The pipe surface to be protected are cleared, free from scale, rust, oil, grease or the foreign matters to quality as specified in BS7079. Part O and A1, Swedish standard SIS 05-5900 or any applicable standard.
External protection
1. Priming: Pipes and specials are primed with a compatible priming coat in accordance with BS 4147 and BS 4164.
2. Bitumen sheathing: The pipes and specials are covered with a layer of sheathing material of natural or blown petroleum bitumen mixed with an inert filler and applied as a hot coating or mastic to provide a seamless, consolidated and smooth layer as specified thickness.
3. Reinforced bitumen sheathing: Bitumen sheathing with the addition of an overlapping spiral wrapping of woven glass cloth firmly embedded.
4. Bitumen enamel wrapping (filled bitumen with glass tissue): Bitumen containing a mineral filler applied hot and an inner wrapping of glass tissue and an inner wrapping of bitumen impregnated reinforced glass tissue, the inner wrapping being embedded in the bitumen.
5. Reinforced bitumen enamel wrapping: This is as specified in 4 except that the outer wrappings are of heavy duty materials.
6. Coal tar enamel wrapping (filled coal tar with glass tissue): A thick layer of filled coal tar applied hot (as specified in BS 4164) and an inner wrapping of glass tissue and an outer wrapping of coal tar impregnated reinforced glass tissue, the inner wrapping embedded in the coal tar.
7. Painting: For exposed or elevated water pipes.
Internal protection
1. Priming: Pipes and specials are primed with a compatible priming coat in accordance with BS 4147.
2. Bitumen lining of pipes: A uniform blend of natural or blown bitumen mixed with an inert filler to produce a homogeneous composition (as specified in BS 4147). The lining material, in a hot fluid condition, is applied to straight lengths of pipe to give a smooth continuous lining, having a minimum thickness as specified.
3. Coal tar lining of pipes: The same procedure is applicable to coal tar enamel internal lining specified under ANSI/AWWA C203-78 for internal protection.
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