Remote E Stop Solution

SicknoteX said:

Thanks for the responses.

The remote location is an hour's drive from the 2 sites - Not quite Christchurch to Auckland but I would think the same design considerations would apply.

With regard to the conformity and electrical regs, these E Stops are used to trigger ESD code within the PLC. They aren't used for electrical or mechanical interlocking like they would in a workshop or production line.
Do you know if there are applicable regs for this scenario?

Thanks

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If the remote location where you want the new "E-Stop" located is an hour away I wouldn't consider it an "E-Stop". I would imagine whatever the safety codes are in your location they probably would also not consider it an E-Stop either.

This opens a can of worms, firstly is the plan to move control to a remote location ?, if so will people still be at each plant. To move e-stops even by a few tens of yards could compromise safety. Adding extra is not a problem providing the original e-stops are not compromised. I would suggest any remote stops are not considered e-stops but plant stops.
One question arises, does putting a stop of some description in an e-stop loop compromise the integrity of the loop (no but although it does the same job cannot considered to be a e-stop if it does not meet current regulations).
It's a bit of a dilemma, for example, a fuse in-line with an e-stop (or Guard switch loop) will if removed or blown de-energise the safety devise as would switching off the power to the panel, however you can fit a fuse in an e-stop loop so why not a contact if you state this is not a safety device providing you do not compromise the rest of the circuit, again it's all down to risk assessments & current regulations. also if the sites are to become remote unmanned this also must be taken into consideration.

Too late, the can is opened.

having a remote control site at another location, even if it's in the same plant requires additional safety precautions and redundancy.

if there is anyone in the area of the machinery at the actual site, they MUST have e-stops so they can get to them.

the remote site now MUST meet stricter electrical control regulations, get safety approval, local approval, EU approval, and be tested in all sorts of ways to get final approval. one system will be opened and the other must do it's job.
then switch the systems around. then you must have a power failure option.

this is from memory on a similar job the company I used to work for did years ago.
james

I agree James, If you upgrade a safety system or change it's operation in any way it must be re-assessed. But this may apply not only to the safety system in place but the whole system. If a potential risk exists and it cannot be engineered out then a safe systems of work must be put in place. This is usually added in any legislation with the words "so far as reasonably practicable", I love those words (NOT).

Hey everyone,
Sorry for the slow response - middle of night in NZ!

To answer everyone's questions -
The E stops are connected to 2 GE Gas Turbines (Woodward Micronet Controllers) and the Gas Supply Controller. We have been given no further details but I'm going to try to get a lot more information today.

The picture attached shows the buttons next to the operators' desk
Just to clarify, these buttons aren't being moved - they will remain in place

Jeev said:

It is asymmetric. It needs another 2 buttons on the left.

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That made me laugh because I was thinking the same thing.....

SicknoteX said:

To answer everyone's questions -
The E stops are connected to 2 GE Gas Turbines (Woodward Micronet Controllers) and the Gas Supply Controller.

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Do these implement shut-down of the turbines and the gas supply (ESD - Emergency Shut-Down)? Is it correct to say that these are an extension of the shut-down function built locally into the turbines and controller?

Jeev said:

Do these implement shut-down of the turbines and the gas supply (ESD - Emergency Shut-Down)? Is it correct to say that these are an extension of the shut-down function built locally into the turbines and controller?

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Yes, that is correct

I'm going to bow out of this one. This is well above my pay grade.

Absolutely, positively, find someone local who is experienced in this type of thing and who has done it before to advise on your situation.

ASF said:

I'm going to bow out of this one. This is well above my pay grade.

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+1, and I have a CESE qualification as well as years of machine safety experience.

SicknoteX - You need to engage both Hazardous Area and Process Safety consultants. At very least get a copy of AS ISO 21789-2014. Section 5.20.8 details ESD. Sections 5.20 and 5.21 are relevant to your questions.

I know in Australia, the gas industry doesn't mess around anymore when it comes to safety. For reasons. I think what your client really asked was "please quote to set up a meeting with the appropriate certified safety engineers etc, because we want this remote ESD done right."

To familiarise yourself with typical safety processes, read Rockwell Safety Handbook cover to cover. Even those not doing safety themselves should know this book. An extension, and for anyone implementing any form of safety themselves (which is not a cookie cutter certified example from a vendor) ISO 13849 is required reading.

Don't worry, I've passed this up the chain!!

Voiced my concerns to my boss and the client. It's in their hands now

since you mentioned gas turbines and gas supply controller.

are these customer owned and not for generating power to the public?

as already mentioned, you need to get a degreed licensed engineer to look at what you propose.

individual load analysis, and lot's of other things must be considered.
it's been to many years since I was involved in this type of work and must also
bow out.

james