Absolute pressure gauges are always used when, particularly with measurement of low pressure or vacuum, influence from atmospheric air pressure fluctuations which could falsify measurements has to be ruled out.
The design and materials are selected to allow the instruments to satisfy the stringent demands of the chemical industry. They are used with aggressive media (fluids) and/or in aggressive environments. With highly viscous or crystallizing media, the instruments are fitted with open process connections, thus facilitating rapid and thorough cleaning.