Most of us are by now very familiar with the idea of Risk Assessment in the design of Mechanical and Electrical system (M & E) within tunnels, but the truth of the matter is far to many designers do not actually apply them. The basic philosophy is quite simple, firstly look at the concept design and attempt to foresee the possible hazards, and then mitigate the hazards at the design stage, thus becoming "Safe by Design". This philosophy has thankfully in recent years been used more and more in the design of bothroad and rail tunnels. The introduction in tunnel design of meaning full Risk Assessments have been brought about in the main by the public outcry at what seems to be a recent glut of fires in tunnels. Fires in tunnels are in fact common events, many major road tunnels have several each year albeit they are normally small and quickly extinguished (in most cases before the emergency services actually get on site); in most instances there are no or only minor casualties and minimal damage to the tunnel and the tunnel is quickly reopened. The key to the success of the Safety/HazOp process in the elimination or reduction of risk is the structured approach it uses from early stages of the project and the iterative actions throughout the project life cycle. The several iterative stages of the Safety/HazOp process, all of which make up the overall risk assessment, are listed. Any mitigation while reducing a particular hazard may introduce another hazard,hence the need for the iterative process. It should also be noted that for a given risk any combinations of mitigations might be required to reducethe risk to an acceptable level and not just a single mitigation. Active and passive mitigations are described, with the objective of making the level of risk as low as is reasonably practicable. For the covering abstractsee ITRD E134653.
Samenvatting