ISA-77.70.02:2014

This standard covers the mechanical design, engineering, fabrication, installation, testing, and protection of fossil power plant instrumentation sensing and control lines. The boundaries of this standard span the process tap root valve to the instrument connection. This standard applies to all fluid media (liquid, gas, or vapor).
This standard establishes the applicable installation requirements and limits of instrumentation sensing and control lines and their instruments in fossil power plants.
This standard addresses the requirements of maintaining the pressure boundary integrity of the instrumentation sensing line (in accordance with the appropriate parts of American National Standards Institute [ANSI] standards).