Various methods are used to specify and purchase flowmeters. When flowmeters

are purchased by specifying only the model number, the manufacturer is excluded

from providing any expertise that may improve the measurement system, providing

information that may deem the flowmeter be suitable for the application, or reducing

costs.


Composing the flowmeter description may exhibit the same pitfalls as those of

specifying the model number, depending upon the type and amount of descriptive

information that is provided to the manufacturer. It is truly amazing that the correct

instrument is purchased, given the wide diversity of literary styles and varying

amounts of technical substance used to specify flowmeters.


Instrument specification forms, such as those presented herein, allow the user

to virtually avoid varying literary styles and inconsistent technical content. The

concise fill-in-the-blank specification format allows the user to generate a complete

technical document by completing the form and perhaps adding some notes.

This approach allows the manufacturer to better evaluate the suitability of the

instrument in a specific application.


ISA-The Instrumentation, Systems, and Automation Society has developed

several specification forms for flow measurement instruments (ISA-S20-1981,

Specification Forms for Process Measurement and Control Instrumentation, Primary

Elements and Control Valves); check with ISA for updates to this standard.

When ISA specification forms are not available for a particular type of flowmeter,

specification forms from sources other than ISA have been included.