Taking the Energy Out of Danger
Many types of maintenance and repair work necessitates physically neutralizing all energies of an equipment or machinery to prevent electrocution from contact with live circuits and accidental activation of a machinery on which a worker is repairing, which can result in amputation and fatalities.
Despite that requirement, many accidents continue to occur due to the failure to lock and tag out equipment. According to the National Institute of Occupational Safety and Health in Washington, D.C., 28 fatalities and 227 serious injuries were related to lockout/tagout procedures in food manufacturing from 2003 to 2013, with the largest number of incidents taking place in meatpacking and poultry slaughtering and processing.
An effective and well-defined lockout policy typically involves five steps: developing a lockout policy; identifying lockout situations; drawing up procedures; training workers; and enforcing and updating the policy, according to the Workplace Safety & Prevention Services (WSPS) in Mississauga, Ontario. The written lockout policy should also make reference to the company’s general oh&s policy.
Locking out does not mean de-energizing only electrical energy; it is also important to de-energize other sources of energy that could activate an equipment, WSPS advises. The following is a breakdown of how to deactivate power sources other than electrical energy:
– Hydraulic systems: Hydraulic presses, rams, cylinders and hammers should be deactivated by shutting off, locking (with chains, built-in lockout devices or lockout attachments) and tagging valves. Bleed off and blank lines as necessary. Information from Ontario’s Ministry of Labour adds that workers who are servicing hydraulic systems should always follow instructions in the operator’s manual. Where appropriate, a properly qualified and certified mechanic should perform repairs and maintenance.
– Pneumatic energy: For lines, pressure reservoirs, accumulators, air surge tanks, rams and cylinders, the same procedure above applies. Make sure that excess air has been bled off. If pressure cannot be relieved, block any possible movement of machinery.
– Kinetic energy: For blades and flywheels that are powered by kinetic energy, stop and block machine parts, review the entire cycle of mechanical motion and ensure that all motions have stopped. Block material from moving into the area of work.
– Potential energy: Stored energy, or energy that an object has the potential to release due to its position, can come in the form of springs in air-brake cylinders, actuators, counterweights, raised loads and the movable part of a press or lifting device. If possible, lower all suspended parts and loads to the lowest or rest position, block parts that might be moved by gravity and release or block spring energy.
– Thermal Energy: For thermal energy stored in supply lines, storage tanks and vessels, shut off, lock and tag valves. Bleed off excess liquids or gases and blank lines as necessary.
Each party in a workplace has a responsibility in the lockout program. According to the Canadian Centre for Occupational Health & Safety in Hamilton, Ontario, the lockout/tagout responsibilities of management, supervisors and authorized workers are outlined as follows:
• Responsible for drafting, periodically reviewing and updating the written program;
• Identify the employees, machines, equipment and processes included in the program;
• Provide the necessary protective equipment, hardware and appliances; and
• Monitor and measure conformance with the locjout/tagout program.
• Distribute protective equipment, hardware and any appliance and ensure their proper use;
• Ensure that equipment-specific procedures are established for the machines, equipment and processes in their area;
• Make sure that only properly trained employees perform service or maintenance that require lockout; and
• Ascertain that employees under their supervision follow the established lockout procedures where required.
• Adhere to the procedures that have been developed; and
• Report any problems associated with those procedures, the equipment or the process of locking and tagging out.
Jean Lian is editor of OHS Canada.