W20 & Milan Ranges

Performance - The windows shall meet the air infiltration, water penetration and wind loading performance criteria set out in NZS 4211, appropriate to the specified design wind pressure.

Appearance - Steel profiles shall be so selected that typical perimeter sightlines of fixed lights shall not exceed 50mm and of hinged opening sashes / doors 80mm. Fixed light and sash glazing infill shall be in the same plane.

Material - Profiles shall have a nominal width of 32mm for W20 and 38mm for Milan, hot rolled from mild steel and cold straightened.

Construction - Frame and sash joints shall be welded, dressed square and flat. The straightness of any framing member in a plane parallel or perpendicular to the face of the window should be within ± 2 and any length of 1 metre and within ± 3 in the total length and total height of the window. The difference in length of all diagonals should be within 3mm.

Finish - Frames and ancillary profiles shall be positively rust-proofed by steel grit blasting and zinc metal spraying, to a minimum 75µ zinc layer. Finish all significant surfaces with either a polyester powder-coat or a 2-coat epoxy (maximum 150µ build).

Weatherseals - Where required sashes and steel on steel couplings (other than structural), shall be weathersealed with Crittall self-adhesive weatherseal to form an external rainscreen, internal airseal and a pressure equalised cavity.

Fittings - Hinged sashes to have steel weld-on or concealed variable geometry friction hinges. Pivoting doors to have floor mounted floor springs and top pivot gear.
A variety of handles, catches, stays and openers are available in different finishes (we strongly recommend consulting us before specifying any hardware for steel joinery, as excess lead times and poor functionality may disappoint).

Fixing - Windows and doors will be supplied to site to suit the builder's specified openings. Units can either be fixed though the framing members or fixed through welded lugs. Rust-proofed screws, plugs or bolts should be used (ideally stainless steel). Appropriate sealants shall be applied to the external perimeter. Steel windows are not fitted with jamb liners.

Glazing - Windows and doors will be generally glazed on-site, from inside or outside, depending on the steel section configuration specified. Units can be single or double glazed, using a variety of steel beading, bedding and capping products, or traditional putty products.