scope:

SCOPE AND LIMITATIONS

This standard shall apply to rotary and linear motion control valves. Bellows, diaphragms and tubular stem seals are not covered by this standard.

This standard shall not apply to valves that are governed by conflicting national or international standards.

Municipal, state and federal regulations may require additional qualifications testing that is beyond the scope of this standard.

The test results from this standard shall only be used to predict leakage at conditions within the qualified pressure and temperature rating.

The laboratory proof of the design as described may not guarantee similar results when the control valve is exposed to different field process conditions.

PURPOSE

This standard classifies control valve stem seals by their ability to withstand mechanical and thermal cycles at a specified set of temperature and pressure conditions. Bellows, diaphragms, and tubular seals are not covered by this standard.