15.4.3.1 Test procedure
An ignition source shall be placed first close to the inner surface of the breathing and draining
device and subsequently in one or more places if a high peak explosion pressure and rate of
rise of pressure at the face of the device is likely to occur. Where the enclosure has more than
one identical device, the device to be tested shall be that which gives the most unfavourable
results. The test mixture within the enclosure shall be ignited. The test shall be made five times
for each position of the ignition source.