U Value whole window method of calculation?

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U Value whole window method of calculation?

Postby Meccarroll » Wed Nov 27, 2013 7:46 am

Hi to all.

I have started this topic with the hope that any members with mathematical skills and spreadsheet knowledge can get together with me to devise a method of whole window U Value calculation that conforms to ISO 10077.

The reason: if you make and install windows in most properties ( ie those not in conservation areas or historical buildings) you are required in most cases to perform a whole window U value calculation for the installed window.

Unless the replacement window/s are one off bespoke, they will also one have to have a CE Mark associated with them. Part of the CE Mark requirement is for the window to have a whole window U Value calculation.

Has any member of this forum performed the calculation needed for the Whole window U Value?

Calculating U values for single elements such as centre pane of glass is not too difficult but combining all the components to form a whole window combined U value to ISO 10077 is a bit tricky.

Has anyone done this.

Mark

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Re: U Value whole window method of calculation?

Postby jfc » Wed Nov 27, 2013 8:11 am

A couple of companies have a program you can input your data and get the result . Have a look at mighton products for one example .

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Re: U Value whole window method of calculation?

Postby Meccarroll » Wed Nov 27, 2013 8:27 am

jfc wrote:A couple of companies have a program you can input your data and get the result . Have a look at mighton products for one example .


I have just taken a look at Mighton site and do not see a programme for calculating the whole window U Value. Even if Mighton did make a calculator public (which is doubtful as most companies make money from them) it could be withdrawn at ant time leaving you stuck. There are a few sites such as the British wood working federation site and Certas that have the ability to perform the calculation for you but at a price! It can be in the £....! (Hundreds) if you use these companies and that's very prohibitive for most of us.

I think it's worth looking into to see if members of this site can collectively share their knowledge and skills to devise a method we can all share freely.

Mark

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Re: U Value whole window method of calculation?

Postby Meccarroll » Wed Nov 27, 2013 8:33 am

If we develop a calculator open to all woodworkers that would help hundreds if not thousands of us. All the companies that I know of that have whole window U Value calculators only perform the calculation for a pricy fee.

Anyone so far attempted the calculation using the methods in ISO 10077?

Mark

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Re: U Value whole window method of calculation?

Postby jfc » Wed Nov 27, 2013 8:48 am

Mightons is free to use if you order the products to make the window from them . You have to order them from somewhere so I think that's pretty fair of them seeing as they have spent many thousands getting the software available .
Having said that if you are smart enough to work out the calculations and explain it so the rest of us can understand then go for it .
I will dig out some of my old calculations later for you to look through :shock:
I think youre on to a good idea but I don't think its going to be easy .

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Re: U Value whole window method of calculation?

Postby Meccarroll » Wed Nov 27, 2013 9:38 am

jfc wrote:Mightons is free to use if you order the products to make the window from them . You have to order them from somewhere so I think that's pretty fair of them seeing as they have spent many thousands getting the software available .
Having said that if you are smart enough to work out the calculations and explain it so the rest of us can understand then go for it .
I will dig out some of my old calculations later for you to look through :shock:
I think youre on to a good idea but I don't think its going to be easy .


I have used Mighton before also reddiseal and have obtained information on the products they supply such as sash weights, sash springs, friction hinges, espag locks etc. but so far as I am aware they don't supply complete window kits anymore which would have Uvalue calculation. I will check further to see if they have a programme available to calculate the whole window U value.

A basic starting point is the R value. The thermal resistance of a component of the window.

R is the thermal resistance for a material. You need to know the k value and thickness of material to calculate the R value.

So the basics are to find the conductivity (k value) of each component of the window. Measure the component in m, and calculate the R value of the component.

An example calculation :

Material k value for softwood is 0.13

Timber section size of window component say .
100mm in meters this would be written 0.1

The R value is calculated by: R= 0.1/0.13

R= 0.769

Mark

R is m squared degC/W

k is W/mdegC

Can anyone take this further? Or do I need to be corrected so far?

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Re: U Value whole window method of calculation?

