Thermal comfort is the feeling of comfort and wellbeing experienced by the wearer of a garment. If your body isn’t thermally balanced, then your physical performance may suffer and this may necessitate the use of other devices to bring your body up to temperature in cold weather, or cool it when it’s hot. UNE-EN ISO 11079:2009 Ergonomics of the thermal environment – Determination and interpretation of cold stress when using required clothing insulation (IREQ) and local cooling effects – describes two thermal stress situations that a person may find themselves in owing to their clothing.

Standards and tests to prevent cold stress

There are two standards designed to prevent cold stress: UNE-EN 342:2017 for suits and single garments to protect the wearer against temperatures below -5ºC, and UNE-EN 14058:2017, for single garments to protect the wearer against temperatures above -5ºC . The former specifically tests a garment’s thermal resistance (Rct).

“Both are complementary but it is the test using a thermal mannequin that provides more in-depth data, as it provides information for the user on the degree of cold protection the garment or article offers”.

Standards and tests to prevent heat stress

Various protection standards include a measurement for water vapour resistance (Ret) according to UNE-EN ISO 11092:2015 in their requirements. However, this test on its own is insufficient to determine heat stress, as it only evaluates materials. ASTM F2370-22 Standard Test Method for Measuring the Evaporative Resistance of Clothing Using a Sweating Manikin – provides more in-depth data, as it measures the breathability of whole garments (including the component materials and the overall design).

Tests to measure thermal comfort

AITEX has two tests to measure the thermal wellbeing of a wearer in real thermal stress situations. One uses the Centre’s thermal mannequin connected to simulation software that recreates a wearer’s thermo-regulatory system on the mannequin’s body to determine the wearer’s feeling of thermal comfort.

The other involves measuring thermal comfort on real subjects. The test determines the feeling of comfort and wellbeing of a subject in real situations using temperature and moisture sensors placed on the subject’s body, heat cameras and detailed questionnaires.

Thermal comfort then, is essential to ensuring the optimum wellbeing and performance of the wearer, and is affected by environmental conditions and the clothing worn. In the Centre’s thermal laboratories, we evaluate thermal wellbeing, and our sights are firmly set on researching and developing thermal comfort solutions for a wide range of environmental conditions.