A fuel fire in the MER or an AMR can be caused by a leak at a fuel oil or lube oil pipe flange connection. Even the smallest leak can spray fine droplets of oil on nearby hot surfaces. To reduce this possibility, FLANGE SAFETY SHIELDS are provided around piping flanges of inflammable liquid systems, especially in areas where the fire hazard is apparent. The spray shields are usually made of aluminized glass cloth and are simply wrapped and wired around the flange.

PIPE HANGERS

Pipe hangers and supports are designed and located to support the combined weight of the piping, fluid, and insulation. They absorb the movements imposed by thermal expansion of the pipe and the motion of the ship. The pipe hangers and supports prevent excessive vibration of the piping and resilient mounts or other materials. They are used in the hanger arrangement to break all metal-to-metal contact to lessen unwanted sound transmissions.

One type of pipe hanger you need to become familiar with is the variable spring hanger. This is used to support the ship's bleed air piping. It provides support by directly compressing a spring or springs. The loads carried by the hangers are equalized by adjustment of the hangers when they are hot. These hangers have load scales attached to them with a traveling arm or pointer that moves in a slot alongside the scale. This shows the degree of pipe movement from cold to hot. The cold and hot positions are marked on the load scale. You should check the hangers when they are hot to ensure that the pointers line up with the hot position on the load scales. You can adjust hangers that are out of position by loosening the jam nut on the hanger rod and turning the adjusting bolt of the hanger.

INSPECTIONS AND MAINTENANCE

Reasonable care must be given to the various piping assemblies as well as to the units connected to the piping systems. Unless the piping system is in good condition, the connected units of machinery cannot operate efficiently and safely. You should be familiar with all the recommended maintenance procedures and observe the safety precautions when working on piping systems.

The most important factor in maintaining piping systems in satisfactory condition is keeping joints, valves, and fittings tight. To ensure this condition, you need to make frequent tests and inspections.

Piping should be tested at the frequency and test pressure specified following the PMS and the applicable equipment technical manual. Test pressure must be maintained long enough to show any leaks or other defects in the system. Instruction manuals should be available and followed for the inspection and maintenance of piping systems and associated equipment; however, if the manufacturer's instruction manual is not available, you should refer to the NSTM, chapter 505, for details of piping inspection and maintenance.

PIPING SYSTEM IDENTIFICATION MARKING

All piping should be marked to show the name of the service, destination (where possible), and direction of flow (fig 9-60)

Figure 9-60.-Pipe markings.

The name of the service and destination should be painted on by stencil or hand lettering, or by application of previously printed, stenciled, or lettered adhesive-backed tape. Lettering will be 1 inch high for a 2-inch or larger OD bare pipe or insulation. For smaller sizes, lettering size may be reduced or label plates attached by wire or other suitable means.

Direction of flow will be indicated by an arrow 3 inches long pointing away from the lettering. For reversible flow, arrows are to be shown on each end of the lettering.

Black is used for lettering and arrows. However, on dark-colored pipe (including oxygen piping), white is used.

Markings will be applied to piping in conspicuous locations, preferably near the control valves and at suitable intervals so every line will have at least one identification marking in each compartment through which it passes. Piping in cabins and officers' wardrooms will not normally be marked.