All the amending and adjusting and sitting down with as many professionals as you like, will NOT put this scheme right . It is fundamentally flawed, the science is wrong, whether that was by accident or by design only one or two people will ever be able to comment. I do however have my own thoughts on that issue.

The Document that Giles refers to “BFRC report “Deriving A and B factors for the UK climate” dated 22 September 2003 “ is no more than a smokescreen that pretends to offer a scientific approach , while taking the “baffle with bulls**t” approach

I view with concern all the problems and costs incurred trying to implement this scheme, however the science needs putting right first. It seems to me a bit like an industry currently chasing rainbows!

As I referred to earlier , as the BFRC might not actually realise what they got lumbered with , it might be prudent to research their own product a little further, OK may the horse has already run away but the stable door still needs shutting !

I don’t think I will get an answer to the reference source of the solar flux data , I never did to be honest, but it is still worth asking .

1.The majority of the Directors of the BFRC have admitted that they don’t really understand the principles of the simulation process and those who do, it could be argued, may have commercial reasons for not wanting changes to the scheme.

2.The BFRC do not understand how the window industry functions. One example that came to light well over a year ago was that they assumed that the fabricators always supply fully glazed windows – being totally unaware that most installers prefer to purchase sealed units from their local suppliers who provide the level of service they require. There are numerous other examples that confirm my opinion.

3.Their knee jerk responses to problems that have arisen confirm this ignorance.
a.The installers or Approved Retailers Scheme – Is expensive and virtually impossible to control (audit) properly with the scheme in its present form. Perhaps this is why there has been an extremely limited up take and is not recommended by consultants and some Independent Agencies (IA’s). All an installer wishes to do is to be able to buy their compliant units from their preferred supplier and match them with the frame that they buy. This is relatively easy to accomplish and a simple “paper trail” could provide the necessary evidence for any auditor to confirm full compliance.
b.The Multiple Label Scheme. On the face of it, this is a good idea but auditors and IA’s have informed me that it is a time consuming process to audit (expensive) and the chance of windows going out incorrectly labelled increases exponentially with the increase in label numbers. The cost appears to be low but the sting in the tail is that simulations in the fabricators name (or cascaded from the profile supplier) have to be available for the IA’s to inspect and this leads to hidden expense!

4.These schemes have all been introduced without consulting the industry experts and representative bodies. They have not been and probably will not ever be embraced by the industry enthusiastically.

5.The BFRC scheme is claimed to be “very robust”. I would agree that the simulation process is certainly robust, perhaps to the point of being proscriptive and restrictive and maybe this is the reason for the recent threats of legal action. However, after this robust process the whole system breaks down because.
a.There is no rule book for the Independent Agencies (IA’s) to work to
b.The IA’s do not have the auditors with the necessary experience to adequately “police” the scheme.
c.The fabricators do not have to have the robust scheme the IGU Manufacturers are forced to comply with. Although the fabricators are cascading EN Test results down from their profile suppliers they are not required to have a quality system in place to ensure that the frames made conform to those tested. i.e They do not have to prove their frames are fit for purpose.
d.The whole scheme appears to be open to abuse and “cooking of the books” has been noted but not exposed officially.

6.It is a common misconception that A Rated windows relate to quality – this is not the case and the scheme only relates to the thermal efficiency of the product when it leaves the factory fully glazed – there lies another anomaly within the scheme!

7.The BFRC have ignored advice given relating to the thermal properties of sealant used in the construction of double glazed sealed units and other components. This is symptomatic of their arrogance and ignorance and will probably come back to bite them in a way that may well threaten their future as a force within the industry. However, it will probably leave the door open to alternative schemes!

8.The BFRC have apparently sought clarification of the thermal properties from certain component manufacturers but have not been so even handed with others.

9.Substitution of components of equivalent or better value is a principle that most quality standards embrace. Until recently the BFRC has been intransigent on allowing this. However, when pushed by major players, they have allowed a number of exceptions i.e. The substitution of beads of a better value and the substitution of a major glass suppliers new glass that has better values. That is good step to make but why only for these products and not for others?

10.In simulations there is an insistence to “name” products – surely the use of their values would enable a simple substitution system and encourage new products to come to market?

