UFC 3-420-01
25 October 2004
permitted. Size and locate commercial water hammer arresters in accordance with PDI
WH201-1992, Water Hammer Arresters and manufacturer's recommendations. Provide
access doors or removable panels when water hammer arresters are concealed."
H.
SECTION 605.1 Water compatibility. Add after the last sentence: "Selection
of pipe, valves, and fittings will be in accordance with the quality of the water. For Army
Projects, water quality is classified under the following categories:
(a) Category 1: Calcium plus magnesium content 0 to 35 parts per million (ppm)
expressed as calcium (Ca). For this type of water, pipe, valves, and fittings will be
nonferrous for both hot-and cold-water services.
(b) Category 2: Calcium plus magnesium content 35 to 75 ppm. For this type of
water, pipe, valves, and fittings may be ferrous for cold water service, when sulfates
(SO4) are less than one and one-half times the calcium content. If the sulfate content is
more than one and one-half times the calcium content, pipe, valves, and fittings will be
nonferrous for cold-water service. All pipe, valves, and fittings for hot-water service will
be nonferrous.
(c) Category 3: Calcium plus magnesium content more than 75 ppm. For this
type of water, pipe, valves, and fittings may be ferrous for cold-water service and
nonferrous for hot-water service if the sulfates (SO4) are less than twice the calcium
content. If the sulfates are more than twice the calcium content, pipe, valves, and
fittings will be nonferrous for hot and cold-water service.
(d) Category 4: Pipe and fittings for salt-water service will be of thermoplastic or
thermosetting plastic. Valves will be plastic or nonferrous metal.
In the absence of actual experience at a specific location, the categories
shown above, especially category 1, are satisfactory for the selection of potable water
piping. Non-ferrous piping is recommended for hot-water service regardless of water
category and is also recommended for cold water installations when piping is concealed
in walls, partitions, and floors, where replacement would be difficult and expensive, and
when the piping is 3 inches (76 mm) diameter or less. High-chloride content, especially
in category 2 and 3 waters, will have a corrosion-causing effect similar to high-sulfate
content. If local experience shows that ferrous piping in category 2 and 3 waters has a
satisfactory life of 20 to 25 years, ferrous pipe may be used for cold-water service,
provided piping is not concealed and replacement can be accomplished economically.
Where dissimilar metals are joined underground or at water heaters, insulated joints will
be installed at those points to break the galvanic couple."
I.
Add "SECTION 606.5.11 Sizing booster systems and pumps. Water
pressure may be increased by using a hydro-pneumatic system consisting of a tank,
pumps, compressed air system, and associated control devices.
606.5.11.1 Tank Pressure. The minimum pressure maintained within the
tank is at low-water level and is equal to the pressure required to meet the
fixture demands. The high pressure at high water level depends on the
operating pressure differential selected for the system. A reasonable and
most commonly selected pressure differential is 20 psi (138 kPa).
606.5.11.2 Pumps. Pumps normally are provided in duplex. For Army and
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