For design of underground piping system General Civil Design Basis shall be followed.
All underground C.S .Pipes shall be painted/ coated as per painting/coating specification. All underground C.S pipes shall be provided with corrosion resistance protection as per the specification for coating & wrapping. Steps for Coating and Wrapping involve surface preparation by sand blasting, tape wrapping and holiday detection. Corrosion resistance protection given to underground C.S. pipes shall extend up to 500mm above/beyond grade on both sides
To the extent possible, fire water header shall be laid above ground except around process area where it shall be laid underground .In case it is to be laid U/G, it shall be laid in RCC trenches covered with pre-cast RCC slabs in RCC paved area, whereas in unpaved area it shall be laid directly buried.
All underground-buried firewater piping shall be externally protected from corrosion by wrapping & coating as per the specifications provided.