Mechanical interlocks reduce risks by ensuring dangerous processes happen only in a designated sequence. Interlocks are relatively simple, specialised, mechanical fit attachments to the host equipment. These interlocks are attached to the host equipment (any valve, closures, equipment needing human intervention) and compose of a simple lock and key design. Workers transfer specific keys from lock to lock (equipment to equipment) in a particular sequence. The next step in the process is only allowed once the previous step has been completed. The sequence must be followed in the exact order to completion. Mechanical interlocks are ideally suited to integrate with work procedures. They ensure safety, rather than place responsibility on the operator.
Mechanical interlocks make sense from a productivity standpoint too. Interlocks can ensure the safe transfer of product. For example, Smith Flow Control’s (SFC) valve interlocking system was installed on a Malaysian LNG installation at Bintulu in Sarawak, East Malaysia, to prevent accidental product spillage while tankers are loading. By integrating a safety system into the process it eliminated the risk of human error or negligence when loading the tanker, which could lead to a vessel leaving the transfer area, still connected to the onshore facilities via a loading arm.