Trapezoidal mounting rail ISO 290mm

It is a short piece of aluminium profile that is fixed directly onto the corrugated sheet roof and onto which the panel is fastened. Instead of long bars stretched over the whole roof, each module rests on a few such short rails, placed on the crests of the sheet. The result is less aluminium used and a smaller additional weight placed on the roof, which matters on halls with a lightweight structure.

The rail sits on the top of the rib, i.e. on the raised part of the sheet, where water does not stagnate, and is fixed with self-drilling screws - screws that make their own hole in the sheet - fitted with a sealing washer. On the foot of the rail there is a gasket, usually of EPDM, which is flattened onto the sheet when tightened; together with the washer, it stops infiltrations through the hole that has been made. The panel is fastened to the upper channel of the rail, with mid and end clamps, so the position of the module can be adjusted lengthwise. How many rails go on one module and how many screws on each rail are established by calculation, not as a flat rule, depending on the thickness of the sheet and on the wind and snow loads.

Short mini-rail type rail, length 290 mm, extruded aluminium with an EPDM sealing gasket. Module interface: upper channel for clamps with a hammer-head bolt. Fixing with self-drilling or self-tapping screws with a sealing washer, screwed into the crest of the rib; sizing is done according to the thickness of the sheet, the width and pitch of the crests and the wind and snow loads. Stainless steel fixing elements are recommended, for galvanic compatibility with the aluminium of the rail and with the module frame.

Who it suits

Suitable for halls and roofs of trapezoidal sheet where the modules are installed parallel to the plane of the roof and minimum added weight is sought.

Terms explained

• Trapezoidal sheet: Roof sheet with an angular wave profile; the raised part is called the crest, and the fixing is done there.
• Mini-rail: A solution with short rails placed individually instead of long continuous bars, which uses less material.
• Self-drilling screw: A screw that drills its own hole in the sheet, with a rubber washer that seals the perforation.

Technical specifications

Recommended applications

• Roof-parallel mounting on industrial halls with trapezoidal sheet
• Residential roofs with trapezoidal metal tile
• Installations where a reduced additional weight on the roof is wanted
• Configurations without continuous longitudinal rails

Technical details

Generic product — standard specifications

The short 290 mm mounting rail is intended for fixing photovoltaic modules directly onto trapezoidal sheet roofs, in the so-called mini-rail solution. Unlike the classic installation with continuous longitudinal rails, here each module is supported by several short rails placed on the crests of the sheet, which reduces the amount of aluminium used and the additional weight added to the roof.

The profile is of extruded aluminium and has an upper channel for the hammer-head bolts of the mid and end clamps, while on the seating foot a sealing gasket is provided, usually of EPDM, which is compressed onto the sheet when tightened. Fixing is done with self-drilling or self-tapping screws with a sealing washer, screwed into the crest of the rib; the gasket plus sealing washer combination ensures the tightness of the penetration of the roof covering.

The solution suits the roofs of halls and industrial buildings, where the modules are installed parallel to the plane of the roof. The number of short rails per module and the number of screws per rail are established by calculation, according to the thickness of the sheet, the width and pitch of the crests and the wind and snow loads. Stainless steel fixing elements are recommended, for galvanic compatibility with the aluminium of the rail and with the module frame.