7.2　Installation of Regulating Cock，Exchange Cock and Orifice Plate Box

7.2.1　The regulating cock，exchange cock and orifice plate box shall meet the requirements of design documents，and are installed after pressure test is qualified.

7.2.2　The odd and even number and on/off state of the exchange cock and the indication of the engraved direction shall meet the requirements of design documents.

7.2.3　Gaps of upper and lower positions between exchange cock wrench and cock square head shall not be larger than 0.3mm，and gaps shall not occur on left and lower sides.

7.2.4　The center of the exchange cock shall be on the straight line，and allowable deviation shall be 3.0mm.

7.2.5　The installation of flanges of regulating cock，orifice plate box and exchange cock shall meet the requirements of Code for Construction and Acceptance of Industrial Metallic Piping GB 50235 as current national standard.