- Mardome Flat Glass Skylight with Upstand 2000 x 1000£1,581.25 £1,317.71
The double glazed glass panel is made up of: 6mm toughened outer, a 90% argon filled cavity, with a laminated inner (inc. 1.5mm PVB interlayer). The inner pane thickness varies with rooflight size, see table on page 3. All double glazed units include a soft coat Low E coating.
The frame is extruded aluminium, with a powder coating (RAL 7016) to provide a premium appearance and highly appealing finish, and is thermally isolated to provide excellent thermal performance. The kerbs are manufactured from Lead & Cadmium free un-plasticised PVC rigid multi-wall extruded profile, with internal white finish. The Glass, PVC-U and Aluminium which comprise the product can be recycled at the end of useful product life.
Brett Martin Flat Glass units are expected to remain fit for purpose in normal industrial conditions for a period of 20 years (guaranteed for 10 years), i.e. they will not become perforated, lose significant structural integrity or distort to the extent of losing weather-tightness. Electrical actuators (where present), are guaranteed for a period of 1 year; actuators have a design life of at least 10,000 cycles. Insulated glass used in the construction of the rooflight is guaranteed for 5 years.
Safety Requirements and CDM
Brett Martin Flat Glass achieves CWCT TN-67 non-fragility for class 1 roofs* and ACR[M]001 class B non-fragility when new and fully installed in accordance with Brett Martin Daylight Systems’ installation guides. Foot traffic on rooflights should always be avoided; impacts such as foot traffic or a falling person may cause damage which could necessitate rooflight replacement. All glass panels are BS EN12150, BS 14449 and BS 1279 compliant.
All fixed Brett Martin Flat Glass units are fitted to a structural, insulated builders upstand or a PVC kerb using self-drilling fixings concealed using colour-matched cover caps. Fixed variants are accredited by Secured by Design based on independently assessed testing in accordance with PAS24:2016. Optional security grilles are designed to fit beneath the foot of the kerb to provide additional security where required.
Building Regulations Approved Document B (2019 edition, amended 2020) sets out the rules for fire safety of buildings, which can be met by achieving specific fire ratings to European (BS EN 13501) test standards. Glass is designated Class A to EN13501 part 1, as it is included in the list of CWFT (classified without further test) materials published in the Official Journal of the EU (see European Commission Decision 96/603/EC).
Brett Martin Flat Glass Rooflights are deemed to achieve Class BROOF(t4) to EN13501 part 5 by Approved Document B of the Building Regulations (see Approved Document B1 paragraph 12.8 and Approved Document B2 paragraph 14.8).
These classification mean there is no restriction on where Brett Martin Flat Glass rooflights can be used on roofs of buildings in England.
Brett Martin Flat Glass units are suitable for flat roof applications with a pitch of 2O-15O. 2O is typical for a ‘flat roof’. If a roof is less than 2O, packers (not supplied) will need to be placed under the kerb of the unit or on the top of a builders upstand to raise to the minimum 2O. This is to prevent water ponding on the glass leading to rapid dirt build up. A minimum of 4O pitch is required for sizes where both the length and width are larger than 1650mm.
Brett Martin Flat Glass achieves a Ud-value (defined in accordance with NARM NTD02) of 1.16 to 1.66 W/m2K and a centre pane U-Value of 1.1 W/m2K which exceeds requirements of Approved Document L of the Building Regulations.
Brett Martin Flat Glass units achieve a direct airborne sound insulation value of 38db (Rw). This value can be improved further by the fitting of a kerb acoustic pack. The acoustic pack is not available with vented or opening options.
Wind and Snow Loads
Brett Martin Flat Glass has been tested to show that, when correctly fitted in accordance with our instructions, will resist wind loads calculated in accordance with BS EN 1991-1-4: 2005, and imposed loads in accordance with BS EN 1873: 2005
Brett Martin Flat Glass rooflights are manufactured using double glazing which includes an inner pane of annealed, laminated safety glass, which is essential for ensuring the safety of those above the rooflight through non-fragility, and those below the rooflight through the prevention falling glass from accidental breakage.
In some circumstances, annealed, laminated safety glass can be subject to thermal stress fracture in the event of uneven heat build-up directly under the glass. Installation of blinds, or any other alterations made to the lightwell below the rooflight, must be done so with consideration to the risk of thermal stress fracture. In the case of blinds, the risk of thermal stress fracture can never be fully removed, but it can be reduced by choosing light coloured blinds, positioning them as far away from the glass as possible, and adding ventilation to the rooflight specification