This chapter relates to air pipes, sounding pipes, scupper pipes, sanitary pipes, bilge pipes and ballast pipes.
For information about vent pipes, fuel oil pipes, heating pipe and cooling pipes and sounding systems for cargo oil tanks of tankers, please refer to the relevant chapters in this blog.
Some of the contents of this chapter are more relevant to the checking of drawings during the plan approval stage, but this information will also be useful to surveyors undertaking construction surveys.
Confirmation of drawings
Checks should be made to ensure that the pipe arrangement, height, diameter, thickness etc. are as specified in the approved drawings and piping list.
In general, the material of all air pipes, sounding pipes, overflow pipes, bilge and ballast pipes is steel. For some parts of the sanitary lines, however, PVC pipes are accepted.
Fixing of pipes
Pipe lines should be firmly attached to the hull structure to avoid damage due to vibration. The fastening of pipes may be confirmed by shaking or kicking. Sometimes lock nuts of pipe band may have loosened.
Minimum pipe thickness
The requirements for the thickness of various kinds of pipes are specified in Rule as below example:
Penetration of pipes
Where pipes are led through watertight bulkheads, decks and top plates, bottom plates and bulkheads of deep tanks, inner bottom plating and “A” and “B” class division walls for fire protection, measures are to be taken to ensure the tightness of the structure (MPI both side can be applied in lieu of Air test for saving the building time).
Minimum radius of curvature
With regard to where pipes are bent, the radius of curvature at the center line of the pipes is generally not to be less than twice the external diameter of the pipes. In these days, the minimum pipe bending is normal over 3D to 5D base on type of material.
Survey and Inspection Items
a) Type, grade, diameter and thickness of each pipe
b) Fitting of pipe bands
c) Inclination of pipes
d) Curvature of bent pipes
e) Penetration of pipes through bulkheads, decks etc.
f) Protection of pipe lines from cargo and other damage
If such an arrangement is inevitable, piping is to be well protected.
The detail of piping outfit inspection will be discussed on next part.