Boise USA made 420mm wooden composite "I" beams were use in a new school in
Milton Keynes, England in 2003 - Giles Brook, Tattenhoe, Milton Keynes. A
batch of them failed entailing the closure of the school. Portakabin
classrooms have been installed on the playing fields and the pupils are
moving into these until the beams are replaced and the school building back
in order. Ceilings and florrs have been ripped up.
A whole school has moved after first bussing the pupils around the city to
spare classrooms in other schools. Now into temporary portakabins. Serious
The problem is a manufacturers failure of the beams. Boise sent over a
techie for the USA who agreed with TRADA an independent testing house
specialising in timber construction and the Building Research Establishment.
The failure was the laminated flange coming away from the OSB web.
The builders narrowed the failed beams to a particular day - they are date
and time stamped and which team made them - the builders said all beams made
on that day will be replaced. TRADA testers narrowed it down to 10 minutes.
This is the 10 minutes when the two types of glue did not mix properly in
the beam making process.
Within this 10 minutes about 1000 metres of beam estimate to have been made
with over 700 metres going to the school in England. Now Boise have to
track down where the other 300 metres of beams went - if they can. Could be
to the UK, US or Canada or wherever. The date of manufacture is 31 Jan
2003. So if you have 420mm Boise beams check the day of manufacture as they
will have a high risk of failure.
Who pays for the replacements and the extra cost of the temporary school
will be determined by lawyers I'm sure. The council is not using wooden
composite "I" beams any more in new builds. Enough is enough for them.
Doing a Google on Boise they have a poor environmental record and poor at
other things too.
There's no need to Google the fact that using wood beams in what should
be a masonry/steel structure is a poor choice. There's plenty of blame
to be assigned to the code officials, architect, engineer and school
board as well.
I've used trusses constructed of pressure treated lumber and stainless steel
plates when combustion was an issue.
Not to mention the code issue of sprinklers in attic/contained spaces.
We all now know what *can* happen to (exposed) steel when subjected to
It actually can be rational. I'm not sure it applies to beams of this
style as they tend to have pretty think webs, but heavy rectangular
section wood beams withstand a fire MUCH better than a steel beam sized
for the same load. Wood burns, but it takes a long time to burn a heavy
beam enough for collapse. A steel beam heats up quickly and will yield
long before the wood beam has failed.
Your point about large section wood members having superior fire
resistive properties is valid - assuming that the wood beam is of
sufficient size and that the steel isn't adequately fireproofed.
The school isn't timber framed. The webs and chords of engineered
joists and trusses and other small pieces of wood are commonly referred
to as "kindling".
Private home, personal risk. Public building, public risk. Higher
standards should be in effect.
The point is that higher standards and material selection aren't
related. You can build to higher standards with any material and you
can build substandard structures with any material. Look at which
structures fail most often in earthquakes. Hint: it isn't heavy timber
Steel, concrete, masonry and timber all have their advantages and
disadvantages. The issue with this school isn't material selection it
is a quality control issue with the fabrication. This is no different
than a steel building with poor welds or a concrete building with
They are related, just not necessarily in a one to one relationship.
Look at what people build, worldwide, when they need a literally
bomb-proof building. Hint: it isn't heavy timber.
Look at what people build, worldwide, when they need a fireproof, not
fire resistive building. Hint: it isn't heavy timber.
Starting out with a clear picture of the objectives will help determine
the best materials for any construction within the confines of the
budget. That was my point from the beginning. I believe that there
are better choices than engineered I-joists for schools. YMMV
Agreed. Something hidden is something hidden, but something that
should have been obvious, such as the off-color glue joints the OP
indicated, was not noticed due to either inexperience or faulty quality
control processes in the field. That's why I said there was enough
blame to go around.
I would hazard a guess that no inspection was done of the I-joists at
all, other than for quantity and size. Carpentry crews don't have the
necessary skills and experience to inspect I-joists for manufacturing
defects. Carpenters will reject split or broken members, but a wrong
color glue joint would not send up any red flags.
A steel fabrication or precast plank would undergo a more stringent
inspection, and the crews installing them would most likely notice any
obvious manufacturing defects.
It depends on the requirements. Engineered I-joists are very good
choices for schools or many other structures.
I disagree. There are many grades of steels for W sections, bolts,
welding rod, etc. There is almost no way in the field to know that a
given piece of steel is the composition specified and has the proper
heat treatment for that composition. A quality control lapse at a steel
factory could have exactly the same consequences as with these wood
joists and be equally hard to detect.
