BFRC Substitution Rules for Glazed Units

The following Substitution Rules are for use where a simulation cannot be undertaken. In the case of a Simplified Energy Licence substitution of the IGU can take place if the WER remains in the same band or higher.

If the issued Licence is of the current form, i.e a Detailed Energy Licence (DEL) then the calculated Energy Index must not be lower than that contained within the original Licence. A WER calculation will be available to aid this process but the rules set out below should also be helpful in reaching a decision on whether or not a substitution is allowed.

1.) Centre-pane U value of the replacement IGU must be equal to or lower than the original licensed window.

2.) g value of the replacement IGU must be equal to or higher than the original licensed window.

3.) The dimensional configuration of the replacement IGU must be identical to that in the original licensed window e.g 4-16-4.

4.) Spacer bars (including primary sealant and desiccant) may be substituted when the replacement has an equal or lower effective thermal conductivity (measured to 3 decimal places) than the spacer bar specified in the original licence. Effective thermal conductivity of the spacer (including the primary sealant) shall be determined either by simulation according to EN ISO 10077-2, or measured using a relevant physical test (more details available from BFRC).

5.) In order for a substitution of secondary sealant to take place, the effective thermal conductivity of the secondary sealant of the replacement IGU must be the same as, or lower than, the original licence.

General Notes

a) Rules 1,2 and 3 above must be considered together and all must be satisfied.

b) If the sealed unit supplier is changed then the BFRC need to be informed and documentation demonstrating compliance with BS EN127-5 needs to be supplied within 10 days.

c) BFRC are developing an IGU comparison tool, which will be available on the BFRC website. The following groups will have access to this comparison tool:

1.) BFRC Licence Holders

2.) BFRC Authorised Retailers

3.) Component Manufacturers (who supply data)

4.) Certified Simulators and IA's

It is planned that the user will enter the specification of the IGU on the original licence, and then enter the specification of the proposed substitute / additional IGU. The comparator will determine and inform the user is all substitution criteria have been met succesfully, and if so will allow the user to print a certificate with both sealed unit specifications listed.

d.) There shall be no charge for substitution of components. We do however reserve the right to apply an administration fee in the future.

e.) Substitution of components in accordance with the BFRC rules are an endorsement to a BFRC Licence.

f.) A substitution will be reviewed on an annual basis.

g.) Application forms and Guideline for Certificates of Addition and Substitution processes are available on the BFRC website.

h.) Labelling: When substitution has taken place the Energy Label will NOT be changed because the performance of the complete window will either be equal or better than that achieved by the original specified product (DEL only)

In the case of Energy Labels which do NOT display the ENERGY INDEX i.e. simply displaying A,B, or C, the substituted product needs to remain within the same band or higher (SEL only).

Explanatory Note

Simulators now have the ability to simulate mixed glasses within a WER. Hitherto both glasses used within the construction of the sealed unit have needed to come from the same manufacturing company in order for the g value to obtained. The g value for a particular combination of glass can be obtained from BFRC - Fee £50.00