Pressure gradient the air to make it move as wind. Note that the pressure gradient force points from high towards low pressure zones, it is thus oriented in the opposite direction from the pressure gradient itself. Sound waves and shock waves are events that can induce very large pressure gradients, but these are often transitory disturbances. In acoustics the pressure gradient is proportional to the sound particle acceleration according to Euler's equation. Pressure gradient In atmospheric science (meteorology, climatology and related fields), the pressure gradient (typically of air, more generally of any fluid) is a physical quantity that describes in which direction
Reduced pressure zone device by an accredited tester. In the UK all RPZD Valve Testers have to be WRAS Accredited 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). Backflow preventers are categorized into three groupings, an Assembly, a Device or a Method. With the exception of elimination, these are the only ways one can control backflow from