Anti - siphon valve are a keen example of how edifice code evolve . They also show how the code can contain rules that seem to make no sense but in reality solve significant problems . Most building codes now require anti - siphon valve in several different places in a menage , include all external hose joining and sometimes intoiletfill valve .
First , have ’s specify asiphon . A siphon is any piping , hose or tube that is used to move a liquidity from a higher position to a lower fix . To use a siphon , you replete the pipage or hose with the liquid and stick one end of the pipe in the liquid at the high-pitched localisation . Then you let the liquidity start draining at the low location . As the liquidity run out out of the tube at the lower location , avacuumdevelops that give suck the pee from the higher location . Gravityand suction do all the work , so no ticker is expect ! you could use siphons to enfeeble ponds , empty gun barrel , removegasolinefrom a gas tank , etc .
Here ’s the job anti - siphon valve solve : rent ’s say you take your garden hosiery and you stick it in the 300 - gallon marine museum you have in your upstair bedchamber to occupy the marine museum . When you twist on the water , you fill up the hose with water supply . As the marine museum fills , the close of the hosepipe inside the aquarium gets covered with urine . If the water insistency go ( for example , because you live in a rural area with a private well and the power drop dead out , or in the city because someone open a ardour hydrant and importantly lowers the water system pressure on your block ) , what will happen is that the piss in the aquarium will syphon back through the hose into the body of water system . So the next time you wrick on the water in the kitchen , you are drinking aquarium water . Yuck ! The problem is even spoiled if you are using the hosepipe to fill a pesticide tankful . In the case of a lawn irrigation arrangement , if there is stand urine in the yard then the siphon effect can suck fertilizer , weed killers , dog poop and all variety of other thing into your home ’s plumbing . two-fold - yuck !
The anti - siphon valve prevents all of this . An anti - siphon valve is nothing more than aone - directional valve . It can be as elementary as a outpouring - loaded flap that let water flow in only one direction .
A central affair to note is that many masses skip the anti - siphon valve . Either they do n’t know about it , or they do n’t understand it , or they guess it cost too much or they only do n’t care to be " told what to do . " In the process , they endanger their own health and the health of their neighbors , because there is an existent trouble that the anti - siphon valve solves . That ’s why there are build code and construction review .
