ASME A112.1.2 pdf free download

ASME A112.1.2-2012 pdf free download.Air Gaps in Plumbing Systems (For Plumbing Fixtures and Water-Connected Receptors).
ASME A112.1.2 identifies methods of providing protection against backsiphonage through means of an air gap and establishes physical requirements and methods of testing air gaps for plumbing fixtures and water receptors.
1.2 Units of Measurement
The values stated in either SI (Metric) or inch/pound units are to be regarded as the standard, In this Standard, the inch/pound units are shown in parentheses. The values stated in each measurement system are equivalent in application; however, each system is to be used independently. Combining values from the two measurement systems can result in nonconformance with this Standard. All references to gallons are to U.S. gallons.
1.3 References
The following documents form a part of this Standard to the extent specified herein. Unless otherwise spedfied, the latest edition shall apply.
ASSE/ANSI 1002, Water-Closet Flush Tank Ball Cocks’ Publisher: American Society of Sanitary Engineering (ASSE), 901 Canterbury Road, Westlake, OF! 44145 (www.asse-plumbing.org)
CSA 8125.3, Plumbing Fittings
Publisher: Canadian Standards Association (CSA), 5060 Spectrum Way, Mississauga, Ontario L4W 5N6. Canada (www.csa.ca)
1.4 Definitions
air gap: a vertical distance through the atmosphere between the lowest potable water outlet and the highest level of the source of fluid contamination.
air gap, critical: the air gap that will prevent backsiphonage under laboratory conditions, with still water, wide-open control valve, and a vacuum of at least 635 mm Hg (25 in. Hg).
air gap, minimum required.: an air gap greater than the critical air gap by a factor of safety to cover service conditions. The air gap required to prevent backsiphonage through a water supply opening (faucet or valve), under the action of atmospheric pressure and a vacuum in the water supply system, depends principally on
(a) the size of the effective opening
(b) the distance between the end of the supply fitting outlet (spout) pipe and a nearby wall
The minimum required air gap shall be measured vertically from the lowest point of the faucet, spout, or supply pipe to the flood-level rim of the fixture or receptor (see Figs. 1 and 2).
backflow: the flow of water or other liquids into the distributing pipes of a potable supply of water from any source or sources other than the intended source. Backsiphonage and backpressure are types of backuiow.
backflow connection or condition: any arrangement whereby backflow can occur.
backflow prevenhion device: a device or assembly (combination of devices) designed to prevent backflow.
critical level: the level at which backsiphonage will not occur, including any required factor of safety.
critical level mark: the manufacturer’s designated critical level.
effective openinç: the smallest cross-sectional area in a faucet, device, or a supply pipe through which water fkns’s to an outlet. II two or more lines supply one outlet, the effective opening shall be the sum of the cross-sectional areas of the individual lines or the area of the outlet, whichever is smaller.
NOTE: To illustrate the practical use ol the term ‘elfective opening ,” refer to Fig. 1. With ordinary plumbing 5upply fittings. the minimum cross-sectkmal area usually occurs at the seat of the control valve, B; but, in other cases, it may be at the point of discharge (spout or at the inlet to thc control valve, X.
elevation: the air gap—related term applied to drinking fountain nozzles.
flood-leve’l rim: the top edge of the receptor from which water will flow out of the receptor (an overflow opening is not considered a flood-level rim).ASME A112.1.2 pdf download.