Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc. into KNm?

On 21/04/2010 14:16, David WE Roberts wrote:
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc. into KNm?

You need access to a copy of BS648 for the weights of various materials.

Jim wrote:
On 21/04/2010 14:16, David WE Roberts wrote:
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc. into KNm?

You need access to a copy of BS648 for the weights of various materials.

Anyone know why the average punter can't gain access to BS standards?

It looks strange that a standard can be laid down, but we can't see the
details involved.


Dave

In article ,
Dave writes:
Jim wrote:
On 21/04/2010 14:16, David WE Roberts wrote:
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc. into KNm?

You need access to a copy of BS648 for the weights of various materials.

Anyone know why the average punter can't gain access to BS standards?

Anyone can buy a copy.
Some libraries can give you access.

Or did you mean why can't you see it for free?
We don't have the law which exists in a number of US states which
requires that standards which are called up by law have to be freely
available.

It looks strange that a standard can be laid down, but we can't see the
details involved.

You can see it - buy a copy.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

[Default] On Wed, 21 Apr 2010 18:20:01 +0000 (UTC), a certain
chimpanzee, (Andrew Gabriel), randomly hit
the keyboard and wrote:

We don't have the law which exists in a number of US states which
requires that standards which are called up by law have to be freely
available.

US Building Regulations aren't free. As far as I can tell, they are
written by private companies, and adopted piecemeal by each county or
even each city (a "city" being three shacks and a gas station in the
USA) in each state. Some of the 'codes' can be viewed but not
downloaded or printed for free. ANSI standards are (AFAIK) not free to
view or download.

British Building Regulations and Approved Documents/Technical
Standards can be viewed and downloaded for free. British Standards
have to be paid for.

The reason why the average punter can't gain access to BS standards
(for free) is because of the joys of capitalism. British Standards is
a private monopoly run for profit, not a public service paid for by
the taxpayer.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have I strayed"?

Hugo Nebula wrote:

The reason why the average punter can't gain access to BS standards
(for free) is because of the joys of capitalism.

Membership of certain libraries grants you online access to them,
Manchester does, I believe they allow on-line signing up regardless of
your physical location, you have to wait for an entitlement card to
arrive in the post though.

On Mon, 26 Apr 2010 21:15:58 +0100 Hugo Nebula wrote :
The reason why the average punter can't gain access to BS standards
(for free) is because of the joys of capitalism. British Standards
is a private monopoly run for profit, not a public service paid for
by the taxpayer.

British Standards don't come cheap, even if you are member and can
buy at half price. In my field (structural engineering) you'll often
find that a good textbook includes all the useful content and costs
just £25+/-

--
Tony Bryer, Greentram: 'Software to build on' Melbourne, Australia
www.superbeam.co.uk www.eurobeam.co.uk www.greentram.com

In article ,
Hugo Nebula abuse@localhost writes:
[Default] On Wed, 21 Apr 2010 18:20:01 +0000 (UTC), a certain
chimpanzee, (Andrew Gabriel), randomly hit
the keyboard and wrote:

We don't have the law which exists in a number of US states which
requires that standards which are called up by law have to be freely
available.

US Building Regulations aren't free. As far as I can tell, they are
written by private companies, and adopted piecemeal by each county or
even each city (a "city" being three shacks and a gas station in the
USA) in each state. Some of the 'codes' can be viewed but not
downloaded or printed for free. ANSI standards are (AFAIK) not free to
view or download.

Many of the counties/cities have to republish them under their own
name, to make them available for free. Often they modify them in
the process.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Dave wrote:
Jim wrote:
On 21/04/2010 14:16, David WE Roberts wrote:
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc.
into KNm?

You need access to a copy of BS648 for the weights of various
materials.

Anyone know why the average punter can't gain access to BS
standards?
It looks strange that a standard can be laid down, but we can't see
the details involved.

PDF version here -
http://www.jugarcorp.com/bs-648-1964-t-5299.html

"David WE Roberts" wrote in message
...
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc. into KNm?

One KN is about the force you get from 100Kg weight.

Now all you need to do is workout the weight of the materials per meter and
add in a suitable safety margin for snow, ice, falling volcanic ash, birds,
etc.

