Emergency Stop Buttons in Boiler Rooms

[AC Power]

We are from Alberta, and I own an electrical company.

I have been asked by a BC Mechanical P. Eng. to install an emergency STOP button at the man-door to the boiler room. It's intent is to 'halt' the operation of the boilers in the room should there be an emergency. He is demanding that I do this by de-energizing the main primary power feeding the power! Dumping the incoming power kills all the VFD's, and PLC's, and the CPU to the boiler! Why not control the boiler's control circuit??? I find this odd and illogical.

1) Understandably, emergencies happen, however, what emergency is this intended to apply to (gas leak, CO, combustion downdraft, etc...)?

2) Why does the incoming AC power require to be de-energized? Why can't the control circuit that operates (enable, safety stop, etc....) operation of the boiler be interrupted?

3) Is this an AESHRAE code, of a CGA gas code? If so, can I be referred to the code so I can read the article and/or rule/sub-rule?

I am so puzzled by this, I am almost about to contest this with the Mech. P. Eng.

Example: On conveyors, saws, benders, or any automatic machine that can harm someone, we ALWAYS use the control circuit to stop (or halt) the operation of the respective equipment.

Thanks So Much

 

[MASSO]

Try the Health and Safety Executive, they have guidance on this it used to be PM 5 but has been withdrawn. I worked on a project which required a boiler alarm and shutdown panel to be installed in the gatehouse as this was the only area manned 24/7

 

[oz-plumber]

Can you not have an emergency stop installed to the gas supply.

We, in Australia, have had solenoids on the gas supply, controlled by an emergency stop.

We have had new regulation that require and emergency stop on commercial kitchens and other places.
I won't list the 'other places' due to reprisals if I give incorrect information.

 

[Gasmk1]

Can you not have an emergency stop installed to the gas supply.

We, in Australia, have had solenoids on the gas supply, controlled by an emergency stop.

We have had new regulation that require and emergency stop on commercial kitchens and other places.
I won't list the 'other places' due to reprisals if I give incorrect information.

 

[MASSO]

Sorry the first post I sent I did not read your post correctly, what the mechanical engineer is asking for is completely illogical and only he can qualify why he is asking for the disconnection of the supply to the boiler panel. I doubt there are any codes anywhere in the world that would require you to do this.
As you quite rightly said the boiler should be provided with its own shutdown system which should comply with the country code in which it is installed, this is normally achieved using the control circuit.
The mechanical engineer may have purchased a boiler package on the cheap which may not comply with the country code. He maybe trying to get round this by asking you to provide the isolation of the main power supply. You need to have a conversation with the mechanical engineer to establish why he wants the emergency stops installing
I assume that if you were too comply with his request you would fit a circuit breaker or similar with an under voltage coil connected to an emergency stop pushbutton. However you would need to speak to the boiler manufacture before doing so to ensure that isolating his equipment in such a manner would not damage his equipment eg PLC,VSD, CPU etc.
The only occasion I have ever had to trip the mains supply to a piece of equipment was on a chiller package. All the electrical equipment on the chiller including the starter panel and motor were only suitable for operation in a safe area. The refrigerant gas in the chiller was ammonia, large quantities of ammonia gas can create a hazardous area. Operating safe area equipment in a hazardous area can cause an explosion. If a gas leak was detected on the chiller package the main three phase supply to the chiller was automatically disconnected via a remote 400A MCB fitted with an under voltage trip coil to prevent such an explosion.

 

[oz-plumber]

In that case, just get the Mechanical Engineer to document ( put in writing ) what he wants you to do.
Put an Emergency Stop in the Plant Room, which cuts off power.
That should stop gas supply ( at the boilers gas control ) and everything else.

I wouldn't, if I were you, be too concerned about the ramifications on the equipment if you have followed his instructions.

Put all documentation in a folder, with the Electrical Plans and leave a copy in the Plant Room in the Switchboard.
Put his recommendations for this as first page.

When things hit the fan at a later stage, provide the documents and charge for repairs.

I went to a facility recently where the control system shut the power off to (2) 150 kW boilers.
They wondered why they had to keep resetting the boilers numerous times a day.
When there was no call for heat, the power supply was cut to the boilers, shutting primary and secondary pumps down.

I told them the system was wired and set up incorrectly and damage will be done.
Did they care ? Probably not, because it's not the answer they were looking for.

They'll start taking notice when boilers or boiler components have to be replaced.