A unit of thermal resistance used to describe textiles. It was mainly used to describe how “warm” duvets, sleeping bags and baby buntings were. One tog is one square meter-Kelvin per watt, multiplied by ten and rounded to the nearest whole number.
Some typical values:
|sheet of polyethylene||2|
|summer quilt or sleeping bag||4|
|winter quilt or sleeping bag||12|
The tog was devised by the Shirley Institute in Britain in the 1960's, who also produced an instrument to measure it, the Shirley Togometer.
The tog is often converted into the clo at the rate of 1 tog = 0.645 clo. However, the clo measures clothing, the tog measures cloth.
The tog has been replaced by the comfort ratings required by European Norms, EN13537 for sleeping bags and EN12934 for quilts.
British standard describing the tog test.
The values were expressed in togs (the tog value of a fabric is defined as 10 times the temperature difference in °C between its two faces when the heat flow is equal to 1 w/m²). For example, the thermal resistance of an unbrushed blanket is 15 tog.
Anne-Louise Ponsonby, Terence Dwyer, Laura E Gibbons, Jennifer A Cochrane, Michael E Jones and Michael J McCall.
Thermal environment and sudden infant death syndrome: case-control study.
BMJ, vol 304, page 278 (1 Feb 1992)
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Last revised: 7 November 2013.