Are the IEC requirements for overpressure testing of flameproof equipment appropriate?

For the IEC flameproof standard IEC 60079- 1 there is an apparent lack of research data to clearly support all the factors that are applied to the pressure determination figures in order to do the overpressure test. Even in cases where data does exist, the tests may not reflect the best approach based on the data. The standard does not address impact of temperature on pressure figures in the standard temperature range. An investigation is shown into existing information and data, both published and unpublished. In addition, the minutes of the first meetings of TC 31 commencing in 1948 are examined to look at the decisions leading to the requirements in the first standard which was issued in 1957. The evolution of the testing requirements are then examined for subsequent revisions. A critical analysis is subsequently made on that evolution and the supporting data, with particular emphasis on the effect of temperature. Gaps are identified in the supporting data. The paper recommends potential changes to the existing standard based on existing data and recommends additional investigative testing that is needed to clarify the situation, and which could lead to changes in the next edition of the standard.