E-stop buttons
E-stop buttons
(OP)
Besides being red in color are e-stop buttons required to have a mushroom-like shape.
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RE: E-stop buttons
On the matter of red, I don't know if thats is an absolute. What would happen if your operator was red color blind? The button needs to be well labeled and recognizable is what I use as a criteria.
RE: E-stop buttons
SO FAR every E stop I have seen is pull out to run push in to stop. Does NFPA address that I wonder??
For red I have seen red button for stop green for go so I would guess that is where that came from.
Dan Bentler
RE: E-stop buttons
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It does't mention shape or color though
<short citation>
1.2.4.
Stopping device
Normal stopping
Each machine must be fitted with a control whereby the machine can be brought safely to a complete stop.
Each workstation must be fitted with a control to stop some or all of the moving parts of the machinery, depending on the type of hazard, so that the machinery is rendered safe. The machinery's stop control must have priority over the start controls.
Once the machinery or its dangerous parts have stopped, the energy supply to the actuators concerned must be cut off.
Emergency stop
Each machine must be fitted with one or more emergency stop devices to enable actual or impending danger to be averted. The following exceptions apply:
- machines in which an emergency stop device would not lessen the risk, either because it would not reduce the stopping time or because it would not enable the special measures required to deal with the risk to be taken,
- hand-held portable machines and hand-guided machines.
This device must:
- have clearly identifiable, clearly visible and quickly accessible controls,
- stop the dangerous process as quickly as possible, without creating additional hazards,
- where necessary, trigger or permit the triggering of certain safeguard movements.
The emergency stop control must remain engaged; it must be possible to disengage it only by an appropriate operation; disengaging the control must not restart the machinery, but only permit restarting; the stop control must not trigger the stopping function before being in the engaged position.
Complex installations
In the case of machinery or parts of machinery designed to work together, the manufacturer must so design and construct the machinery that the stop controls, including the emergency stop, can stop not only the machinery itself but also all equipment upstream and/or downstream if its continued operation can be dangerous.
RE: E-stop buttons
RE: E-stop buttons
RE: E-stop buttons
In NFPA 79 13.2 Buttons shall be colored RED with YELLOW backgrounds with palm or mushroom-head types.
RE: E-stop buttons
RE: E-stop buttons
RE: E-stop buttons
RE: E-stop buttons
RE: E-stop buttons
RE: E-stop buttons
RE: E-stop buttons
(iii) Stop. Emergency stop bars on hazardous machines such as rubber mills, wire blocks, flat work ironers, etc., shall be red. Stop buttons or electrical switches which letters or other markings appear, used for emergency stopping of machinery shall be red.
(2) [Reserved]
(3) Yellow. Yellow shall be the basic color for designating caution and for marking physical hazards such as: Striking against, stumbling, falling, tripping, and ‘‘caught in between.’’
...
RE: E-stop buttons
RE: E-stop buttons
For many processing facilities the only thing that is identified as an "Emergency" stop is a confirmed fire as identified by multiple fire detectors or operator confirmation. It takes days to stop some refineries and chemical plants. Where an actual emergency stop button exists, they are normally red. I am a believer in the big red button even with the most reliable SIL 3 rated shutdown system. My red button kills the power to the fail-safe I/O module outputs.
RE: E-stop buttons