11.Manipulation of Simulations – Many suppliers to the industry have openly admitted that they manipulate simulations to provide the best rating possible. Although this is understandable it is in the following examples a recipe for a repeat of the wholesale unit failures experienced in the late 1980’s.
a.Depth of seal – The depth of seal over the back of the spacer bar has been reduced to a level that effectively brings the spacer further down in the glazing rebate – Improving the thermal efficiency of the window. However, this means that the IGU manufacturer is making units that are outside the sealant suppliers’ recommendations and is taking the risk that they will fail prematurely. Assuming it is possible to make units consistently to this specification, I doubt if the manufacturer has had units of this configuration tested to EN 1279 Parts 2 and 3. Modifying their System Description to include these low parameters as their minimum depth should result in IA’s rejecting any units found to have sealant depths above this minimum depth claimed. Incidentally it will be the company putting the product to market that will be the one liable – The Installer!
b.Clearance around the unit: It is common practice to deduct 5mm off the window size to provide adequate clearance around the IGU for glazing purposes. Some simulations have been “adjusted” to only deduct 3 mm from the tight size, again improving the BFRC WER Rating. It is obvious that glazing into a fixed opening using this configuration is perhaps possible but impossible to “toe & heel” a unit into an opener. Even if glazing was possible the 3mm clearance in the glazing channel would not allow adequate drainage as the surface tension of water would result in the water being trapped between the unit and the frame!
Effectively these manipulations will result in lower life expectancy of the IGU’s and this will be exacerbated by the units sitting in water. What effect on the “Carbon Footprint” will all these failures give?

12.FENSA – yet another body owned by the GGF. What (and how) will they be looking for when inspecting windows for compliance to the new regulations? Perhaps this subject can be debated on this site as at present there is, for one example, no way of ascertaining what type of glass (exact coating or glass type) has been used within the IGU!

13.EN 14351. There has been some debate within the industry as to whether this European Standard is mandatory or not. Perhaps it is an irrelevant question as the change of the CPD to the CPR, which will occur in the next few years, will once and for all answer the question. However, the frame manufacturers must have a quality system in place that proves they are making their frames exactly to the profile manufacturers’ recommendations. After all they are using (cascading) test data that has been conducted to a European Standard by a notified body test house and as such they need to prove they emulate the windows tested!

Might I be so bold to suggest to Giles Willson and his colleagues that, rather than just announce changes to their scheme that may be totally unworkable, they come up with some suggestions and then use the expertise within the industry to establish if they are viable.
To name but a few that are eminently qualified and almost certainly willing to assist are:-
Mark Hickox – Thermoseal. Component Supplier
Gaby Mendham – Ecoglass. IGU Manufacturer
Richard Bate – Build Check Ltd. Simulator and IA
Mike Gaillard – CENSolutions Ltd. Auditor and Consultant
Richard Sellman – HB Fuller. Sealant and GGF IGU Component Group Chairman
Andy Jones – Edgetech. Organic Spacer supplier.
And a glass expert representing all the glass suppliers.

May I quote from Dr Robin Kent, which is likely the result of the government funded, academia and peer review process, that you eluded to in your original answer.

http://www.tangram.co.uk/TI-Glazing-Energy_Rating_for_Facades.html

Paper presented at ‘The whole life performance of facades’ conference at CWCT, Bath 18 April 2001.

From which I will quote ..

“The British Fenestration Rating Council (BFRC) has produced a Domestic Window Energy Rating Scheme (DWER) to produce a single rating number for window energy efficiency.
The rating number is calculated from the individual values of the major energy transfer mechanisms. These are:
1. The U-value, which measures the overall window U-value and not just the glass component.
2. Solar heat gain coefficient (g), which measures how well a product transmits solar radiation and is a number between 0 and 1. A lower g means less solar heat gain.
3. Air Infiltration (L50), which measures air leakage through the window when it is closed.
These values are applied via the formula:
DWER = (25.9g – 11U – 0.12L50) + 74 (1)
where the correction factor 74 is used to produce a rating number from 1 to 100 for ease of understanding by consumers.”

Now, we see that the BFRC has produced this formula, and while it is produced in a different scale, it is the ratio of gain to heat loss that interests us.
Formula ratios , original formula 25.9 / 11 = 2.35
2003 formula 218.6 / 68.5 = 3.2
So we can see that in 2003, the government funded, academia etc etc etc formula was re written and presented with 36% higher solar gain ratio.

Hence my question, can you identify that reference source of the climate data that was used to re write the formula please?
I have to say , I have just had a thought that you may not be familiar with this work, or the alterations I report , but from the lack of help from some at your organization I was presuming that you (BFRC) were just trying to ignore me and suppress the information. So please forgive me, if I have come across a little ‘forceful’.
I hope this helps to clarify my position and has not confused you further, but just to clarify.. can you identify that reference source of the climate data that was used to re write the formula in 2003 please?