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Backflow Preventer
A backflow prevention device is used to protect potable water supplies from contamination or pollution due to backflow. In water distribution systems, water is normally maintained at a significant pressure to enable water to flow from the tap, shower, or other fixture. Water pressure may fail or be reduced when a water main bursts, pipes freeze, or there is unexpectedly high demand on the water system (for example, when several fire hydrants are opened). Reduced pressure in the pipe may allow contaminated water from the soil, from storage, or from other sources to be drawn up into the system. Terminology Backflow means the undesirable reversal of flow of a liquid, gas, or suspended solid into the potable water supply; a backflow preventer is designed to keep this from happening. Points at which a potable water system connects with a non-potable water system are called cross connections. Such connections occur naturally in appliances such as clothes washers and dishwashers, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Back Siphon Example Hosepipe Up Hill
The human back, also called the dorsum, is the large posterior area of the human body, rising from the top of the buttocks to the back of the neck. It is the surface of the body opposite from the chest and the abdomen. The vertebral column runs the length of the back and creates a central area of recession. The breadth of the back is created by the shoulders at the top and the pelvis at the bottom. Back pain is a common medical condition, generally benign in origin. Structure The central feature of the human back is the vertebral column, specifically the length from the top of the thoracic vertebrae to the bottom of the lumbar vertebrae, which houses the spinal cord in its spinal canal, and which generally has some curvature that gives shape to the back. The ribcage extends from the spine at the top of the back (with the top of the ribcage corresponding to the T1 vertebra), more than halfway down the length of the back, leaving an area with less protection between the bottom of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plumbing Code
A plumbing code is a code that provides regulations for the design, installation and inspection of building plumbing and sanitary systems. In the United States, jurisdictions enact their own codes, some of which are based upon model plumbing codes. The most widely adopted plumbing code in the United States is the International Plumbing Code published by the International Code Council (ICC). This code is also used as the basis for the plumbing codes of some other countries. Another model plumbing code published and utilized widely across the United States is the Uniform Plumbing Code, published by the International Association of Plumbing and Mechanical Officials (IAPMO), a multinational operation with offices in 13 nations. IAPMO codes are developed using ANSI consensus development procedures. This code serves as the basis for the national plumbing codes in India and Indonesia. Plumbing codes mainly focus on venting. Improper venting can release noxious fumes into homes and buildings ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spill Resistant Pressure Vacuum Breaker Assembly
A spill occurs when the contents of something, usually in liquid form, are emptied out onto a surface, person or clothes, often unintentionally. Spill may also refer to: *Oil spill *Chemical spill *Data spill *Leadership spill *Spill (audio), where audio from one source is picked up by a microphone intended for a different source *Variable spilling, a side effect of register allocation *Thin sticks of wood or tightly rolled paper tapers, used for transferring fire, and stored in a spill vase *SPILL – an acronym for St Pancras International Low Level, the Thameslink platforms at St Pancras railway station in London As a proper name *Thomas Spilsbury, soccer player nicknamed ''Spill'' *Spill (band), a British dance duo *Spill.com, a movie review website People with the surname *Daniel Spill (1832–1887), English entrepreneur *Steve Spill (born 1955), American magician Literature *'' Spill. En damroman'', a 2010 Swedish novel by Sigrid Combüchen *'' Spill: Scenes of Black Femin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure Vacuum Breaker Assembly
A pressure vacuum breaker (PVB) is a type of backflow prevention device, used to keep non-potable (or contaminated) water from entering the water supply. A PVB is similar to an atmospheric vacuum breaker (AVB), except that the PVB contains a spring-loaded poppet. This makes it acceptable for applications that are high hazard or where valves are downstream. Pressure vacuum breakers must be protected from freezing when installed outdoors. PVBs usually have test cocks, to which specially-calibrated gauges are attached, in order to ensure that they are functioning properly. Backflow prevention devices such as PVBs are regulated by the Uniform Plumbing Code, but may also be required by government regulations. See also * Air gap * Atmospheric vacuum breaker * Chemigation valve * Double check valve * Hydrostatic loop * Reduced Pressure Principle BFP A reduced pressure zone device (RPZD, RPZ, or RPZ valve) is a type of backflow prevention device used to protect water supplies from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dual Check Valve
A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination. It is different from the two-way check valves (sometimes erroneously referred to as double check valves) used in air brake systems on heavy trucks which select from the highest pressure source. It consists of two check valves assembled in series. This employs two operating principles: firstly one check valve will still act, even if the other is jammed wide open. Secondly the closure of one valve reduces the pressure differential across the other, allowing a more reliable seal and avoiding even minor leakage. Small valves may be so compact as to be barely noticeable particularly when they are integrated into the bodies of existing taps (faucets). Larger check valves may be installed with ball valves at the ends, for isolation and testing. Often, test cocks (very small ball valves) are in place to attach test equipment for evaluating whether th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Check Valve
