Chapter 14. -PIPING, FITTINGS, AND VALVES 



DISCHARGE STOP VALVE 



SUCTION STOP 

 CHECK VALVE 



DISCHARGE 

 VALVES 



PUMP 



DISCHARGE 



CONNECTION 



PUMP SUCTION CONNECTION 



47.63X 



Figure 14-29.— Valve manifold. 



IDENTIFICATION OF VALVES. 

 FITTINGS, FLANGES. AND UNIONS 



Most valves, fittings, flanges, and unions used 

 on naval ships are marked with identification 

 symbols of various kinds. The few valves and 

 fittings that are made on board repair ships or 

 tenders or at naval shipyards are usually marked 

 with symbols indicating the manufacturing activ- 

 ity, the size, the melt or casting number, and 

 the material. They may also be marked with an 

 arrow to indicate the direction of flow. 



Commercially manufactured valves, fittings, 

 flanges, and unions may be identified according 

 to the requirements of the applicable specifica- 

 tions. However, many valves, fittings, flanges, 

 and unions are now identified according to a 

 standard marking system developed by the Manu- 

 facturers Standardization Society (MSS) of the 

 valves and fittings industry. Identification mark- 

 ings in this system usually include the manu- 

 facturer's name or trademark, the pressure and 



service for which the product is intended, and 

 the size (in inches). When appropriate, material 

 identification, limiting temperatures, and other 

 identifying data are included. 



The MSS standard identification markings 

 are generally cast, forged, stamped, or etched 

 on the exterior surface of the product. In some 

 cases, however, the markings are applied to an 

 identification plate rather than to the actual 

 surface of the product. 



The service designation in the MSS system 

 of marking usually includes a letter to indicate 

 the type of service and numerals to indicate 

 the pressure rating in psi. The letters used in 

 service designations are: 



A air 



G gas 



L liquid 



O oil 



W water 



D-W-V drainage, waste, and vent 



387 



