ANSI-ISA-TR12-24-01-1998
Recommended Practice for Classification of Locations for Electrical Installations Classified as Class I, Zone 0, Zone 1, or Zone 2 ISBN: 978-1-55617-649-4
Published: 1998
Length: 66 pages

Price: $100.00

This technical report is concerned with the classification of hazardous areas where flammable gas or vapor risks may arise, in order to permit the proper selection and installation of apparatus for use in such hazardous areas.

This standard covers airborne contaminants and biological influences that affect industrial process measurement and control equipment. Specifications for other environmental conditions, including nuclear radiation and hazardous atmospheres, are beyond the scope of this standard.

This standard establishes airborne contaminant classes for fixed (non-mobile) installations during normal operation (nonemergency conditions) or during transportation and storage.

The classes of environmental conditions stated in this standard are suitable for use in activities related to process instrumentation, including design, manufacturing, sales, installation, test, use, and maintenance. These classes may also be used as a guide when establishing requirements for environmental control of buildings or other protective housings for industrial process measurement and control systems.

These classifications pertain only to the environment external to the equipment which may affect the equipment externally or internally.

The effects of environmental conditions on safety, comfort, and performance of operating and maintenance personnel are not considered in this standard.

CAUTION — Airborne or biological contaminants not listed in this document could cause equipment damage. Caution should be used when a combination of factors approach or surpass class.

The purpose of this standard is to classify airborne contaminants that may affect process measurement and control instruments. The classification system provides users and manufacturers of instruments with a means of specifying the type and concentration of airborne contaminants to which a specified instrument may be exposed. This document is one of a series of standards on environmental conditions for process measurement and control systems.