"David WE Roberts" wrote in message
...
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc.

Multiply weight in Kg by 9.81 to get Newtons.

mark

mark wrote:
"David WE Roberts" wrote in message
...
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc.

Multiply weight in Kg by 9.81 to get Newtons.

Is my memory finally failing or are all the experts who have responded
to this thread more than half asleep to let such an obvious mistake go
unremarked?

IIRC if you multiply weight in Kg by 9.81 you get Kgf. In SI metric mass
and force are numerically equal.

"Roger Chapman" wrote in message
...
mark wrote:
"David WE Roberts" wrote in message
...
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc.

Multiply weight in Kg by 9.81 to get Newtons.

Is my memory finally failing or are all the experts who have responded to
this thread more than half asleep to let such an obvious mistake go
unremarked?

IIRC if you multiply weight in Kg by 9.81 you get Kgf. In SI metric mass
and force are numerically equal


It's a good job you're not a structural engineer then.

mark

mark wrote:

snip

Multiply weight in Kg by 9.81 to get Newtons.
Is my memory finally failing or are all the experts who have responded to
this thread more than half asleep to let such an obvious mistake go
unremarked?

IIRC if you multiply weight in Kg by 9.81 you get Kgf. In SI metric mass
and force are numerically equal


It's a good job you're not a structural engineer then.

And you are of course.

mark wrote:

snip

So how do you translate the weight of a roof plus joists etc.
Multiply weight in Kg by 9.81 to get Newtons.
Is my memory finally failing or are all the experts who have responded to
this thread more than half asleep to let such an obvious mistake go
unremarked?

IIRC if you multiply weight in Kg by 9.81 you get Kgf. In SI metric mass
and force are numerically equal


It's a good job you're not a structural engineer then.

It must be nice to be able to resort to insults without the need to
check your facts.

http://en.wikipedia.org/wiki/Kilogram-force

Roger Chapman wrote:
mark wrote:

snip

So how do you translate the weight of a roof plus joists etc.
Multiply weight in Kg by 9.81 to get Newtons.
Is my memory finally failing or are all the experts who have
responded to this thread more than half asleep to let such an obvious
mistake go unremarked?

IIRC if you multiply weight in Kg by 9.81 you get Kgf. In SI metric
mass and force are numerically equal


It's a good job you're not a structural engineer then.

It must be nice to be able to resort to insults without the need to
check your facts.

http://en.wikipedia.org/wiki/Kilogram-force


I think that was possibly ambiguous. It certainly didn't say what I
intended to mean. 1 Kgf is 9.81 N. I just got it the wrong way round for
which I am sorry. Blame it on my education that didn't include SI
metric, just Imperial units and cgs and mks metric.

"Roger Chapman" wrote in message
...
mark wrote:

snip

So how do you translate the weight of a roof plus joists etc.
Multiply weight in Kg by 9.81 to get Newtons.
Is my memory finally failing or are all the experts who have responded
to this thread more than half asleep to let such an obvious mistake go
unremarked?

IIRC if you multiply weight in Kg by 9.81 you get Kgf. In SI metric mass
and force are numerically equal


It's a good job you're not a structural engineer then.

It must be nice to be able to resort to insults without the need to check
your facts.

http://en.wikipedia.org/wiki/Kilogram-force


I wouldn't know. Is it? :-)

mark

"Roger Chapman" wrote in message
...
mark wrote:

snip

So how do you translate the weight of a roof plus joists etc.
Multiply weight in Kg by 9.81 to get Newtons.
Is my memory finally failing or are all the experts who have responded
to this thread more than half asleep to let such an obvious mistake go
unremarked?

IIRC if you multiply weight in Kg by 9.81 you get Kgf. In SI metric mass
and force are numerically equal


It's a good job you're not a structural engineer then.

It must be nice to be able to resort to insults without the need to check
your facts.

http://en.wikipedia.org/wiki/Kilogram-force



Try reading the stuff you link to.

"So one kilogram-force is by definition equal to 9.80665 newtons"

As stated, its a good job you aren't a structural engineer, or a scientist,
or an engineer, etc.

