ISA TR91.00.02

Introduction

Process operating facilities utilize instrumentation to monitorand control processes. The performance of this instrumentation tiesdirectly into product quality and product throughput. In addition,the process may become hazardous to operating facility personnel,the community, and the environment if control is lost.

Some instruments perform essential functions during emergencyresponse activities and a high degree of confidence is required toensure that instrumentation will function correctly during anemergency.

This guideline is developed to assist engineering, operations,and maintenance personnel with establishing the classification oftheir instrumentation, thus facilitating all aspects of designingand maintaining reliable operating facility instrumentation. Globalinstrumentation manufacturers classify their equipment according tovarious country classification standards (see clauses 6.3, 6.7,6.8).

Some process sector facilities utilize criticalityclassification methods to:

• Facilitate understanding of how these classifications can beused in the design process.

• Reduce design costs by using prescriptive design approach foreach classification to ensure consistency, understanding, and costeffective design.

• Relate instrumentation requirements to corporate, local,national, and international standards.

• Facilitate communication to those responsible forinstrumentation, electrical, mechanical, chemical, measurement, andoperating technologies.

• Allow clear communication with integrators, auditors and otherthird parties

• Identify training and maintenance needs compatible to theneeds of the application.

This guideline does not mandate what the classification of eachinstrument should be. It does provide information to assist eachoperating facility in determining the classification of its processinstrumentation. It is the responsibility of an operatingfacility’s management to determine whether criticalityclassification is needed.

This guidance will deal primarily with instrumentation used inthe process industries. The operating facility may haveinstrumentation associated with the machinery sector, themedical/drug sector, the railway sector, etc. For example, thisguidance will address the machinery and combustion sectors onlywhere equipment associated with these sectors is utilized in theprocess (e.g., product heating, range drives, product conveying).This guideline addresses asset and safety critical issues as wellas other issues.

Requirements exist for each of the noted sectors (e.g., process,machinery) and are addressed in the following clauses for theirrelationship to the process sector and its requirements.

Note that all applications, regardless of classification, shouldadhere to good engineering practices.

Edition:

03

Published:

01/02/2003

Number of Pages:

30

File Size:

1 file , 260 KB