sábado, 24 de outubro de 2009
BACKFLOW PREVENTER : PROTECTION OF POTABLE WATER SUPPLY
Double Check Detector Assembly (DCDA) backflow prevention device
What is a backflow device?
Backflow devices are simply components of plumbing systems installed to prevent contaminated or polluted water from backflowing into the fresh water supply. This can be the result of backpressure, where the pressure on the supply side (fresh water coming into the building or irrigation system) is exceeded by something causing greater pressure (a fertilizer pump, a big tank on top of a tower or tall building, etc.). If the pressure on the supply side drops below the pressure on the demand side, the potentially bad water can be forced back into the fresh water supply. When this happens, many people can get sick or die as a result of being exposed to the contaminated or polluted water. If a backflow incident should occur resulting in the contamination of the public water supply, the responsible owner or occupant could be held liable for damages. With backflow devices installed, the water cannot flow back, as it is stopped by a check valve (or two) that only allows water to travel in one direction.
Typical commercial buildings have the three most common types of devices. While you may not realize it, you see them all the time The most easily recognized backflow device is called a DCDA, or double check detector assembly. Usually painted bright red, these are large (usually at least 6” in diameter) pipes with rising-stem shutoff valves located near the curb. While some are hidden behind hedges or walls, they're hard to miss.