Postby thatsnotafestool » Wed Nov 27, 2013 10:08 am

Broadly speaking you are going in the right direction. You need to be able to measure the heatloss through the wood elements of the window as well as the glass as you've already indicated. A pedantic approach would also take into account the heatloss through glazing bars. Obviously factor in whether hard or softwood. But :

a) what do you do if you get a jobsworth building control bloke who is fixated on heatloss through windows (and there will be at least one somewhere). Then he's going to want to pore over your spreadsheet or dismiss it out of hand.

b) it's already been done. I've got a PC program somewhere or other IIRC that is sitting on a geriatric laptop that might/might not still be functional.

c) IMO they have taken this whole business of heatloss through windows to ludicrous extremes. Especially when you are talking about older houses and replacement windows. Where the heatloss through the walls etc is probably 1000% more then that lost through small windows. When i looked at the last round of changes I reckoned I would lose more heat in a days farting then any microscopic improvement brought in by the changes.
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Re: U Value whole window method of calculation?

Postby Meccarroll » Wed Nov 27, 2013 11:01 am

thatsnotafestool wrote:Broadly speaking you are going in the right direction. You need to be able to measure the heatloss through the wood elements of the window as well as the glass as you've already indicated. A pedantic approach would also take into account the heatloss through glazing bars. Obviously factor in whether hard or softwood. But :

a) what do you do if you get a jobsworth building control bloke who is fixated on heatloss through windows (and there will be at least one somewhere). Then he's going to want to pore over your spreadsheet or dismiss it out of hand.

b) it's already been done. I've got a PC program somewhere or other IIRC that is sitting on a geriatric laptop that might/might not still be functional.

c) IMO they have taken this whole business of heatloss through windows to ludicrous extremes. Especially when you are talking about older houses and replacement windows. Where the heatloss through the walls etc is probably 1000% more then that lost through small windows. When i looked at the last round of changes I reckoned I would lose more heat in a days farting then any microscopic improvement brought in by the changes.


Whether or not we agree with the changes, they DO affect us. If you manufacture whole windows and fit them 'you' have to CE mark them and part of that marking system involves having a window energy rating U Value for the whole window, you can comply by calculating to ISO 10077. Building control also require a whole window U Value rating (some exceptions exist) and calculations to ISO 10077 should satisfy this. If you want to stay on the right side of the law you need to comply.

It's probably better looking at ways of complying now rather than once you have fitted the windows and find you have to take them out because they don't comply. Using IGU units with a centre pane value of 1.6 will not meet the requirements in most cases, the new regulations require a 'whole window' U Value of 1.6 or better. ISO 10077 has methods for achieving this calculation it is just reading and understanding the method requirements in the first case then putting these onto a spreadsheet for calculation.

If you have already done this before you are well ahead of me and could help by providing what you have done so far.

Mark

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Re: U Value whole window method of calculation?

Postby jfc » Wed Nov 27, 2013 11:08 am

Saint gobain also have a free calculator but mine seems to have set its self to demo mode . Ive also just ordered some parts from Mighton and spoke to them about the U-Value calculator . You need to call them up and register to use it .
We went through this a few years ago on this site and I seem to remember the calculations alone where not good enough to get the windows passed . The larger firms that supply a calculator have the calculations backed up by tests done in a controlled environment .
I still like the idea of what you are thinking though .

P.S Just had an email back from Caluwin but you will need to contact them for a password and register . Its free ...... I think :lol:

There is a new version of caluwin available.

You can download it at: http://www.sommer-informatik.de/010196/ ... aluwin.zip

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Re: U Value whole window method of calculation?

Postby Meccarroll » Wed Nov 27, 2013 12:47 pm

jfc wrote:Saint gobain also have a free calculator but mine seems to have set its self to demo mode . Ive also just ordered some parts from Mighton and spoke to them about the U-Value calculator . You need to call them up and register to use it .
We went through this a few years ago on this site and I seem to remember the calculations alone where not good enough to get the windows passed . The larger firms that supply a calculator have the calculations backed up by tests done in a controlled environment .
I still like the idea of what you are thinking though .

