INTRODUCTION
1 This circular gives advice on the precautions to be taken against the toxic, fire and explosion hazards presented by refrigeration systems containing ammonia. These are most likely to be found by LA enforcement officers at cold stores and food distribution warehouses. It applies to the entire system not simply the compressor house. It provides interim advice on matters of concern to enforcement officers pending revision of BS 4434:1980.
2 Appendix 1 outlines the general principles of refrigeration, Appendix 2 gives information on the results of the programme of special visits carried out in 1983 by Factory Inspectorate (F1) to examine present standards in the food industry and Appendix 3 gives detailed guidance on electrical standards. Enforcement officers should not overemphasise the hazards of ammonia compared with other refrigerants.
HAZARDS
Toxicity
3 Ammonia is a chemically reactive gas that is very soluble in water and is much lighter than air (vapour density 0.59 of that of air). Cold vapour (e.g. from leaks) may however be denser than air. Although there have been incidents of exposure to harmful concentrations of...