Compressed Air Piping Recommendations for Compressor ...

1 Hitachi Industrial Equipment WHITE PAPER. White Paper: Ambient Air's Impact on Compressed Air System Performance Compressed air Piping systems are complex and require careful planning. Compressed Air Piping Recommendations for Compressor Discharge and Plant Distribution By Nitin G. Shanbhag, Senior Manager, Air Technology Group, Hitachi America Compressed air Piping I. Piping MATERIAL 99 (National Fire Protection system designers face many SELECTION AND Association) Standard is used for challenges to designing systems Recommendations healthcare facilities.

2 Compressed without pressure losses and BY USE air Piping materials can be divided contaminants. This paper will into two basic types: metal and review Piping material selections, Consult federal, state and local non-metal. Non-metal pipe is distribution and Compressor codes before deciding on the commonly called thermoplastic discharge Piping guidelines, type of Piping to be used. For pipe. In our experience, and the basic causes of pressure industrial plants, ASME thermoplastic should be used losses in Compressed air Piping is the reference standard, while only in some air Compressor inlet systems.

3 The latest version of NFPA Piping situations, which are not 1. Hitachi Industrial Equipment WHITE PAPER. White Paper: Ambient Air's Impact on Compressed Air System Performance may be shorter downstream of the air Compressor . Copper Piping Copper pipe is a common selection for sensitive Compressed air systems and when correctly sized and connected is very durable and effective. Type M hard, type L. hard and type K soft copper has a working pressure of 250 psig (17 bar). Type K hard copper Extruded aluminum alloy Piping is corrosion resistant, mechanically strong and easy to install.

4 Is rated for 400 psig (27 bar). Copper Piping is resistant to part of the scope of this paper. and extruded aluminum alloy, high temperatures with limits Metal pipe can be black iron, it is much heavier and harder to rated at 400 F (204 C). Even if copper, stainless steel work with-significantly increasing copper does fail, it will do so in a or extruded aluminum alloy. installation time. predictable manner with the pipe ends separating. Never join pipes Many engineers select galvanized or fittings by soldering. Lead- Black Iron Piping tin solders have a low ultimate inlet Piping for 100 psig (7 bar).

5 Black iron Schedule 40 Piping Piping systems. This pipe coating strength, a low creep limit and in Compressed air systems is does help black iron inlet Piping depending on the alloy, start commonly used due to price and resist corrosion better than melting at 361 F (183 C). Silver durability. Pipe diameters of 3" standard Schedule 40 pipe. Over and hard soldering are forms and below are normally threaded time, however, when corrosion is of brazing and should not be while larger diameter headers present, the galvanizing material confused with lead-tin soldering.

6 Use welds and flanges. Black peels off. The inlet Piping now Silver and hard soldering is iron pipe, however, will corrode becomes a source of potentially brazing with a silver alloy type when exposed to condensed destructive contaminants able of filler material, which melts moisture with the resulting to affect the mechanical integrity in the range of 1145-1800 F. solid particulates becoming a of the air Compressor . The (618-982 C). major source of contamination. same holds true for galvanized Internal corrosion becomes even air Compressor discharge and Extruded Aluminum more significant when exposed distribution Piping .

7 Often, Alloy Piping to the aggressive high-acid due to the aggressive acidic characteristics of some types of Extruded aluminum alloy characteristics of condensate, condensate. Compared to copper Compressed air Piping has the life of the galvanized coating 2. Hitachi Industrial Equipment WHITE PAPER. White Paper: Ambient Air's Impact on Compressed Air System Performance become very popular. It is very assembly and subassembly while black iron requires three resistant to corrosion and is production areas. Aluminum alloy (weld, fill and cover).

8 Stainless lightweight allowing for easier can be installed or removed with steel normally does not seal installation. A lack of internal no skilled labor or soldering and well when threaded, performing corrosion translates into a smooth has a broad range of temperature much better with grooved type inner surface reducing pressure ratings from 4 to 176 F (15-80 C). connections. losses due to friction. Other Note that these ratings will vary characteristics offering better air from brand to brand. Air Compressor handling include internal flush Discharge Piping connections and inside diameters Materials Stainless Steel Piping the same size as the pipe size Schedule 10 stainless steel is Discharge air temperatures rating.

9 Type K 4" copper pipe, lightweight (compared to black from centrifugal, reciprocating in contrast, has a " internal iron) and is corrosion resistant. and oil-free rotary screw air diameter. Another important Because it is easy to handle, it compressors can range from 250- feature of aluminum alloy is will normally have lower handling 350 F (121-177 C). Discharge the enhanced flexibility of the costs but skilled labor will be air temperatures from lubricated connections allowing for a required for welding. For welded rotary screw air compressors can Piping system to easily adapt to connections, stainless steel range from 200-220 F (93-105 C).

10 An industrial plants ever-changing usually requires just one bead Even if the air Compressor has Table 1: Piping Material Features and Characteristics Extruded Aluminum Piping Features Stainless Steel Black Iron Copper Alloy Schedule 10 Schedule 40. Light Light Weight Lighter Heavy Corrosion Resistant Yes No Yes Yes Vulnerable to Friction- No Yes No No generated Pressure Loss Mechanical Strength Very Strong Very Strong Strong Strong High Temperature Rating Yes Yes Yes Yes Installation Ease Less Difficult Difficult Less Difficult Easy Installation Cost 30% / 70% 25% / 75% 40% / 60% 80% / 20%.