CLEANING OF EQUIPMENT FOR OXYGEN SERVICE - AIGA

1 General
Appendix C: Cleaning of carbon steel pipeline
43
AIGA 012/04
This annex deals with the distribution network from the supply stations of oxygen plants to the
distribution stations at customers works.
It does not deal with other parts of a complete network such as piping in the oxygen plant, distribution
piping in the workshop, or at the points of use.
2 Specific Design Requirements
Pipeline shall be designed such that it can if necessary be cleaned by a 'pigging' operation.
Consideration must be given to minimum bend radii and changes involving reductions in pipe
diameter.
Low level points where liquids or debris can accumulate should be avoided.
Where this is not possible low point drains should be provided to facilitate drainage and visual
examination.
Drain points should be permanently blanked after pressure testing and/or cleaning has been
completed.
3 Materials and Components
1 Pipe material - Carbon Steel
2 Pipe fittings - Carbon Steel
3 Proprietary – Pig launcher and catcher.
4 Alternative A
Involving use of components pre-cleaned to oxygen clean standard.
4.1 Initial Cleaning Method
All pipe lengths and pipe fittings to be purchased with internal surfaces blast cleaned. (surface finish
Sa 2 1/2 to ISO 9501-1).
4.2 Initial Inspection
Inspection by direct visual method as per Para. 4.2.1 and 4.2.2 is normally sufficient. Pipe lengths and
pipe fittings to be sealed with caps and waterproof masking tape immediately after cleaning.
Desiccant bags should be placed inside each pipe and fitting as per Para. 6 on pages 27 & 28.
4.3 Fabrication
Exercise care in order to maintain cleanliness throughout subsequent fabrication and testing.
Welds should be inspected as work progresses and any weld repairs executed. Pipe ends must be
sealed at all times except when fabrication is actually taking place. A gas purge should be maintained
during welding and between fabricating operations.
Nitrogen gas may be substituted for argon back purge between welding. Paper dams to limit use of
argon back purge should not be used. Trenches must be adequately drained of water.
Attach pig launcher and catcher to ends of pipeline.