ASTM F3340-18

1.1 This test method covers the measurement of the thermal resistance of camping mattresses in conditions of steady-state heat transfer, using a two-plate apparatus. The camping mattress is held under constant compressive force between a guarded hot plate and a cold plate. The primary heat transfer for this method is one dimensional, vertically through the camping mattress thickness. As such this measured thermal insulation value is a repeatable comparative measurement. However, it should be noted that this value may not always correlate to actual insulation performance as real-world heat transfer may differ slightly because of additional heat losses possibly involved (for example, edge heat loss, uncovered surface heat loss, compression rate changes or posture changes during sleep).