Fire protection of steels

[Post and beam]

I have 2 steel joists running across the living room. They will not be visible once the plasterboard ceiling is installed. 10 inch posi joists carry the rest of the ceiling/s. Building control have asked for fire protection of these steels.    Is it acceptable to just use 15mm fire  rated plasterboard across the entire living room ceiling. Or do they need to be encased? 

[nod]

Presuming your over three floors 

If BC is asking for an hour fire protection You will be ok to just use a single layer of fire check Don’t forget to seal around the perimeter of the room 

[ETC]

5 hours ago, Post and beam said:

I have 2 steel joists running across the living room. They will not be visible once the plasterboard ceiling is installed. 10 inch posi joists carry the rest of the ceiling/s. Building control have asked for fire protection of these steels.    Is it acceptable to just use 15mm fire  rated plasterboard across the entire living room ceiling. Or do they need to be encased? 

No. If the steelwork requires FR speak to British Gypsum or Harmon for the correct way to fire protect steelwork.

[Post and beam]

10 hours ago, nod said:

Presuming your over three floors 

If BC is asking for an hour fire protection You will be ok to just use a single layer of fire check Don’t forget to seal around the perimeter of the room 

No not 3. Standard 2 storey cottage style.  Please elaborate on what you mean by 'single layer of fire check'  . Can i do what i described or do i need to encase them?

[nod]

If it’s two story the steels don’t need to be fire protected 

[ETC]

18 minutes ago, nod said:

If it’s two story the steels don’t need to be fire protected 

Yes they do.

[Big Jimbo]

Re @nod and @ETC . The last time I fitted a steel, I painted it with a load of gloopy bollom fire paint. The building inspector when he saw it said "no need to bother with that anymore"  ??

[nod]

12 minutes ago, Big Jimbo said:

Re @nod and @ETC . The last time I fitted a steel, I painted it with a load of gloopy bollom fire paint. The building inspector when he saw it said "no need to bother with that anymore"  ??

I do fireproofing as part of my business

We are never asked for any protection for two story homes But once that extra floor is added You will need an hour protection Some insist on the beams being wrapped Then boarded Others are happy to treat them like an integral garage Two layers of fire line board It should really be on the drawing 

 

Our last two builds are full of steels supporting the floors No protection needed 

 

This is our current build 

Note no mention of unnecessary fire protection from the SE 

[Nickfromwales]

1 hour ago, ETC said:

Yes they do.

If they’re exposed then yes, but if they’re enclosed by a layer of standard plasterboard (which has been plastered) then they need zero extra protection.

 

If you can ‘see’ a steel so can an open flame, that is what you protect a 1 or 2-storey dwelling against, 3-storey will come with its own prescribed methodology by your various professionals.

 

A “single compartment dwelling” has even fewer requirements, no need for FR spots or other usual stuff; SCD’s have open-plan hall / stairs / landing, and usually the architect will have specified escape windows to all FF habitable rooms.

 

Pointless for a steel beam to be in tip top condition when everyone in the building has already either died from smoke inhalation or been roasted, FR are there primarily for preservation of life not property.
 

3-storey dwellings do require the property to remain structurally intact for rescue to be made, hence the extended timescales for fire resistance / protection of the build fabric, plus fire doors etc. This also assumes jumping from a 3rd storey window wouldn’t be practical.

[saveasteading]

I read the regs as the beam needs 30 minutes protection.  That isn't onerous and some beams have that inherently.

 

It's not something to dabble with. The rules are clear. 

It gets complex with the weight of beam and exposure, and the house geometry, so isn't for us to calculate on here.

Anyway, It sounds as if the beam is above the pb ceiling. That is fire protection.  Fire can't reach the beam....beam can't melt.

 

But it is easy to encase the steel. Bang timber noggins between the flanges and screw pb over. It doesn't have to be pretty.  Or buy some fancy clips and rails if it does.

 

Speak to the bco.

 

[Post and beam]

It was BCO woman that asked me to do this. There is nothing on the build drawings from the TF supplier that mentions this at all.

 

They are above the ground floor living room ceiling and will not be visible.

 

Fire proof 15mm plasterboard on the living room ceiling it is then?

[Nickfromwales]

43 minutes ago, Post and beam said:

It was BCO woman that asked me to do this. There is nothing on the build drawings from the TF supplier that mentions this at all.

 

They are above the ground floor living room ceiling and will not be visible.

 

Fire proof 15mm plasterboard on the living room ceiling it is then?

Nope. Standard PB + skim is fine. 15mm FR plasterboard if it wasn't skimmed (tape & joint).

 

BCO lady needs to brush up!!!!!

 

Ask specifically if this is requisite or a recommendation, as last few (almost all BCO's) have rescinded when challenged tbh on many things.