On Thu, 22 Apr 2010 11:04:17 +0100, Roger Chapman
wrote:

IIRC if you multiply weight in Kg by 9.81 you get Kgf. In SI metric mass
and force are numerically equal.


Wrong. A kgf (kilogramme force) is the force exerted by one kg due to
gravity. There is no 9.81 involved. 1 kg exerts 1 kgf.

These units are no longer used for structural design - kgf has not
been in general use since the 1970s. Absolute units of force are used
instead, based on the Newton, which is the force required to
accelerate 1 kg by 1 m/s per second (1 m/s^2).

The acceleration due to gravity is approximately 9.81 m/s^2. So the
force exerted by one kg due to gravity is 9.81 N.

A kilonewton (kN) is 1000 Newtons, or the force exerted by 102 kg due
to gravity, because 1000 divided by 9.81 is approximately 102.

On Wed, 21 Apr 2010 14:16:36 +0100, "David WE Roberts"
wrote:
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc. into KNm?


Beware, because none of the three replies that I have read so far on
here have even recognised the meaning of "kNm". Even the data sheet
gets it wrong, writing it as "KNm". Also, there is more to it than
just "the weight of a roof plus joists etc.".

The figure given in kNm is the bending moment that the lintel can
accept in service, in kiloNewton-metres. If you don't know what
"bending moment" means, or how to work it out, you really should get a
structural engineer or technician engineer to calculate it for you and
select the appropriate lintel. He/she won't cost you a lot and could
save you a lot of heartache and hassle, plus you will have the comfort
of knowing that the finished job will comply with the building
regulations and not collapse.

Your local newspaper classified ads will have a selection of people
offering "plans drawn" and suchlike. This is the best place to start.

Bruce wrote:
On Wed, 21 Apr 2010 14:16:36 +0100, "David WE Roberts"
wrote:
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc. into KNm?


Beware, because none of the three replies that I have read so far on
here have even recognised the meaning of "kNm". Even the data sheet
gets it wrong, writing it as "KNm". Also, there is more to it than
just "the weight of a roof plus joists etc.".

The figure given in kNm is the bending moment that the lintel can
accept in service, in kiloNewton-metres.

I am not an expert in this field, but I thought that the term was
related to torque and not bendind.

Dave

"Dave" wrote in message
...
Bruce wrote:
On Wed, 21 Apr 2010 14:16:36 +0100, "David WE Roberts"
wrote:
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc. into KNm?


Beware, because none of the three replies that I have read so far on
here have even recognised the meaning of "kNm". Even the data sheet
gets it wrong, writing it as "KNm". Also, there is more to it than
just "the weight of a roof plus joists etc.". The figure given in kNm is
the bending moment that the lintel can
accept in service, in kiloNewton-metres.

I am not an expert in this field, but I thought that the term was related
to torque and not bendind.

Dave

You bend something by applying a torque to it. Beams have the added
complication of distributed load. The calculations are not difficult but
the concepts take a little thought. Anyone with A level Maths or a science
based degree would find little difficulty. There are plenty of sources on
the 'net. That's how I found out how to do the calculations!

Lawrence

"Lawrence" wrote in message
...

You bend something by applying a torque to it. Beams have the added
complication of distributed load. The calculations are not difficult but
the concepts take a little thought. Anyone with A level Maths or a
science based degree would find little difficulty. There are plenty of
sources on the 'net. That's how I found out how to do the calculations!


Nope. You bend something by applying a load to it. If you apply a torque
you twist it.

Roof wrote:
"Lawrence" wrote in message
...

You bend something by applying a torque to it. Beams have the added
complication of distributed load. The calculations are not difficult but
the concepts take a little thought. Anyone with A level Maths or a
science based degree would find little difficulty. There are plenty of
sources on the 'net. That's how I found out how to do the calculations!


Nope. You bend something by applying a load to it. If you apply a torque
you twist it.



Let's not quibble. Moment (torque) = force * distance.
From http://en.wikipedia.org/wiki/Torque :
Torque, also called moment or moment of force (see the terminology below), is
the tendency of a force to rotate an object about an axis,[1] fulcrum, or pivot.
Just as a force is a push or a pull, a torque can be thought of as a twist.

