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ASTM D3786/D3786M-18

Standard Test Method for Bursting Strength of Textile Fabrics— Diaphragm Bursting Strength Tester Method

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Principle

  • Specimen is clamped over an expandable diaphragm; the diaphragm is expanded to the point of specimen rupture.
  • The difference between the total pressure required to rupture the specimen and the pressure required to inflate the diaphragm is reported as the bursting strength.

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ASTM D3786

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Scope

  • Applicable to knits, wovens, or nonwovens
  • Mainly for knits and stretch wovens (tensile tests not appropriate)

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Definition

  • Bursting Strength
    • The force or pressure required to rupture a fabric by distending it with a force, applied perpendicular to the plane of the fabric.
    • Note that machine and cross-machine direction are not differentiated.

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Apparatus

  • Flexible diaphragm
  • Hydraulic (fluid; 96% USP glycerin) or pneumatic (gas; air) inflation
  • Pressure control & measurement
  • 31 ± 0.75 mm diameter circular clamp

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Sampling

  • Lab Sample
    • 1 m full-width �(discard first meter of roll)
  • Test Specimens
    • Avoid selvage (10% of fabric width)
    • 10 specimens
    • 125 mm (5 in) circles or squares
    • Different warp/course and fill/wale

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Conditioning

  • Bring specimens to moisture equilibrium before testing as directed in ASTM D1776

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  • Does not specify to test in standard atmosphere

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Procedure

  • Clamp specimen smoothly and securely
  • Apply pressure until specimen bursts
  • Release diaphragm pressure and remove specimen
  • Determine pressure required to distend diaphragm only
    • Test to the same height as used to burst specimen
    • Use known value from foil calibration

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ASTM D3786

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Calculation

  • Subtract tare pressure from burst pressure for each specimen
  • Average the 10 specimens
  • Average lab samples in each lot if applicable

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Report

  • Test method used
  • Material tested
  • Individual and average bursting strengths (kPa or psi)
  • Type of tester

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Calibration

  • Standard aluminum sheets
    • Test monthly (minimum)
    • 5 specimens
    • ± 5% of indicated strength
  • Self-calibrating instruments

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Calibration Foils

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Troubleshooting

  • Examine clamp for wear and distortion
  • High-stretch fabrics may need to be (uniformly) pre-stretched before clamping
  • Eliminate specimen creases and folds before clamping

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Troubleshooting

  • If pressure stops before specimen bursts, report “stretch exceeds dimensional limitations of the tester.”
  • If specimen slips from clamp, discard and retest.

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Troubleshooting

  • Burst (on pneumatic tester) should take 15-25 seconds.
    • Preliminary trials may be needed to set control valve correctly

ASTM D3786