Key changes in standards will have a noticeable impact on self-contained breathing apparatus (SCBA) and personal alert safety systems (PASS).
By Mike Rupert
Two newly revised standards from the National Fire Protection Association (NFPA) were issued on Dec. 20, 2006. NFPA 1981-2007 – Standard on Open-Circuit Self-Contained Breathing Apparatus for Fire and Emergency Services – and NFPA 1982-2007 – “Standard on Personal Alert Safety Systems” – feature some changes that could impact respiratory protection and responder safety in the near future.
Although these new, 2007-edition standards are already in effect, NFPA does permit SCBA and PASS manufacturers to continue shipping NFPA 1981-2002-edition SCBA and NFPA 1982-1998-edition PASS devices through Aug. 31. After August 31, NFPA will no longer permit the use of previous-edition approval labels on newly manufactured products.
At the time of this writing, no product has yet received approval from the National Institute for Safety and Health (NIOSH), which still is testing products submitted by various manufacturers.
Changes to SCBA
Protection from chemical, biological, radiological and nuclear (CBRN) agents initially was proposed and then removed from the standard during the voting of the technical committee, but it was reinstated by the NFPA Technical Correlating Committee to keep the standard consistent with NFPA 1500 – Standard on Fire Department Occupational Safety and Health Program. This standard requires all newly purchased SCBA to be CBRN-compliant. With most brands of SCBA, the additional cost for CBRN protection is little, and the differences related to non-CBRN SCBA are virtually transparent.
Because this was not the case with all brands of SCBA (some did have more-noticeable differences), this issue was much-debated. Ultimately, however, CBRN protection was believed to be valuable protection for all first responders in all locations, due to the unpredictable and random nature of terrorist attacks, and it is now part of the standard.
Changes to PASS
Mechanical voice diaphragm performance changed from a minimum score of 72 percent to 80 percent at a distance of 5 feet. An additional requirement for voice communication systems, which may call for an electronic amplifier, has been set at an 85 percent minimum score at a 10-foot distance.
This requirement provides firefighters with a greater ability to communicate in a noise-filled emergency scene. It was anticipated that an electronic amplifier would be required to meet the 85 percent level. To ensure that firefighters have effective communications if their electronics fail, the 80 percent requirement is specific to a mechanical system.
More rigorous water-immersion testing has been added to both the 1981 and 1982 standards. All electronic devices must function properly and remain watertight following six cycles of heat at 350° F for 15 minutes and water submersion to 1.5 meters deep. Previously, PASS devices had to undergo temperature stress tests from -4º F to 160º F; then, after being conditioned to a nominal 113º F, they had to remain watertight after water immersion for 2 hours at a 1-meter depth. HUD (heads-up display) devices on SCBA underwent a liquid splash test and had no immersion requirements.
This requirement will help to ensure that electronics function properly in the field after repeated exposure to heat and water. PASS device failures, like those reported by MSNBC recently, have been associated with water ingress as a contributing cause. For example, with MSA’s product, this change means permanently sealing electronics enclosures by hermetic sonic welds, and placing radial-sealed threaded caps on battery compartments.
A challenging 3-hour tumble test has been added to PASS devices only. The primary reason for this change is to ensure that electronic circuitry can endure long-term rough handling and transportation. The test is based upon an apparatus that companies like MSA have used for years in the development of products, to ensure durability during rough handling.
The test consists of a 4-foot-diameter “squirrel cage” that rotates and tumbles its contents. Circuitry modifications will likely be required to most products on the market to better protect them from the impact and vibration. Early screening tests revealed that some products had difficulty enduring only minutes of testing.
A new muffle test has been added to PASS devices. In this test, the device must emit 95 dBA of sound at 3 meters while the wearer is positioned in each of five orientations (face down, supine right and left and fetal right and left). The test helps to protect against the accidental muffling of a PASS device in various orientations.
It appears that air cylinders are effective in elevating the user enough to prevent muffling. Therefore, a potential solution is to place sound emitters behind the SCBA cylinder.
In 2005, NIOSH’s Fire Fighter Fatality Investigation and Prevention Program contacted organizations representing firefighters and rescue workers to tell them that exposure to high-temperature environments may cause the loudness of PASS alarm signals to be reduced, causing the alarm signal to become indistinguishable from background noise at the incident scene.
With the revised standard, the high-temperature performance of PASS devices has been raised from 200° F for 15 minutes to 500° F for 5 minutes, after which the PASS must emit 95 dBA of sound at 3 meters. Because this will require design modifications to all products on the market, it is probably the most challenging aspect of the new standard.
MSA has developed a unique horn to meet this requirement. The horn has consistent performance (sound output and power use) over a complete range of temperatures and is one of the most innovative features of MSA’s new PASS product.
While it may be possible to overdrive conventional piezo sound emitters to meet this test, their performance will likely be compromised, as they may be too loud at typical temperatures, consume excessive battery power, and possibly shorten their service life.
Data-logging will be a new requirement for all PASS devices. Most brands on the market do not have this feature. An independent pressure gauge (mechanical or electronic) that is not affected by the failure of the HUD will be required on all SCBA, and will likely result in a chest-mounted mechanical gauge. Also, the tightness of the CGA cylinder valve handwheel will be tested to prevent it from loosening during use.
In summary, these changes represent the most significant differences between the new and previous-edition standards, although there were several more – relatively minor – changes. Most SCBA will need to undergo a redesign of their electronics to meet the new standards. However, pneumatic air-delivery systems will probably not be affected.
Mike Rupert is product group manager for MSA’s first responder products, including SCBAs, TICs, Cairns helmets, ballistic body armor and other vital equipment. Currently a member of NFPA’s 1981 Committee, Rupert has worked as an engineer and product manager for MSA’s safety products since 1990.