ISO 21809-4-2009 pdf free download

ISO 21809-4-2009 pdf free download.Petroleum and natural gas industries — External coatings for buried or submerged pipelines used in pipeline transportation systems — Part 4:Polyethylene coatings (2-layer PE)
Industries du pétrole et du gaz nature! — RevOtements externes des conduites enterrées ou immergées utilisées dans les systemes de transport par conduites — Partie 4: Revétements a base de polyéthylêne (PE bicouche).
Afl steel defects and irregularities (e. g. laminations, slivers, scratches) shall be removed by an approved grinding method. Grinding of steel defects shall not reduce the wall thickness below the specified minimum wall thickness of the pipe.
All pipe shall be dry prior to entering the abrasive blast cleaning unit(s). Pipe temperature shall be at least 3 °C above the dew point immediately prior to abrasive blast cleaning.
10.2.2 Abrasive blast cleaning
The abrasives used in the coating plant shall be in accordance with the requirements of ISO 11124. NOTE If the pipe being coated is of a high-strength grade, e.g. L555, L690 or L839 (USC equivalents: X80. X100 or X120, respectively) harder abrasives can be needed to pmvide the required cleanliness and surface profile.
The abrasives (including recycled materials) shall be maintained clean, dry and free from contaminants in accordance with ISO 11125 so as not to contaminate the substrate.
For system A and B, the cleanliness achieved prior to application shall be in accordance with the requirements of ISO 8501-1:2007, Grade Sa 2.
For system C, the cleanliness achieved prior to application shall be in accordance with the requirements of ISO 8501-1:2007, Grade Sa 2Y.
For systems A and B, the height of the surface profile attained shall be within 40 pm and 100 pm as measured in accordance with the requirements of ISO 8503-4:1988, stylus method, or ISO 8503-5:2003. replica tape method,
For system C, the height of the surface profile attained shall be within 50 pm and 100 pm as measured in accordance with the requirements of ISO 8503-4:1988, stylus method or ISO 8503-5:2003, replica tape method.
If grinding is required after blast cleaning, the maximum allowable area of grinding shall be 10 cm2 per metre of pipe length.
10.2.3 Surface cleanliness
The surface cleanliness shall be measured in accordance with the requirements of ISO 8502-3:1992.
pressure-sensitive tape method. The maximum allowable level shall be Class 2.
10.2.4 Surface pre-treatment
If the applicator chooses a surface pre-treatment (e.g. deionized water or phosphoric acid pre-treatment), the pre-treatment process shall be agreed with the purchaser.ISO 21809-4-2009 pdf free download.