When it is necessary to join two different diameters of pipe, valves, fittings, etc., the smaller of the two must be fitted with a shouldered end.
In selecting the proper type ring for use with shouldered fabrication, consideration must be given to pressures, installation conditions, wall thickness and fabrication procedures. Type rings are most commonly used for installation of shouldered end valves and may be applied to the pipe end as cast, threaded or welded. The ring material shall be manufactured of a mild steel or ductile iron.
For pipe material that is not conducive to welding, the threaded shoulder will usually surface.
COUPLINGS
Housings shall be made up with two or more identical segments manufactured form ductile iron forming to ASTM 536 or malleable iron conforming to ASTM A-47.
Gaskets shall be manufactured in accordance with AWWA C-606 Section 2 and be of the center leg design. Bolt and nut selection may vary depending on application (see section 200).
