Wednesday, July 11, 2012
Posted by Ankit Chugh on 1:56 AM
The various causes of accidents are:
· Defect in Design
· Defect in Construction
· Defect in Material of Equipment
· Faulty Operation or Maintenance
· Lack of Monitoring
Sometimes adequate design factors have not been provided while doing the design. Design factors are essential component in order to give a margin of safety in the design. Design factors may be appropriate in either the mechanical engineering design or in the process design where factors are often added to allow some flexibility in process operation. For mechanical and structural design the magnitude of design factors should allow for uncertainties in material properties, corrosion, design methods, fabrication and operating loads. It is also possible that appropriate material for equipment and piping has not been specified leading equipment failure or piping failure resulting in the release of hazardous or flammable or toxic material.
Defect in material for equipment and piping, defect in manufacturing, fabrication and defect in construction or installation including inspection and testing may lead to equipment or piping failure. Release of hazardous or flammable or toxic material can occur as a result.
Erroneous operation and maintenance like not following correct procedures may lead to accident. Inadequate maintenance also can be cause of accident, for example:
· Failure to inter-change operating and standby equipment as and when required.
· Lack of attention to the special instrument like vibration monitor, corrosion monitors, gas humidity analyzer etc.
Human error, often due to inadequate training causes accident. For example:
· Opening or closing wrong valves, without fully understanding operating instructions, may lead to rise in pressure, temperature or flow in the system and resulting in the release of hazardous or toxic material.
· Operator taking wrong reading of parameters indicators (pressure, temperature, flow etc.) and taking wrong actions which may lead to accident.
· Adjusting the set point of a control to a wrong value, thus leading to accident.
There could be several other causes of accidents:
· Natural calamities like earth quake.
· Lack of monitoring
· Lack of training
It is difficult to avoid accidents due to natural calamities, unless the impact of natural calamities have been considered during selection of the site and designing of the facilities to withstand the impact. Even the unforeseen events may occur. It is very important to have an Emergency Response Plan and mitigation for such contingencies.
Lack of monitoring as per operating and maintenance procedures are often cause of accidents. As a simple instance, let us take the case of a long distance cross country pipeline carrying hydrocarbons. Regular surveillance of the pipeline is very important to avoid unauthorized work along the pipeline route, digging, sabotage etc. Normally this is done by use of helicopters, automobiles, satellites images etc. Still a surprisingly high number of accidents occur in gas pipelines due to unauthorized digging.