in the facepiece. This test is done on a breathing machine.
At this point in the test cycle, it is assumed that a test subject can safely wear the mask and human-subject testing begins.
84.98: Tests during low-temperature operation. Done at applicant specified minimum operating temperature. The device is precooled for four hours and then a subject enters the cold chamber, dons the respirator and begins stepping on to and off of a 21.5-cm-high step. He steps at 30 cycles per minute. After one minute he rests for one minute on a chair and then repeats. The test runs for 30 minutes at temperatures well below freezing. Most repeat test subjects are Canadian hockey fans or firefighters. The SCBA are checked for facepiece fogging, malfunctions and excessive breathing resistance during the test.
84.100: Man test 4. This is a vigorous test of the respirator while being worn by a person. The number of repetitions of each exercise is set to fill up the duration time of the apparatus. The exercises are:
- Walk at 3 mph for two minutes.
- Climb vertical treadmill for one minute.
- Walk at 3 mph for two minutes.
- Pull a 45-pound weight to five feet 60 times in five minutes.
- Walk at 3 mph for two minutes.
- Run at 6 mph for one minute.
- Carry a 50-pound weight.
- Take a two-minute break while samples are taken.
- Repeat for specified duration.
84.101: Man test 5. Sitting at rest for maximum duration of the device, this addresses different aspects of the apparatus than the previous test.
84.104: Gas tightness test. An isoamyl acetate (banana oil) fit test is conducted for the entire system.
The NFPA-approval testing is conducted by the Safety Equipment Institute. The NFPA certification includes numerous tests to ensure the apparatus is suitable for fire service duty. These include testing air-flow, environmental temperature, vibration, heat and flammability, accelerated corrosion, particulate and communication.
The NFPA amends this standard on a five-year cycle, adding and improving the SCBA technology to keep NFPA devices state of the art for firefighting. For example, among the many improvements, the 2002 edition added the rapid-intervention company universal air connection, and the 2007 edition added improved flammability requirements and enhanced requirements for voice communication. The changes to the 2007 edition also include a new requirement for NIOSH CBRN certification as a component of NFPA 1981 approval.
The NIOSH CBRN SCBA approval builds on the combined NFPA 1981 and 42 CFR requirements. Several special performance requirements are added. Complete CBRN requirements can be found at www.cdc.gov/niosh/npptl/standardsdev/cbrn/scba. The CBRN SCBA requirements in outline are:
- Approval under 42 CFR 84, Subpart H.
- Compliance with the most recent edition of NFPA 1981.
- Chemical agent permeation and penetration resistance against distilled sulfur mustard and sarin.
- Laboratory respirator protection level fit tests.
The LRPL is a test of the respirator face mask capability to maintain an adequate seal when worn by an appropriately fitted worker during a series of exercises. The test is performed on a panel of subjects representing a cross section of face sizes as defined by the Los Alamos National Laboratory Panel. More than 30 subjects are generally required for this test.
A modified SCBA facepiece is used during CBRN tests. The facepiece is detached from the SCBA and fitted with an adapter and air-purifying filters. All accessories such as the heads-up display and the voice emitter remain on the facepiece. A sampling probe is added to the facepiece in the worker's breathing zone. The subjects are fit-tested according to the manufacturer's instructions. Then they enter a chamber with a generated corn-oil atmosphere. The ratio of the concentration of contaminant inside the facepiece to concentration outside the facepiece is measured while the subjects conduct a series of exercises developed by the military. The LRPL test is a good indicator of adequate face seal characteristics. This requirement is beneficial for positive-pressure SCBA for two reasons: it decreases the probability that inward leakage will occur during a high breathing rate event and it decreases the probability of air capacity loss due to mask seal leakage.
The NIOSH-approved CBRN SCBA is a premium device. It benefits from the basic 42 CFR 84 industrial approval, the increased performance requirements of NFPA 1981, the additional NIOSH CBRN chemical agent-resistance standards and face seal performance requirements of the LRPL test. Twenty-one SCBA models compliant with the 2007 edition of NFPA 1981 were approved last year and additional models are currently in testing (See table, opposite).
In addition to the initial quality requirements, NPPTL regularly conducts audits of the manufacturer's production facilities. NIOSH conducted site audits at five of the seven manufacturers with NFPA-approved SCBA in 2007:, ISI, , Scott Health & Safety, and Survivair. These audits are thorough and review the relevant aspects of the manufacturer's quality-control program. NPPTL also has a certified product investigation program that probes reports of field performance problems of approved products. NIOSH solicited additional firefighter input to the CPIP program at the 2006 Challenges in Protecting First Responders conference at Virginia Tech. The response from fire departments to that request has resulted in a number of issues with field-deployed firefighter SCBA being addressed. TEB also conducts tests of respirators in conjunction with the FFFIPP program on request. The branch has opened 57 requests from FFFIPP and closed 44 over the history of that program.
In 2006 and 2007, TEB conducted an information-gathering activity on Personal Alert Safety Systems and provided that information to support NFPA's effort, resulting in the improved NFPA 1982, Personal Alert Safety System, 2007 edition.
In 2007, NPPTL brought a new LRPL exposure facility on line at the Pittsburgh facility. This new facility is state of the art and will allow TEB to perform the generated corn-oil atmosphere test, where the atmosphere contains 20 to 40 mg/m3 corn-oil aerosol, in many applications including the CBRN SCBA, the air purifying full-facepiece respirators (CBRN APR) and the powered air-purifying respirators (CBRN APR).
