Stop-Time Measurement Service

Calculating Minimum Safety Distances.

Stop Time Measurement

Current OSHA regulations and ANSI standards requires that a machine’s stop time be measured to determine how long it takes a machine to stop after a stop signal is given. Most accidents occur as a result of a reflex action or simply not paying attention to one’s surroundings. Often a machine operator will instinctively reach for something when there is a problem. Or they will be focused on a task and enter a hazardous area without thinking about it. Tripping towards a hazard is another common occurrence. In these situations, it is necessary that the machine’s safety devices stop the machine before the hazard is reached.

Stop-time measurement readings taken on individual machines are used to determine the minimum safety distance required for placement of the machine’s operating controls or safeguarding devices used during production. This is critical when using presence sensing devices like light curtains, pressure mats, laser scanners, etc.

Location of a safety component, whether physical barrier or electronic, is based upon the machine’s stopping time. Simply stated, a safety component should be placed far enough away from the risk area that it is not possible to reach the hazard before the machine has stopped. Safety devices are then installed using the minimum safe distance. Reference our OSHA Safety Distance Guide Slide Chart.

Stop time measurement should be performed on an annual basis (or sooner) in order to ensure that the machine stop time has not changed. Machine maintenance, brake wear, machine alterations and other factors can extend the machine’s stopping time. If the machine stops slower than it once did, then the current safety components will need to be adjusted to continue providing the correct level of safety. For these and other reasons it is important to perform an annual stop time analysis.

Rockford Systems provides stop-time measurement services on various reciprocating (stroking or cycling) machines such as mechanical or hydraulic press and press brakes. We also provide these stop-time measurements on machines that rotate such as lathes, mills, and drills.

At your request, our trained technician will visit your facility and use a stop-time measurement device to measure the time it takes a machine to stop after a signal is given. The compiled information is then used in the OSHA and ANSI safety formulas to calculate the minimum safety distance required for the location of the machine operating controls/safeguarding device in relation to the nearest hazard.

Our stop-time measurement services can also be used periodically to check the machine’s stopping time to ensure that the current safety distance corresponds to the current condition of the machine’s stopping ability. We recommend that stop-time measurements be done on a regular basis, at least once a year.

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