Testing EPIC® by Nextec
MVTROverview: MVTR is a measurement of the amount of moisture vapor that can pass through a fabric under very controlled conditions.
Procedure: There are many different methods to determine MVTR, most involve small cups of water covered with a sample of fabric and placed inside a climate-controlled chamber. After 24 hours the cups are weighed and the moisture vapor transfer rate is calculated (units g/m2/day.)
Relevance: The very nature of the standardized conditions required to perform the MVTR tests limit their usefulness. Without incorporating temperature or pressure gradients, the test cannot account for real world variables. Claims of high breathability numbers in the lab are not necessarily representative of field results.
Dry Time
Overview: Measures drying time of a fabric which has been made wet under standardized conditions.
Procedure: A fabric specimen is placed in distilled water and allowed to come to equilibrium, then placed on a balance at specified temperature and humidity. The balance is interfaced with a computer and the change in weight is recorded every second. Weight loss is equal to the amount of water lost to evaporation. The time the fabric takes to reach consistent weight is considered dry time for the material.
Relevance: Drying time is an important element of fabric performance. A garment that remains wet and cold will draw heat from the body. The faster a garment dries, the less likely the wearer is to experience heat loss and discomfort.
SUTEROverview: The benchmark waterproofness test, it measures the amount of pressure it takes to pass water through a fabric.
Procedure: Water is steadily pressed against fabric until the water penetrates the fabric.
Relevance: The concentrated water pressure created in the Suter test is an extreme exaggeration of that encountered in real world conditions, therefore the test is not an accurate gauge of performance in the field. The Suter test also disregards how greatly breathability is sacrificed in pursuit of extreme water repellency.
BUNDESMANNOverview: Comprehensive measurement of performance properties.
Procedure: Fabric samples are secured over the top of metal cups. Crossbars rotate behind the fabric simulating body movement inside a garment. Water falls from a height of five feet onto fabric samples. A visual scale measures how well water beads up and rolls off the fabric (repellency.) The fabric is weighed before and after the test to determine how much water it has absorbed. The volume of water in the cup is measured to determine how much water, if any, has passed through the fabric.
Relevance: With the severity and duration of this test, the Bundesmann creates a performance profile that relates closely to how the fabric will perform in the real world.