P.S Just had an email back from Caluwin but you will need to contact them for a password and register . Its free ...... I think :lol:

There is a new version of caluwin available.

You can download it at: http://www.sommer-informatik.de/010196/ ... aluwin.zip" onclick="window.open(this.href);return false;


Hi I am checking with Saint-Gobain (Swisspaer) who provide the 'Cauluwin' software, to see if it will perform a whole window U Value using Saint-Gobain components and custom window sections manufactured by independent manufacturers such as small businesses. I have made a check with Mighton and the answer they gave in relation to them having software to calculate a whole window was they have none. Mighton can help with the calculation of sash weights etc but unfortunately not Whole window U value calculations.

ISO 10077 is a document setting out methods for achieving calculations that do satisfy CE regulations for U value calculations. It is published by British Standards and also known as BS EN 10077-1 and BS EN 1007-2. These contain methods of calculating a whole U Value. It is simply a matter of correctly using the methods and performing the calculations.

Take a look at these: ftp://law.resource.org/et/ibr/et.iso.10077.1.2006.pdf

And as they state they are identical to the ISO 10077-1 2006 (version)

ISO is an intentional standard and ISO 10077-1 and should be the same no matter weather is is published in the UK by British Standards or another countries nationally recognised standards body.

I think that working on a spreadsheet based on ISO 10077 could be the way forward. If correctly done it will satisfy CE legislation and very likely Building Control too.

Take a look at this and see what you think: ftp://law.resource.org/et/ibr/et.iso.10077.1.2006.pdf

Mark

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Re: U Value whole window method of calculation?

Postby Meccarroll » Wed Nov 27, 2013 12:59 pm

Meccarroll wrote:
jfc wrote:Saint gobain also have a free calculator but mine seems to have set its self to demo mode . Ive also just ordered some parts from Mighton and spoke to them about the U-Value calculator . You need to call them up and register to use it .
We went through this a few years ago on this site and I seem to remember the calculations alone where not good enough to get the windows passed . The larger firms that supply a calculator have the calculations backed up by tests done in a controlled environment .
I still like the idea of what you are thinking though .

P.S Just had an email back from Caluwin but you will need to contact them for a password and register . Its free ...... I think :lol:

There is a new version of caluwin available.

You can download it at: http://www.sommer-informatik.de/010196/ ... aluwin.zip" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;


Hi I am checking with Saint-Gobain (Swisspaer) who provide the 'Cauluwin' software, to see if it will perform a whole window U Value using Saint-Gobain components and custom window sections manufactured by independent manufacturers such as small businesses. I have made a check with Mighton and the answer they gave in relation to them having software to calculate a whole window was they have none. Mighton can help with the calculation of sash weights etc but unfortunately not Whole window U value calculations.

ISO 10077 is a document setting out methods for achieving calculations that do satisfy CE regulations for U value calculations. It is published by British Standards and also known as BS EN 10077-1 and BS EN 1007-2. These contain methods of calculating a whole U Value. It is simply a matter of correctly using the methods and performing the calculations.

Take a look at these: ftp://law.resource.org/et/ibr/et.iso.10077.1.2006.pdf" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

And as they state they are identical to the ISO 10077-1 2006 (version)

ISO is an intentional standard and ISO 10077-1 and should be the same no matter weather is is published in the UK by British Standards or another countries nationally recognised standards body.

I think that working on a spreadsheet based on ISO 10077 could be the way forward. If correctly done it will satisfy CE legislation and very likely Building Control too.

Take a look at this and see what you think: ftp://law.resource.org/et/ibr/et.iso.10077.1.2006.pdf" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

Mark



This link might work better: https://ia601606.us.archive.org/15/item ... 1.2006.pdf" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

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Re: U Value whole window method of calculation?

Postby jfc » Wed Nov 27, 2013 1:27 pm

Mighton do have a system in place as ive used it many times over the last few years . You need to speak to Sam in sales at Mighton as he is the eco man . Nick may also pop in here to give you more information on it .
I use the Mighton system for my sash windows and the Caluwin system for my casements and doors . Never had either questioned by building control .
Are you just wanting a way to get your windows and doors passed or are you looking to work out how to do the calculations ? If its the former then both methods above work and are very easy to use .

