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Application and use of interlock safety devices.

Pettit-TA; Concha-SR; Linn-H
Hazard Prev 1983 Nov; :4-9
The application and use of interlock safety devices in industrial safety were discussed. The nature of interlock safety devices was considered. Examples of typical interlock devices were listed. An interlock device consists of a sensing element and activating (operating) element that maintains the safety of a system or machine without operator (or manual) intervention. Types of hazards that could be controlled by interlock devices were discussed. These included hazards resulting from interrupting the energy supply of a machine, operating a machine or system outside its safe operating limits, approaching hazardous levels of energy or materials through enclosures, and performing operations involving large amounts of energy out of sequence. The question of when interlocks should be used was discussed. General guidelines for choosing interlock devices were presented. Interlock verification and maintenance were discussed. Periodic assessment of interlock application was considered. Examples of interlock hazard control applications were given. The authors conclude that any part, component, or system can function as a safety interlock device. No absolute recommendations as to when interlocks should be used as a substitute for alternate hazard control techniques can be made. Criteria for using interlocks in individual cases will depend on the specific factors of each case.
NIOSH-Author; Industrial-safety; Accident-prevention; Safety-research; Equipment-design; Occupational-hazards; Industrial-equipment; Safety-measures
Publication Date
Document Type
Journal Article
Fiscal Year
Source Name
Hazard Prevention
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division