Building physical material properties
The transfer of mass and energy in materials are studied in the building physics laboratory. In practice, this means material properties related to heat, air flow and humidity.
Equipment characteristics
Heat flow meters
- Thermal conductivity λ [W/(m·K)] ja thermal resistance R [m2·K/W] is measured with heat flow meter apparatus.
- Thermal conductivity is used e.g. when calculating structural elements’ thermal transmittance coefficient i.e. U-value U [W/(m2·K)].
- Thermal conductivity can be measured in different temperatures and relative humidity conditions to represent material’s properties in different conditions.
- Tests can be done for most of the building materials e.g. thermal insulations, wooden materials, concrete, plaster and various plates.
An Automatic Free Water Uptake Equipment
It will be especially important to know the capillary properties of the building materials when analyzing the structures exposed to rainwater or moist soil. These properties are examined by a free water intake test. The test is performed in the laboratory; the specimen is immersed in water and the weight change is measured. The following material characteristics can be determined with the test equipment:
- Water Absorption Coefficient (Aw)
- Water Penetration Coefficient (Bw)
- Water Content at Capillary Saturation (wcap)
- Maximum Water Content (wmax)
- Liquid Water Permeability (w)
- Water Suction Height (hcap)
Pressure plate equipment
Soil Moisture 15 and 100 bar pressure chambers. The equipment is used to determine the desorption curve of the material in the capillary (95–100% RH) region. In the experiment, pieces saturated with water are dried using excess pressure. The resulting capillary equilibrium moisture curve can be presented as a function of average pore pressure or air humidity. The standards NT Build 481 and ASTM C1699-09 are used in the tests.
Vacuum chamber
The side dimensions of the chamber are 300 mm, and the device achieves an absolute pressure of less than 10 Pa. The equipment can be used to determine the material's dry and wet density and porosity.
Water vapor permeability test equipment
Vapor permeability and resistance are determined by cup tests, where a moisture flow is created through the object using different air humidity inside and outside the cup. The test can be carried out in the area of low or high relative humidity using different humidity pairs.
Dynamic vapor sorption analyzer
Dynamic vapor sorption equipment (dynamic vapor sorption DVS). Determination of the hygroscopic adsorption and desorption curve with small samples weighing < 1.5 g. The equipment weighs the test piece in real time, which provides dynamic, i.e. time-dependent, data on the behavior of the material. An additional advantage of the equipment is faster curve determination than traditional methods due to the small size of the test pieces.
Climate rooms
Two automatically controlled climate rooms for 10–30 °C and 30–90% RH humidity. In addition to the rooms, there are also humidors for 11–94% RH conditions.
Air permeability measurement equipment
Two air permeability measuring devices that can be used to measure the material properties of solid bodies of different sizes, sheet insulation and blown insulation:
- airflow resistance AFr [(kPa·s)/m2]
- air permeability Ka [m3/(m·s·Pa)]
- modified Rayleigh number Ram (together with thermal conductivity tests)
- Pressure differences: in the basic case, the maximum pressure difference is 50 Pa, the pressure difference can be increased if necessary. Air flow velocity range: <1 mm/s – 0.5 m/s.
Latest publications
Vanttinen K., Tuominen O., Tuominen E., Valovirta I., Karjala P., Tuurala I., Vinha J. (2023) Equilibrium Moisture Content of High Strength Concrete Used in Hollow Core Slabs. Journal of Physics: Conference Series, 2654 (1). https://doi.org/10.1088/1742-6596/2654/1/012032
Tuominen, O., Tuominen, E., Vainio, M., Ruuska, T., Vinha, J. (2019) Thermal and moisture properties of calcium silicate insulation boards. MATEC Web Conf. 282 02065 https://doi.org/10.1051/matecconf/201928202065
Vinha, J., Tuominen, E., Valovirta, I., Hietikko, J., Tuurala, I., Huttunen, P., Jokela, T., Forss, A., Saari, A., Joensuu, T., Malaska, M., Alanen, M., Salkinoja-Salonen, M., Vaali, K., Brander, J. Moisture-proof and environmentally friendly timber structures with wood shavings insulation – Final report of the ECOSAFE and ECOSAFE 2 projects [in Finnish] Tampere University. Civil Engineering. Research report 8. https://urn.fi/URN:ISBN:978-952-03-2958-7
Vinha J., Laukkarinen A., Kaasalainen T., Pihlajamaa P., Teriö O., Jokisalo J., Annila P., Harsia P., Hedman M., Heljo J., Kallioharju K., Kauppinen A., Kero P., Kivioja H., Lehtinen T., Marttila T., Moisio M., Mäkinen A., Paatero J., Raunima T., Ruusala A., Sankelo P., Sekki P., Sirén K., Tuominen E., Tuominen O., Uotila U. & Uusitalo S. Comprehensive development of nearly zero-energy municipal service buildings (COMBI). Introductory and summary report of the research project. Tampere University of Technology. Civil Engineering. Research report 168. 2019. https://urn.fi/URN:ISBN:978-952-15-4306-7
Tuurala, I. (2022) Building Physical Properties of Wood Shavings Insulation Materials. Master's thesis. Tampere University. Tampere. https://urn.fi/URN:NBN:fi:tuni-202206155671
Tuominen, O. (2020) Moisture Properties of Inner Shell and Hollow-Core Slab Concretes and Improvement of Measuring Methods. Master's thesis. Tampere University. Tampere. https://urn.fi/URN:NBN:fi:tuni-202005095134