UNE-EN ISO 13938-1:2019

• Test surface: Surface of the sample included inside the annular clamping device.
• Bursting pressure (pressure at the time of bursting): Maximum pressure applied to a sample fixed on a membrane located below until the specimen breaks.
• Bursting strength (strength at the time of bursting): Pressure obtained by subtracting the membrane pressure from the mean bursting pressure.
• Membrane pressure: Pressure applied to the membrane, without the sample, to deform it up to the mean burst strain of the specimen.
• Deformation at burst (deformation at the moment of bursting): Expansion of a sample at the bursting pressure. It is expressed well in burst height, well in burst volume.
• Bursting height: Distance between the upper surface of the sample before deformation and the same surface at the moment of bursting pressure.
• Burst volume: Volume of pressure fluid pumped at the time of burst pressure.
• Bursting time: Time elapsed to deform a sample until bursting.

A test piece is fixed to a membrane by means of a clamping ring. An increasing fluid pressure is applied on the lower face of the membrane, causing deformation of the membrane and the tissue. The volume of fluid is increased at a constant rate per unit of time until the bursting of the specimen. Bursting strength and strain are determined.

• Eclatometer: must be able to produce different constant rates of volume increase per unit time between 100 cm3/min and 500 cm3/min, within ±10% of the indicated value
• The burst pressure must be indicated with an accuracy of ±2% of the full scale value.
• Burst height up to 70 mm must be indicated with an accuracy of ±1 mm
• A test surface of 50 cm2 (79.8 mm diameter) should be used.
• Other test surfaces of 100 cm2 (112.8 mm diameter), 10 cm2 (35.7 mm diameter), and 7.3 cm2 (30.5 mm diameter) may be used if the preferred surface cannot be applied with existing test equipment or in case of high or weak fabric expansion, different fabric requirements
• The membrane must meet the following requirements:
  • maximum thickness of 2 mm;
  • high expandability;
  • if the same membrane is to be used several times, it must be elastic in the range of bursting heights observed during the test

• A test surface of 50 cm2 is prepared
• For most fabrics, mainly knitted fabrics, it is possible to use the 50 cm2 test area. For fabrics with low extensibility (known from previous experiences or previous tests), for example fabrics for technical uses, a test surface of 100 cm2 is recommended.
• The apparatus is regulated at a constant speed of volume increase, located between 100 cm3/min and 500 cm3/min.
• The flat test piece is placed on the membrane without tension or deformation in its own plane and is adjusted to the zero position.
• Pressure is applied on the specimen until the fabric bursts.
• Immediately after the burst, if the burst occurs near the restraint, it should be noted. Jaw breaks that occur less than 2mm from the clamping line should be rejected. The test is repeated at least four times at different locations on the fabric.
• For wet tests, the test piece is left submerged for 1 h in class 3 water, in accordance with EN ISO 3696:1995, at a temperature of (20 ± 2) ºC.

• Mean burst strength: Calculate the arithmetic mean of the burst pressure in kilopascals.
• Mean burst height: Calculate the arithmetic mean of the burst height in millimeters
• Mean burst volume: Calculate the arithmetic mean of the burst volume in cubic centimeters
• Coefficient of variation: Calculate the coefficient of variation and 95% confidence limits for burst pressure, burst height, and, if necessary, burst volume
• Confidence limits at 95% in units of the corresponding mean values, if necessary.
• EN11612 requirements:
  • • 100 kPa Area 50 cm2
    • 200 kPa Area of 7.3 cm2