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Re: U Value whole window method of calculation?

Postby Meccarroll » Wed Nov 27, 2013 3:04 pm

jfc wrote:Mighton do have a system in place as ive used it many times over the last few years . You need to speak to Sam in sales at Mighton as he is the eco man . Nick may also pop in here to give you more information on it .
I use the Mighton system for my sash windows and the Caluwin system for my casements and doors . Never had either questioned by building control .
Are you just wanting a way to get your windows and doors passed or are you looking to work out how to do the calculations ? If its the former then both methods above work and are very easy to use .


I have just telephoned Mighton again and Nick is going to clarify the situation. I'll let you know what he tells me.

The distributors of Caluwin still have to get back to me as yet but I'll also keep you informed about hat they have to say.

Do you have any screen shots of the Caluwin software showing the final resultant calculation. I have looked at some technical reference to calculations performed on wooden windows but they tend to be generalised and not specific to a specific window design with section sizes.

I have a Mac computer and at the moment and can't load the software as Caluwin is only downloading in windows versions, so can't see if it would do a whole window U Value calculation on my Mac system.

The situation, the legal need, regarding CE marking only came into place this summer so a lot/most small independent manufacturers are not aware of the implications yet, and what has been accepted so far may not continue. Building Control have always taken a sympathetic view when I have worked on older properties which present complication adhering to Building Regulations and have always been very helpful in resolving any difficulties.

I'd like to work on an accepted method on spreadsheet that will produce compliance with current legislation without relying on others to do the calculation for you.

At the present time I have the ability to calculate U values for building elements such as walls floors etc and can simulate these in spreadsheet form, but the methodology for Whole window and door calculations is a bit of a mysterious grey area. Major organisations seem to have the information and tools to do the calculations but charge a nice fee for doing a calculation for you. It's only a calculation, and once a spreadsheet is produced, away you go!

If a calculator can be produced that we can all use freely, it will be very helpful to us all.

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Re: U Value whole window method of calculation?

Postby thatsnotafestool » Wed Nov 27, 2013 3:22 pm

Just taking another look at your OP, you need to take into account all three dimensions of the timber used in the frame etc IIRC.
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Re: U Value whole window method of calculation?

Postby Meccarroll » Wed Nov 27, 2013 3:33 pm

thatsnotafestool wrote:Just taking another look at your OP, you need to take into account all three dimensions of the timber used in the frame etc IIRC.


Thank's for your input but can you explain further?

Mark

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Re: U Value whole window method of calculation?

Postby thatsnotafestool » Wed Nov 27, 2013 4:11 pm

Meccarroll wrote:
thatsnotafestool wrote:Just taking another look at your OP, you need to take into account all three dimensions of the timber used in the frame etc IIRC.


Thank's for your input but can you explain further?

Mark


My bad...it is the area of the frame you need ...you can ignore the thickness of the frame. http://www.youtube.com/watch?v=n5rc5T9ea1U
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Re: U Value whole window method of calculation?

Postby Meccarroll » Wed Nov 27, 2013 5:08 pm

jfc wrote:Mighton do have a system in place as ive used it many times over the last few years . You need to speak to Sam in sales at Mighton as he is the eco man . Nick may also pop in here to give you more information on it .
I use the Mighton system for my sash windows and the Caluwin system for my casements and doors . Never had either questioned by building control .
Are you just wanting a way to get your windows and doors passed or are you looking to work out how to do the calculations ? If its the former then both methods above work and are very easy to use .


After talking to Nick at Mighton products he said:

Mighton do not have a calculator for customer designed systems for whole window U value calculations but they can supply a drawing to a design they have had tested and if you manufacture to that design using Mighton parts they can issue you with a certificate from LABC which states compliance and the whole window U Value (currently 1.6 or 1.4 depending on the design).

The design range is the ECO Sash, ECO Safe and ECO Tilt.

Mighton do not provide a calculator a but a set of ready tested designs that carry a certificate and are able to be used in confidence knowing that the windows will comply.

