ASTM for Determining R-Value of Camping Mattresses

The guarded hot plate method is certainly the best. The ratiometric method is also good. I have built a couple of them over the years. I note that they do mention the pressure as well. Good stuff.

Cheers

That ASTM test device features an inverted guarded hotplate above and a cold plate below (with the sleeping pad placed in-between) to simulate the conditions a camping mattress experiences in use – warm body on top, cold ground below. And yes, a compression force can be applied (via weight bars).

The device looks like this, and it’s already being used by several brands you’d probably recognize:

Yes, I’ve heard this is in the works.  Even though R-value testing for pads isn’t perfect, it at least provides some kind of basis for comparison.  I would love to try some of Nemo’s products, but their temperature rating system (and Big Agnes’) just doesn’t inspire confidence.  The adoption of the EN system for sleeping bag testing did a lot to level the playing field for those products.

“Even though R-value testing for pads isn’t perfect, it at least provides some kind of basis for comparison.”

To provide any reasonable basis for comparison, they should be required to measure the R value of air mattresses when  the thickness is reduced by 50 percent, and be tested at 0 Celsius. That way they can roughly approximate what happens when someone sleeps on their side, and what happens to R value in freezing weather.

(an X-Lite’s R value claim is 3.2, while an RidgeRest SOLite’s is R 2.8, yet everyone knows the SOLite is “warmer” under normal use, since it’s a ccf pad.)