High-pressure area the opposite direction of clockwise is referred to as anticlockwise, making the label "anticyclones" a logical extension. A simple rule is that for high-pressure areas, where generally air flows from the center outward, the coriolis force given by the earth's rotation to the air circulation is in the opposite direction of earth's apparent rotation if viewed from above the hemisphere's pole. So, both the earth and winds around a low-pressure area rotate counter-clockwise in the northern hemisphere, and clockwise in the southern. The opposite to these two cases occurs in the case of a high. These results derive from the
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