7　Pipeline Construction

7.1　Pipeline Setting-out Survey and Check-acceptance Survey

7.1.1　Setting-out survey and check-acceptance survey shall be done for pipeline construction.

7.1.2　The pipeline setting-out survey shall proceed to the following procedures:

1　Recheck the setting-out survey conditions in construction diagrams.

2　Traverse survey.

3　Draft setting-out survey scheme，and calculate setting-out suevey data.

4　Field setting-out survey.

5　Fill out the record sheet for setting-out survey.

6　Compile the information of setting-out survey and apply for check-acceptance survey.

7.1.3　The main technical specifications for traverse survey with level three EDM（Electro-optical Distance Measurement）traverse shall comply with the specifications in Table 7.1.3-1.The main technical specifications for mapping EDM traverse shall comply with the specifications in Table 7.1.3-2.The traverse may be annexed at the same hierarchic for once in the region where the control points are sparse.

7.1.4　Setting-out Survey shall meet the following requirements:

1　For setting-out survey，drafting setting-out survey scheme shall be based on the approved routing design construction diagram and setting-out survey conditions，and the setting-out survey data for pipeline feature points and hectometer pile shall be calculated.

2　For pipeline setting-out survey data，azimuth may be calculated to 1″or 0.1′per requirements，and the distance，coordinate and elevation shall be calculated to“mm”.

3　Stations are occupied on traverse points，and polar coordinate method should be used to survey pipeline points and a good setting-out survey record should be kept.

4　In case that the pipeline pile cannot be nailed down due to obstruction，identification post may be nailed on the centerline of pipeline.the post number shall be specified，the distance between identification post and design post shall be specified in setting-out survey information.

5　Setting-out survey may use the existing mapping control and construction control.However，the existing control point shall be examined before such use，and the check tolerance for control points shall comply with the specifications in Table 7.1.4.When side length is less than 50m，the comparation error between actually measured side length and known side length shall be less than or equal to±2cm.

6　In setting-out survey，the root mean square error of plane position of point shall be less than or equal to±5cm，and the root mean square error of height shall be less than or equal to±3cm.

7.1.5　The vertical control survey shall comply with following requirements:

1　Vertical control survey should use mapping control leveling，and the technical specification shall meet the requirements in Article 9.2.8 of this Code.

2　When vertical control survey uses EDM trigonometric leveling，the technical specifications shall meet the requirements in Article 9.2.9 of this Code.

7.1.6　After completion of setting-out survey，the check-acceptance survey shall be done.The checkacceptance survey shall meet the following requirements:

1　Recheck the setting-out conditions in construction diagrams and conduct field check-acceptance survey.

2　Check-acceptance survey shall meet requirements in Article 7.1.4 of this Code.

3　The technical specifications for check-acceptance survey shall meet requirements in Table 7.1.6.

7.1.7　Pipeline setting-out survey and check-acceptance survey shall be comply with the specifications in the current applicable standard GB 50026 Code for Engineering Surveying and SH 3100 Specification for the Engineering Survey in Petrochemical Industry.