Page 386 - Reciprocating Compressors Operation Maintenance

Safety in Operation and Maintenance 371

Step 9. Check previous steps; try to operate the machine to ensure it
will not work.
Step 10. Proceed with servicing.

The following steps are required to restart locked-out or tagged-out
equipment.

Step 1. Remove all nonessential tools, materials, or parts from the
immediate area or the machine.
Step 2. Ensure that all guards and safety equipment have been reinstalled.
Step 3. Ensure that employees are completely clear of machinery or
equipment.
Step 4. Remove all lock-out or tag-out devices.
Step 5. Turn on main power, electrical disconnect switches, air sys-
tem, etc.
Step 6. Announce aloud that machinery is going back on. Ensure that
employees in area understand.
Step 7. Turn equipment on.

Compressors can be dangerous if not designed, installed, operated, and
maintained properly. Consequently, a periodic review of common prob-
lems that could lead to downtime or safety incidents is helpful to operat-
ing and maintenance personnel.

Depressurization is required following shutdown. Purging may be
required where gases are involved. Isolation is best assured where piping
can be disconnected from the system. Block valves and slip blanks can be
used where safety procedures are in place. Be absolutely certain that there
is zero pressure in the compressor cylinder before valve removal is begun.
One hundred psi on a 6" inlet valve applies a force of over 2800 pounds.
Suppose the valve was stuck on the valve seat even with the center
bolt and cover removed. What would happen if one attempted to dislodge
the valve by hand and it suddenly blew out of the port? Never trust a
closed gate valve that reads charge line and never believe a pressure
gauge that reads zero. A safety valve is located between the compressor
cylinders and the gate valve. Remove it so that any trapped gas leaking
by a gate block valve can vent to atmosphere.