The testing of materials and the selecting of appropriate fabric is one of the most important stages in the development of new products. Only the most suitable material with the perfect cut and effective design is guaranteed to produce 100% functional sport and leisurely clothing.
In order to ensure that a quality and functional material has been chosen, it is necessary to test all parameters not only by wearing the final products (Direct Alpine test team) but also by testing them in the laboratory. In this way, we cooperate with the Department of Clothing Technology at the Textile Faculty (TUL) at the Technical University of Liberec. Their top-notch laboratories provide the most up-to-date measuring devices. The department also actively participates in the developing of new technologies in the textile industry. For outdoor garments, the most important parameters are: waterproof, windproof, vapor permeability, abrasion-proof.
Let’s have a look at a brief overview of the testing devices that are used by our company prior to carrying out fabric selection and the subsequent production.
This machine is used to determine the endurance of material in relation to abrasion and lint resistance (“pilling”). This test is carried out by rubbing the material against the same textile and measuring the level of pilling. In the case of testing the abrasion level, the material is rubbed by a specific, standardized wool material, a kind of “sand paper.” The results of this measurement are evaluated visually using etalons. The limit of the suitability of any given material is approx. 15,000 rotations without remarkable damage (approx. 3 years of garment use without the forming of lint balls).
See below for the pilling tests of materials Patrol and Badile after 20,000 and 40,000 rotations.
Badile (20.000 rotations) Badile (40.000 rotations)
Patrol (20.000 rotations) Patrol (40.000 rotations)
This machine measures the textile’s level of water penetration; in other words, it is an “evaluation of repellence.” The device provides the possibility to set the desired waterproof level as well as the resistance of materials to water absorption. Measuring is carried out via rain simulation on the tested material for a given amount of time with a given amount of water. Immeability and “non-absorption” of textiles are evaluated visually by using photo-etalons and by weighing the material. Primarily we use Kudos XR from Toray or Nano tech and DWR (durable water repellency) impregnation technologies. In some cases, using a perfect waterproof repellency is better than using a membrane (i.e., products where high vapor permeability and sufficient wind and waterproofing is required).
Human skin simulation
The measuring of vapor permeability is one of the most important features of not only outdoor clothing, but also for membrane materials. This machine measures resistance to vapors. The basis for this test is a heated and moist porous panel that simulates the human skin. The measurement comes from the relation between evaporation and heat flow. The simulation illustrates the evaporation of moisture from skin and its permeability through the textile. For this kind of test, DIRECT ALPINE uses membranes g/m2/24h (it is also possible to use the Ret Method). The higher the level of vapor permeability (v g/surface/time), the better the ability of the textile to evaporate moisture. Of course, the practical functionality in terms of vapor permeability is related to the surroundings as well (temperature, air moisture, air circulation, etc.).
The system of membrane materials is based on the well-known principle of porous membranes which, thanks to “micro-pores,” vapors are able to evaporate from the inside. On the other hand, “micro-pores” are so small that, for example, a single rain drop cannot pass through (it is much bigger than the water and vapor molecules). Water penetration is not determined by the membrane itself, but by the difference between the temperatures and partial pressures inside and outside. The porousness of the membrane is clearly visible on the membrane Entrant DT (Mallet, Midi) – size of a rain drop vs. vapor. In our production, we use membranes from the Japanese company Toray (different kinds of Enrant) and our own 4-way Tex.
Human comfort simulation
Physiological properties of clothing are one of the properties desired from functional clothing and are important because they significantly influence not only the wearer's feelings, but also their psyche and performance (e.g., athletes, soldiers, police officers, etc.) The most objective way is to carry out testing with probands. These can be carried out under real conditions – using clothing in real situations or under controlled climatic conditions in a laboratory. Measurement under controlled conditions has significant advantages as testing conditions are reproducible and sensors can be connected to a person's body with the aim of acquiring objective data. Such data may include heart rate, temperature, and skin moisture that is measured on various points of a proband's body (in the limit layer or in the clothing structure, including the sensory assessment of clothing). The research activity consists of testing various types of apparel and materials and all according to pre-defined conditions of the environment, including the choice of monitoring selected quantities which provide possibilities of measuring clothing comfort.
The togmeter measures thermal insulating features of materials. The higher the thermal resistance, the better the material’s insulating features. We use this device mainly when choosing winter product materials (Polartec, Primaloft). In spite of having a higher weight/m2, some materials have low thermal resistance. Therefore, the objective of this measurement is to achieve maximum thermal resistance along with minimal weight and compressibility.
Shirley hydrostatic head tester
This device is used for measuring the water column (the resistance of fabric to water penetration); the device measures whether water pressure is adequate in relation to the water column. Compressed air and water from the machine’s nozzle apply pressure on the fabric. The limit for an outdoor barrier textile is a minimum of 10,000 mm (kneel down in the snow – 10,000 mm of water column pressure, according to the weight of the person). The membranes that we use in our Mountain Top Series achieve 20,000 mm (Mallet, Midi – 30,000 mm). In spite of the relatively high water column numbers of the materials we use, our main focus is on the vapor permeability of membranes produced by the Toray company; Toray guarantees their functionality as does their long-standing reputation.
The thermal imager is one of the most progressive methods for measuring temperature fields. This method detects the temperature field on the surface of materials by measuring the intensity of the infrared radiation.
Our measurements are primarily focused on:
- detecting both the overt and hidden locations of heat loss on the human body in relation to a specific outfit
- comparing the protection against the cold of various outfits along with various insulating materials
- determining the optimal combination of outer and insulation materials and thus resolving design details
This device assists immensely when choosing the best insulation materials and construction. IT allows us to objectively select materials with the most favorable price/performance ratios. With a thermal imager it is possible to eliminate heat loss through seams, pockets, and other details and to resolve the optimal design of clothing.
This device is used for measuring resistance to wind. This test measures the level of a material’s resistance to the influence of wind coming from the outside. The lower the permeability of the material, the better its resistance to wind.
RIPPER - Strength in tension - Lab Test 2050
This ripping device is used for the measuring of strength and elasticity. The device is controlled by a computer and is fully configurable. In the laboratory it is equipped with a 5000 N sensor (for fabrics) and a 250 N sensor (for threads). During testing, a sample with the defined dimensions is stretched at a constant rate until it rips. The maximum force reached is recorded as well as the corresponding elongation at the ripping point, represented by the ratio of the elongation of the sample in comparison with its initial length which is expressed as a percentage. This process is used for verifying the strength of fabrics or knitted materials as well as for threads and/or utilized zippers.
With this device we are able to guarantee a consistent production quality that encompasses the durability of the product as well as the optimal choice of materials.
This a machine used for testing the waterproofness of sealed seams.