Many thank's for the info. A real bonus for small businesses and diy woodworkers.

Still need help on a calculator!

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Re: U Value whole window method of calculation?

Postby jfc » Wed Nov 27, 2013 5:19 pm

Well im a small business and have used mightons design quite a few times over the last few years . You havnt even tried it ( its free ) and your dismissing it . all you have to do is buy the draught proofing and the like from them .
Both Caluwin and Mightons calculators are under licence and have copyright attached so I wont be putting up a screen shot as I need to use the very handy free calculators they provide to pass my windows and doors . :D

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Re: U Value whole window method of calculation?

Postby Meccarroll » Wed Nov 27, 2013 6:21 pm

jfc wrote:Well im a small business and have used mightons design quite a few times over the last few years . You havnt even tried it ( its free ) and your dismissing it. all you have to do is buy the draught proofing and the like from them .
Both Caluwin and Mightons calculators are under licence and have copyright attached so I wont be putting up a screen shot as I need to use the very handy free calculators they provide to pass my windows and doors . :D


Thank's for your reply. I started this thread to find out if anyone is interested in trying to put together a whole window calculator.

I to am a small business and have used Mighton products many times for traditional sliding sash windows and think their forward thinking in providing a set of designs that can be certificated for free is a real bonus to the small window manufacturer (such as us). I wish more suppliers provided the same level of service Mighton do because it's the way forward in helping small businesses survive. and a huge benefit to DIY woodworkers. I was not aware that Mighton provided this service so am very pleased you have brought it to my attention.

I am not sure what you are getting at when you say I have not even tried it (it's free) and dismissing it! What exactly have I dismissed? I try to look into things in depth as much as I can before forming an opinion and don't think I have formed a dismissive opinion on anything discussed today. Maybe I have worded my replies to you incorrectly or inadvertently offended you, I can assure you if I have done so It's not been intentional and your input has been helpful.

I am very grateful to those ho have contributed.

Mark

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Re: U Value whole window method of calculation?

Postby jfc » Wed Nov 27, 2013 8:23 pm

You've not offended me but your reply about Mighton seemed a bit off to me as I know they spent a lot of money getting the system ready for people like us . Ok they use it to sell products but they are in sales and in my opinion had no reason to bother doing what they have . As far as I am aware there is no other company in the UK that has bothered to offer a free service .
St Gobain are a massive company and have also offered a service . Pilkington .... nothing as far as I am aware .
I would love this site to host a free calculator or spread sheet for people to use , that's the point of the site . We are in no ones pockets so can do what we like but we cant be nicking peoples stuff and hosting it as they might get really angry and tell us off ;)

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Re: U Value whole window method of calculation?

Postby Meccarroll » Thu Nov 28, 2013 6:22 am

jfc wrote:You've not offended me but your reply about Mighton seemed a bit off to me as I know they spent a lot of money getting the system ready for people like us . Ok they use it to sell products but they are in sales and in my opinion had no reason to bother doing what they have . As far as I am aware there is no other company in the UK that has bothered to offer a free service .
St Gobain are a massive company and have also offered a service . Pilkington .... nothing as far as I am aware .
I would love this site to host a free calculator or spread sheet for people to use , that's the point of the site . We are in no ones pockets so can do what we like but we cant be nicking peoples stuff and hosting it as they might get really angry and tell us off ;)


Hi not sure hat you are getting at, Quote: " your reply about Mighton seemed a bit off" ?

Can you quote the sentence/s in question so I can see what you say seemed a bit off?

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Re: U Value whole window method of calculation?

Postby sainty » Thu Nov 28, 2013 6:42 am

Good thread. I've found that Ethiopian iso document before to do exactly the same thing. I never got any further with it though, but I think it should be relatively straight forward.

Like you say, you just need the thermal properties of the materials. I think you can use generic numbers for softwood and hardwood, the glass is known, and the linear thermal transmittance due to the spacer bars which is also easy to find out. Then you just plug the numbers into a spreadsheet with your dimensions and away you go!

I think I gave up as I was trying to do it for doors and it was looking like a long job to make it flexible enough to cope with what we do.

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Re: U Value whole window method of calculation?

Postby mark270981 » Thu Nov 28, 2013 8:03 am

I should have paid far more attention at university when we covered this module, but I didn't so I can't help.

However I will send an email to the lecturer and see what he comes up with??
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Re: U Value whole window method of calculation?

Postby thatsnotafestool » Thu Nov 28, 2013 8:13 am

Oh, all right. Twist my arm and call me Mary. Here is the damn formula.

The Uw-value for the window is stated by the manufacturer for the entire construction (glazing and frame / sash) in W/m2K.

A window's Uw specifies the amount of heat loss through the window calculated in relation to the actual window size. The U-value expresses how many watts passes through the window at a temperature difference of 1 degree Kelvin.

The window manufacturer typically indicates the window's Uw-value for a European standard sized window 1.23 m x 1.48 m, but on request from customers the U-value for a current window size has to be given. The exact U-value is crucial information in energy framework calculations.

Uw = Ag x Ug + Af x Uf + Lg x Psig / (Ag + Af)

Ug = pane U-value measured in the middle, stated in W/m2K
Uf = frame/sash U-values stated in W/m2K
Psig = linear thermal transmittance loss of the glazing spacer stated in W/m2K
Ag = glass area stated in m2 (glass or equivalent)
Af = area of sash, frame and glazing bars stated in m2
Lg = circumference of the glass stated in metres

and even a picture
Uw picture.jpg
Uw picture.jpg (27.83 KiB) Viewed 9611 times


Can I go back to sleep now, please ?
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Re: U Value whole window method of calculation?

Postby mark270981 » Thu Nov 28, 2013 8:42 am

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Re: U Value whole window method of calculation?

Postby jfc » Thu Nov 28, 2013 8:44 am

Whos Kelvin ?

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Re: U Value whole window method of calculation?

Postby thatsnotafestool » Thu Nov 28, 2013 8:59 am

mark270981 wrote:as found here

http://www.rationel.co.uk/professionals ... t-loss-uw/" onclick="window.open(this.href);return false;



:lol: bang to rights :lol: :lol: How's the timber supply service out of curiosity?
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Re: U Value whole window method of calculation?

Postby thatsnotafestool » Thu Nov 28, 2013 8:59 am

jfc wrote:Whos Kelvin ?


Runs Surrey Timbers.

Oh no...that's Kevin.
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Re: U Value whole window method of calculation?

Postby mark270981 » Thu Nov 28, 2013 9:33 am

Timber supply never really took off nothing ventured nothing gained.

I think Bob may have mentioned the problem of having retired fellas come in and want to chat for 3 hours before they walk off with a 5 quid off cut!! This happened on a regular basis.
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Re: U Value whole window method of calculation?

Postby Meccarroll » Thu Nov 28, 2013 3:01 pm

mark270981 wrote:I should have paid far more attention at university when we covered this module, but I didn't so I can't help.

However I will send an email to the lecturer and see what he comes up with??


Well that would be very helpful Mark, let us know when you have a reply.

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Re: U Value whole window method of calculation?

Postby Meccarroll » Thu Nov 28, 2013 3:30 pm

thatsnotafestool wrote:Oh, all right. Twist my arm and call me Mary. Here is the damn formula.

The Uw-value for the window is stated by the manufacturer for the entire construction (glazing and frame / sash) in W/m2K.

A window's Uw specifies the amount of heat loss through the window calculated in relation to the actual window size. The U-value expresses how many watts passes through the window at a temperature difference of 1 degree Kelvin.

The window manufacturer typically indicates the window's Uw-value for a European standard sized window 1.23 m x 1.48 m, but on request from customers the U-value for a current window size has to be given. The exact U-value is crucial information in energy framework calculations.

Uw = Ag x Ug + Af x Uf + Lg x Psig / (Ag + Af)

Ug = pane U-value measured in the middle, stated in W/m2K
Uf = frame/sash U-values stated in W/m2K
Psig = linear thermal transmittance loss of the glazing spacer stated in W/m2K
Ag = glass area stated in m2 (glass or equivalent)
Af = area of sash, frame and glazing bars stated in m2
Lg = circumference of the glass stated in metres

and even a picture
Uw picture.jpg


Can I go back to sleep now, please ?



If you give us the whole of the 'working calculations', you can, lol

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Re: U Value whole window method of calculation?

Postby jonnyd » Thu Nov 28, 2013 9:04 pm

I can't be bothered making windows now. In the past however our building control just looked at the sticker on the planitherm glass and said it was ok.

Cheers

Jon
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Re: U Value whole window method of calculation?

Postby jfc » Thu Nov 28, 2013 9:41 pm

My BC are pretty much the same . I use 20mm units with planitherm , swisspacer and argon gas and leave the caluwin calcs on site or send them to BC if the customer doesn't want to deal with things .
If its a sash I put the Mighton sticker on it but still back it up with the other stuff . BC have told me they like going to pass my work as it nice to see something pretty ( I think they where talking about me ) Rather than just another plastic window .

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Re: U Value whole window method of calculation?

Postby Meccarroll » Thu Nov 28, 2013 10:47 pm

jonnyd wrote:I can't be bothered making windows now. In the past however our building control just looked at the sticker on the planitherm glass and said it was ok.

Cheers

Jon


I can see where you are coming from. Regulations are becoming prohibitive because of a lack of information that makes them easy to understand in helping small businesses comply.

JFC (site administrator) uses a couple of methods that satisfy his local building control. These have already been mentioned in this thread by him (it's worth looking at his comments).

You can download a free online copy of current building regulations: http://www.planningportal.gov.uk/upload ... B_2011.pdf" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; (note this is for existing buildings, New buildings are covered by other free donwloads)

Some properties are exempt from Building Control Notification, if you have the above document page 8 generally covers buildings covered by the regs, exempt buildings. Historical Buildings and buildings in conservation areas are the ones that do not generally need to meet building full/part regulations, but do check to ensure before carrying out any work. You probably/may still have to contact your local authority "Planning officer" and/or ask advice of the local authorities "conservation officer" to clarify the areas in which buildings are covered by them instead of the regulations but it's quite an informal procedure, just contact your local authority and ask, they are usually very helpful in helping you comply with their guidelines in relation to any work you do on dwellings not covered by building control. It's a niche market for woodworkers to get involved with, and if you want to continue making traditional windows and allows full use of traditional skills and methods of construction to be retained and used this area of work is excellent.

Mark



You will find that if

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Re: U Value whole window method of calculation?

Postby woodsmith » Fri Nov 29, 2013 8:55 am

In my area getting consent for new windows/doors in listed buildings is far from an informal procedure. That used to be true in the past but now they want full planning approval which involves stacks of drawings and paperwork. Building Control also get involved and there is often an argument between BC and Conservation over what they will allow; like Jon I've given up making windows.

Let them have PVC :evil:
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Re: U Value whole window method of calculation?

Postby Meccarroll » Fri Nov 29, 2013 11:14 am

woodsmith wrote:In my area getting consent for new windows/doors in listed buildings is far from an informal procedure. That used to be true in the past but now they want full planning approval which involves stacks of drawings and paperwork. Building Control also get involved and there is often an argument between BC and Conservation over what they will allow; like Jon I've given up making windows.

Let them have PVC :evil:


So far as I am aware Listed Buildings come under the control of the The Local Planning Department Not Local Building Control and Planning have overall say in what you can and can't do to them- please correct me if I am wrong. It would be interesting to know more about the project you are referencing to, such as scope of work involved, documents required and the exact type of building, for example was it a listed building.

Building Regulation Approved Document LB1 (Conservation of fuel and power in existing buildings)

Page 8 coveres Dwellings exempt from the energy efficiency requirements
Dwellings exempt from the energy efficiency requirements
3.6 There are two exemptions from the energy efficiency requirements that may apply to building work to existing dwellings or extensions to existing dwellings:
a. Buildings which are:
• listed in accordance with section 1 of the Planning (Listed Buildings and Conservation Areas) Act 1990;


Back to WindpwU Values


Building Regulation Approved Document LB1 Page 14 Gives guidance on how to comply with the regulations for windows

If you have no calculations showing the U Values for your windows you could use SAP 2009 Table 6e (page 189) as mentioned in the relevant Approved Document.


