Pressure System

$.$ A fixed air compressor, with a capacity of over $250$ bar litres is situated in the open air, outside the factory. It is powered by a $400$v$,3-$phase electrical supply, with a screw compressor feeding an air receiver, protected by a pressure valve. It operates at or above a $2\mathrm{.}5$ bar pressure and has been used by Cover Up for many years. When in operation it is very loud and creates hissing noises at various pipework connections. The information plate on the compressor has become difficult to read, but there is an operating procedure kept in the office. The procedure states the operating limits of the unit, although the system itself has never been measured or checked by workers.

The pneumatic guns used for powder coating, and shot blasting are fed from this air compressor. Other air$-$operated equipment includes three compressed air blow guns located inside the factory. They are used to dry and clean materials by blowing any loose debris from them. Often workers use them to blow dust off their clothes before they go home. These compressed air blow guns are connected to the compressed air outlets, via ten$-$metre flexible hoses trailing along the floor. There is no indication of which flexible hose leads to which outlet other than following the line to its termination point. Workers feel it is a waste of time checking the pressure gauges as there is plenty of force behind the air stream. The compressor unit has a leak that requires repairing.

$($a$)$ Four reasons Why would the compressor unit be considered as a pressure system?

$($b$)$ What $15$ measures should be taken to prepare for safe maintenance of the compressor unit?

$($c$)$ Explain what $12$ improvements could be made to help reduce the risk of a pressure system failure.