Fireman past and present,

What would happen if you attended a fire at a freestanding warehouse but couldn't get to the electrical isolator within the building safely?

Are the hoses pumping enough not to worry about it or would you just prevent risk of further spread beyond that building and let it burn?

Although the structure is a portal frame warehouse its being used as telesales floor so lots of PC's and phones throughout. I've spotted that to get to the isolator you would have to enter the building at the opposite end and cross the entire floor before getting to incoming services. I'm going to recommend changing one of the primary exits closer to it into door that can be opened from the outside but I don't want to make a mountain out of a molehill.

I would expect a full and prompt evacuation so there shouldn't be anyone inside.

As a past fire officer who knows about the present in Merseyside here goes:
Upon receiving a fire call at the station the responding crew will walk to the appliance and get dressed into fire kit before mounting the appliance. The driver will don his fire kit then set the Satnav and start the engine. They will then respond to the premises.
On arrival the officer in charge will carry out a risk assessment, or await the arrival of a more senior fire officer for him/her to do the ra.

There are not as many pumps available at present due to cost savings and cutbacks so the first pump crew may await the arrival of a second pump from a station further away before carrying out any fire fighting. This as long as all persons are accounted for – by this time the evacuation should be complete and a report made to the senior attending fire officer.
This brigade now has a duty system that allows some fire-fighters to be at home during night time so any response during those times will incur even more delay.
Be aware that all responsibility for rescue is now placed on the Responsible Person, not the FRS?
Regarding the electrical isolation switch – does it really matter? After all that time if the fire is electrical the RCD or fuse should have acted, if not an electrical fire the fire fighters will eventually seek out the main switch but not make it a priority as dealing with the fire will take priority – if they can enter the premises safely.

It would be desirable for easy access to the main switch, or even make it a part of your fire procedures for someone to switch off as long as that does not adversely affect the evacuation (hours of darkness etc.)

You may need to maintain power to essential machinery or equipment that needs to be kept running for whatever reason.

As previously stated prevention is better than cure so make sure your FRA is up to date and your fire precautions suitable for the risk.

Train all staff how to evacuate properly and sound the fire alarm at the earliest opportunity.

Smurf, in the past firefighters would tackle the fire no matter what, but I can't speak for today's firefighters.

Why now make a call to your local fire safety officer and ask them?

IMO I can't see it preventing access, it would be part of the operation to isolate power but not putting anyone at risk to do so.

have a look at:

"Guessing you were a FBU man Chris? Or maybe one of the old smoke-eaters?"

A little bit of both.

I joined in 66 as a Jfm, then operational 1968. Didn't do my BA initial for 18 months so had to eat smoke! Having said that it wasn't fashionable to wear BA way back then.

Happy days eh.

Not really my area, but a close friend of mine works in a large car dealership near my home.
The premises was a total loss fire a few years ago, cars on ramps in the air collapsed to the floor type of job.
The F&RS had the DNO out to do a live cut in the street while they were fighting the fire to prevent any possible fuelling of the flames I am told, I know the premises insurance broker too!
So, and please note that I'm not a "fire" type bod, but do know about lectwikery, I would not worry, DNO response time on this would be minutes and it only takes them minutes to cut the supply cable.
One last comment I am presuming that there is no HV on site, as that would be another issue.

Did you ever try a Siebe Gorman Proto set? 1 or 2 hour oxygen - closed circuit with the expelled air recirculated through a bag of absorbent granules.

Not very heavy and quite well balanced as the O2 cylinder was at the rear with the bag at the front.

Now they were the good old days.

Low Voltage then Smurf, I stick by my comments above.
HTH