8　Equipment on the Top of Coke Oven

8.1　Installation of Gas Headers and Liquid Ammonia Pipes

8.1.1　The gas headers should be made in sections，and may be installed after passing examination according to the requirements of design documents and Code for Construction and Acceptance of Field equipment，Industrial Pipe Welding Work GB 50683 as current national standard.

8.1.2　Two pipe sections of the gas headers shall be connected by using the externally-lapped connecting plate，and the weld of the gas headers shall be subjected to nondestructive examination according to the requirements of design documents.

8.1.3　For the installation of the ammonia water branch pipe，the connector position shall be checked according to design documents，and the pipeline run is set according to the actual site.

8.1.4　The liquid ammonia pipesline shall be subjected to water pressure test according to the requirements of design documents.When the design does not have requirements，test pressure shall be 1.5 times of working pressure，and the liquid ammonia pipesline is qualified without leakage after 30 minutes.

8.1.5　After the pressure test of the liquid ammonia pipesline is qualified，the liquid ammonia pipesline shall be subjected to water washing and air purge.

8.1.6　Before closing，the gas headers may be closed after being cleaned.

8.1.7　The gas headers should be installed in the cold state and shall be in compliance with the following requirements:

1　The center of the gas headers is adjusted，and allowable deviation shall be 3.0mm；

2　The elevation of the gas headers is adjusted，and allowable deviation shall be±5.0mm；

3　The longitudinal and lateral centers of the gas headers and the water seal valve connecting flange is adjusted，and allowable deviation shall be 3.0mm；

4　The elevation of the water seal valve flange of the gas headers is adjusted，and allowable deviation shall be±3.0mm.