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GAS SUPPLIES AND GAS DISTRIBUTION SYSTEM central gas storage. If any important component of the system is damaged, changed or replaced, the system shall be inspected again and a new installation certificate issued. The layout of the central system The layout of the central system and various components are shown in the drawing on the next page. The central store where the cylinders are kept must be situated on or above the upper continuous deck, and it must have access to the open deck. The door to the central store must be marked with a notice warning of gas under pressure.

Fastening arrangements (1) for the number of Acetylene and Oxygen cylinders to be kept on board are to be welded to the bulkhead. The design of the fastening clamps makes it very easy to release the cylinders in case of a fire. From the cylinders the gas is carried through high-pressure hoses (2) to T-valves (3). The connection nuts for the highpressure hoses are right-hand threaded for Oxygen and left-hand threaded for Acetylene, to eliminate the possibility of the hoses being wrongly connected. Non-return valves are fitted to prevent gas from flowing back through the T-valve to the gas cylinders.

By using several T-valves connected by expansion pipes (4) it is possible to connect in series any desired number of cylinders. The last T-valve in the series is closed with a blind plug and connecting nut (5). From the T-valves the gas is led to a shut-off valve (6) where the central regulator R520(7) is located. The regulator has an adjusting

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screw with a locknut for pressure regulation. When the correct pressure has been set on the regulator (8 bar for oxygen and 0.8 bar for acetylene), the setting is locked by tightening the locknut. This makes it unnecessary to reset the pressures every time the plant is used, the gas flow being controlled simply by opening and closing the shutoff valve (6). The desired working pressure is set by means of a regulating valve at the outlet station, as required for the individual welding and cuffing operations. The safety valve of the central regulator (8) must be connected to a pipe to carry any escaping gas out to the open deck. The end of this pipe must be located not less than 3 metres above deck, and the outlet must be marked with a regulation sign as follows: “Gas danger. Fire, open lights and smoking prohibited.”

From the low-pressure side of the regulator the gas is fed through a lowpressure steel expansion pipe (9) and connected to the permanent piping system. The pipelines are colourcoded. Blue pipes are for Oxygen and red for Acetylene.

Where a pipe passes through bulkheads or decks it must be led through bushings (10), and the pipes are to be fastened to bulkheads with pipe clamps (11) at intervals of about 2.5 metres. The outlet stations are to be installed at suitable locations which are well ventilated and where the outlet station is protected from mechanical damage. The standard cabinet (12) which is delivered with the outlet station is a steel plate design for mechanical protection indoors.