John Smith, Project Leader, and Tony Petrilli, Equipment Specialist
One of the simple pleasures enjoyed by firefighters at the end of the day is a few hours of sleep nestled inside a comfortable sleeping bag. That pursuit will soon be enhanced by the introduction of a new cold weather sleeping bag to the General Services Administration (GSA) lineup (figure 1).
Figure 1—Paper sleeping bags were used
during the 1970s; the new cold weather bag
uses
the latest synthetic fibers for insulation.
GSA currently offers firefighters two sleeping bag options, warm weather and cold weather bags. Federal workers, who responded to a questionnaire in 2009, pointed out shortcomings of both bags. Addressing the issues with the current cold weather sleeping bag was determined to be the first and most important step toward better meeting the needs of firefighters; cold weather sleeping bags are used more frequently than warm weather bags.
- Changes in insulation and length were needed to increase warmth and comfort of the cold weather sleeping bag.
- These changes made almost no noticeable difference in weight or bulk.
- The improved cold weather sleeping bag retains its basic design with an integrated hood and two-way zipper
The key attribute identified for improvement in the cold weather bag was its ability to provide adequate warmth for an occupant. Most field test evaluators rating the new sleeping bag thought it performed much better than the current GSA sleeping bag in keeping them warm (figure 2). The difference is credited to a new type of synthetic fiber that is used for the bag's insulating material.
Figure 2—The test bag was rated good or excellent
for warmth by 88
percent of
the respondents
compared to 49 percent of the respondents who rated
the
current General Services Administration (GSA)
bag as good or excellent
The European Norm (EN) 13537 laboratory mannequin testing methodology for sleeping bags is preferred by many popular outdoor equipment stores and sleeping bag manufacturers. The Institute for Environmental Research at Kansas State University used this methodology during August 2012 to test sleeping bag performance. The redesigned sleeping bag EN Comfort Rating for women is 28 °F; this is the lowest temperature at which a "standard" woman can expect to sleep comfortably. The EN Lower Limit Rating for men is 17 °F; this is the lowest temperature at which a "standard" man can expect to sleep comfortably. The EN Extreme Rating, a survival rating for women, is minus 16 °F; this is the lowest temperature at which a "standard" woman can remain for 6 hours in the redesigned sleeping bag without risk of severe hypothermia. These temperatures are about 13 °F lower than the current bag. The EN 13537 testing reflects the scientific determination that, on average, women are colder than men when sleeping in identical conditions. The EN 13537 defines the "standard" woman as 25 years old, 5 foot 3 inches tall, and weighs 132 pounds; the "standard" man is defined as 25 years old, 5 foot 8 inches tall, and weighs 176 pounds.
The second attribute targeted for improvement was the current sleeping bag's sizing. To address a length concern of taller individuals, the test bags were 5 inches longer than the current GSA bag. As a result, the majority of field test evaluators rated the length of the test bags considerably higher than the current GSA bag (figure 3). This increase in length was found "satisfactory" by field test evaluators as tall as 6 feet 4 inches. The width of the sleeping bag is unchanged from the current bag and also was found "satisfactory."
Figure 3—The test bag was rated good or excellent
for length by 100 percent of the
respondents
compared to 53 percent of the respondents who rated
the current
General Services Administration (GSA)
bag as good or excellent.
- Sleeping pad—Besides cushioning, a sleeping pad insulates the occupant in the bag from the ground.
- Tent—Using a tent can increase sleeping temperature as much as 10 °F.
- Clothing—Wearing long underwear, socks, and a cap will help insulate the body but be careful of overheating.
- Hood—Cinching the hood of the sleeping bag with the draw string can reduce body heat loss.
These two improvements to the sleeping bag, better insulation and increased length, were accomplished without increasing the bulk and weight of the new bag. In fact, the test bag weighs in at about a half of a pound lighter than the current bag. The overall bulk is not noticeably different, both bags stuff into the current GSA personal gear pack (red bag) with about the same degree of effort.
The new sleeping bag remains a mummy-type design with an integrated hood and a two-way zipper that can be unzipped from either end to help regulate temperature. As the standard bag carried by the National Interagency Support Cache system, it is made to withstand required repeated washing and drying.
The new cold weather sleeping bag is now available from GSA for $92.26 per bag. The national stock number (NSN) is 8645–01–602–3355; the National Fire Equipment System number (NFES) is 0128.
About the AuthorsJohn Smith joined MTDC as an equipment specialist in 2005 and was a project leader until his retirement in 2011. He graduated from the University of Montana with a bachelor's degree in education and taught elementary school in Ovando, MT. He began his Forest Service career in 1974 as a wildland firefighter for the Lolo National Forest's Superior Ranger District. A Missoula smokejumper for more than two decades, Smith applied his experience as assistant loadmaster foreman and master parachute rigger when developing equipment for firefighters.
Tony Petrilli is an equipment specialist for the fire and aviation and safety and health programs at MTDC. He has a bachelor's degree in education from Western Montana College. Petrilli began working for the Forest Service in 1982 and joined MTDC full time in 2000. He has worked as a firefighter for the Lewis and Clark and Beaverhead National Forests and as a smokejumper for the Northern Region.
Additional single copies of this publication may be
ordered from:
USDA Forest Service
Missoula Technology and Development Center
5785 Hwy. 10 West
Missoula, MT 59808–9361
Phone: 406–329–3978
Fax: 406–329–3719
Email: wo_mtdc_pubs@fs.fed.us
Electronic copies of MTDC's publications are available
on the Internet at:
http://www.fs.fed.us/eng/pubs
Forest Service and Bureau of Land Management
employees can search MTDC's documents, CDs, DVDs,
and videos on their internal computer networks at:
http://fsweb.mtdc.wo.fs.fed.us/search/
For additional information about the cold weather
sleeping bag improvements, contact MTDC:
Phone: 406–329–3900
Fax: 406–329–3719
