2. July 1970 1051
INTRODUCTION
An automatic drip valve drains water which may leak past a closed valve into piping which must be
kept dry. A common use is on fire department connections. The automatic drip valve is normally open
and closes when the water flowing through it exceeds 4 to 10 gpm.
FM Approval is based on examination and test of production samples, inspection of the manufacturing
and/or quality control facilities. Particularly considered are functional suitability, adequacy of design and
workmanship, uniformity and dependability of production, effectiveness of quality control, and assurance
of service and replacement parts.
These requirements are guides. Mere conformity does not assure Approval since other considerations
may control. Nor is strict conformity necessary; devices having different characteristics may be considered
and Approved.
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I REQUIREMENTS
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A Design
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An automatic drip valve shall:
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1. Close at a water flow between 4 and 10 gpm.
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2. Pass between 1 and 2 gpm at 100 psi inlet water pressure when in the closed position.
3. Open before the pressure decreases to 5 psig from 100 psig.
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4. Show readily by inspection within about one minute that it is in its proper position and the movable
parts are free.
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B Strength and Durability
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1. The valve shall have sufficient strength and durability to withstand normal stresses imposed when water
is admitted to the associated piping or vessel, and to function properly under normal use for many years.
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Internal working parts and waterway shall be of corrosive resistant material.
2. The valve shall have a rated working pressure of 175 psig minimum.
FM APPROVALS 1
3. 1051 July 1970
II TESTS
1. Strength
When in the closed position, a sample valve will be subjected to a water pressure of 200% rated working
pressure. There shall be no rupture, permanent distortion of parts, or other ill effects as a result of this test.
2. Flow for Closure
Representative samples will be tested to determine the water flow in gpm at which the valve closes.
3. Leakage
After closure in test 2, above, the water pressure will be increased to 100 psig. At this point, the leakage
shall be between 1 and 2 gpm.
4. Reliability to Open
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The pressure will be reduced to determine the pressure at which the valve opens. The reopening pressure
shall be 5 psig minimum.
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5. Durability
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A sample valve will be subjected to the following endurance test:
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The valve will be connected to a chamber consisting of a 1 in. pipe 12 in. long. Water at 90 to 120 psig
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will be introduced suddenly to the chamber. Shortly after the drip valve closes, the water will be shut off
permitting the valve to open and drain the chamber. This cycle will be repeated 500 times. No damage or
change in operating characteristics shall result.
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III MARKING
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The valve shall show plainly and permanently the manufacturer’s name or recognized trademark.
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2 FM APPROVALS
