7 Heating and Exchange Device under the Coke Oven
7.1 Installation of Gas Main Pipelines，Branch Pipeline and Downspouts
7.1.1 The datum line of pipe installation shall be set on the foundation according to the datum line of coke oven.
7.1.2 The models and specifications of various valves shall meet the requirements of design documents，and various valves shall be installed after air-tight test is qualified.
7.1.3 The assembly and welding of gas pipeline shall meet the requirements of design documents and Code for Construction and Acceptance of Industrial Metallic Piping GB 50235 as current national standard.
7.1.4 When the branch pipe is connected to the main pipe，the open pore diameter of the main pipe is larger than the outer diameter of the branch pipe，but should not exceed 5.0mm，and the inserting depth of the branch pipe should not exceed 3.0mm.
7.1.5 The installation of the fixing bracket and sliding bracket of the main pipe shall meet the requirements of design documents.
7.1.6 The pipeline shall incline in the water flow direction，and the gradient shall meet the requirements of design documents.
7.1.7 After being installed，the gas pipeline shall be subjected to the air-tight test of the system and shall meet the requirements of design documents and Code for Construction and Acceptance of Industrial Metallic Piping GB 50235 as current national standard.
7.1.8 Installation of gas main pipelines，branch pipeline and downspouts shall be in compliance with the following requirements:
1 Centers of mixed gas main pipes on the coke pusher side and coke guide side and coke oven gas main pipe are adjusted，and allowable deviation shall be 5.0mm；
2 Elevations of mixed gas main pipes on the coke pusher side and coke guide side and coke oven gas main pipe are adjusted，and allowable deviation shall be±5.0mm；
3 The center of distribution stand pipe is adjusted，and allowable deviation shall be 3.0mm；
4 The levelness of distribution stand pipe flange is adjusted，and allowable deviation shall be 1/500 of outer diameter of flange；
5 The elevation of distribution stand pipe flange is adjusted，and allowable deviation shall be±5.0mm；
6 The perpendicularity of the downspouts is adjusted，and allowable deviation shall be 3.0mm.