Access may vary during each stage of the machinery and equipment life cycle. For example: • installation or removal o complete access from every area may be required and involve disconnection or connection of services, such as water, air, pipes, installation of electrical cable to switch board • operation o access for set up, operation and adjustment • maintenance, repair, cleaning, alteration or adaptation o access to remote areas may be required.
Captive key systems do not provide full isolation of the power source, but may provide limited temporary access under controlled conditions.
Failure to replace guards, damaged perimeter fences that allow access, and bypassed or disabled interlocking systems, are examples of critical safety systems failures that require immediate attention to ensure the safety of people.
Administrative controls, such as effective supervision, instruction and training, are required to ensure that only one key is available for the system, and the key is not removed from the access gate or guard by a second operator while a person is exposed to the danger area of the plant. Operations such as maintenance, repair, installation service or cleaning may require all energy sources to be isolated and locked out to avoid accidental start-up.