Sleeping Bag Ratings
Sleeping gear keeps you more than just warm and comfortable at night. If Scouts have inadequate sleeping gear or their gear gets wet, they will be miserable and are at risk of hypothermia.
Sleeping Bag Ratings
Temperature ratings can be misleading or flat out completely false. Beware of temperature ratings, especially on bags not made by the reputable manufacturers.
Reputable Sleeping Bag Brands Include:
Mountain Hardwear
Marmot
REI Co-Op
Therm-a-Rest
NEMO
Big Agnes
Sea-to-Summit
Kelty
Feathered Friends
Zpacks
European Norm and International Standards Organization Ratings
Prior to 2005, sleeping bag ratings were whatever the manufacturer was willing to set for a bag. This led to significant inaccuracies and risk of harm if campers used ratings as stated.
In 2005, the EN 13537 Standard was introduced - creating the first real standardized rating system.
In April 2017, the ISO 23537 Standard updated the EN 13537 Standard and created a new testing protocol for sleeping bags.
ISO Standards were revised in January 2018 and again in March of 2022.
Beware of NON-EN/ISO Ratings! These are misleading and potentially dangerous.
Read more about ratings at backpackinglight.com/standards-watch-sleeping-bag-temperature-ratings.
EN/ISO Standards
The EN/ISO Standards provides a Range of temperatures
Maximum
Rarely seen test
Tested with manikin with arms out, zipper open, flattened hood and no face mask
Not shown in graphic above
Comfort
Considered the range where a "standard woman" is comfortable
"not feeling cold" in a "relaxed posture"
Of the 3 ranges generally shown on a sleeping bag rating, this will be the highest range
Limit
"Standard man" "in a situation of fighting against cold (posture is curled up inside the sleeping bag), but in thermal equilibrium"
Curled up but not shivering
aka "Transition"
Of the 3 ranges generally shown on a sleeping bag rating, this will be the middle range
If a single rating is used, this is generally the rating shown
Extreme
"In this range, a strong sensation of cold has to be expected. There is risk of health damage by hypothermia. A sleeping bag should only be used in this range in an emergency"
aka "Risk"
Of the 3 ranges generally shown on a sleeping bag rating, this will be the lowest
Note: Sleeping bag ratings are based on a person
Wearing long underwear and socks
Sleeping on an insulated pad with an R-value of 5.5
Note that some reputable manufactures still do NOT use EN/ISO standards for testing. These include Western Mountaineering, Big Agnes, and Feathered Friends.
Bag/Pad Rating Recommendation
Which bag rating should you use?
Cold Sleepers should use "Comfort Rating"
Warm Sleepers can use "Transition Range"
10-Degree Buffer Rule
The 10-Degree rule is to take the expected nighttime low temperature and subtract 10 degrees for your bag.
Example: if you are going on an outing with an expected nighttime low of 20 degrees, you should pack a sleeping system rated for 10 degrees or lower.
20-Degree Rule
20-degree ratings should be appropriate for most 3-season adventures in our part of the world. A 20-degree bag can be used in the winter (Washington State) with an extra blanket, insulated clothing, proper precautions and skilled supervision.
0-Degree Rule
0 degree ratings should cover most winter adventures you will take a scout on in Washington State- assuming they are equipped with proper gear, know the basics and has skilled adult supervision.
Mountain Rule
The mountain is unforgiving. Extreme temperatures require specialized training, precautions and supervision. Gear selection needs to be discussed with a knowledgeable and experienced adult guide.