3.2　Base Line and Base Mark for Equipment Installation

3.2.1　Before the equipment erection，the base line and base mark shall be set for its installation and comply with the following requirements:

1　The arrangement of base lines and base marks shall be prepared in accordance with the design construction drawing and surveying control network，hereby determining the positions of central guide boards and base marks.

2　The central guide boards and base marks shall be arranged according to the above arrangement.

3　The survey assignment shall be issued to the surveyor.

4　The surveyor shall submit the report of survey results to related superiors and also hand over the base lines and base marks to the installation personnel at site.

3.2.2　Main equipment（converter，electric arc furnace，refining furnace，etc.）and continuous production line（continuous casting production line，etc.）shall be arranged with permanent base lines and base marks.The central guide boards and base marks should be made of copper or stainless steel.