Hi guys, we are currently planning on an office move and are putting in 4 porta cabins, 1 stacked on top of the other.  The porta cabins will be placed within our warehouse which has a fire allarm system.  I have spoken to the Project Manager in regards to having a fire alarm system put into the porta cabins, he has said that it is not part of the specs and that does not believe it is necessary because of the fire alarm system that is in the warehouse.  My stand on this, is a fire alarm system is required and should be connected to the current one, but I would like to know what you think.  It is planned to be a permanent structure and will have between 12 and 15 employees working within.

It would be down to what comes out of your fire risk assessment.  In any case your insurers may well have a view on the addition of new buildings inside the warehouse and may insist on fire alarms being fitted.  It feels like that stacking them would increase both the travel distance and the difficulty of getting to clear air in the event of a fire, especially if it started in one of the lower cabins.  I would be looking to fit alarms in the cabins and integrating them in to the main fire system. 

Edited by user 02 September 2020 13:06:18(UTC)  | Reason: Spelling

If its going to be a permenant set up as you suggest, then i would be pushing for an detection point in there at least its likely not going to be occupied 24/7, though it doesnt necessarily need sounders if the warehouse sounder volumes are audible within.

As the other replies state, the route of escape has changed and so should the risk assessment. Given the cabins will be located within the warehouse, i think there is a case for property protection as an un-detected fire within those cabins could easily get out of hand before the alarm is raised and it can be dealt with.

What your project manager means is that they failed to consider fire alarm arrangements and as they put a price on the total job which was "signed off" does not want the project to suffer cost over run.

Trouble is this omission will end up with a domino effect on yearly operational costs so needs to be corrected.

You do not necessarily need fire detection within an inner room - that could be for example, where a single level portable cabin(s) is set within a warehouse. A clear window affording a view of the warehouse may be sufficient, depending on what is stored in the warehouse, travel distances, exit route layout and so on. If a window is not possible, fire detection is required, but only in the access room (warehouse in this example) 

However a four storey permanent stack of cabins is taking the risk to another another level - so to speak! ;)

Basic fire detection (Cat L system) is designed to promote life safety objectives of raising the alarm and giving people time to escape. A basic system will need detection in escape routes and room leading onto escape routes, plus manual call points at each level.

Those in the top cabin will have quite a trek down the staircase. They may have to pass doors and windows to other cabins and the whole set up is a permanent one. 

Frankly how people here can give definite 'you should' answers is beyond me from what has been described, but from that description it is quite likely an extension to the exisiting detection system is likely

In any case, this change will trigger a review of the fire risk assessment and if you are in doubt as to what provisions are required, advice from a competent person should be sought. That probably wont be the project manager

Originally Posted by: toe

Second, portacabins are made of steel

Are you absolutely sure?

Just like hoover the name portacabin has become a description of a type of product rather than a specific brand.

Even those offices made from converting shipping style containers normally have timber floors.

I'm looking into the same type of set up for extra office space in our warehouse and I'm meeting with a Representative of Portacabin on Monday afternoon.  If I glean anything useful from that meeting I will post again.  I do stress though that I will be meeting with Portacabin (with a capital P) not a company that does modular buildings that are Portacabin look alikes. 

I believe the fire alarm systems that come with the Portacabins can be linked in to the main site ones.    Just needs a bit of electrical wizardry, we looked at temporary office accommodation a couple of years back and that is one of the questions I asked our fire alarm company.  I will check that this is still the case when I meet with Portacabin.