Lawrence wrote:
"Dave" wrote in message
...
Bruce wrote:
On Wed, 21 Apr 2010 14:16:36 +0100, "David WE Roberts"
wrote:
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc. into KNm?


Beware, because none of the three replies that I have read so far on
here have even recognised the meaning of "kNm". Even the data sheet
gets it wrong, writing it as "KNm". Also, there is more to it than
just "the weight of a roof plus joists etc.". The figure given in kNm
is the bending moment that the lintel can
accept in service, in kiloNewton-metres.

I am not an expert in this field, but I thought that the term was
related to torque and not bendind.

Dave

You bend something by applying a torque to it. Beams have the added
complication of distributed load. The calculations are not difficult
but the concepts take a little thought. Anyone with A level Maths or a
science based degree would find little difficulty. There are plenty of
sources on the 'net. That's how I found out how to do the calculations!

Just as I hit the send button, It came to me. Sorry for the post.

Dave

On Wed, 21 Apr 2010 19:26:39 +0100, Dave
wrote:

Bruce wrote:
On Wed, 21 Apr 2010 14:16:36 +0100, "David WE Roberts"
wrote:
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc. into KNm?


Beware, because none of the three replies that I have read so far on
here have even recognised the meaning of "kNm". Even the data sheet
gets it wrong, writing it as "KNm". Also, there is more to it than
just "the weight of a roof plus joists etc.".

The figure given in kNm is the bending moment that the lintel can
accept in service, in kiloNewton-metres.

I am not an expert in this field, but I thought that the term was
related to torque and not bendind.


A torque is a turning force that rotates something. A bending moment
is a turning force that bends something such as a beam or slab.

Torque and bending moment have the same units (force times distance)
but basically one is about rotating, therefore it is dynamic, and the
other is about bending, which is static. One rotates, the other
doesn't move, except to deflect.

Lintels have to be designed for both bending moment (along their
length) and twist (across their cross section). The twisting force is
often called a torque to differentiate it from longitudinal bending.
although there isn't any significant rotation unless the beam fails.

Without wishing to complicate it, there is also the issue of shear
forces.

"Bruce" wrote in message
news
Without wishing to complicate it, there is also the issue of shear
forces.

Why is shear force a complication? What do you think governs the design of
a beam or lintel?

"Bruce" wrote in message

...you really should get a structural engineer ...to calculate it for
you...

Well, at least something has finally sunk in

On Wed, 21 Apr 2010 19:35:42 +0100, "Roof" wrote:
"Bruce" wrote in message

...you really should get a structural engineer ...to calculate it for
you...

Well, at least something has finally sunk in


No thanks to you, ****wit.

"Bruce" wrote in message
...
On Wed, 21 Apr 2010 19:35:42 +0100, "Roof" wrote:
"Bruce" wrote in message

...you really should get a structural engineer ...to calculate it for
you...

Well, at least something has finally sunk in


No thanks to you, ****wit.


Not sure I follow you Bruce, me old mucker. Last time I contributed to this
newsgroup I told you, you shouldn't give out structural advice. I went on
to say that the best course of action was to engage the services of a
structural engineer. You've clearly listened to that advice, taken it on
board and you now gleefully pass it on as if it was your own. Kudos to you
for that.

On Wed, 21 Apr 2010 21:50:13 +0100, "Roof" wrote:

Not sure I follow you Bruce, me old mucker.


For the avoidance of doubt, **** off, and don't come back.

Meanwhile, congratulations on your restoration to my kill file.

"David WE Roberts" wrote in message
...
Just looking at lintels and Travis Perkis has a table
http://www.trademate.co.uk/ProductEx...tels_Table.pdf
which shows loadings on lintels in KNm.

So how do you translate the weight of a roof plus joists etc. into KNm?

You seem to be mis-reading the manufacturers data. They've provided a table
giving the safe uniform working load a lintel can take for a particular
lintel size and clear span. If the load isn't uniform then they've provided
the equivalent service moment. If you don't understand the figures then it
probably means you need someone to assist you.