Machinery and Device Safety

Compressed Air Machinery

Safety Requirements for Operating and Maintaining Compressed Air Machinery:  

All components of compressed air systems should be inspected regularly by qualified and trained employees.  Maintenance superintendents should check with the state insurance department to determine if they require inspection of this equipment.  Operators need to be aware of the following:

A. Air receivers:  

The maximum allowable working pressures of air receivers should never be exceeded except when being tested.  Only hydrostatically tested and approved tanks shall be used as air receivers.  

Metal receivers should be hydrostatically tested in accordance with the requirements of ASME Boiler and Pressure Vessel Code, Section VIII.

1. Air tanks and receivers should be equipped with inspection openings, and tanks over 36" in diameter should have a manhole.  Pipe lug openings should be provided on tanks with volumes of less than 5 cu. feet. 
2. The intake and exhaust pipes of small tanks, similar to those used in garages, should be made removable for interior inspections.  
3. No tank or receiver should be altered or modified by unauthorized personnel. 
4. Air receivers should be fitted with a drain cock that is located at the bottom of the receiver.  
5. Receivers should be drained frequently to prevent accumulation of liquid inside the unit.  Receivers having automatic drain systems are exempt from this requirement.  
6.  Air tanks should be located so that outside surfaces can be easily inspected.  Air tanks should not be buried or placed where they cannot be seen for frequent inspection.  
7. Each air receiver shall be equipped with at least one pressure gauge and an ASME safety valve.   
8. A safety (spring loaded) release valve shall be installed to prevent the receiver from exceeding the maximum allowable working pressure. 
9. Only qualified personnel should be permitted to repair air tanks and all work must be done according to established safety standards. 

B. Air Distribution Lines:

1. Air lines should be made of high quality materials fitted with secure connections. 
2. Only standard fittings should be used on air lines.  
3. Operators should avoid bending or kinking air hoses. 
4. Air hoses should not be placed where they will create tripping hazards. 
5. Hoses should be checked to make sure they are properly connected to pipe outlets before use. 
6. Air lines should be inspected frequently and any defective equipment repaired or replaced immediately.  
7. Compressed air lines should be identified as to maximum working pressures (psi) by tagging or marking pipeline outlets.

C. Pressure regulation Devices:

1. Only qualified personnel should be allowed to repair or adjust pressure regulating equipment.  
2. Valves, gauges and other regulating devices should be installed on compressor equipment in such a way that cannot be made inoperative. 
3. Air tank safety valves should be set no less than 15 psi or 10% (whichever is greater) above the operating pressure of the compressor but never higher than the maximum allowable working pressure of the air receiver.  
4. Air lines between the compressor and receiver should usually not be equipped with stop valves. Where stop valves are necessary and authorized, ASME safety valves should be installed between the stop valves and the compressor.  
5.  The safety valves should be set to blow at pressures slightly above those necessary to pop the receiver safety valves. 
6. Blow-off valves should be located on the equipment and shielded so sudden blow-offs will not cause personal injury or equipment damage. 
7. Cast iron seat or disk safety valves should be ASME approved and stamped for intended service application.  
8. If the design of a safety or a relief valve is such that liquid can collect on the discharge side of the disk, the valve should be equipped with a drain at the lowest point where liquid can collect.  
9. Safety valves exposed to freezing temperatures should be located so water cannot collect in the valves.  Frozen valves must be thawed and drained before operating the compressor.  

D. Air Compressor Operation: 

1. Air compressor equipment should be operated only by authorized and trained personnel. 
2. The air intake should be from a clean, outside, fresh air source.  Screens or filters can be used to clean the air.  
3. Air compressors should never be operated at speeds faster than the manufacturers recommendation.  
4. Equipment should not become overheated.  
5. Moving parts such as compressor flywheels, pulleys and belts should be effectively guarded.

E. Compressed Air Equipment Maintenance:

1. Only authorized and trained personnel should service and maintain air compressor equipment.  
2. Exposed, noncurrent-carrying metal parts of compressor should be effectively grounded. 
3. High flash point lubricants should not be used on compressors because of its high operating temperatures.  
4. Equipment should not be over lubricated.  
5. Gasoline or diesel fuel powered compressors shall not be used indoors. 
6. Equipment placed outside but near buildings should have the exhausts directed away from doors, windows and fresh air intakes.  
7. Soapy water or lye solutions can be used to clean compressor parts of carbon deposits, but kerosene or other flammable substances should not be used.  Frequent cleaning is necessary to keep compressors in good working condition. 
8. The air systems should be completely purged after each cleaning.  
9. During maintenance work the switches of electrically operated compressors should be locked open and tagged to prevent accidental starting.  
10. Portable electric compressors should be disconnected from the power supply before performing maintenance.

Lifting Devices:

Operators of mechanical lifting devices must be qualified and trained  in the safe operation of this equipment. 

A. Hazards

overloading, dropping and slipping of the load are caused by improper hitching, slinging, clearance or misuse of the machine.  Strict observance to the following standards will reduce this type of accident.  

1. The rated load of the vehicle should be plainly marked on each side.  
2. The operator should be informed of the weight of each load.  
3. Hooks, ropes, chains, brakes and other mechanical operations should be inspected for defects daily.  All defective equipment must be immediately repaired or replaced.  
4. Hand signals to operators should be those prescribed by the applicable ANSI standard for each type of crane. 
5. Hoisting, lowering, swinging or traveling is not permitted while anyone is on the load or hook.  Loads must not be carried over the heads of people without adequate and prior warning.  
6. The operator must not leave his position at the controls while the load is suspended.  
7. The lift machine, particularly the boom or its load, should not be permitted to come within 10' of any energized electrical power line.  A permanent warning sign should be placed on the lifting device to indicate this requirement.  
8. When making a hook up, the hook must be centered over the load to prevent swinging.  Tag lines should be used on free-swinging loads to help guide them.  
9. The hoist must be equipped with a self-setting brake on the shaft or some part of the gear train. For powered hoists, holding brakes must be applied automatically when the power is off. 

B. Rigging Equipment:  

The following are precautions for avoiding hazards in using rigging equipment: 

1. Hooks must have no cracks or other deformation.  
2. The rated capacity of the hooks must be equal to the rating of the chain.   Job hooks or makeshift fasteners constructed from bolts, rods, etc., must not be used.  
3. Rope slings, including end connections must be in good condition without broken strands, kinks or twists in the line.  
4. Manila rope must be used in accordance with manufacturer's recommendations. Knots may not be used in lieu of splices. 
5. All hoisting equipment, slings, webbing and rope cable must be inspected visually every day for unusual wear and serviceability.  All defective equipment must be immediately taken out of service. 
6. Protruding ends of strands in splices or slings and bridles must be coffered or blunted.  
7. Wire rope must not be tied or secured with knots.  
8. An eye splice made in any wire rope may not have less than three full tucks. 
9. When used for eye splices, the 'U' bolt must be applied so that the 'U' section is in contact with the dead end of the wire rope. 
10. Synthetic webbing (nylon, polyester and polypropylene) must be coded to show the name or trademark of manufacturer, rated capacities for the type of hitch and the type of material.  (The rated capacity must not be exceeded.)