ASME A112.1.3:2000 pdf download AIR GAP FITTINGS FOR USE WITH PLUMBING FIXTURES, APPLIANCES, AND APPURTENANCES
NOTES:
Water level Vacuum source The distance between the vacuum gauge, V , and the highest level of air port opening, P , shall be not more than 19.7 in. (0.5 m) including not more than 9.8 in. (0.25 m) of vertical distance. The interior cross sectional area of the conduit between the fitting under test and the vacuum gauge shall be at least as large as the minimum cross sectional area of the main flow path within the fitting but not less than 0.20 in. 2 (130 mm 2 ), except as permitted by Note 3.
An air gap fitting with an integral inlet too small to be connected directly to a conduit of at least 0.20 in. 2 (130 mm 2 ) interior cross sectional area, and whose manufacturer’s installation instructions recommend operational connection by conduit smaller than 0.20 in. 2 (130 mm 2 ), may connect that inlet to the rest of the test conduit (of at least 0.20 in. 2 (130 mm 2 )) by a length of smaller conduit.
This smaller conduit shall be no more than 5.9 in. (0.15 m) long and shall have the largest ID recommended by the manufacturer’s installation instructions for operational use. Connection fittings used with such a smaller conduit must be the same as recommended by the manufacturer’s installation instructions for regular installations.
FIG. 1 ARRANGEMENT FOR CRITICAL LEVEL AND BACK SIPHON TESTING
5.1.2 Lower the water level so that it is no more than 0.12 in. (3 mm) below the highest level of air port opening, and apply a continuing vacuum of at least 25 in. Hg (85 kPa) while the water level is gradually lowered further. The elevation at which si- phonage ceases shall be recorded. A continuing vacuum of 25 in. Hg (85 kPa) shall then be applied as thewater level is gradually raised. The elevation at whichback siphonage begins shall be recorded. The lower ofthe two elevations shall be considered the critical level.
5.1.3 The manufacturer’s critical level mark on thefitting shall be at or below the critical level determinedby this test.
5.2 Back Siphonage
5.2.1 Test Method. The fitting shall be installedin accordance with Fig. 1 and with the manufacturer”sinstructions and submerged to the manufacturer’s criticallevel mark. The following vacuum loads shall be appliedin the sequence listed and the presence of water inthe sight tube，if any，shall be noted:
(a) A vacuum of 25 in.Hg (85 kPa) shall be appliedand held for a period of five (5) min.
(b)The vacuum shall be raised from 0 to 25 in.Hg (85 kPa),then shall be reduced to 0.
(c) A surge effect shall be created by operating avalve which travels between closed and fully openwithin 2 sec. The applied vacuum shall vary between0 and at least 25 in. Hg (85 kPa).
(d) For devices with multiple water inlets，tests5.2.1(a)，(b),and (c) shall be conducted on the inletsindividually. The conditions at the other inlets areto include: water flowing at the manufacturer’s ratedmaximum,the inlet blocked,and the inlet open toatmosphere. The test matrix is to include these threeconditions existing at all possible location combinations.5.2.2 Any entrance of water in the sight tube shallbe cause for the rejection of the fitting.
5.3 Back Siphonage Cross Flow Test for
Fittings With Multiple Inlets
5.3.1 Test Method. Each water inlet of a devicewith multiple water inlets is to be individually testedas follows.The inlet is to be connected to a vacuumsource with a sight tube in accordance with the dimen-sions in Fig. l and a continuing vacuum of at least25 in.Hg (85 kPa) applied while specific combinationsof water flows are present at the other inlets. Testinstallation is to be in accordance with the manufactur-er’s instructions. The test matrix is to include allcombinations of the water flow increments listed below,also including zero flow. These tests shall include thefollowing increments of water flow: 0.031 gpm (0.117L/min) for maximum rated flow of less than 1 gpm(3.785 L/min); 0.5 gpm (1.892 Lmin) for maximum
ASME A112.1.3:2000 pdf download
