Competent personnel operating and maintaining any machine keep it performing as efficiently as possible. In order to achieve peak performance from a compressed air plant, they take steps to prevent or minimize the occurrence of any condition which might reduce plant capacity or result in serious damage. All personnel should take every possible precaution to prevent potential explosions, especially when operating high pressure systems. Safety precautions which will aid you in preventing explosions and in maintaining a plant in satisfactory operating condition are listed below.

1. Minimize the possibility of explosions in an air compressor, discharge line, or receiver by taking steps to prevent or eliminate the following:

a. Dust-laden intake air.

b. Presence of oil vapor in compressor or receiver.

c. Leaking or dirty valves.

2. Make sure that the compressor intake receives only cool, dry air.

3. Use only prescribed agents for cleaning compressor intake filters, cylinders, or air passages. DO NOT use benzene, kerosene, or

Figure 7-1.PMS tests and inspections for compressed air plants.

other light oils that vaporize easily and that, under compression, form a highly explosive mixture.

4. Use only the minimum amount and the proper grade of oil for cylinder lubrication.

5. Secure a compressor immediately if there is an abnormal rise in the temperature of air discharge from any stage.

6. Be sure a relief valve is installed between a compressor and a stop valve, or a check valve is installed between a compressor and the receiver. If there is no relief valve and the compressor is started against a closed valve or a deranged check valve, the air will not be able to escape and an explosion will result.

7. Do not leave a compressor station after starting a compressor, especially a new compressor or one that has been idle for some time, until you are positive that the control, unloading, and governing devices are working properly.

8. Do not disconnect any part of a compressor

if the system is under pressure. To avoid serious accidents, the following precautions should be taken before working on, or removing, any part of a compressor:

a. Leave all pressure gages open.

b. Be sure the compressor is actually secured and cannot be started automatically or accidentally.

c. Be sure the compressor is completely blown down.

d. Be sure all valves, including the control or unloading valves, between the compressor and the receiver are closed.

9. Operate a compressor at recommended speeds and maintain proper cooling water circulation to prevent damage from excessive temperatures.

10. Drain the circulating water system of a compressor if it is to remain idle for an extended period, or if it is to be exposed to freezing temperature.