1. All pipelines shall be suitable to pass pigs, even if pig traps are not permanently installed.
2. Pigging should be used for the pre commissioning, commissioning and decommissioning of pipelines, cleaning and corrosion control (removal of wax, debris and stagnant liquids, batch inhibition), the control of liquid hold-up in gas lines, inspection with intelligent pigs, and pipeline repairs if required.
3. Permanent pigging facilities should be justified based on an analysis of pigging frequency and operational constraints.
4. The maximum acceptable distance between pigging stations should be decided on the basis of anticipated pig wear and amount of collected solids.
5. The use of spheres should be limited to batch inhibition and to liquids removal in two-phase lines.
6. Spheres may be considered when automatic launching is envisaged, or for pigging of branch lines, when the use of conventional pigs is not possible.
7. Permanent pig signallers should only be fitted when frequent pigging operations are anticipated. Otherwise, temporary strap-on pig signallers or pig location devices should be used.
8. Ancillary equipment should be flush mounted and barred tees should be used on main line sections of the pipeline.
9. In the case of spheres, sphere tees should be used with drainage provision to prevent collection of debris and liquids which could cause corrosive conditions in the sphere tee annulus.
10. Sphere tees should not be used subsea because of the difficulty in providing drainage.
11. Pig trap systems for pipelines shall be designed as per company standard.