General Questions & Answers

What are the applicable standards for using a gear-operated valve instead of a standard handwheel with a rising stem?

The handwheel or lever on manually operated valves is designed so that reasonable effort by the operator(s) is sufficient to operate the valves. MSS SP-91: Guidelines for Manual Operation of Valves provides recommendations in this regard. This standard defines an operator as a person who can apply approximately 670 N (150 lbf) of force to a lever with an effective length of 300 mm (12 inches).