Height of Timber Frame Buildings

armchairninja

Hi All,

Was on here a while back about doing my Arch. Tech. dissertation on Fire. I've since changed and then changed again, but I'm sticking with my choice this time. I plan on doing a comparison between Precast Concrete Multistorey Structures and Prefab Timber Multistorey Structures, and the different systems, pro's/cons etc.

I'm just wondering if someone can point me in the direction of some information though. Im aware that you can only go so high with Timber Frame in Ireland, but I've read through the TGD's and can't seem to find a definitive figure, would anyone on here be able to point me towards a document that would contain that height - it has to be able to be referenced for the dissertation, so I can't just say 4-storey and continue on - unfortunately
And any other info that I have, TF2000 etc., is all UK based, but I'd prefer to have an Irish doc, I'm assuming one exists.

Anyway, if someone could help me out with this, that would be great.

Thanks

sinnerboy

Im sure you'l find this helpful

Retail Hell

Go directly to the source and talk to there marketing managers
Kingspan Century Homes
IJM Timber Enginering

Mellor

Their marketing dept won't be a suitable reference for building height.
You're right that it's 4 stories, I can't remember where this is from though.
Was it in SB's link?

YouWantWhat

armchairninja wrote: »

Hi All,

Was on here a while back about doing my Arch. Tech. dissertation on Fire. I've since changed and then changed again, but I'm sticking with my choice this time. I plan on doing a comparison between Precast Concrete Multistorey Structures and Prefab Timber Multistorey Structures, and the different systems, pro's/cons etc.

I'm just wondering if someone can point me in the direction of some information though. Im aware that you can only go so high with Timber Frame in Ireland, but I've read through the TGD's and can't seem to find a definitive figure, would anyone on here be able to point me towards a document that would contain that height - it has to be able to be referenced for the dissertation, so I can't just say 4-storey and continue on - unfortunately
And any other info that I have, TF2000 etc., is all UK based, but I'd prefer to have an Irish doc, I'm assuming one exists.

Anyway, if someone could help me out with this, that would be great.

Thanks

You cannot go more than two storeys in timber frame, see TGD B 3.2.5.6

YouWantWhat

Sorry, I should clarify that last point, in buildings other dwellings party walls must be constructed from non-combustible materials 3.2.5.5, in dwellings, party walls cannot go higher than two storey in timber frame.

Detached buildings are different storey, you'd need to look further into the requirement for separating/compartment walls and floors, fire spread (escpecially in cavities).

In timber frame you'd also probably have a major problem with noise.

DOCARCH

The BRE in the UK have done extensive tests on multi-storey timber frame buildings (with a few shocking outcomes!). They built a couple of timber farme buildings and then basically burt them down. There was an article summarising the findings in the RIBA Jouurnal sometime last year. Worth digging out if you can find.

No6

YouWantWhat wrote: »

You cannot go more than two storeys in timber frame, see TGD B 3.2.5.6

Yes you can but I wouldn't reccomend it!!. Once you are over two stories for most building types you require 1hr fire resistant constrcution through out which can be difficult to achieve in timber frame. It is also not very suited to non domestic projects which require large clear spans as you then have to introduce steel or laminated structural timber frames.

In awnser to the original post I think the buildings of a height of top story over 10m be not be permitted in timber frames as TGD B 3.2.5.2 and 3.2.5.4 requires compartment walls and floors to be on non combustable construction, so in effect you are limited by this to the 4 flooors which you refer to.

Mellor

YouWantWhat wrote: »

You cannot go more than two storeys in timber frame, see TGD B 3.2.5.6

It's a god thing you clarified this, as well, its wrong.

YouWantWhat wrote: »

Sorry, I should clarify that last point, in buildings other dwellings party walls must be constructed from non-combustible materials 3.2.5.5, in dwellings, party walls cannot go higher than two storey in timber frame.

Detached buildings are different storey, you'd need to look further into the requirement for separating/compartment walls and floors, fire spread (escpecially in cavities).

On the first point, a timber frame building can have a masonry party wall. It's still timber frame.

As mentioned in the second, its compartmentation that restricts the height.

No6 wrote: »

In awnser to the original post I think the buildings of a height of top story over 10m be not be permitted in timber frames as TGD B 3.2.5.2 and 3.2.5.4 requires compartment walls and floors to be on non combustable construction, so in effect you are limited by this to the 4 flooors which you refer to.

Thanks for digging out the section. I really hate part B

Just to clarify, its the height from the lowest point of ground level to the level of top story FFL.

sinnerboy

No one read my link ?

