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Detailed specifications of all panel and field instruments typically are prepared in Construction Specifications Institute (CSI) format by design engineers as part of the contract documents. The CSI specifications are not a substitute for ISA specification forms, although there is some overlap in these documents. Owners and engineers should require that completed ISA forms be provided by the system integrator as part of a complete set of submittals to ensure compliance with contract requirements and uniformity of the information provided (see the “Specifications” section in Chapter 6 for more details). Instrument specification forms are also available from the ISA in both paper and electronic formats. International Society of Automation specification forms, which are typically provided by system integrators and those responsible for actual procurement of instruments, address the following:

• Type of instrument;

• Materials of construction for wetted and nonwetted parts;

• Process and environmental conditions in which the instrument is used (i.e., outdoors, corrosive area, or hazardous area);

• National Electrical Manufacturers Association rating;

• Power requirements;

• Signal output requirements;

• Alarm signal requirements, if any;

• Special mounting hardware required;

• All options to be furnished;

• Instrument span, calibrated range, and engineering units;

• Process connections (e.g., size and type of connections, i.e., flanged or threaded);

• Transmitter requirements (i.e., whether remote or integral to sensor); and

• Manufacturer model numbers (note that specific manufacturer model numbers will depend on the selected manufacturer after the bid is awarded).

It is also a good idea to include any manufacturer support services required for successful installation, calibration, training, and startup of the specified instruments (see Chapters 8 and 9 for more details). This is important for specialty items or most analytical or water quality analyzers.

However, because most public works projects require competitive bidding for procurement, the design engineer’s specifications should be general enough to enable several reputable vendors to bid on the project, but detailed enough to supply them with the necessary information to realistically bid. It is incumbent on the design engineer to possess the knowledge and skill to offer this balance. Providing detailed instrument specifications using ISA forms could be a bid-submittal requirement for I&C contractors.