ISO aluminium rail 4300mm trapezoidal

The rail is the aluminium bar that actually holds the panels, the way a shelf holds books. It is fixed to the roof through hooks or brackets, and the panels are clamped onto it. Along the whole length of the bar there is a channel, a kind of T-shaped groove, into which the clamp bolts are inserted, which is why the panels can be positioned anywhere on the bar, without drilling on site.

The 4300 mm length typically covers 2 panels mounted in landscape or 4-5 panels mounted in portrait, so for a longer row several bars are joined end to end with rail connectors. Aluminium naturally resists rain and moisture thanks to the oxide layer formed on the surface, and stainless steel bolts do not cause corrosion in contact with it, so the structure requires no maintenance. The bar is delivered in a natural finish, called mill finish, or anodised, the difference being mainly aesthetic. On trapezoidal sheet roofs the rail is laid across the sheet ribs and fixed on U- or L-type brackets.

Extruded aluminium profile, usually from alloys in the EN AW-6063 or EN AW-6005A group, in the solution heat-treated and artificially aged condition, with one or more T-type longitudinal channels for M8 hammer-head bolts. Fixing on trapezoidal sheet through U/L-type brackets or short rails, with self-drilling screws with EPDM washer fastened into the rib crest; the joining of sections is done with a rail connector (splice). The span between support points is determined by structural calculation, according to the snow and wind loads at the site, in accordance with SR EN 1991-1-3 and SR EN 1991-1-4.

Who it suits

Suitable for halls, outbuildings and houses with trapezoidal sheet roofing, where long rows of panels are installed and a long bar is preferred instead of many short sections.

Terms explained

• Channel for hammer-head bolt: The groove in the bar into which the bolt is inserted at an angle and locks when turned; it allows the clamps to be moved anywhere along the length of the bar.
• Trapezoidal sheet: Sheet metal corrugated in steps, with straight ribs, used on industrial halls and on some house roofs.
• Splicing: Joining two bars end to end with an intermediate piece, so as to obtain a longer continuous row.

Technical specifications

Recommended applications

• Load-bearing structure for PV modules on halls and industrial trapezoidal sheet roofs
• Residential roofs with trapezoidal-type metal tile
• Long rows of modules, by splicing with rail connectors
• Configurations with modules mounted in portrait or landscape, on two parallel rails

Technical details

Generic product — standard specifications

The extruded aluminium mounting rail with a length of 4300 mm is the horizontal load-bearing element of a photovoltaic structure installed on a trapezoidal sheet roof. The profile is provided with one or more T-type longitudinal channels, into which the hammer-head bolts of the mid clamps, end clamps and fixing brackets are inserted, which allows continuous positioning of the modules along the whole length of the bar, without additional drilling on site.

Profiles of this type are made by extrusion from structural aluminium alloys (usually from the EN AW-6063 or EN AW-6005A group, in the solution heat-treated and artificially aged condition), a material that offers a good strength/weight ratio and natural resistance to atmospheric corrosion through the oxide layer; the surface is commonly delivered natural (mill finish) or anodised. The aluminium-A2 stainless steel combination at the clamping elements avoids galvanic corrosion in the joints.

On trapezoidal sheet roofs the rail is laid across the sheet ribs and fixed on U/L-type brackets or on short rails, with self-drilling screws with EPDM washer fastened into the rib crest. The 4300 mm length typically covers 2 modules mounted in landscape or 4-5 modules mounted in portrait, and the sections are spliced with rail connectors for continuous rows. The span between support points is determined by structural calculation, according to the snow and wind loads at the site in accordance with SR EN 1991-1-3 and SR EN 1991-1-4.