NPPTL is researching the applicability of air-purifying CBRN devices for certain emergency response activities. Air-purifying respirators offer advantages in stages of an emergency response where the exposures levels are known and are below immediately dangerous to life and health levels. This effort responds to a need expressed by emergency responders during the post-Sept. 11 NIOSH RAND study of safety management practices and issues related to the protection of emergency workers www.cdc.gov/niosh/npptl/guidancedocs/rand.html. The University of Arizona study noted above on the use of air-purifying canisters against fire gases is an element of this research.
For air-purifying respirators, the CBRN approval testing also includes environmental testing, flammability testing and testing against a wide range of toxic industrial chemicals. These tests provide a wide range of protection from a single canister. These CBRN statements of standard also adopt performance requirements similar to the NFPA 1981 environmental and flammability requirements that are not traditionally part of NIOSH respirator-approval test program. NPPTL has certified CBRN APR and CBRN APR with either tight-fitting facepieces or with loose-fitting hoods. These apparatus have potential applications relevant to emergency responders. There are currently nine CBRN APR models and six CBRN PAPR models.
NPPTL is actively engaged in supporting the development of new standards for PPE for emergency responders. NIOSH has an active role on the interagency board that coordinates equipment standards and requirements across the federal agencies. And NPPTL staff serve on a number of ASTM, ANSI and ISO committees.
2007 NIOSH CBRN Certifications
|Approval Number||Model||Pressure (psig)||Max Duration (min.)|
|SCOTT HEALTH & SAFETY|
|INTERNATIONAL SAFETY INSTRUMENTS|
|TC-13F-551CBRN||Viking Z Seven 300015||2,216||30|
|TC-13F-552CBRN||Viking Z Seven 300016||4,500||30|
|TC-13F-553CBRN||Viking Z Seven 300017||4,500||45|
|TC-13F-554CBRN||Viking Z Seven 300018||4,500||60|
|TC-13F-546CBRN||FireHawk M7 Airmask||2,216||30|
|TC-13F-547CBRN||FireHawk M7 Airmask||3,000||30|
|TC-13F-548CBRN||FireHawk M7 Airmask||4,500||30|
|TC-13F-549CBRN||FireHawk M7 Airmask||4,500||45|
|TC-13F-550CBRN||FireHawk M7 Airmask||4,500||60|
NIOSH's First Responder Programs
The NPPTL effort is just part of an overall NIOSH program for firefighters and other emergency responders that includes research, surveillance and standards development.
The NIOSH Firefighter Fatality Investigation and Prevention Program aims to:
- Better define the characteristics of LODDs.
- Develop recommendations for the prevention of deaths and injuries.
- Disseminate prevention strategies.
The FFFIPP program encompasses both traumatic injuries and cardiovascular injuries. The cardiovascular project investigates the environmental, organizational and personal circumstances of the death. Data is used to generate individual fatality reports and a database to develop hypotheses for prevention and intervention activities.
The traumatic injury project aims to prevent fatalities by identifying high-risk work situations and formulating prevention strategies. Narrative reports with recommendations for preventing future deaths from similar causes and summary documents for specific hazards and topics are broadly distributed. They are posted on the Web, reprinted in trade journals and mailed to fire departments around the nation.
Information on this program can be accessed at www.cdc.gov/niosh/fire.
NIOSH also has a broad-based program on emergency response resources that reaches across the several NIOSH divisions and laboratories. Information on this program can be accessed at www.cdc.gov/niosh/topics/emres/responders.html.
The NIOSH Program Portfolio Service Sector Program contains research programs that address the concerns of first responders. The next-generation structural firefighting PPE ensemble program Project HEROES is funded by the Technical Support Working Group of the Interagency Board for Equipment Standardization and Interoperability and managed by the International Association of Fire Fighters. The goal of Project HEROES is to develop new materials and designs for a firefighting ensemble that will meet the requirements of NFPA 1971 and 1994.
NPPTL's primary role on the project is to support the development of test methods to ensure all ensembles and materials are tested appropriately. NPPTL will conduct all physiological testing of the prototype firefighter PPE ensembles. NPPTL also will supply language and support to standards organizations to remove design restrictions and allow advanced technologies to be investigated.
Also in the program portfolio is the Spirometry Pulmonary Function Monitoring Program. This program includes development, implementation and evaluation of a model spirometry screening program for respiratory conditions among the firefighters at the Phoenix Fire Department. Lung-function test data collection procedures and the quality and precision of the existing spirometry tests over a 19-year period were evaluated. NIOSH then conducted a two-day spirometry training course and has since provided continuous support for implementation of the model program. The project will develop computer software to identify clinically important changes to individual lung function tests as well as provide data to evaluate spirometry test precision over time.
The Program Portfolio Cross-Sector Program on Personal Protective Equipment contains several programs of interest to firefighters. The Firefighter SCBA Evaluations Program looks at SCBA involved in firefighter fatality incidents. The program on personal protective equipment is supported by the research of many NIOSH divisions and laboratories. The effort is lead by NPPTL.
The findings and conclusions in this report have not been formally disseminated by [the Centers for Disease Control and Prevention/the Agency for Toxic Substances and Disease Registry] and should not be construed to represent any agency determination or policy.
Heinz Ahlers is the chief of the Technology Evaluation Branch of the National Personal Protective Laboratory in Pittsburgh. NPPTL is a part of the Centers for Disease Control and Prevention National Institute for Occupational Safety and Health. Heinz has been with NIOSH since 1987 and with TEB since 2005. He has a bachelor's and master's in physics from Xavier University and juris doctor from Toledo University.