12 May 2003
Including change 1, 19 January 2007
Piping System Design Criteria. Design compressed air piping to
conform to commercially available standard practices. Also, the designer may consult
MIL-HDBK-1003/8, Exterior Distribution of Steam, High Temperature Water, Chilled
Water, Natural Gas, and Compressed Air. In addition, provide corrosion protection of
steel pipes. Consider an extruded polyethylene or polypropylene exterior coating.
Extruded plastic coatings must contain an ultraviolet inhibitor. For coated pipe, use
polyethylene, heat-shrinkable sleeves and/or tape wrapping at joints and fittings.
Provide pipe hangers and associated support assemblies in accordance with paragraph
2-4.1.3. Identify piping and outlets and color-code in accordance with Chapter 6.
Quality. Compressed air should normally be "commercial" quality. Where
breathing quality air and/or an oil-free system is necessary use an oil-free source and/or
purification systems. Compressed breathing air compressors must meet the
requirements of 29 CFR 1910.134 and the requirements for Grade D breathing air
described in ANSI/Compressed Gas Association Commodity Specification for Air, G-
7.1-1989. Locate compressors used to supply breathing air so as to prevent entry of
contaminated air into the air supply system and breathing air couplings are incompatible
with outlets for nonrespirable worksite air or other gas systems.
Size of Piping. For single berths, size the mains in accordance with air
quantity per ship data given in Appendix C. Multiple pier demand data for use in design
of new compressed air plants and at new facilities should be obtained by evaluating
demands at operating Naval berthing and repair facilities which are similar to the
proposed facility. The designer should consult with the cognizant NAVFAC EFD/EFA
OR USACE DISTRICT. For multiple berthing at a single pier or wharf, including nested
ships, use the following diversity factors:
NUMBER OF SHIPS
5 or more
Branches. Branch-pipe sizes should be in accordance with the ships'
usage data defined in APPENDIX C. Where a variable mixture of ships is probable at a
given pier, all branch lines should be 76.2 mm (3 in) minimum. However, where carriers
may be berthed, branch lines should be 101.6 mm (4 in) minimum.
Sizing Method. Determination of pipe size should be in accordance with
available friction loss tables. Size mains for a pressure drop of not greater than 34.47
kPa (5 psi) total friction loss from pier or wharf entrance to farthest outlet, and as based
upon the designed flow rates. For looped mains, assume flow in both legs of the loop.
In all cases, mains should be sized to supply the most outboard ship with 100 percent of
the quantity defined in APPENDIX C, and then adjusted for its full-diversified demand.