Safety requirements for analytical instruments

In a hazardous environments made dangerous by flammable gases precautions can include continuous provision of air to dilute the flammable gas to safe concentrations. The authors describes the continuous dilution requirements in terms both of principle and of detail, and illustrate why requirements are likely to become progressively more detailed to cover the various types of instrument involved. In view of the increasing complexity, proposals are made for simplifications of the approach that may be considered both by the supplier and the user of the equipment