Featured Research

from universities, journals, and other organizations

Study finds failure points in firefighter protective equipment

Date:
December 12, 2011
Source:
National Institute of Standards and Technology (NIST)
Summary:
In fire experiments conducted in uniformly furnished, but vacant Chicago-area townhouses, researchers uncovered temperature and heat-flow conditions that can seriously damage facepiece lenses on standard firefighter breathing equipment, a potential contributing factor for first-responder fatalities and injuries.

Opening the door provided additional air to a smoldering living-room fire and caused the fire to increase in burning rate and flames to extend out the doorway, resulting in high temperatures and heat flows that melted a hole in the mask. Pressure sensor (brass fitting that was mounted on the face of the headform) is visible through the hole in the lens.
Credit: NIST

In fire experiments conducted in uniformly furnished, but vacant Chicago-area townhouses, National Institute of Standards and Technology (NIST) researchers uncovered temperature and heat-flow conditions that can seriously damage facepiece lenses on standard firefighter breathing equipment, a potential contributing factor for first-responder fatalities and injuries.

The findings are detailed in a report* from a research study sponsored by the U.S. Fire Administration and Department of Homeland Security. The work is an important step toward improving what may be the most vulnerable component of a firefighter's protective gear in high-heat conditions: the facepiece lenses of the so-called self-contained breathing apparatus, or SCBA.

Failure of the lens can expose a firefighter to toxic gases and can result in burns to the respiratory tract as well as asphyxiation. In several SCBA-related deaths, degraded masks were found affixed to the faces of victims while their equipment continued to supply air.

In two of four realistic living-room fire scenarios tested by NIST, "lenses exhibited bubbling and loss of visual acuity, as well as severe deformation, and, in one case, a hole," the NIST team says.

The researchers tested five models of SCBA facepieces, each from a different manufacturer. In all cases of lens degradation, the damage was due to temperatures and heat fluxes that exceeded performance limits of polycarbonate, the lens material commonly used in SCBA for fire fighters.

"Our results do not suggest, in any way, that that lens failures are due to the manufacturers," explains NIST's Nelson Bryner, a co-author of the report. "All the lenses tested were consistent with requirements specified in standards."

In the United States, SCBA makers must submit their products for certification testing before they can be sold. Certification requires passing the "heat and flame test" specified in a standard by the National Fire Protection Association. Citing the conclusions of other researchers, the NIST team notes that this test is conducted at high temperatures, but "it does not capture the conditions of temperature, heat flux and duration that a firefighter might experience."

The townhouse fire experiments will inform efforts to improve the match between standard requirements and real-life conditions. Until now, these efforts have been hampered by lack of information regarding the high-temperature and high-heat-flow performance of polycarbonate lenses and the actual fire-scene conditions that have resulted in lens failures.

The NIST experiments were conducted in two-story townhouses in Bensenville, a suburb northwest of Chicago, in cooperation with the Bensenville and Chicago Fire Departments and the Bureau of Alcohol, Tobacco and Firearms. In each of the four "furnished-house experiments," the conditions were nearly identical, save for the location of polyurethane heads outfitted with a SCBA facepiece and controlled variations in fire exposure conditions, adjusted, for example, by opening and closing of doors and windows at specified times.

Rooms were equipped with devices to record temperatures rapidly at regular intervals between ceiling and floor. Facepieces also were equipped with sensors, on the inside and the outside of the lenses and in the immediately surrounding space. A gauge to measure heat flow, or flux, was positioned next to the facepieces.

The most devastating damage occurred in a scenario akin to one in which a firefighter would enter a burning living room from a front porch. The living room fire smoldered for five minutes after ignition. Opening the front door literally breathed life into the smoldering fire. The rush of heat from the now blazing living room transformed a relatively cool environment on the porch into an inferno. The SCBA lens's exterior surface temperature reached 280 degrees Celsius (536 degrees Fahrenheit), about the midpoint of the range of published polycarbonate melt temperatures. The lens developed a significant hole, according to the NIST report.

"The next step," the NIST researchers write, "is to identify the exposure limit just before thermal degradation occurs. Data on the limits of the equipment would be valuable information for the fire service to help prevent further injuries and fatalities related to SCBA equipment failure."

* A Mensch, G Braga and N Bryner, Fire Exposures of Fire Fighter Self-Contained Breathing Apparatus Facepiece Lenses. NIST Technical Note 1724, Nov. 2011. The report can be accessed at www.nist.gov/manuscript-publication-search.cfm?pub_id=909917.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology (NIST). Note: Materials may be edited for content and length.


Cite This Page:

National Institute of Standards and Technology (NIST). "Study finds failure points in firefighter protective equipment." ScienceDaily. ScienceDaily, 12 December 2011. <www.sciencedaily.com/releases/2011/12/111207105429.htm>.
National Institute of Standards and Technology (NIST). (2011, December 12). Study finds failure points in firefighter protective equipment. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2011/12/111207105429.htm
National Institute of Standards and Technology (NIST). "Study finds failure points in firefighter protective equipment." ScienceDaily. www.sciencedaily.com/releases/2011/12/111207105429.htm (accessed July 25, 2014).

Share This




More Earth & Climate News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Bill Gates: Health, Agriculture Key to Africa's Development

Bill Gates: Health, Agriculture Key to Africa's Development

AFP (July 24, 2014) Health and agriculture development are key if African countries are to overcome poverty and grow, US software billionaire Bill Gates said Thursday, as he received an honourary degree in Ethiopia. Duration: 00:36 Video provided by AFP
Powered by NewsLook.com
Higgins Breaks Record at Mt. Washington

Higgins Breaks Record at Mt. Washington

Driving Sports (July 24, 2014) Subaru Rally Team USA drivers David Higgins and Travis Pastrana face off against a global contingent of racers at the annual Mt. Washington Hillclimb in New Hampshire. Includes exclusive in-car footage from Higgins' record attempt. Video provided by Driving Sports
Powered by NewsLook.com
Storm Kills Three, Injures 20 at Virginia Campground

Storm Kills Three, Injures 20 at Virginia Campground

Reuters - US Online Video (July 24, 2014) A likely tornado tears through an eastern Virginia campground, killing three and injuring at least 20. Linda So reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins