Is there a good website to help calculate optimum radiator sizes for rooms?

Keith

On 2007-07-02 07:48:30 +0100, "Keith Dunbar" said:

Is there a good website to help calculate optimum radiator sizes for rooms?

Keith

No there isn't. They all get it wrong. Some hopelessly wrong. Even
worse are the sites and leaflets that take just the house type into
consideration and spit out a figure. I've tried loads of them and
found all to be of less use than an ashtray on a motorbike. Some even
mix metric units such as metres with deprecated imperial units such as
BTU/hr. Do this, and there is a high probability of calculation
errors.

To do the job properly, you need to calculate the heat losses from each
room first of all. This means taking each element of the construction
(walls, windows, ceiling, floor) amd calculating the heat loss through
it. That calculation is simple. You measure the area in square
metres and multiply by the temperature difference across it and a
factor called the U value. There are table of U values for different
materials. Then you add up the individual numbers. Of course,
there will be some cases where the heat loss is zero - between two
rooms at the same temperature. For heating calculations, one
normally uses -3 degrees for outside, 21 degrees for living rooms, 18
degrees for other downstairs rooms(kitchen, dining room), 22 degrees
for bathrooms and 16-18 degrees for bedrooms.

To these are added the heat loss through air changes. This is done
similarly, except that it is done on cubic metres, a volumetric
equivalent to U value and the number of air changes per hour. There
are tables of typical air change rates for different room types.

If you wanted to, all of this is very easily calculated using a pencil
and paper and calculator or a spreadsheet. Even the computer programs
require you to measure the room, which is most of the work. Some
programs help you a bit by subtracting window area from wall area for
example.

Once you have heat loss on this basis for each room, you can apply
certain loading factors - e.g. 10% for high ceilings, exposed positions
or small usage rate during the day.

Some of the radiator manufacturers have programs to calculate this lot
on their web site. I found the Myson one is the best but is currently
not there. If you drop me an email I can send it to you as an
attachment.

The objective of radiators is to compensate the heat loss and maintain
the temperature.

Now that you have heat loss figures in watts, you can choose the
radiators. The manufacturer data sheets publish nominal outputs for
the radiators in watts, but assuming that the heating water temperature
is 90 degrees. Conventional UK systems work with 82 degrees flow
temperature and 70 degrees return. The data sheet has a list of
correction factors based on mean water to air temperature (MWTA). This
is calculated as the average of the flow and return temperatures (76 in
this example) less the room temperature - so it would be 55 degrees in
a lounge for example. For this example, you should get a factor of
about 0.9 from the table and that should be multiplied by the radiator
output. Thus, if your room needed 900W of heat to maintain
temperature, you would need a 1000W radiator.

At this point you can make another design decision. If this is a new
system and you are going to use a condensing boiler, then you can run
it more efficiently at lower temperatures. For new designs, 70 and
50 degrees are the design figures. Of course this gives a lower MWTA
and you will have a smaller factor from the table - 0.6. The
implication of that is larger radiators or with more panels/fins.
You can trade that with cost saving on the fuel.

This second part of the calculation is not done by any of the
calculation programs or web sites AFAIK.

One final factor is that if you are planning to use radiator cabinets
or other impedimenta to radiator output, you need to factor by up to
30% for those - i.e. 1000W radiator drops to 700W.

Andy Hall wrote:
On 2007-07-02 07:48:30 +0100, "Keith Dunbar" said:

Is there a good website to help calculate optimum radiator sizes for
rooms?

To do the job properly, you need to calculate the heat losses from each
room first of all.

[snip]

Just wondering - are there any heating engineers out there, or has
anyone *ever* come across one, who account for even a fraction of the
parameters Andy listed? TBH most of those I've come across wouldn't
even use one of the dodgy calculators; they'd just eyeball the room and
say 'that needs a 3000 BTU'...

David

On Mon, 02 Jul 2007 07:54:06 GMT, Lobster
mused:

Andy Hall wrote:
On 2007-07-02 07:48:30 +0100, "Keith Dunbar" said:

Is there a good website to help calculate optimum radiator sizes for
rooms?

To do the job properly, you need to calculate the heat losses from each
room first of all.

[snip]

Just wondering - are there any heating engineers out there, or has
anyone *ever* come across one, who account for even a fraction of the
parameters Andy listed? TBH most of those I've come across wouldn't
even use one of the dodgy calculators; they'd just eyeball the room and
say 'that needs a 3000 BTU'...

My Dad, who is a long standing plumbing and heating engineer, has a
calculator whch is several discs of card with a pin in the middle. On
the discs are most of the parameters Andy mentioned, I use it for
sizing rads where I can and I know he's used it a lot over the years.
--
Regards,
Stuart.

On 2007-07-02 08:54:06 +0100, Lobster said:

Andy Hall wrote:
On 2007-07-02 07:48:30 +0100, "Keith Dunbar" said:

Is there a good website to help calculate optimum radiator sizes for rooms?

To do the job properly, you need to calculate the heat losses from each
room first of all.

[snip]

Just wondering - are there any heating engineers out there, or has
anyone *ever* come across one, who account for even a fraction of the
parameters Andy listed? TBH most of those I've come across wouldn't
even use one of the dodgy calculators; they'd just eyeball the room and
say 'that needs a 3000 BTU'...

David

Then I think that one should be seeking a heating engineer and not a
dodgy plumber.

Anybody still using BTUs (let alone the correct nomenclature of
BTU/hr) should be visiting the post office on Thursdays.

There are such things as Mears calculators for doing a ready reckoner approach

On one occasion I did seek quotes from professionals for a complete
heating installation to see whether DIY would be worth it or whether it
would make more sense to outsource the work.

The results were revealing.

There were the bodgers (jobbing plumbers) who would just walk round
eyeballing the room as you say, and there were heating engineers who
did the job properly and produced calculated results.

Of the bodgers, one produced a list which was massively wrong - some
rooms oversized by 100%, others under by the same amount. The other
overdesigned everything to the level of 300% and the radiators would
have almost covered the walls.

All three heating engineers produced properly designed systems. One
did calculations on a form provided by the HVCA, another used a Mears
calculator and the third pencil and paper. The calculated ones were
the most accurate and the Mears one was oversized - i.e. about 30%
sandbagging.

So my reaction to anybody not doing a proper job would be to show them
the door. It's the same principle as employing an electrician who
doesn't test his installation work or a gas fitter who doesn't do a
drop test.

"Lobster" wrote in message
...
Andy Hall wrote:
On 2007-07-02 07:48:30 +0100, "Keith Dunbar" said:

Is there a good website to help calculate optimum radiator sizes for
rooms?

To do the job properly, you need to calculate the heat losses from each
room first of all.

[snip]

Just wondering - are there any heating engineers out there, or has anyone
*ever* come across one, who account for even a fraction of the parameters
Andy listed? TBH most of those I've come across wouldn't even use one of
the dodgy calculators; they'd just eyeball the room and say 'that needs a
3000 BTU'...

I did the full calculation on my house when I put the heating in.. then
screwed it all up the following year by having cavity wall insulation
installed so I had rads that were 40% too big. It didn't matter much as I
have zone valves and stats in each room and don't rely on external
influences to maintain the temps I want.

"Andy Hall" wrote in message
...
snip

Anybody still using BTUs (let alone the correct nomenclature of
BTU/hr) should be visiting the post office on Thursdays.


Why, as long as they only use the deprecated units, and (as you said
in your pervious reply) don't mix imperial with metric, what is
wrong - surely if they know what they are doing the calculations will
come out the same?

On 2007-07-02 09:27:57 +0100, "dennis@home"
said:


"Lobster" wrote in message
...
Andy Hall wrote:
On 2007-07-02 07:48:30 +0100, "Keith Dunbar" said:

Is there a good website to help calculate optimum radiator sizes for
rooms?

To do the job properly, you need to calculate the heat losses from each
room first of all.

[snip]

Just wondering - are there any heating engineers out there, or has anyone
*ever* come across one, who account for even a fraction of the parameters
Andy listed? TBH most of those I've come across wouldn't even use one of
the dodgy calculators; they'd just eyeball the room and say 'that needs a
3000 BTU'...

I did the full calculation on my house when I put the heating in.. then
screwed it all up the following year by having cavity wall insulation
installed so I had rads that were 40% too big. It didn't matter much as I
have zone valves and stats in each room and don't rely on external
influences to maintain the temps I want.

At least it was in the right direction though.

If you have moved or are planning to move to a condensing boiler, this
is convenient as well.

The message
from Lobster contains these words:

To do the job properly, you need to calculate the heat losses from each
room first of all.

[snip]

Just wondering - are there any heating engineers out there, or has
anyone *ever* come across one, who account for even a fraction of the
parameters Andy listed? TBH most of those I've come across wouldn't
even use one of the dodgy calculators; they'd just eyeball the room and
say 'that needs a 3000 BTU'...

And in most cases they will get away with it. Only if it is undersize
will there be any comeback. Stick TRVs on all the radiators and the
'heating engineer' aka coyboy plumber doesn't even need to balance the
system, and if he has bothered to fit a room stat it usually won't cause
such a upset that the householder actually notices the fight between the
stat and the adjacent TRV.

Oh yes and don't use Imperial units in the presence of Andy. It is
likely to start him foaming at the mouth. :-)

--
Roger Chapman

"Andy Hall" wrote in message
...
On 2007-07-02 07:48:30 +0100, "Keith Dunbar" said:

Is there a good website to help calculate optimum radiator sizes for
rooms?

Keith

No there isn't. They all get it wrong. Some hopelessly wrong. Even
worse are the sites and leaflets that take just the house type into
consideration and spit out a figure. I've tried loads of them and found
all to be of less use than an ashtray on a motorbike. Some even mix
metric units such as metres with deprecated imperial units such as BTU/hr.
Do this, and there is a high probability of calculation errors.

To do the job properly, you need to calculate the heat losses from each
room first of all. This means taking each element of the construction
(walls, windows, ceiling, floor) amd calculating the heat loss through it.
That calculation is simple. You measure the area in square metres and
multiply by the temperature difference across it and a factor called the U
value. There are table of U values for different materials. Then you
add up the individual numbers. Of course, there will be some cases
where the heat loss is zero - between two rooms at the same temperature.
For heating calculations, one normally uses -3 degrees for outside, 21
degrees for living rooms, 18 degrees for other downstairs rooms(kitchen,
dining room), 22 degrees for bathrooms and 16-18 degrees for bedrooms.

To these are added the heat loss through air changes. This is done
similarly, except that it is done on cubic metres, a volumetric equivalent
to U value and the number of air changes per hour. There are tables of
typical air change rates for different room types.

If you wanted to, all of this is very easily calculated using a pencil and
paper and calculator or a spreadsheet. Even the computer programs
require you to measure the room, which is most of the work. Some programs
help you a bit by subtracting window area from wall area for example.

Once you have heat loss on this basis for each room, you can apply certain
loading factors - e.g. 10% for high ceilings, exposed positions or small
usage rate during the day.

Some of the radiator manufacturers have programs to calculate this lot on
their web site. I found the Myson one is the best but is currently not
there. If you drop me an email I can send it to you as an attachment.

Andy - tried to e-mail you as invited but bounced.


The objective of radiators is to compensate the heat loss and maintain the
temperature.

Now that you have heat loss figures in watts, you can choose the
radiators. The manufacturer data sheets publish nominal outputs for the
radiators in watts, but assuming that the heating water temperature is 90
degrees. Conventional UK systems work with 82 degrees flow temperature
and 70 degrees return. The data sheet has a list of correction factors
based on mean water to air temperature (MWTA). This is calculated as the
average of the flow and return temperatures (76 in this example) less the
room temperature - so it would be 55 degrees in a lounge for example.
For this example, you should get a factor of about 0.9 from the table and
that should be multiplied by the radiator output. Thus, if your room
needed 900W of heat to maintain temperature, you would need a 1000W
radiator.

At this point you can make another design decision. If this is a new
system and you are going to use a condensing boiler, then you can run it
more efficiently at lower temperatures. For new designs, 70 and 50
degrees are the design figures. Of course this gives a lower MWTA and you
will have a smaller factor from the table - 0.6. The implication of
that is larger radiators or with more panels/fins. You can trade that
with cost saving on the fuel.

This second part of the calculation is not done by any of the calculation
programs or web sites AFAIK.

One final factor is that if you are planning to use radiator cabinets or
other impedimenta to radiator output, you need to factor by up to 30% for
those - i.e. 1000W radiator drops to 700W.

On 2007-07-02 09:41:13 +0100, ":Jerry:" said:


"Andy Hall" wrote in message
...
snip

Anybody still using BTUs (let alone the correct nomenclature of
BTU/hr) should be visiting the post office on Thursdays.


Why, as long as they only use the deprecated units, and (as you said
in your pervious reply) don't mix imperial with metric, what is
wrong - surely if they know what they are doing the calculations will
come out the same?

The chances of error are high because the numbers are odd values rather
than 10s and some manufacturers are publishing data in SI units only.

In any case, it's long past time that feet, inches and all the rest of
it were dumped for the consistent and superior metric system.

I also think that there should be ten days to a week and ten months to
a year, but the Sun won't co-operate with that. In the meantime,
we'll have to make do with the Revolutionary Calendar.

On 2007-07-02 10:50:31 +0100, "Keith Dunbar" said:

Andy - tried to e-mail you as invited but bounced.


On its way

Andy Hall wrote:
On 2007-07-02 08:54:06 +0100, Lobster
said:

Just wondering - are there any heating engineers out there, or has
anyone *ever* come across one, who account for even a fraction of the
parameters Andy listed? TBH most of those I've come across wouldn't
even use one of the dodgy calculators; they'd just eyeball the room
and say 'that needs a 3000 BTU'...

Then I think that one should be seeking a heating engineer and not a
dodgy plumber.

Anybody still using BTUs (let alone the correct nomenclature of
BTU/hr) should be visiting the post office on Thursdays.

I still maintain that those BTU's were a lot warmer than these new fangled
Calories - and less fattening. I've put on weight since they came out so it
must be true.


--
Dave
The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

"Andy Hall" wrote in message
...
On 2007-07-02 09:41:13 +0100, ":Jerry:"
said:


"Andy Hall" wrote in message
...
snip

Anybody still using BTUs (let alone the correct nomenclature of
BTU/hr) should be visiting the post office on Thursdays.


Why, as long as they only use the deprecated units, and (as you
said
in your pervious reply) don't mix imperial with metric, what is
wrong - surely if they know what they are doing the calculations
will
come out the same?

The chances of error are high because the numbers are odd values
rather than 10s and some manufacturers are publishing data in SI
units only.

Not so far out that it will matter, in this subject, and as long as
any error is positive rather than of a negative influence,


In any case, it's long past time that feet, inches and all the rest
of it were dumped for the consistent and superior metric system.
snip

I agree, but unless you are going to enter into brain wiping and
thought control it will never happen.

On 2007-07-02 11:28:44 +0100, ":Jerry:" said:


"Andy Hall" wrote in message
...
On 2007-07-02 09:41:13 +0100, ":Jerry:"
said:


"Andy Hall" wrote in message
...
snip

Anybody still using BTUs (let alone the correct nomenclature of
BTU/hr) should be visiting the post office on Thursdays.


Why, as long as they only use the deprecated units, and (as you
said
in your pervious reply) don't mix imperial with metric, what is
wrong - surely if they know what they are doing the calculations
will
come out the same?

The chances of error are high because the numbers are odd values
rather than 10s and some manufacturers are publishing data in SI
units only.

Not so far out that it will matter, in this subject, and as long as
any error is positive rather than of a negative influence,

The trouble is that at least one conversion is about a factor of 3
(ignoring decimal places) (BTU/hr - W)

That may go unnoticed but create a real problem.

The message
from "The Medway Handyman" contains
these words:

I still maintain that those BTU's were a lot warmer than these new fangled
Calories - and less fattening. I've put on weight since they came out
so it
must be true.

I don't think you understand ISO metric. Calories have been consigned to
the dustbin of history along with centimetres, dynes, ergs, etc.

--
Roger Chapman

Roger wrote:
The message
from "The Medway Handyman" contains
these words:

I still maintain that those BTU's were a lot warmer than these new
fangled Calories - and less fattening. I've put on weight since
they came out
so it
must be true.

I don't think you understand ISO metric. Calories have been consigned
to the dustbin of history along with centimetres, dynes, ergs, etc.

Arrrgh!! Now what are we supposed to use? I've only just mastered
centimetres!


--
Dave
The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

On 2007-07-02 12:17:53 +0100, "The Medway Handyman"
said:

Roger wrote:
The message
from "The Medway Handyman" contains
these words:

I still maintain that those BTU's were a lot warmer than these new
fangled Calories - and less fattening. I've put on weight since
they came out
so it
must be true.

I don't think you understand ISO metric. Calories have been consigned
to the dustbin of history along with centimetres, dynes, ergs, etc.

Arrrgh!! Now what are we supposed to use? I've only just mastered
centimetres!

Building Industry. Millimetres.

However the sizes are ridiculous. 2440 x 1220 for a sheet of ply, yet
bizarrely it is 18mm thick

"Andy Hall" wrote in message
...
On 2007-07-02 12:17:53 +0100, "The Medway Handyman"
said:

Roger wrote:
The message
from "The Medway Handyman"
contains
these words:

I still maintain that those BTU's were a lot warmer than these
new
fangled Calories - and less fattening. I've put on weight since
they came out
so it
must be true.

I don't think you understand ISO metric. Calories have been
consigned
to the dustbin of history along with centimetres, dynes, ergs,
etc.

Arrrgh!! Now what are we supposed to use? I've only just mastered
centimetres!

Building Industry. Millimetres.

However the sizes are ridiculous. 2440 x 1220 for a sheet of ply,
yet bizarrely it is 18mm thick


Err??????!!!!!

What else should it be, would it really be better to quote 2m 440mm x
1m 220mm, that (to me) is as bad as mixing centimetres and
millimetres!

On 2007-07-02 13:01:06 +0100, said:

On 2 Jul,
Andy Hall wrote:

However the sizes are ridiculous. 2440 x 1220 for a sheet of ply, yet
bizarrely it is 18mm thick

ITYM 8' x 4' x 3/4"

I would do except that it really is 18mm and not the deprecated unit.

On 2007-07-02 12:57:13 +0100, ":Jerry:" said:


"Andy Hall" wrote in message

Building Industry. Millimetres.

However the sizes are ridiculous. 2440 x 1220 for a sheet of ply,
yet bizarrely it is 18mm thick


Err??????!!!!!

What else should it be, would it really be better to quote 2m 440mm x
1m 220mm, that (to me) is as bad as mixing centimetres and
millimetres!

I meant as opposed to 2000mm by 1000mm or 1500mm.

"Andy Hall" wrote in message
...
On 2007-07-02 12:57:13 +0100, ":Jerry:"
said:


"Andy Hall" wrote in message

Building Industry. Millimetres.

However the sizes are ridiculous. 2440 x 1220 for a sheet of
ply,
yet bizarrely it is 18mm thick


Err??????!!!!!

What else should it be, would it really be better to quote 2m 440mm
x
1m 220mm, that (to me) is as bad as mixing centimetres and
millimetres!

I meant as opposed to 2000mm by 1000mm or 1500mm.


That's even more daft!

In an earlier contribution to this discussion,
Andy Hall wrote:


The trouble is that at least one conversion is about a factor of 3
(ignoring decimal places) (BTU/hr - W)

That may go unnoticed but create a real problem.

But if you work throughout in one consistent set of units, there's no
conversion to do!
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

In an earlier contribution to this discussion,
Andy Hall wrote:


Arrrgh!! Now what are we supposed to use? I've only just mastered
centimetres!

Building Industry. Millimetres.


Have you tried buying concrete in cubic millimetres? For most jobs, you'd
need rather a lot of them!
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

On 2007-07-02 13:42:02 +0100, ":Jerry:" said:


"Andy Hall" wrote in message
...
On 2007-07-02 12:57:13 +0100, ":Jerry:"
said:


"Andy Hall" wrote in message

Building Industry. Millimetres.

However the sizes are ridiculous. 2440 x 1220 for a sheet of
ply,
yet bizarrely it is 18mm thick


Err??????!!!!!

What else should it be, would it really be better to quote 2m 440mm
x
1m 220mm, that (to me) is as bad as mixing centimetres and
millimetres!

I meant as opposed to 2000mm by 1000mm or 1500mm.


That's even more daft!

The only reason is because the sizes have been taken from deprecated
imperial units. It's the same as pots of jam weighing 464g rather
than 500g or pints of beer vs 500ml

On 2007-07-02 13:59:12 +0100, "Roger Mills" said:

In an earlier contribution to this discussion,
Andy Hall wrote:


The trouble is that at least one conversion is about a factor of 3
(ignoring decimal places) (BTU/hr - W)

That may go unnoticed but create a real problem.

But if you work throughout in one consistent set of units, there's no
conversion to do!

Assuming that you can get all of the data in one set of units. There
are manufacturers who have dumped BTUs/hr and so a conversion is
implied if you wanted to make life hard and work in those units.

On 2007-07-02 14:00:57 +0100, "Roger Mills" said:

In an earlier contribution to this discussion,
Andy Hall wrote:


Arrrgh!! Now what are we supposed to use? I've only just mastered
centimetres!

Building Industry. Millimetres.


Have you tried buying concrete in cubic millimetres? For most jobs, you'd
need rather a lot of them!

Then I should get a better discount.

The message
from Andy Hall contains these words:

I meant as opposed to 2000mm by 1000mm or 1500mm.

Which is the way plasterboard has gone, which really ****s up any work
involving existing framework built to Imperial standards. It wouldn't be
so bad had they gone for a slight increase in size rather than a
decrease but no, they had to downsize. Presumably selling more waste was
an integral part of their marketing strategy.

--
Roger Chapman

On 2007-07-02 14:29:08 +0100, Roger said:

The message
from Andy Hall contains these words:

I meant as opposed to 2000mm by 1000mm or 1500mm.

Which is the way plasterboard has gone, which really ****s up any work
involving existing framework built to Imperial standards. It wouldn't be
so bad had they gone for a slight increase in size rather than a
decrease but no, they had to downsize. Presumably selling more waste was
an integral part of their marketing strategy.

I can see the point, although 2000 x 1000 makes for much easier handling.

In an earlier contribution to this discussion,
Andy Hall wrote:



The only reason is because the sizes have been taken from deprecated
imperial units. It's the same as pots of jam weighing 464g rather
than 500g or pints of beer vs 500ml

Unfortunately. you can't buy paint in 568ml tins. There are a lot of jobs
for which half a litre ain't enough, whereas a pint would have been fine.
Similarly with litres and quarts.

If only the powers that be would follow the age-old adage "If it ain't
broke, don't fix it!"

You seem keen to dismiss out of hand anything which is "deprecated" - which
simply means disapproved of (by whom?) or non-preferred.

But there are a hell of a lot of people about who still think in Imperial
units and have an instinctive feel for what 7'6" looks like, or how heavy
half a cwt feels.

Personally, I don't particularly care - being reasonably multi-lingual,
having trained in Physics in the 60's (using CGS rather than MKS or S.I.
units!), and having spent the early part of my career predicting the
accelerative performance of motor cars in fps units.

If people want to design their heating systems using British Thermal Units
and degrees Fahrenheit, good luck to them!
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

Roger Mills wrote:
In an earlier contribution to this discussion,
Andy Hall wrote:



The only reason is because the sizes have been taken from deprecated
imperial units. It's the same as pots of jam weighing 464g rather
than 500g or pints of beer vs 500ml

Unfortunately. you can't buy paint in 568ml tins. There are a lot of
jobs for which half a litre ain't enough, whereas a pint would have
been fine. Similarly with litres and quarts.

I think that's deliberate - they know how much paint an average room needs &
sell it in tins deliberately too small.

Conspiracy theory followers - to me!


--
Dave
The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257

On 2007-07-02 15:51:23 +0100, "Roger Mills" said:

In an earlier contribution to this discussion,
Andy Hall wrote:



The only reason is because the sizes have been taken from deprecated
imperial units. It's the same as pots of jam weighing 464g rather
than 500g or pints of beer vs 500ml

Unfortunately. you can't buy paint in 568ml tins. There are a lot of jobs
for which half a litre ain't enough, whereas a pint would have been fine.
Similarly with litres and quarts.

Hmm.....


If only the powers that be would follow the age-old adage "If it ain't
broke, don't fix it!"

But it is broken.


You seem keen to dismiss out of hand anything which is "deprecated" - which
simply means disapproved of (by whom?) or non-preferred.

It's hard to justify a system of counting and measuring that involves
counting in 12s, 16s and so on. What kind of nonsense is that?



But there are a hell of a lot of people about who still think in Imperial
units and have an instinctive feel for what 7'6" looks like, or how heavy
half a cwt feels.

That will change in the next 10-20 years as they pop their clogs.


Personally, I don't particularly care - being reasonably multi-lingual,
having trained in Physics in the 60's (using CGS rather than MKS or S.I.
units!), and having spent the early part of my career predicting the
accelerative performance of motor cars in fps units.

If people want to design their heating systems using British Thermal Units
and degrees Fahrenheit, good luck to them!

One only has to look at what happens in countries still using it. In
the U.S. you end up with special calculators to do fractions. A
complete mess.

"Andy Hall" wrote in message
...
On 2007-07-02 13:42:02 +0100, ":Jerry:"
said:


"Andy Hall" wrote in message
...
On 2007-07-02 12:57:13 +0100, ":Jerry:"
said:


"Andy Hall" wrote in message

Building Industry. Millimetres.

However the sizes are ridiculous. 2440 x 1220 for a sheet of
ply,
yet bizarrely it is 18mm thick


Err??????!!!!!

What else should it be, would it really be better to quote 2m
440mm
x
1m 220mm, that (to me) is as bad as mixing centimetres and
millimetres!

I meant as opposed to 2000mm by 1000mm or 1500mm.


That's even more daft!

The only reason is because the sizes have been taken from deprecated
imperial units. It's the same as pots of jam weighing 464g rather
than 500g or pints of beer vs 500ml


No the size is chosen as a standard for many reasons, mostly
usability, handling, storage and packaging/transportation.

The message
from Andy Hall contains these words:

It's hard to justify a system of counting and measuring that involves
counting in 12s, 16s and so on. What kind of nonsense is that?

No, the real nonsense is that decimal took hold when the ignorami
started counting on their fingers. Base 12 makes for a more sensible
system. I have a vague idea that base 16 plays some small part in
computers but 16 is a less versatile number than 12 being divisible only
by some powers of 2. (2, 4 and 8). 12 is divisible by 2, 3, 4 and 6
while 10 only by 2 and 5.

The inch, foot, yard and even fathom have the additional advantage of
being practical units, approximating to width of thumb, length of foot,
length of stride and out of depth.

--
Roger Chapman

On 2007-07-02 17:59:36 +0100, Roger said:

The message
from Andy Hall contains these words:

It's hard to justify a system of counting and measuring that involves
counting in 12s, 16s and so on. What kind of nonsense is that?

