ASTM D3786:2023

A sample is clamped onto an expandable diaphragm. The diaphragm is expanded by fluid pressure to the point of rupture of the specimen. The difference between the total pressure required to rupture the specimen and the pressure required to inflate the diaphragm is reported as the burst force.

• Diaphragm Rupture Robber
• Clamps, to firmly and evenly secure the sample between two durable, parallel, annular surfaces, without slippage during testing. Use enough pressure to effect practicable minimization of slippage. The upper and lower clamping surfaces shall have a circular coaxial opening 31 ± 0.75 mm (1.22 ± 0.023 in.) in diameter. Clamp surfaces must be durable and any edges that may cause a cutting action must be rounded to a radius of not more than 0.4mm. The bottom clamp will be just as integral with the chamber as a pressure medium swells the rubber diaphragm.
• a diaphragm of molded synthetic material or natural rubber, held between the lower clamping plate and the remainder of the apparatus so that before the diaphragm is stretched by pressure below it the center of its top surface is nominally level with the plane of the clamping surface.
• Pressure gauge
• Pressure system to apply controlled pressure
• Hydraulic pressure is produced by a fluid displaced at the rate of 95 6 5 mL/min.
• Pneumatic pressure is produced by controlling the flow of clean, dry air through a valve.
• Pneumatic pressure is produced by controlling the flow of clean, dry air through the valve.
• Aluminum sheet to check the performance of the equipment.
• Pressure record.

• Lot sample according to applicable material specification.
• Lab sample: one full-width sample 1m (1yd) long from the end of each roll of fabric in the lot sample, after first discarding a minimum of 1 m (1yd) of each roll or piece of circular knit fabric selected.

• Cut a band at least 305 mm (14 ft) wide.

• According to Standard D1776.
• Take ten tissue lab test tubes. Each specimen shall be at least a 125 mm (5 in.) square or a 125 mm (5 in.) diameter circle.

• Hand-operated hydraulic equipment:
  • Insert the conditioned cylinder under the tripod, tension the specimen through the plate, and clamp the specimen in place by moving the clamping lever all the way to the right.
  • Rotate the handwheel clockwise at a uniform speed of 120 rpm until the cylinder bursts.
  • Stop turning the handwheel when the specimen breaks.
  • Immediately after breaking and in quick succession, release the clamping lever on the sample. Release the tension on the diaphragm by turning the wheel, counterclockwise to its initial position and record the required pressure the pressure required to inflate the diaphragm.
  • Record the total pressure required to break the specimen.

• Motor Driven Hydraulic Equipment:
  • Insert the sample between the top and bottom with the clamp making sure that the sample is free of wrinkles and creases. Hold the sample firmly. Operate the pressure until the sample bursts.
• Pneumatic equipment:
  • Adjust the control valve of the bursting equipment so that the mean time to burst the sample is 20 ± 5 s. The burst time between the start of tumbling and the bursting of the test sample shall be recorded.

• Calculate the burst pressure of the specimen by subtracting the set pressure required to inflate the diaphragm from the total pressure required to rupture the specimen.
• Inform the type of breaking equipment used according to Standard D3786.
• Describe the material or product.
• Give the burst strength of each individual specimen and its average in kPa (psi). If the cloth does not burst, the report should indicate the maximum burst pressure of the instrument and that the sample had not burst at that pressure.