A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination. It is different from the two-way check valves (sometimes erroneously referred to as double check valves) used in air brake systems on heavy trucks which select from the highest pressure source. It consists of two check valves assembled in series. This employs two operating principles: firstly one check valve will still act, even if the other is jammed wide open. Secondly the closure of one valve reduces the pressure differential across the other, allowing a more reliable seal and avoiding even minor leakage. Small valves may be so compact as to be barely noticeable particularly when they are integrated into the bodies of existing taps (faucets). Larger check valves may be installed with ball valves at the ends, for isolation and testing. Often, test cocks (very small ball valves) are in place to attach test equipment for evaluating whether t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemigation Valve
Sometimes called a check valve or a backflow preventer, a chemigation valve is an apparatus designed to protect water supplies from agricultural chemicals used during chemigation, the application of chemicals such as fertilizers and pesticides through irrigation water. Most chemigation valves consist of a spring-loaded check valve, a low pressure drain, an air and vacuum relief valve, and an injection port for introducing the chemicals downstream of the check valve. Many chemigation valves also have a 4-inch inspection port so that a person can reach inside and feel if the check valve is still functional. Some governments require the use of two chemigation valves installed in series if hazardous chemicals are to be injected. The following policies require or encourage the installation of these valves: Texas State law Chapter 344.73 in Subchapter D - 1.(b) : "An irrigation system which adds any chemical is considered to be a 'high health hazard'. Such an irrigation system mus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Check Valve
A check valve, non-return valve, reflux valve, retention valve, foot valve, or one-way valve is a valve that normally allows fluid (liquid or gas) to flow through it in only one direction. Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave. There are various types of check valves used in a wide variety of applications. Check valves are often part of common household items. Although they are available in a wide range of sizes and costs, check valves generally are very small, simple, and inexpensive. Check valves work automatically and most are not controlled by a person or any external control; accordingly, most do not have any valve handle or stem. The bodies (external shells) of most check valves are made of plastic or metal. An important concept in check valves is the cracking pressure which is the minimum differential upstream pressure between inlet and outlet at which the valve will operate. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Vacuum Breaker
An Atmospheric Vacuum Breaker (AVB) is a backflow prevention device used in plumbing to prevent backflow of non-potable liquids into the drinking water system. It is usually constructed of brass and resembles a 90-degree elbow with a hood on its top to allow air to enter the water system if a siphon attempts to form. Inside this elbow is a poppet valve that is held "up" by the water pressure found in the system, closing the air entrance to the device. If the pressure in the "upstream side" is reduced to atmospheric pressure or below, the poppet valve drops and allows air to enter the system, breaking the siphon. These devices, since they work on atmospheric principles, cannot be installed in an enclosure containing air contaminants. Those contaminants could be drawn into the device, thus fouling the pipes. AVBs must be installed a minimum of 6 inches above the highest usage point in the system (i.e. sprinkler, drip emitter, etc.) Underground installation of AVBs is ''entirely ine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Gap (plumbing)
An air gap, as related to the plumbing trade, is the unobstructed vertical space between the water outlet and the flood level of a fixture. Air gaps of appropriate design are required for water safety by legislation in many countries. A related term in computer security is ''network air gap''. A simple example is the space between a wall mounted faucet and the sink rim (this space is the air gap). Water can easily flow from the faucet into the sink, but there is no way that water can flow from the sink into the faucet without modifying the system. This arrangement will prevent any contaminants in the sink from flowing into the potable water system by siphonage and is the least expensive form of backflow prevention. A common use of the term "air gap" in home plumbing refers to a fixture that provides back-flow prevention for an installed dishwasher. This "air gap" is seen above the sink as a small cylindrical fixture mounted parallel with the faucet. In the base cabinet under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reduced Pressure Zone Device
A reduced pressure zone device (RPZD, RPZ, or RPZ valve) is a type of backflow prevention device used to protect water supplies from contamination. RPZDs may also be known as reduced pressure principle (RP), reduced pressure principle backflow prevention devices, reduced pressure zone assemblies (RPZA), or reduced pressure principle assembly (RPPA). * ASSE Standard 1013 - Reduced Pressure Backflow Assembly * ASSE Standard 1015 - Double Check Valve Assembly * ASSE Standard 1020 - Pressure Vacuum Breaker * ASSE Standard 1047 - Reduced Pressure Detector Assembly * ASSE Standard 1047 - Reduced Pressure Detector Assembly Type II * ASSE Standard 1048 - Double Check Detector Assembly * ASSE Standard 1048 - Double Check Detector Assembly Type II * ASSE Standard 1056 - Spill Resistant Vacuum Breaker Backflow preventers are categorized into three groupings: Assembly, Device or Method. With the exception of elimination, these are the only ways one can control backflow from taking place. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Environmental Protection Agency
The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it began operation on December 2, 1970, after Nixon signed an executive order. The order establishing the EPA was ratified by committee hearings in the House and Senate. The agency is led by its administrator, who is appointed by the president and approved by the Senate. The current administrator is Michael S. Regan. The EPA is not a Cabinet department, but the administrator is normally given cabinet rank. The EPA has its headquarters in Washington, D.C., regional offices for each of the agency's ten regions and 27 laboratories. The agency conducts environmental assessment, research, and education. It has the responsibility of maintaining and enforcing national standards under a variety of environmental laws, in consultation with state, tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
