ASTM D 3786D 3786 M18 Standard Test Method

Principle • Specimen is clamped over an expandable diaphragm; the diaphragm is expanded to

Scope • Applicable to knits, wovens, or nonwovens • Mainly for knits and stretch

Definition • Bursting Strength • The force or pressure required to rupture a fabric

Apparatus • Flexible diaphragm • Hydraulic (fluid; 96% USP glycerin) or pneumatic (gas; air)

Sampling • Lab Sample • 1 m full-width (discard first meter of roll) •

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

Procedure • Clamp specimen smoothly and securely • Apply pressure until specimen bursts •

Calculation • Subtract tare pressure from burst pressure for each specimen • Average the

Report • Test method used • Material tested • Individual and average bursting strengths

Calibration • Standard aluminum sheets • Test monthly (minimum) • 5 specimens • ±

Troubleshooting • Examine clamp for wear and distortion • High-stretch fabrics may need to

Troubleshooting • If pressure stops before specimen bursts, report “stretch exceeds dimensional limitations of

Troubleshooting • Burst (on pneumatic tester) should take 15 -25 seconds. • Preliminary trials

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ASTM D 3786/D 3786 M-18 Standard Test Method for Bursting Strength of Textile Fabrics— Diaphragm Bursting Strength Tester Method

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. ASTM D 3786

Scope • Applicable to knits, wovens, or nonwovens • Mainly for knits and stretch wovens (tensile tests not appropriate) ASTM D 3786

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. ASTM D 3786

Apparatus • Flexible diaphragm • Hydraulic (fluid; 96% USP glycerin) or pneumatic (gas; air) inflation • Pressure control & measurement • 31 ± 0. 75 mm diameter circular clamp ASTM D 3786

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 ASTM D 3786

Conditioning • Bring specimens to moisture equilibrium before testing as directed in ASTM D 1776 • Does not specify to test in standard atmosphere ASTM D 3786

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 ASTM D 3786

ASTM D 3786

Calculation • Subtract tare pressure from burst pressure for each specimen • Average the 10 specimens • Average lab samples in each lot if applicable ASTM D 3786

Report • Test method used • Material tested • Individual and average bursting strengths (k. Pa or psi) • Type of tester ASTM D 3786

Calibration • Standard aluminum sheets • Test monthly (minimum) • 5 specimens • ± 5% of indicated strength • Self-calibrating instruments ASTM D 3786

Calibration Foils ASTM D 3786

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 ASTM D 3786

Troubleshooting • If pressure stops before specimen bursts, report “stretch exceeds dimensional limitations of the tester. ” • If specimen slips from clamp, discard and retest. ASTM D 3786

Troubleshooting • Burst (on pneumatic tester) should take 15 -25 seconds. • Preliminary trials may be needed to set control valve correctly ASTM D 3786