This International Standard describes the physical requirements for the safe operation of the process analyser measuring system installed in an AH in order to ensure its protection against fire, explosion and health hazards. This standard extends beyond IEC 60079-16 to include houses with Zone 2 interiors and to apply to toxic hazards. (Appropriate national guidelines on toxic hazards are to be followed.)
This standard does not address facilities where dust is the hazard.
Clause 4 addresses the location of the AH and connection within the process plant areas.
Clause 5 addresses the design, construction and layout of the AH. It does not address parts of the analyser measuring system installed in other locations such as sample conditioning rooms (SCR) or switchgear rooms.
Clause 6 addresses measures for reducing the danger of explosion for AHs while permitting maintenance of equipment with the power on and the case open.
NOTE For most fluids, the major constraint is that the concentration of vapours, which are hazardous for personnel, is lower than the lower explosive (flammable) limit (LEL) (see Clause 7).
Using n-Pentane as an example, the LEL is 1,4 % or 14 000 x 10. The level immediately dangerous to life or health (which is the maximum level from which a worker could escape within 30 min without any escape-impairing symptoms or any irreversible health effects) is only 0,5% or 5 000 x 10.
Classification of a house interior as Zone 1 may imply that no technician can enter without protective equipment such as breathing gear. Placing an AH in a Zone 1 area would usually imply that no technician could approach the house without wearing protective equipment.
Clause 7 addresses those measures for protecting personnel from materials in the atmosphere of AHs that are hazardous to health.
BS EN 61285:2004 history
2015BS EN 61285:2015 Industrial-process control. Safety of analyzer houses
2005BS EN 61285:2004 Industrial-process control - Safety of analyser houses
1995BS EN 61285:1995 Industrial-process control - Safety of analyser houses