My point is that you were pointing the finger at the material when the
problem isn't the material at all. And this problem isn't
material-specific, as any material could have the same problem. Rarely
is every bolt and piece of steel field tested for composition and
strength. Same for concrete. Some projects may sample every single
batch of concrete for strength, but I don't think this is uniformly
done. Just look at the Big Dig if you want to see quality control
issues with steel and concrete.
There are area limitations on the size of wood framed buildings.
Loopholes are sometimes used to circumvent those code restrictions.
Modeling a single building as three separate buildings to circumvent
code makes me uncomfortable. How do you feel about it? How do you
feel about it in regards to school buildings in particular?
I have no problems with any particular building material. I have
problems with how they're employed, why they're employed and how
they're detailed. I already stated my opinion on wood I-joists in
school buildings, numerous times. I already wrote YMMV - you're
entitled to your opinion. Maybe if you keep talking you'll convince
me, but I wouldn't count on it as you've offered nothing but your
opinion. That by itself shouldn't convince me, should it?
I disagree with the choice of materials. I do not solely blame the
material. I thought I had made that clear. Apparently what you were
misreading is what I wrote originally, "There's plenty of blame to be
assigned to the code officials, architect, engineer and school board as
well." I could have sworn that I referred to that in the post you are
responding to. Let me check...yep.
Can you offer any references, other than those sponsored by the wood
industry, that prove the superiority of light member engineered wood
structures in anything other than cost? If not, you're simply saying
that cost is the overriding factor. In many situations that is
obviously the case. I don't work that way and I disagree that having a
larger, less safe building is a wise use of the money.
I find it curious that you never addressed my other points, such as
need for public shelters, etc.
That wasn't quality control, that was graft. If your quality control
inspector is on the take, well, all bets are off, aren't they?
I'm not in favor of subverting building codes, even when they are
stupid. It doesn't matter to me what type of building it is, the code
should be followed.
Only if it makes sense.
No, cost isn't the overriding factor. The factors vary by region and
circumstances. In areas where wood is plentiful and the local labor
force is familiar with wood, it is an excellent choice. In areas where
wood isn't readily available, but masons are, then masonry is often the
better choice. Likewise, with steel. Steel is great for skyscrapers
where its high strength to weight and size are extremely important.
However, as we saw with the WTC and with other structures, fire is a big
problem with steel, even fireproofed steel. Fireproofing steel is very
hard to do uniformly as field tests have often demonstrated. However,
in a skyscraper wood and even concrete really isn't practical so you
just accept the fire danger.
When I built my lot house everyone thought I was going to pay high
insurance rates because of how easily wood burns. Well, log homes
actually get preferred rates in many areas (mine being one) as they are
actually seldom damaged beyond repair by a fire as is the case with
standard stud frame construction or steel stud construction. Unless the
fire department doesn't show up at all, typically at most 1/4" of a
heavy beam will be damaged and that in many cases can be sanded off, the
wood refinished, and you are back in business.
I wasn't trying to address every point. How would you like that point
adressed? Public shelters for what purposes and from what hazards?
It was both graft and quality control. And, yes, in cases like that all
bets are off.
It's been quite a while since you've posted pictures of your house.
I'm sure there are more than a few people reading who've never seen
How about simply the efficacy of combining functions in municipal
buildings by having public schools serve as public shelters. Do you
think that increasing the cost of the school building to have it do
double duty, while eliminating the need for a dedicated shelter
building makes sense?
16/12 pitch roof. Doggies.
I likes me a steep roof.
Saw a guy installing metal on a 12/12 roof the other day, in the rain, he
walked right up it like he was on level ground.
Musta had on them sucker boots or sumfink.
I get terrified on my 6/12 roof, (and I'm a ex-paratrooper) specially close
to the edge on the back.
You fall off back there it;ll take 3 days to hit the ground..........
Just to provoke the two of you:
I guess I don't have a problem with having wood hold up the school.
But I do have a problem with GLUE holding up a school.
Of course with parents being parents, you'll immediately get 5 or 6 who
say their kids are dying from the outgassing and 10 or 12 who say that
their kids are allergic to pine/oak/balsa or whatever other type of
wood is used.
As for metal, well metal is fine but metal trusses aren't terrible good
in a fire. That's why NY and NY require the truss warning beside the
doors if trusses are used -- even metal ones.
Out where I live, almost everything is 1 and 2 stories, so we don't go
quite a high as many places.
Changing subjects. We had a fire in town last night during the
blackout. It wasn't a mile from the fire dept and they could be their
within 3 or 4 minutes of the alarm. They did a good job of saving the
slab. Oh, it was a construction company's lumber storage shed. Man,
that burned. But as I said, they saved the slab.
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