16.1.2 When the second method is chosen, the routine test consists of
– either an explosion test with, inside and outside the enclosure, the appropriate explosive
mixture specified in 15.1.2 (for the determination of explosion pressure) at 1,5 times
atmospheric pressure,
– or a dynamic overpressure test as described in 15.1.3.2 for type tests, followed by a nontransmission
test with explosive mixtures as specified in 15.2.1.2 or 15.2.2.1 (test for nontransmission
of an internal ignition, with enlarged gaps) inside and outside the enclosure at
atmospheric pressure,
– or a dynamic overpressure test as described in 15.1.3.2 for type tests, followed by a static
test at a pressure of at least 2 bar.
16.1.3 For the routine test, it is sufficient to test the enclosure empty. However, if the routine
test is dynamic and the enclosed apparatus influences the pressure rise during an internal
explosion, the test conditions shall be decided by agreement between the manufacturer and the
testing station.
The individual parts of a flameproof enclosure (for example, cover and base) can be tested
separately. The test conditions shall be such that the stresses are comparable to those to
which these parts are exposed in the complete enclosure.
16.2 Routine tests are not required for enclosures with a volume less than or equal to 10 cm3.
This exception also applies to enclosures with a volume greater than 10 cm3 when the
prescribed type test has been made at a static pressure equal to four times the reference
pressure. However, enclosures of welded construction shall in every case be submitted to the
routine test.
For enclosures where reference pressure measurement is impractical, exemption from routine
pressure testing shall not apply.