No, the real nonsense is that decimal took hold when the ignorami
started counting on their fingers. Base 12 makes for a more sensible
system. I have a vague idea that base 16 plays some small part in
computers but 16 is a less versatile number than 12 being divisible only
by some powers of 2. (2, 4 and 8). 12 is divisible by 2, 3, 4 and 6
while 10 only by 2 and 5.

This would all hold some water if one base were used. Having three
makes no real sense.



The inch, foot, yard and even fathom have the additional advantage of
being practical units, approximating to width of thumb, length of foot,
length of stride and out of depth.

Possibly, but we don't use cubits any more either.

On 2007-07-02 16:50:04 +0100, ":Jerry:" said:


"Andy Hall" wrote in message

The only reason is because the sizes have been taken from deprecated
imperial units. It's the same as pots of jam weighing 464g rather
than 500g or pints of beer vs 500ml


No the size is chosen as a standard for many reasons, mostly
usability, handling, storage and packaging/transportation.

Pull the other one.

In an earlier contribution to this discussion,
Andy Hall wrote:


It's hard to justify a system of counting and measuring that involves
counting in 12s, 16s and so on. What kind of nonsense is that?


My computer seems to manage to count in 2's and 16's ok! g

Besides which, most things around the house can be measured in inches and
decimal inches - which gives more manageable numbers than millimetres.


But there are a hell of a lot of people about who still think in
Imperial units and have an instinctive feel for what 7'6" looks
like, or how heavy half a cwt feels.

That will change in the next 10-20 years as they pop their clogs.


God help us when the world is run by the current generation of youngsters
who can't even add 2 and 2 together without using a calculator - and have no
instictive feel whatsoever for what the result of a calculation should be,
making it impossible for them to do a sanity check on calculator/computer
output. The units are a secondary consideration!
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

On Mon, 02 Jul 2007 18:53:57 +0100, Owain
wrote:

Andy Hall wrote:
Building Industry. Millimetres.
However the sizes are ridiculous. 2440 x 1220 for a sheet of ply, yet
bizarrely it is 18mm thick

Would that be 6' x 3' x 3/4" by any chance?

If you went into my local timber merchant/sawmill and asked for 3m of
100mm x 50mm you'd be laughed out of the place.

--
Frank Erskine

On 2007-07-02 18:54:58 +0100, "Roger Mills" said:

In an earlier contribution to this discussion,
Andy Hall wrote:


It's hard to justify a system of counting and measuring that involves
counting in 12s, 16s and so on. What kind of nonsense is that?


My computer seems to manage to count in 2's and 16's ok! g

Besides which, most things around the house can be measured in inches and
decimal inches - which gives more manageable numbers than millimetres.

Oh nonsense. It's much easier to deal with whole numbers




But there are a hell of a lot of people about who still think in
Imperial units and have an instinctive feel for what 7'6" looks
like, or how heavy half a cwt feels.

That will change in the next 10-20 years as they pop their clogs.


God help us when the world is run by the current generation of youngsters
who can't even add 2 and 2 together without using a calculator - and have no
instictive feel whatsoever for what the result of a calculation should be,
making it impossible for them to do a sanity check on calculator/computer
output. The units are a secondary consideration!

There I would certainly agree

On 2007-07-02 20:27:25 +0100, Frank Erskine
said:

On Mon, 02 Jul 2007 18:53:57 +0100, Owain
wrote:

Andy Hall wrote:
Building Industry. Millimetres.
However the sizes are ridiculous. 2440 x 1220 for a sheet of ply, yet
bizarrely it is 18mm thick

Would that be 6' x 3' x 3/4" by any chance?

If you went into my local timber merchant/sawmill and asked for 3m of
100mm x 50mm you'd be laughed out of the place.

Curious.

Not here. They do everything in metric, and that's sawmills and even
questionable places like Travis Perkins.

Is it possible that Napoleon needs to march a bit further north?
Either that or the Duke of Wellington, native of these parts,
distracted him?