SCBA has evolved to greater levels of sophistication and capability over the past several decades. Transitions that increased the level of respiratory protection started with the mandatory requirement in the mid-1970s to use open-circuit SCBA in lieu of canister- or filter-based respirators in what was originally known as NFPA 19B, Standard on Respiratory Protective Equipment for Firefighters.
This gave way to development of NFPA 1981, Standard on Open-Circuit, Self-Contained Breathing Apparatus for Fire and Emergency Services in the early 1980s.
NFPA 1981 initially set requirements for positive-pressure operation and a minimum 30-minute service life above and beyond the existing federal regulations provided for SCBA by the National Institute for Occupational Safety and Health.
Successive editions of NFPA 1981 have added several requirements over the years including:
- Maintenance of positive pressure operation through various expected environmental use conditions.
- Overall system heat and flame resistance.
- A minimum of two different end of service time indicator alarms.
- Mandatory voice communications intelligibility while wearing the facepiece.
- A heads up display showing remaining air supply and other alarms.
- A universal air connection for rapid intervention team use.
- Chemical, biological, radiological and nuclear protection for the demonstrating chemical agent, biological agent, and radiological particulate hold out for entire SCBA.
NFPA 1981 is currently in a 2007 edition. Revisions worked on over the past five years will be incorporated into a new edition slated to take effect at the end of 2012 and carry a 2013 edition date. The committee responsible for this standard has researched several areas for changing the standard and developed new requirements aimed at improving the respiratory protection provided by SCBA.
Low-air alarm
The most significant of the changes to NFPA 1981 is a provision that lets fire departments and other organizations specify the time that their end of service time indicator alarm goes off (within certain limits). Currently, this indicator alarm is set to go off when the air supply reaches 25 percent of the remaining air. This is based on current requirements from NIOSH, the principal government organization responsible for baseline respirator certification.
NFPA 1981 requires SCBA meet the federal regulations for general SCBA in Title 42 Code of Federal Regulations Part 84 that pertain to SCBA. However, the committee responsible for NFPA 1981 responded to a series of requests from fire service members to in having this alarm set to go off at a higher level of remaining air supply.
These requests came as the result of fire departments realizing that they never get the full length of rated service time for their breathing apparatus. SCBA rated for 30 minutes may last only 15 minutes under hard work conditions and high breathing rates, leaving only minutes of air in the cylinder once the alarm goes off.
Many departments consider this time too short, even opting for a longer-rated SCBA is still considered inadequate. The new requirement will dictate the system to alarm at 33 percent of the full cylinder pressure as opposed the current 25 percent of the SCBA original air supply.
In addition, manufacturers will be required to change the head-up-display (HUD) to provide heads-up display signals at 100 percent, 75 percent, 50 percent, and 33 percent. SCBA are currently only required to display a signal at 50 percent; however, many manufacturers show other percentages as part of their SCBA HUD.
While NFPA was able to gain a consensus for implementing this change, it did not come easy. A change of this type is counter to the current federal regulations and would invalidate the NIOSH SCBA certification if the alarm time is other than 25 percent.
The committee had to approach the federal government to request a change in the NIOSH regulations. This change must go through a public rule-making process, which provides a means for the government to solicit comments from interested organizations or individuals regarding the proposed changes.
That process has begun. The notice of the intended change in federal regulations appears at this website link with comments to be submitted through Aug. 24.
Buddy breather
Another change is the ability to recognize and certify SCBA as having an emergency breathing support systems, more commonly known as buddy breathing systems. This type of equipment, though used within the fire service, was prohibited by NIOSH.
Due to fire service insistence and the investigation that such systems could be adequately and safely employed, NIOSH changed its regulations to permit this type of equipment and practice. Fortunately, this change was not subject to same formal rule-making process as was the alarm time setting.
Radiant-heat resistance
A requirement was added to evaluate and set minimum criteria for the radiant-heat resistance of the facepiece, which will result in changes for the types of lenses materials used. This requirement introduces a new test method to replicate an extreme fireground exposure and evaluates the resistance of the facepiece to deformation or degradation that would result in a loss of positive pressure.
NFPA has recently released a notice on the possible shortcomings of existing SCBA facepieces being able to survive extreme emergency conditions as found during a number of fatality investigations. This notice was released by the NFPA at this website address.
Facepiece integrity
An additional evaluation of the entire SCBA for continued positive-pressure operations under a prolonged high-heat exposure has been added to supplement the current overall heat and flame test.
The current edition specifies preheating the full SCBA worn on a half-manikin and attached to a breathing machine for a 15 minute at 203 degrees Fahrenheit exposure. This preheating period is followed by a 10-second exposure to a direct flame and dropping the SCBA to create shock to the SCBA suspension.
An additional test is being added where the same sequence will be followed, but the preheating period will be shorter and at a higher temperature (5 minutes at 500 degrees). The new test will address greater survivability of the SCBA in extreme environments and is coupled with the new facepiece test for demonstrating resistance to high-heat exposure degradation of SCBA components.
Clear communications
An improved communications test has been added to provide a quantified assessment of the ability of firefighters to speak and be heard through the facepiece.
The new test replaces a current method involving human subjects and listeners with a method for simulating sounds and voice communications through the facepiece using specialized test equipment. It is intended to overcome the inconsistencies associated with using human subjects and provide more objective procedures for evaluating the effects of SCBA in allowing clear and understood voice communications.
These significant changes will impact the design of all SCBA in the U.S. market. It will likely be several months after the new standard comes out when SCBA manufacturers will be able to offer new products and have them certified to these requirements.
In the meantime, it is important for the fire service to understand these changes and their implications in anticipating newer edition SCBA or retrofits to existing SCBA.