SAP 2009 Table 6e gives values for different window configurations that can be used in the absence of test data or calculated values.

The first window to comply in the SAP Table uses "triple-glazed, air filled (low-E,0.2, hard coat) with a gap of 16mm, which conforms to a U Value of 1.6.

So Triple glazed Wood windows glazed as above should satisfy your local building control......No calcs needed!

Download to references: LB1 Page 8,14: http://www.planningportal.gov.uk/buildi ... k/approved" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

Download to SAP 2009 Page 189: http://www.bre.co.uk/filelibrary/SAP/20 ... 9_9-90.pdf" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

Mark

It is always best to check with the local authority first before commencing any works.


Corrections with references are always welcome.

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Re: U Value whole window method of calculation?

Postby woodsmith » Fri Nov 29, 2013 5:37 pm

Although Planning have the final say, building control still have to sign off the work and in my area they have been loath to do so if the work does not comply with current regs.

Some years ago Conservation just wanted a simple plan and front elevation together with details of materials and finishes. For my last job they wanted an area plan showing the local area (only an ordinance survey map would do which cost about £30 to download), a site plan, front elevation, side elevation, cross sectional drawings of every part of the structure, a design and access statement and samples of all the materials and finishes used. This was for 3 windows replace like for like for a Grade 2 listed building in a conservation area.

The problem is, who pays for all this work? The customer should of course but I found they are very reluctant to pay for all this bureaucracy on top of the cost of the windows. Especially when a FENSA registered firm will just come along and swap the windows without getting any consents. In fact while we were replacing the above windows a firm turned up and replaced all the windows of the house opposite with PVC abominations.
Keith

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Re: U Value whole window method of calculation?

Postby mark270981 » Fri Nov 29, 2013 10:00 pm

I have a bit of a strange question, but why bother to tell them? Will they actually ever know? Unless of course you doing the property up to sell within few years.

The. Again

Someone I know bypassed all the bureaucracy by having timber windows installed with double glazed units. When he came to sell the house he simply said I've painted them. He got away with it

I'm fed up with bureaucratic b*llsh*t
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Re: U Value whole window method of calculation?

Postby mark270981 » Sat Nov 30, 2013 6:23 am

The answer below in full from my previous lecturer.



Hello Mark.

You ask about thermal transmittance calculations so I will tell you a little (in fact almost all) of what I know on the subject. It is coming up to four years since retirement so I could be way out of touch.
The acceptable calculation procedures are defined in Part L of the Building Regulations and Approved and Associated Docs. – available freely on line (planningportal.gov.uk). BRE report BR443 is relevant. The calc used to be very simple (merely the reciprocal of the total resistance) but is now complicated by the need to apportion resistance values of cavities etc. But don’t let that put you off – it is fairly straightforward to work thro the standard pro forma. Some practices (e.g. try Elmhurst Energy) have produced computer progs to do this but to be acceptable for Bldg. Regs. applications the software must be third party accredited so there is likely to be a fee involved. If you are hot on Excel you may be able to design a spreadsheet to do the calcs but I couldn’t and of course it would not be accredited. The use of accredited "standard" details reduces the amount of calculation evidence required.

I remember that some of the larger materials suppliers e.g. Celcon, Rockwool had on their websites simple (not accredited) progs tied in with the application of their products.

Good luck and let me know if I can be of any more help

Regards, John
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Re: U Value whole window method of calculation?

Postby woodsmith » Sat Nov 30, 2013 8:16 am

mark270981 wrote:I have a bit of a strange question, but why bother to tell them? Will they actually ever know?

t


With Listed buildings it is against the law , rather than just planning regs, to alter them without permission. Whilst some big firms and cowboys seem to be able to flout the regs a small conscientious local trader could well have the book thrown at them.
Keith


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