ASME A112.18.3:2002 pdf free download PERFORMANCEREQUIREMENTS FORBACKFLOWPROTECTION DEVICES AND SYSTEMS IN PLUMBING FIXTUREFITTINGS
6.1 Functional
Backflow prevention devices shall be designed to pre-vent pollution and contamination of the potable watersystem.
6.2 Materials
Materials in contact with potable water shall complywith the requirements of ASME A112.18.1M.
6.3 Environment
6.3.1 Working Pressure. Backflow prevention devicesshall be designed to function at water working pressuresup to 125 psig (861 kPa gage).
6.3.2 Working Temperature. Backflow preventiondevices shall be designed to function at water supplytemperatures ranging from 40°F to 160°F(4.4C to 7ic).6.4Reliability
Backflow prevention devices shall be resistant tomechanical wear, deposition of minerals, aging, and cor-rosion of the materials as determined by the test proce-dure of para.7.The manufacturer shall establish thereliability of the individual backflow prevention device,and it shall be confirmed by durability tests in accor-dance with para.7.
7EVALUATION OF BACKFLOW PREVENTIONDEVICES
7.1 Sample Size
The minimum initial sample size per set shall be sevenspecimens.The incremental increases and cumulativesample sizes shall be as shown in Table 1.
7.2 Test Methodology
7.2.1 Facilities.The backflow prevention devicesshall be tested individually in fittings or test fixturesrepresenting the dimensions and tolerances specified bythe device manufacturer.
7.2.2 Protocol.The functional performance of thedevice shall be determined before and after the durabil-ity test sequence.The functional performance of a device
shall be determined in accordance with para. 11.Thedurability test sequence for a device shall be conductedin accordance with para.15.The process for evaluationof backflow prevention devices is illustrated in Fig. 1.
Two sample sets,each consisting of a minimum ofseven specimens,shall be evaluated for durability bytests defined in para. 15.At the start of the evaluation,
both sets samples shall be tested for functional perform-ance (para.11).Thereafter, one sample set shall be testedfor mechanical wear and mineral deposition (para.15.2),and the second sample set shall be tested for aging andcorrosion (para.15.1). When retested, there shall be amaximum of three incremental increases.
7.3 Conformance
Any physical damage to internal devices known topreclude functional performance shall be cause for rejec-tion.The allowable failures shall not exceed the valuesshown in Table 1.
8FIXTURE FITTINGS wITH INTERNAL DEVICES
COMPLYING WITH PARAS.6 AND 7
The purpose of this paragraph is to define the require-ments and test procedures for the evaluation of finishedproducts incorporating certified backflow protectiondevices which have been demonstrated to be in compli-ance with paras. 6 and 7 of this Standard.
8.1 Health and Safety
8.1.1There shall be at least two backflow preventiondevices, in series proven by tests as in compliance withpara. 7 of this Standard.They shall operate indepen-dently as integral parts of the fixture fitting.At leastone device shall be a check valve, called the primarycheck in this Standard.
Among the protection devices are(a) check valves
b) vents to air
(c) vacuum breakers(d) automatic diverters
8.1.2 Contaminants shall not enter the potable watersystem through backflow nor shall contaminants beallowed to enter the fitting beyond the first barrier whenthe backflow preventer is operating properly.The testshall be in accordance with para.12.
8.1.3 The manufacturer shall specify the type andlocation of the backflow protection system in the productliterature or in the installation instructions.
8.2 Performance Tests
8.2.1 Selection of Test Specimens. To comply withthis Standard, two specimens will be selected at randomfrom a lot of five production fittings. Before mountingthe fixture fittings in the test rig, correct installation of the protecting devices shall be verified as conforming to the manufacturer’s drawings and specifications.
8.2.2 Conformance. The sample shall pass the follow-
ing tests:
(a) back pressure, see para. 12.1;
(b) back siphonage, see para. 12.2;
(c) independence of devices, see para. 13; and
(d) leakage of protection systems with atmospheric vents, see para. 14.
ASME A112.18.3:2002 pdf free download
