Determination of GSM and Water Permeability of Fabric

Textile Testing - GSM Water Permeability

Importance of determining Gram per Square meter(GSM) of fabric:
GSM of fabric determines the weight of the fabric. Fabric weight is important when we talk as far as the application of the material is concerned. There are fabrics with different weights used for different applications like shirting, suiting etc. So calculation method of GSM of fabric is explained in the following article.

About GSM Cutter:
GSM OF FABRIC I.E GRAM PER SQUARE METER can be determined accurately with the help  of GSM cutter. GSM cutter is circular fabric sample cutter with which uniform circular fabric is cut without measuring .The specimen which is cut with the help of GSM cutter is 100cm2 areas. The instrument is equipped with a set of four replaceable blades and a normal cutting pads.

Features of GSM cutter:
  • Depth of cutting up to 5mm.
  • Reliable, rapid and easy to use.
  • Special finishes for contacting surfaces for avoiding slippage of the specimen.
  • 100 Squares cm cutting area.
Testing Procudure:
  • Conditioning of sample
  • Taking the conditioned sample for texting.
  • Placing the fabric on the pad below the GSM cutter, so that no crease or wrinkles are formed.
  • Cutting the fabric with GSM cutter(Cutter of different Dia)
  • Further take weight of the fabric cut with help of GSM cutter in the weighing balance.
  • Multiply the weight we got on the balance with 100
  • We will get the GSM of fabric in Oz/Yds(For Woven) and in Gram per sq meter ( For Knitted)

Water Permeability:
  • Absorbability: It is the ability of the fabric to take up a liquid
  • Shower proof: To treat the material in a manner to delay the absorption and penetration of water. The fabric retain a degree of permeability to air.
  • Water proof : To treat the textile materials with waxes, fats or rubber to prevent the absorption of water.
  • Water Repellent: It is a state characterised by the non spreading of a Globule of water on a textile material.
  • Wetting time test
  • Spray time test
  • Drop Penetration test
  • Hydrostatic test
Spray Test:
To carry out the test , 250 cu. Cm of water at 27 degree centigrade temperature of water are poured steadily into the funnel. The distance from the bottom of the spray to the centre of the fabric is 6 inch. After spraying has finished, the sample holder is removed and the surplus water is removed by tapping the frame six times against a solid object. The assessment of the water repellence of the fabric is judged by the spray rating. After the removal of the surplus water is accomplished, the fabric surface is examined visually by matching against the rating chart.

Rating Test for Spray Test:
100- No sticking or wetting of the upper surface
90  -  Slight random sticking or wetting of the upper surface
80  - Wetting of upper surface at spray points
70  - Partial wetting of whole of upper surface
50  - Complete wetting of whole of upper surface
  0  -  Complete wetting of whole of upper and lower surface

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