JMP Window Systems of Chetser is a Registered Everwhite Installer-view certificate here
Building Regulations are issued by the Department of the Environment, Transport & Regions (formerly Department of the Environment & the Welsh Office). The regulations were set up in 1991 and revised in 1994. They comprise a series of approved documents and are updated with new editions. Finished building work exceeds FENSA building regulations.
The following are brief extracts from windows, doors and conservatories. The extracts are not comprehensive and you are strongly advised to read the relevant up to date full Approved Document (copies of which are available from HMSO publications) or contact our technical department for further details.
approved document B - means of escape (2000 edition)
With the exception of kitchens, all habitable rooms in the upper storey(s) of a house served by only one stair should be provided with a window (or external door) which complies with the regulation.
A window provided for escape purposes should have an unobstructed opening that is at least 0.332 and at least 450mm high and 450mm wide. The route through the window may be at an angle rather than straight through. The bottom of the opening area should not be more than 1100mm above the floor and not less than 800mm above the floor (i.e. Approved Document K specifies a minimum guarding height of 800mm on elevation windows) - except in the case of a roof window where the bottom of the opening may be 600mm above the floor. For fire escape (egress) locations, windows should be ordered with non-locking handles to ensure ease of escape. The question of child restrictors should be addressed with the local Building Inspector, but the fixing of restrictors to a fire escape window should be ‘balanced’ with the requirement of ease of escape.
Fire resistant glazing can be used where it is able to satisfy the relevant performance standard in terms of insulation and integrity according to the building regulations (Appendix A, Table A1, A2, A4). JMP Window Systems in conjunction with John Fredericks has developed a range of hardwood framed windows and screens which can satisfy these requirements. Please ask for details from our technical department.
approved document F - ventilation (1995 edition)
Domestic buildings - New Build - require background ventilation to all rooms. Habitable rooms require 8000mm2, while kitchens, utility rooms, bathrooms and sanitary accommodation require 4000mm together with a mechanical extraction system. Trickle ventilation can be accommodated within the window, either in the head of the casement or over the head of the window in a 41mm add-on. Alternatively, an over glass vent can be specified.
An alternative provision is that background ventilation should be an equivalent to an average of 6000mm2 per room (rooms defined as habitable rooms plus kitchen, utility, bathroom and sanitary) with a minimum provision of 4000mm in each room. Background ventilation can also be achieved with the nite-vent windows, but only to high level top-hung windows above ground floor level to avoid a security risk.
approved document L - conservation of fuel & power (1995 edition)
This document will be revised with the implementations taking effect in February 2002. The revisions follow the Kyoto agreement with a general commitment to reduce greenhouse gas emissions, including therefore the contribution to emissions from buildings. In the case of our PVC-U products, this requirement will apply to windows, doors and some conservatories - both for New Build and window replacement.
For New Build, the document will require that the U value for PVC-U windows (which includes the frame material and the glass) is set at 2.0W/m2K. The U value measures the rate at which heat is lost through a material.
A conservatory that is unheated or is separated from the host building by doors will not need to achieve specified U values. If, however, the conservatory opens into the building without any form of separation (e.g. doors), then it is effectively an extension and must comply with the specified frame U values
For replacement windows the U value requirement is the same as for new build, i.e. 2.0W/m2K. An acceptable alternative is to use glazing having a centre pane U value no greater than 1.2, irrespective of frame performance.
The requirement applies to any replacement window, roof-light or door frame having more than 50% glazing (i.e. replacement doors having less than 50% glazing need not comply).
To meet the U values, the thermal performance of the double glazed unit can be improved - for example, by replacing standard glass with low emissivity glass, maintaining a 16mm air-gap inside the unit cavity, replacing the air inside the unit cavity with an inert glass: argon. PVC-U is a good insulator and therefore the frame material is more energy efficient than, say, a metal frame.
A Decorative window (1200mm x 1200mm) was tested for thermal transmittance on 21st November 2000 by Pilkington Glass. The window was glazed with “Insulight Therm” sealed units (4mm float glass - air filled 16mm cavity - 4mm Pilkington K Low “E”). The resulting U value was 1.85W/m2K.
approved document M - section M3: Access & Use (1999 edition)
From 1st October 1999 the Building Regulations for new build door thresholds have changed so that all front entrance doors are accessible to wheelchairs. The JMP Window Systems door range can incorporate low thresholds as detailed on table 1 below, but the low thresholds do not offer full weather protection.
Alternatively, a draught excluder for situations where no threshold is possible can be fitted to the underside of a modified door bottom rail, but does not offer full weather protection.
The width of a front door leaf should provide a minimum opening of not less than 800mm to allow for wheelchair access. This can be achieved by providing a residential doorset of 950mm wide if the door can only open to the 90° angle because of the reveal detail, and 930mm if the door opening angle is not restricted by the reveal - both opening widths using our SFS hinge range.
approved document N - glazing materials & protection (1998 edition)
REQUIREMENT N1 states that glazing which people are likely to come into contact with while in passage or in or about the building shall: -
1) if broken on impact break in a way that is unlikely to cause injury.
2) resist impact without breaking, or
3) be shielded or protected from impact
Diagram 1 below shows the critical locations in internal and external walls. Some key points to note are: -
1. Safety glazing applies to all areas within 800mm of finished floor level - a critical area.
2. Small panes of glass in a critical area can be in 6mm annealed, as opposed to a safety glass. A small pane is defined as having a maximum width of 250mm and a maximum area of 0.5m2.
Safe Access for Cleaning Windows - N4 Requirement N4 states for windows that cannot be cleaned safely from inside the building, alternative safe cleaning methods should be adopted - for example ;
1.By the safe use of portable ladders.
2.By the provision of walkways for access for cleaning.
3.By the provision of access equipment.
4.By the provison of suitable anchorages for safety harness or abseiling hooks.
Additional Guidance is given in BS 8213 Pt 1.1991