Section 408.4244. Stop valves.

(1) Each steam outlet from a power boiler (except safety valve connections) shall be fitted with a stop valve located as  close  as practicable to the boiler.

(2)   When a stop valve is so located that water  can  accumulate,  ample drains shall be provided. The drainage shall be piped to a safe location and shall not be discharged on the top of the boiler or its setting.

(3)    When power boilers provided with manholes are connected to a common steam main, the steam connection from each boiler shall be fitted with 2 stop valves having an ample free-blow drain between them. The discharge of the drain shall be visible to the operator while manipulating the valves and shall be piped clear of the boiler setting. The  stop   valves  shall consist preferably of 1 automatic nonreturn valve (set next  to  the boiler) and a second valve of the outside-screw-and-yoke type.

(4)    A stop valve shall be used in each supply and return pipe connection of 2 or more heating boilers connected to a common system.

(5)   When a stop valve is used in the supply pipe connection of a single heating boiler, there shall be 1 used in the return pipe connection.

History: 1979 AC.