NEBRASKA ADMINISTRATIVE CODE
Title 195 - NEBRASKA DEPARTMENT OF ENVIRONMENTAL QUALITY Appendix I
Leakage Test
A check valve shall withstand for 1 minute, without leakage at joints or at the valve seat, an internal hydrostatic pressure of two times the rated working pressure of the valve. Slight weeping of water at the valve seat is acceptable for metal-to-metal seats. Leakage past clappers with, or in contact with, resilient seats, is not acceptable.
For the purposes of the test, “slight weeping” is defined as leakage not exceeding 1 fluid ounce per hour (0.008 mL/ sec) per inch (25.4 mm) of nominal valve size.
A Check valve shall withstand for 16 hours, without leakage at the valve seat, an internal hydrostatic pressure equivalent to the head of a column of water 5 feet (1,5 m)high retained within the downstream portion of the valve body. No leakage shall occur as evidence by wetting of paper placed beneath the valve assembly. This test is to be conducted with the valve in both the horizontal and vertical position if intended for such use.
“This material is based on and taken, with permission from Underwriters Laboratories Inc. Standard for Safety for Check Valves For Fire-Protection Services, UL 312, Sixth Edition dated April 21, 1980, Copyright 1975, 1985 (by Underwriters Laboratories Inc.), copies of which may be purchased from Underwriters Laboratories Inc., Publications Stock, 333 Pfingsten Road, Northbrook, IL 60062.”
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