PRINCIPLES OF NAVAL ENGINEERING 



junction of interconnecting systems. Short runs 

 of piping which serve an immediately obvious 

 purpose, such as short vents or drains, need not 

 be marked. As a rule, piping on the weather decks 

 does not require marking; if it does require 

 marking, label plates (rather than stenciled 

 paint or prepainted vinyl labels) are used. 

 Each valve is marked on the rim of the hand- 

 wheel, on a circular label plate secured by the 

 handwheel nut, or on a label plate attached to the 

 ship's structure or to adjacent piping. The valve 

 label gives the name and purpose of the valve, if 

 this information is not immediately apparent 

 from the piping system marking, and it gives the 

 location of the valve. The location is indicated by 

 three numbers which give, in order, the vertical 

 level, the longitudinal position, and the trans- 

 verse position. Consider, for example, a drain 

 bulkhead stop valve that is labelled: 



2-85-1 



The location of this valve is indicated by these 

 numbers. The first number indicates the vertical 

 position— in this case, the second deck. The sec- 

 ond number indicates the longitudinal position by 

 giving the frame number— in this case, frame 85. 

 The third number indicates the transverse posi- 

 tion—starboard side if the number is odd, port 

 side if the number is even. The numbers indicat- 

 ing transverse position begin atthecenterlineof 

 the ship and progress out toward the sides. For 

 example, a second drain bulkhead stop installed 

 on the same level and at the same frame, but far- 

 ther to starboard, would be indentified as 



2-85-3 



In either case, of course, the valve would also 

 be identified as to system (DRAIN BULKHEAD 

 STOP, in these examples) if the piping system 

 identification did not make the system obvious. 



A slightly different system of marking is used 

 for identifying main line valves, cross-connec- 

 tion or split-plant valves, and remote-operated 

 valves in vital engineering piping systems. In- 

 stead of being identified bylocation, these valves 

 are assigned casualty control identification num- 

 bers, by system, as 



Main steam MSI, MS2, MS3, etc. 



Auxiliary steam ASl, AS2, ASS, AS4, etc. 



Auxiliary condensate. . . ACNl, ACN2, etc. 



Auxiliary exhaust AEl, AE2, AE3, etc. 



Fuel oil service FOSl, FOS2, etc. 



On newer ships, the system for marking 

 valves in the vital engineering systems is slight- 

 ly different, consisting of a three-part designa- 

 tion in the following sequence: (1) a number des- 

 ignating the shaft or plant number; (2) letters 

 designating the system; and (3) a number, or a 

 combination of a number and a letter, indicating 

 the individual valve. Individual valve numbers 

 are assigned in sequence, beginning at the origin 

 of a system and going in order to the end of the 

 system, excluding branch lines. In other words, 

 the first valve in the mainline is No. 1, the sec- 

 ond is No. 2, and so forth. Since parallel flow 

 paths frequently exist, it is often necessary to 

 assign a shaft number and a system designation 

 to the parallel flow paths as well as to the basic 

 main line of the system. The valves in the paral- 

 lel flow paths are then numbered in sequence; 

 identical numbers areusedfor valves which per- 

 form like functions in each of the parallel flow 

 paths, but a letter suffix is added to distinguish 

 between the similar valves. This system of iden- 

 tification is illustrated for part of a 'main steam 

 system in figure 9-11. 



It is of utmost importance that all engineer- 

 ing personnel (officer and enlisted) become fa- 

 miliar with the valve markings used in the vital 

 engineering systems. Use of the identification 

 numbers tends to prevent confusion and error 

 when the plant is being split or cross-connected 

 and when damaged sections are being isolated, 

 since it provides a means of ordering any parti- 

 cular valve to be opened or closed without taking 

 time to describe the actual physical location of 

 the valve. However, the identification markings 

 cannot serve their intended purpose unless all 

 engineering personnel are throroughly familiar 

 with the physical location and the identification 

 number of each valve they may be required 

 either to operate themselves or to order opened 

 or closed. 



Most shipboard piping is painted to match and 

 blend in with its surrounding bulkheads, over- 

 heads, or other structures. In a very few sys- 

 tems, color is used in a specified manner to aid 

 in the rapid identification of the systems. For 

 example, JP-5 piping in interior spaces is 

 painted purple. Gasoline valves in interior 

 spaces are painted yellow, except for moving 

 parts of the valves; in exterior locations, part 

 of the valve handwheel or the operating lever Is 

 painted yellow. Green is similarly used to iden- 

 tify oxygen, and red is used for fireplugs and 

 foam discharge valves. 



204 



