Dry riser installation

[PGtips]

Good afternoon all - my first post on this forum. Can anyone tell me, is it ok to have dry riser outlets sharing electrical riser cupboards? The risers in question run the height of the building (new build) and cables are not sealed top and bottom on each floor. Given that a fire is not unusual in an electrical riser, I'm thinking if a fire is in there and the F&RS need to use the riser, they open up (or smash ) the little red box housing the outlet and all the smoke that may be in the riser comes out?  Assuming Building Control have approved the installation? Am I missing something or worrying too much? Wise council much appreciated.

PGtips

[nearlythere]

Welcome PGTips.

Is there any electrical switchgear or other electrical equipment in the cupboards or is it cabling only? Photo might be useful. From where does the cabling entering the shaft and is it sealed at that point?

[Golden]

Hi PG,

Was it like either of these?

[PGtips]

Hi thanks for replies.

its not just cables, there's some equipment (meters etc) in there and cabling.

I've got a pic funnily enough, I think I've attached it but.... (I'm a luddite)

its similar to your first pic, but the part you pout the hose on, is on the outside of the riser rather than on the inside as in your photo. However, if the box its in is opened the riser is no longer holding back any smoke, as there is a nice big gap all around the pipe.  Hope that clarifies a bit!

[PGtips]

"put" not "pout" - that would just be weird!

[nearlythere]

Post a photo PG.  The part you pout the hose on is the landing valve but hose connection would do.  

[Golden]

PG from your photo it would appear that the outlet is in a box outside of the riser and generally this would be alright in my opinion however as you've pointed out if the riser needs to be separated then the box should be sealed too. I'm assuming when you said the "cables are not sealed top and bottom on each floor." you mean that the riser extends top to bottom with no separation at each floor level?

[PGtips]

Hey, I'm learning already!

Yes, apologies loose terminology on my par.

I means the riser is not sealed top and bottom, i.e. it is a continuous shaft to allow the cables through. 60s doors to it on each landing.

So, from what you are saying, if they can fire seal the back of the box - all is good?

[PGtips]

"part" not "par" Grief, this posting and thinking at the same time is hard work!

[PGtips]

Thanks for your help chaps - much appreciated!

[Golden]

Some of us do have to work PG - can't spend all day long on here!!

Anyway the simple answer to your question is yes the cabinet could be enclosed in FR materials however this may be quite tricky and expensive and it would all depend on circumstances - if its in a protected shaft anyway then the full fire resistance rating may not be necessary. Why are you asking the question - if its a risk assessment and the fire loading within the shaft is negligible then simply sealing the pipe against smoke egress may be wise; considerations here would be whether this is a sleeping risk and where could any smoke travel. Its always difficult to give a definitive answer without all of the details but hope this advice helps.

As it is a new installation the client should have a full 'fire strategy' from the builder required under building regulations that show what fire safety precautions should have been installed in the building and it may be worth checking what the FR of this shaft should be.

[PGtips]

Now I feel bad    ...I meant, "thanks a lot chaps", a genuine thanks, not a sarcastic one!

That's the problem with written rather than spoken word I guess.

So, I'll try again. A big thank you to all those who took the time to post a reply, all very useful stuff and a bigger thanks to Golden who took the trouble to reply even though he thought I was being cheeky!

I will take your advice and dig out the Fire Strategy.

[Clevelandfire 3]

Dont worry PG Tips we are a friendly bunch here and golden wasnt having a go at you

[Golden]

No - you'd know if I was having a go!! I think this issue is quite tricky as I believe there is no specific guidance except for the inlet/outlet boxes and this guidance is ancient. This may explain why the responses have been limited.

[nearlythere]

Now I feel bad    ...I meant, "thanks a lot chaps", a genuine thanks, not a sarcastic one!

That's the problem with written rather than spoken word I guess.

So, I'll try again. A big thank you to all those who took the time to post a reply, all very useful stuff and a bigger thanks to Golden who took the trouble to reply even though he thought I was being cheeky!

I will take your advice and dig out the Fire Strategy.

Don't worry PG. Golden is one of the very senior members of the forum and gets a bit cranky at times as I'm sure you will when you get as old as him/her. Buy him a milk stout the next time you fall over him in the bar and you'll be a friend for ever - so long as you keep buying him milk stouts.