Electrical systems are generally recognized as being potentially lethal and all organizations by law must have procedures for isolation of the equipment and adopt safe working practices. Hydraulic and pneumatics are no less dangerous but tend to be approached in a far more laissez faire or casual manner.
A hydraulic system can present the following dangers to an operator:
• High-pressure air or oil released suddenly can attain explosive velocities and can easily cause an accident.
• The unexpected movement or drift of components such as cylinders can be harmful.
• Spilt hydraulic oil is very slippery and can cause accidents.
A few guidelines to ensure safety in hydraulic systems are listed here:
• The implications arising out of any action have to be considered before resorting to it.
• Anything that can move with change in pressure as a result of your actions should be mechanically secured or guarded.
• Particular care should be taken with regard to suspended loads. It must be remembered that fail-open valves will tum ON when the system is de-pressurized.
• Never disconnect pressurized lines or components. The whole system should be de-pressurized before disconnecting any of the lines.
• Put up safety notices to prohibit operation by other people.
• Ensure that the accumulators in the hydraulic system are fully blown down.
• Make proper arrangements to prevent spillage of oil on the floor.
• Where there is an electrical interface to a hydraulic system (e.g., solenoids, pressure switches, limit switches) the control circuit should be isolated, not only to reduce the risk of electric shock but also to reduce the possibility of fire.
• After the work is completed, keep the area tidy and clean. Check for any leakages and confirm correct operation of the system.
• Many components contain springs under pressure. If released in an uncontrolled manner, these can fly out at high speed and cause injury. Springs should be removed with utmost care.
In USA, the Occupational Safety and Health Administration (OSHA) of the Department of Labor describes and enforces safety standards at industry locations where the hydraulic equipment is operated. For detailed information of OSHA standards and requirements, the OSHA publication 2072 can be referred to. The general industry guide for applying safety and health standards, 29 CFR 1910 also provides us with a standard set of safety standards for operating hydraulic equipment.
These standards deal with the following categories:
• Workplace standards
• Machines and equipment standards
• Materials standards
• Employee standards
• Power source standards
• Process standards.
The basic rule to follow is that there should be no compromise when it comes to the health and safety of people at the place of their work.