HAZOP of a Level Crossing 陶维杰 s

Content 1 、 What’s a level crossing 2 、 What’s HAZOP 3 、 HAZOP of a level crossing

1 、 What’s a level crossing

A level crossing is an intersection where a railway line crosses a road or path at the same level, as opposed to the railway line crossing over or under using a bridge or tunnel. A level crossing is an intersection where a railway line crosses a road or path at the same level, as opposed to the railway line crossing over or under using a bridge or tunnel. Other names include railway crossing, grade crossing, road through railroad, and train crossing.

Level crossings constitute a significant safety concern internationally. On average, each year 400 people are killed in the European Union and over 300 in the United States in level crossing accidents. Collisions can occur with vehicles as well as pedestrians; pedestrian collisions are more likely to result in a fatality. In terms of warning systems, level crossings are either passive crossings which have warnings such as signs, or active crossings which have automatic warning devices such as boom gates, flashing lights and warning tones. Fewer collisions take place at level crossings with active warning systems.

The Manfalut railway accident The Manfalut railway accident occurred on 17 November 2012 when a school bus, which was carrying about 70 school children between four and six years old, was hit by a train on a rail crossing near Manfalut, Egypt, 350 km south of the Egyptian capital Cairo. At least 50 children and the bus driver died in the crash, and about 17 people were injured. Witnesses reported that barriers at the crossing were not closed when the crash occurred.

The Manfalut railway accident

2 、 What’s HAZOP A hazard and operability study (HAZOP) is a structured and systematic examination of a planned or existing process or operation in order to identify and evaluate problems that may represent risks to personnel or equipment, or prevent efficient operation.

HAZOP Keywords Primary keywords: a particular aspect of a design intent (a process condition or parameter). Safety:Operability: FlowIsolate TemperatureStart-up PressureShutdown LevelMaintain CorrodeInspect...

HAZOP Keywords Secondary keywords: possible deviations (problems) Guide WordMeaning NO OR NOT Complete negation of the design intent MORE Quantitative increase LESS Quantitative decrease AS WELL AS Qualitative modification/increase PART OF Qualitative modification/decrease REVERSE Logical opposite of the design intent OTHER THANComplete substitution EARLYRelative to the clock time LATERelative to the clock time BEFORERelating to order or sequence AFTERRelating to order or sequence

Methodology – Report format DeviationCauseConsequenceSafeguardsAction E.g. Flow/No Potential cause of the deviation Consequences of the cause and the deviation itself Any existing devices that prevent the cause or make its consequece s less painful Actions to remove the cause or mitigate the conse- quences

Methodology – The process Select a section of the plant For each primary keyword relevant for the plant: For each relevant secondary keyword: Think of significant consequences and record them; Record any safeguards identified; Think of any necessary actions and record them; Think of significant consequences and record them; Record any safeguards identified; Think of any necessary actions and record them; For each discovered cause for the deviation DeviationCauseConsequenceSafeguardsAction Flow/No Problem...

3 、 HAZOP of a level crossing Here

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