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A new fast response measuring instrument (Skin Model) for the non-destructive determination of       water-vapour and thermal resistance or permeability of textile fabrics, nonwovens, foils and paper sheets

Download here the Permetest Manual 2009

      Main technical parameters:

Range of water vapour resistance Ret:                from 1 to 200 m2Pa/W
Range of relative water-vapour permeability:         from 1,5 to 100%
Range of thermal permeability:                           from 1 to 50 W/m2/K
Range of thermal resistance Rct:                        from 0.02 to 1 m2K/W
Range of fabric thickness:                                  from 0,1 to 7 mm (or more at lower precision)
Adjustable main velocity of the parallel air stream:approx. 1,0 and 2,0 m/s
Supply voltage:                                                 120 or 220 V / 50 - 60 Hz, input 50 W
Instrument dimensions:                                      540 x 230 x 130 mm, net weight 7 kg

      Main features of the instrument:

  • very short time constant, given by the application of a special heat flow sensor, whose thermal inertia is similar to that of human skin, therefore the full response while measuring the water vapour permeability (resistance) of synthetic fabrics is achieved within 2- 3minutes, for dry thermal resistance the measurement is completed even within 1 minute (for the simulated human skin temperature 35oC),
  • small size of the measured sample -l ess than 12x12 cm, measured area 80 mm dia,
  • ease of operation and evaluation of the results, which allows to be operated not only in laboratory, but also in the factory conditions,
  • high sensitivity, given by a new concept of measurement, which enables to distinguish even very small changes of water amount absorbed in the fabric during unsteady state of diffusion and to record e.g. the heat of absorption and the effects of the fabrics composition and structure, resulting in very good measurement repeatibility, with CV often under 3%.
  • the possibility to operate both under isothermal and non-isothermal conditions,
  • results are presented in digital form both on the instrument display and on the screen of any modern computer.

The instrument provides all kinds of measurements very similar to the ISO Standard 11092, and the results are evaluated by the identical procedure as required in the ISO 11092. The differences in relation to this standard depend in smaller sample, application the 20-22oC isothermal laboratory temperature instead of 35oC (at the water-vapour resistance measurements) and by the application of the laboratory (environmental) water-vapour concentration (humidity) of the parallel air flow 45 - 60%, instead of the air humidity level of 40%. The heat flow levels used for calculation of water vapour resistance or permeability are displayed on digital indicator + external PC PC and (if required) recorded by means of any sensitive line recorder (nor the PC nor the recorder are included in the standard delivery). The correlation coefficient of measurements related to the ISO Standard SKIN MODEL exceeds 0.9.