TRADE 980x170 01

B (Escape in case of fire)

Most habitable rooms on upper floors shall have window with an opening of at least 0.33m2 AND be at least 450mm high and 450mm wide (note: a window that is 450mm x 450mm would have an area of 0.2m2 which is not sufficient to meet the requirements.


Inspectors are looking to ensure that the compliance is not made worse, most problems surround the replacement of wooden casement windows with PVC of the same design but utilizing friction stays which further restrict the opening of a non compliant window


F (Ventilation)

Most habitable rooms shall have;

• a total window opening of more that 1/20th

of the room’s floor area, and


• a total outside ventilation opening of at least 8000mm2

(4000mm2 for bathrooms and kitchens)


M (Access/facilities for disabled people)

Reasonable provision shall be made for disabled people to gain access and use the building.


Inspectors are looking to ensure that the compliance is not made worse e.g. a replacement door should not prevent wheel chair access if previously it was possible.



produced by Martyn Reed, FENSA Inspection Manager,

British Board of Agrément

FENSA Members, Self-cert & Inspections


With the change to the building regulations all window installations from 1st July 2002 have to comply with the requirements of Approved Documents L1, N, A, B, F, M


The legislation allows members of FENSA to self-certify their own work, and therefore save themselves the time and expense of using the local authority building control system. To ensure that the FENSA scheme remains credible the BBA has been employed to inspect a random sample of installations both after and during installation. Post installation visits are sampled from data that the installer provides to FENSA and unless there is a problem then the installer will not be made aware that the inspection has been conducted.


Inspections to be conducted during an installation are booked with the Installation Company one or two weeks in advance. The inspector will meet with the team on site and after a brief tour undertake an inspection of all the new windows against the Approved Documents. ››

phone.  01638 66 26 36

FENSA Inspections

What are they looking for?

f. 01638 561 486  •  e.

The only way to understand fully the requirements, and the various ways of complying, is to read the Approved Document. This brief description of typical solutions is intended only as a guide.


L1 (Conservation of fuel and power)

For most situations replacement PVC-U double glazed windows will require at least a 16mm air gap and either hard or soft coating in all sealed units. Where the frames are metal, or other designs of sealed unit are used (e.g. argon filled) different designs are possible.


Inspectors are looking for the presence of low e (coated) glass and a suitable air gap.


N (Protection against impact)

Marked safety glass is to be used in all critical situations, which include windows less than 800mm from floor level, doors and glazing adjacent to doors.  Inspectors are looking for the glass to be marked in all critical locations.  For the following Approved Document compliance is not necessarily required but when it is not achieved then the new installation shall not make the situation worse.


A (Structure)

The installation shall be constructed so that it can sustain and safely transmit loads safely.  Inspectors are looking for the presence of reinforcement where appropriate, e.g. Bay windows.

The sophisticated software used to plan the inspections predicts the number of inspections required and prevents that quota being exceeded. Regular reviews will ensure that the predicted inspection rate reflects the volume of installations entering the system. While we will attempt to smooth the inspections over the year you may find that you receive a relatively large number of inspections in quick succession; this is not ideal but be assured that the system will prevent us booking more inspections than the quota set; 1% of the total number of installations with a minimum of 2 & a maximum of 100.


Glass Shop 01 Glass Shop 02