 

One was exactly this subject, with 2 separate BCO's on 2 of my clients builds, where they were adamant that FR plasterboard was needed; 1 where they were saying "but only at / under the steels", and another where the fu@@wit of a BCO was telling the builder (who was also a fu@@wit) that all steels needed to be boxed in with FR PB (before both jobs being boarded over and skimmed!!). Just nonsense.

 

Go back and challenge, but prepare yourself to be polite and pragmatic in your approach so no knickers get twisted  

[Nickfromwales]

TF suppliers are not going to identify this btw. Architect is PD and BCO sense checks them, and usually then garnishes with their 2 cents.

[saveasteading]

2 hours ago, Post and beam said:

Fire proof 15mm plasterboard

Might even be normal pb. I don't have the books to hand.  But it isn't much advertised and barely worth proving or arguing.

[Post and beam]

This is how it looks in reality at the moment.

No room underneath for anything other than the ceiling PB, what ever that turns out to be. And hard up against a posi on one side. The other one is the same.

 

[Nickfromwales]

Nothing needs doing to them.

 

Are those timbers decorative, or load bearing to the steel?

[Thorfun]

2 hours ago, Nickfromwales said:

Ask specifically if this is requisite or a recommendation, as last few (almost all BCO's) have rescinded when challenged tbh on many things.

+1 to this. Our BCO asked us to do something that would’ve costed us thousands so I read the regulations and put forward my arguments as to why it wasn’t necessary and got told I was right. 

[Nickfromwales]

20 minutes ago, Thorfun said:

+1 to this. Our BCO asked us to do something that would’ve costed us thousands so I read the regulations and put forward my arguments as to why it wasn’t necessary and got told I was right. 

Some of them are just completely obtuse penis's.

 

>£4k of costs saved on the one where the fu@@wit wanted all the steels boxed in (bearing in mind that this "beaut" decided to drop this request after I'd 1st fixed for electrics, plumbing, MVHR and drainage!).

[nod]

4 hours ago, Post and beam said:

It was BCO woman that asked me to do this. There is nothing on the build drawings from the TF supplier that mentions this at all.

 

They are above the ground floor living room ceiling and will not be visible.

 

Fire proof 15mm plasterboard on the living room ceiling it is then?

You can do 

But you don’t need to 30 minutes standard plasterboard if fine 

BC don’t always No the regs 

[Nick Laslett]

One thing I don’t miss about the house build is looking at building regs. They are just so badly written and hard to navigate. The fire regs for structural elements table seems to have grown massively since 2019. 
 

 

https://assets.publishing.service.gov.uk/media/67d2bb074702aacd2251cb94/Approved_Document_B_volume_1_Dwellings_2019_edition_incorporating_2020_2022_and_2025_amendments_collated_with_2026_and_2029_amendments.pdf

 

So as others have already said, 2 storey dwelling needs 30 minutes protection for structural elements. 
 

British Gypsum white book has a plethora of solutions

 

https://www.british-gypsum.com/specification/white-book-specification-selector/steel-protection

 

Here is one with 12.5mm FireLine board

 

Edited yesterday at 13:03 by Nick Laslett

[Post and beam]

1 hour ago, Nickfromwales said:

Nothing needs doing to them.

 

Are those timbers decorative, or load bearing to the steel?

Nick they are load bearing. 

 

I am glad you say nothing needs doing to them.  is that because they will have plasterboard below them and are not on show?

 

[Post and beam]

Standard plasterboard provides the 30 minutes protection though doesn't it? 

 

The timber posts and beams are a structural element and the steels sit on them. Nobody has mentioned a thing about providing additional 30 minutes protection of those. Curious.

[nod]

14 minutes ago, Post and beam said:

Standard plasterboard provides the 30 minutes protection though doesn't it? 

 

The timber posts and beams are a structural element and the steels sit on them. Nobody has mentioned a thing about providing additional 30 minutes protection of those. Curious.

I’ve been doing fire protection quotes for 25 plus years 

If you follow my original answer Two story No extra fire protection needed 

Three story Extra needed 

You won’t go far wrong 

There only houses Commercial projects are much more complex 

 

If your steels need protection It would 100% be marked on the SE drawing 

Even the size of the pad stones are on there 

[Thorfun]

30 minutes ago, Post and beam said:

Standard plasterboard provides the 30 minutes protection though doesn't it? 

I think standard 12.5mm and a skim gives 30mins protection. Maybe 15mm standard plasterboard gives the same without a skim?

 

 sure someone knows for sure though. 

[saveasteading]

53 minutes ago, Nick Laslett said:

They are just so badly written and hard to navigate.

That's because it isn't simple.

 

I resort to photocopying the relevant pages and highlighting the relevant clauses, resulting in a narrative. This remains to hand when I inevitably forget the logic, plus can show the bco....who is not our designer.

 

The fire codes themselves are more complex. Eg the hp/a of the steel.

 

BTW I have worked with severely fire damaged buildings and the steel structure was always intact.