The laboratory is used for thermal testing of clothing and equipment and for physiological studies. Testing includes studies on human subjects (click on the picture to see a short movie from our climatic chamber) as well as on thermal manikins. Available instruments can be used also in the field.
Students may use the lab facilities in order to learn how different materials and products feel and behave in cold or hot environments. They can expose themselves to heat and cold, and experience how the body reacts. There are possibilities to do master projects related to our research area.
The Thermal Environment Laboratory has 2 climatic chambers: a warm chamber (height×width×length: 2400×2360×3200 mm) and a cold chamber(2400×2360×2400 mm). The chambers were constructed and taken into use at the end of 2003. The chambers may be programmed in advance to change the temperatures according to experiment needs.
The warm chamber can be adjusted from +5 to +60 °C and temperature standard deviation (SD) from set value is less than ±0.2 °C. The relative humidity in this chamber can be adjusted from 10 to 95 % depending on temperature and humidity SD from set value is less than ±5 %.
The cold chamber can be adjusted from –53 to +20 °C and temperature SD from set value is less than ±0.4 °C.
We possess several thermal manikins: whole body manikins, foot, hand, head and baby models.
The thermal manikin TORE is often used to measure insulation of protective clothing or sleeping bags including standard tests (EN 342 and EN 13537), but also in product development work for manufacturers. In this respect has TORE an important property of being able to simulate walking (click on the picture to download a movie clip). This allows the complex evaluation of not only materials but also design of the garments in respect to air flows around the body and ventilation in the garment ensembles. Another thermal manikin is commonly used to evaluate indoor environments and climate in vehicle cabins. The use of such manikins has increased rapidly within the last years, especially in automobile industry for evaluation of heating and ventilation and air conditioning (HVAC) systems of the cars (ISO 14505 - Part 2).
Body part thermal models have also been developed for more detailed studies of thermal properties. At present there is available a standard for handwear thermal testing (EN 511). A baby manikin has been used for evaluation of incubators for neonatal care.
We have temperature instruments available such as various sensors with loggers (Testo 177-T4 for thermocouples, MSR 145W with options to measure temperature, humidity, pressure and acceleration etc). Stationary skin and body core temperature measuring systems comprise NTC-resistance temperature matched thermistors and YSI probes connected to NI components run by Labview.
For air velocity and flow measurements we use instruments from Swema. Swema has also provided us with a special instrument to measure respiratory flow rates.
Activity levels at the lab can be generated by various equipment. Most common are bench for steptest, ergometer bicycle and treadmill. Physical load can objectively measured by recording oxygen consumption with Metamax equipment.
We have several other environment instruments, e.g. WBGT-meter etc., and computer based tools, e.g. evaluation models, available at the laboratory (see also Tools).
Walkway with built-in force plate and adjustable inclination (0-30 degrees)
A walkway is designed and constructed with a built-in force plate and adjustable inclines. The inclination angle is adjusted using a hydraulic actuator. The walkway surface material is initially made of steel plate. The surface material can be changed and lubricated with different contaminations (water, oil, ice, etc.). The width of the walkway is 1.0 m and the length is 6.1 m. The force plate (600 x 400 mm, Kistler type 9281, Switzerland) is used to measure ground reaction forces when a human subject walks on the walkway. Three dimensional (3D) forces (horizontal anterior-posterior Fy, medial-lateral Fx and vertical Fz) are recorded by a 64ch DAQ System (type 5695A) with BioWare® (2812A) (sampling frequency: 1000 Hz). The available and required coefficient of friction at the shoe-floor interface can be calculated depending on the type of measurements. The walkway makes various studies possible with different combinations of slope angle, surface material, contamination and shoes.
Laboratory tests are often used to evaluate specific conditions for industries, but also for developing standards, mathematical prediction models and to set limit values, e.g. exposure limits. These are often validated during field trials. The field trials are also carried out on the request of industries in order to identify thermal risks and find solutions to their problems. For example, we have carried out tests for Swedish Rescue services, glass industry, power plant at Ringhals, agriculture etc. Also, the functionality of the equipment in extreme climatic conditions may be tested at the laboratory.