Fire Safety

The building is a 20 metre cubic building, but we previously managed to prove that a 30 metre timber building was structurally feasible and fire safe. We base that assertion on the authority of Professor Mario Fontana at ETH University in Zurich whom we visited and consulted; if we were using a misting sprinkler system and the same technology we used in the current building, with further enhanced fire safety measures, it would be safe and technically possible to make such a building. We have all been appalled by the detail of the twin tower collapse, where the floor detail in fire proved so perniciously dangerous, causing progressive collapses to the towers.



Scaffolding on the timber structure lends perspective to the sheer scale of Ireland’s tallest timber frame building


Timber needs to be respected. The great square riggers took people around the world through hurricanes, and didn’t break up for the greater part. Our own intuitive guideline is that if the building is no higher than trees, then nature has already proven the integrity of tree structures! The fire aspect in particular here is a credit to the fire officers concerned. Meath County Council have engineers in their fire department and we found on the earliest consultations, on the superceded 30 metre tower scheme, down to the final fire certificate for this building that we relied on their engineering approach and professionalism of the fire service. They did not ‘throw a rule book’ at us but of course were fully cognisant of the legislation and best practice. We examined the whole building from first principles and in this respect we were very well served by Howard Morgan of International Fire Consultants (ex BRE). He provided a crucial study for the whole building, in terms of the smoke reservoir.

The use of a two staircase approach, the use of smoke venting in a very controlled way in the hands of the fire chief are key . The caveat here is that readers may not take it without question that a five-storey timber building is fire safe. There are many cautionary tales within the literature, from Julius Natterer’s work and others, where the greatest caution must be applied to timber. The size of cross section of timbers available to flame is a key matter. Small scantling sizes are highly vulnerable. Dense timber, designed with appropriate charring rates and with strategic application of spread of flame, non-toxic coatings—all these are key to ensuring a robust fire-safe building. The building uses layers of sacrificial timber, which is a commonplace of timber engineering. Most structural engineers in Ireland don’t like timber because the calculations are much more difficult. The material you’re working with is highly variable, from heartwood to sapwood, and various elaborate stress gradings. There are only one or two engineers in the country who would really have close expertise. It takes time and dedication to become really committed and skilful in this area. Ozelton and Baird’s Timber Designer’s Manual is a key reference for engineers who would like to bring this further.

In Enterprise Ireland there is a very good engineer, Bill Robinson, who was involved in the testing of connections for round-pole structures; give place name here. Bill helped us in early research and contacts on this project. The expertise is in the country, but the cultural confidence to use it generally is not yet there. We are hoping that this middle Europe import will help to stimulate interest in displacing very high embodied energy concrete and steel structures, despite the intimidating concrete lobby in this country. Entrenched commercial interest and entrenched professions are militating against innovation and against widespread uptake of environmentally sound techniques. Unless we break through these barriers and show the way in terms of there being good business opportunities in innovation, we will forever be luddite, and trailing the field in this area, internationally.

armchairninja

Hi All,

Thanks for the replies, been a bit busy with college to be able to reply, and Im still not fully finished with my dissertation, so I haven't got all the facts yet.

But I do know that you can go to 10m with a combustible material (TGD B 3.2.5.2), and also that timber frame compartmentation is not that difficult to achieve with proper detailing and an understanding of the materials.

Also, the technical guidance documents are just that Guidance, and as a result, if you can argue that a building is capable of going above 10m in Timber etc., by proving charring rates on timber still allow a suitable residual section to remain in place after burning etc., you may be able to build above, however you will need to be working with a planning/FSC department that is open minded and willing to look at your proposal instead of just taking the TGD as gospel.

There is also a 9 storey timber frame apartment building in the UK "Stadhaus Murray Grove" that may be of interest to some on here, its constructed from Cross Laminated Timber and was constructed in 27 days by a crew of 3/4 men.

Thanks for the help so far everyone

DOCARCH

As I mentioned above, the fire stopping measures for multi-storey timber frame structures has to be 100% perfect, otherwise you may end up like this:

http://www.bbc.co.uk/news/uk-england-london-10645700

armchairninja

I agree with that 100%, but thats where the proper detailing comes into play imo.
The fire in the TF2000 was reported in an article in RIBA called "smouldering issue" for anyone thats interested - http://www.ribajournal.com/index.php/feature/article/smouldering_issue_july10/

Also neither of the two buildings that are talked about in that article (BBC) were completed at the time of the fire, so its impossible to draw a fair conclusion on the suitability of timber as a material in that situation as the whole building was not present.

sexpot

Hello, I just managed to stumble across this section while doing research for my thesis also. I'm currently doing mine on Cross-Laminated Timber in multi storey construction in Ireland and like you armchairninja I'm comparing it to pre cast concrete from a cost perspective.

Just a note though, the Stadthaus isn't a 'timber frame' building as such and is technically a panellised timber structure. These have two very different meanings in timber construction world. CLT can also surpass most of the provisions set out by Eurocode 5.

Have you looked at IS 440?