Pipelines & Pipeline Safety - PIPELINE SAFETY PDF Print E-mail
Written by Norrie   
Thursday, 29 April 2010 19:53
Article Index
Pipelines & Pipeline Safety
TRANSMISSION OF FLUIDS
JOINING OF PIPELINES
PIPELINE SUPPORTS
PIPELINE ANCHOR POINTS
EXPANSION LOOPS (or BENDS)
PIPELINE SAFETY
'SHAFER' AUTOMATIC LINE-BREAK VALVE
LINE BREAK - SHAFER VALVE CLOSES
AUTOMATIC RESET
RE-OPEN THE SHAFER VALVE
PIPELINE SPHERING
All Pages

PIPELINE SAFETY

  1. Static Electricity : The transfer of materials by pipeline can cause static electricity to be generated. This can build up to high voltages which, in turn can discharge causing electric sparks or give a nasty shock to personnel working near the pipe. All piping should therefore be 'earthed' to prevent this electrical build up.
  2. Another hazard with pipe-work is leakage of material due to damaged gaskets between flanges, leaking valve stems and release of fluids during maintenance operations. Leaks should be reported and dealt with as soon as they are discovered.
  3. A further possibility, is a pipeline rupture, due to over-pressure, corrosion, heavy vibration or physical damage due to a vehicle accident or other heavy blow to the piping.

Where the possibility of over-pressure is present, for example, a section of pipe between two closed valves or an operational upset, 'Safety Relief Valves' are fitted to deal with the problem. In the case of a liquid-full section of isolated piping, the pressure increase for only a small temperature increase, can be tremendous. Such a situation should never be allowed to arise - the forces involved can be extremely high and very dangerous. In these cases, the piping must be adequately protected by vent / relief systems.

Where a very long pipeline is constructed, across an expanse of desert for example, the constant patrolling of the pipeline for fractures, ruptures or other problems, would not be practical. In general the pipeline conditions are monitored in a control room in a plant which may be at some distance along the pipeline. In these cases, pipelines are often fitted with an automatic isolation system which consists of a series of special valves set at intervals along the length of the pipeline.

These valves are activated by the continuous and prolonged pressure drop which occurs when a line ruptures. Two valves will close to isolate the affected section.

Following is an example of a type of automatic shut down and isolation valve system which would help to minimize fluid escape to atmosphere in the event of a pipeline rupture.

(See Figure : 7 and the following pages describing 'Shafer' automatic isolation systems )

Figure : 7



Last Updated on Thursday, 29 April 2010 19:56