Unitisation over Utility

30th September 2003

Unitisation over Utility

Initial Report

Where engines are designed to fulfil a range of duties, there is inevitably an element of compromise. In an effort to make the “package” more compact for an application where space is at a premium, e.g. in a locomotive, the engine builder can introduce access restrictions for maintenance and in some cases introduce unnecessary hazards.

Unfortunately, “one size does not fit all” and where this type of engine is used in a marine application there is generally more space for associated equipment. Therefore, the manufacturer should make more effort to remove hazards and so reduce risk.

For example, on a well known range of engines, [which can be used as marine propulsion or generator engines], both main and auxiliary lubricating oil and fuel filters, together with their associated pipe work & fittings, are mounted across the engine at the non-drive end and above cylinder cover level.

Note: in the safety section of the operation & maintenance manual under “Safety Signs & Labels” a warning label for both duplex filters is shown which reads –

WARNING.   Filter contains hot pressurised fluid when engine is running. Follow instructions on control valve to avoid injury. If rapid air movement exists to blow fluid, stop engine to avoid fire.”

From a maintenance point of view, this means that it is neither practicable nor safe to change filters with the engine running particularly as they are a) at head height and b) are horizontal, therefore impossible to drain fully.

From the safety angle, the position of the duplex filters introduces an unnecessary hazard i.e. potential escape of fuel and hot lubricating oil into an extremely hot area. Poor design and installation of pipe fittings can only exacerbate the risk.

There have been two incidents with this type of engine in recent times where threaded fittings have failed causing leakage of fuel under pressure to spray over the running engine. In the first case, a fire started which eventually led to the loss of the engine room. In the second, the on duty engineer spotted the leakage immediately. He took appropriate action so that no further damaged was caused.

The installations referred to were fully approved by the relevant classification society but perhaps rules should be revised to manage and reduce, the risk by removing hazards to a safer location.

CHIRP would like to hear more on this subject.

Again there are elements of design that may need to be addressed.  The CHIRP discussions on this report also highlighted the need to ensure the work place is designed or adapted to accommodate the characteristics of equipment and its anticipated use.

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