E-Stop regulations on VFD's - Grease Kettles U.S. 5

[Britman1]

I have been asked to design the controls for 2 grease kettles here in the U.S. Each kettle has two motors mounted on the top driving agitators inside. There is a door at the top of each kettle for charging ingredients. The motors are driven by variable speed drives. My concern is that as there is a door at the top, there is always the potential of someone falling inside? Does anyone know if it is mandatory to have E-Stops on this kind of equipment? I have suggested to the client that we include these, but he is against it. If I go ahead and design the controls without E-Stops, can I be liable? Can I pass the onus on to him? There is also a variable speed pump on each outlet of these vessels. Similarly would it be mandatory to have an E-Stop on these?

 

[LionelHutz]

I would think an E-stop would be required and you may also want to install some type of fall-in protection such as a pull cord which is a cable across the opening connected to a switch which will stop the VFD if it's leaned on and pulled. Or possibly use light curtains or something similar. It is hard to say exactly without knowing more details but some type of automatic protection against fall-in may be required.

 

[Britman1]

Hi Lionel,

Thanks for your feedback. I definitely feel that an e-stop ought to be implemented. I am not sure about the pull cord, although it would be a sensible idea? However I have seen many of these kettles in operation and none of them have this protection. Perhaps it is time to start? Maybe no-one has fallen in yet?

 

[itsmoked]

Would falling into hot grease mean death anyway in this setup? The best solution may just be bars or something mechanical to prevent one from physically falling in. If ingress is needed for cleaning or something then E-stops are pointless because you need a lock-out instead.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[LionelHutz]

I missed the grease part. Likely would be too hot to survive swimming in it. Also, the outlet pumps don't really need e-stop unless there would be some process reason you may need to stop them in an emergency.

 

[Britman1]

Thanks Guys, I guess my biggest concern was as to whether there are regulations stating I have to include e-stops? If it's only a matter of interpretation, then I guess the client's request not to have any is acceptable? I just wouldn't like to end up carrying the can for someone else's erroneous desires.

 

[jraef]

Safety rules in the US are not as specific as they are in other areas, we are more generalized. You are required to provide a safe working environment, but how you get there is up to you, and nobody comes around to inspect you ahead of time. But IF there is an accident, then OSHA (Occupational Safety and Health Administration) will do an investigation and if they don't like what they see, they can fine or even shut down a business operation. then once OSHA finds an unsafe condition (and sometimes even if not) the sharkfest begins, where the lawyers swoop in if they see deep pockets to feed on. So it's in everyone's best interest to overdo safety, but it's difficult to convince owners to pay for it up front unfortunately.

Aside from OSHA, there are other agencies and regulations specific to certain industries that do have E-Stop requirements, such as MSHA (Mine Safety...), RIA (Robotic Industry Association) and NFPA79 (National Fire Protection Assoc.) which is a standard specific to metal working machine tools. I don't know of anything specific to food production machinery though and from personal observation if they exist, they are weak, because there is a LOT of violation of what should be considered basic safe practices in that bunch.

"Will work for (the memory of) salami"

 

[ozmosis]

I think I'd be designing in e-stops and a safety interlock on the door.
If your VFD has a function called "safe stop" then I would be using this in line with the interlock on the door as well, but back up with actual lockable safety stops.

Maybe ask OSHA for advice.
My motto with safety:
If you think you should, then do it; if you should be doing it, do it.

 

[Britman1]

Thanks jraef and ozmosis; 2 helpful views - much appreciated. I think the idea of contacting OSHA may be a good one. At least I can say I checked. If they say it should be done, then I'll have something to show the client.

 

[DRWeig]

Great motto, Oz

Best to you,

Goober Dave

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