Sigma Purlin – Albion Sections

Developed in conjunction with the University of Birmingham and under the supervision of Dr Jian Yang.
Designed primarily for use on roofs as secondary sheeting support. Bay widths up to 15m and maximum roof slope of 25 degrees.
Manufactured by cold roll forming pre-hot dipped galvanised steel, grade S450, minimum yield stress of 450N/mm2.
Section properties calculated in accordance with Eurocode 3, BS EN 1993-1-3:2006.
Calculation of ultimate loads and working deflections are based on the results of full scale testing and finite element analysis.
The top flange of the purlin must have adequate restraint provided by robust steel sheeting (or similar) fixed directly to the top flange.
The steel has an external galvanised coating Z275, giving an approximate coating thickness of 20 microns each side.

Albion offer a variety of Sigma purlin systems to suit differing applications.

The Sigma purlin shape provides an efficient, robust profile that suits both short and long span conditions.

In most cases of popular building type sag rods are not required (subject to wind uplift conditions), see table on page 9 of Albion’s Sigma Purlin Brochure.

Sleeves are required to provide continuity to the purlin section across the supporting rafters.

The most popular system, double spanning, has been specifically developed to minimise the number of sleeves, thus reducing the number of components and resulting in savings in installation time and component cost.

The sleeve details have also been considered in terms of simplicity and duplication. All sleeves are the same length with identical longitudinal dimensions, uniformity reducing the chance of errors.

Single Span Butt System
The simplest of the Purlin Systems. Use where design conditions dictate that no connecting Sleeves can be used, i.e. Purlin within depth of Rafter.

Double Span Butt System
The most popular Purlin System combining Double Span lengths with a minimum of Jointing Sleeves.

Single Span Sleeved System
Where Purlins are required to be Single Spanning, but still maintaining continuity over the Rafters, the Single Span Sleeved System can be employed.

Heavy End Bay System
The Heavy End Bay System offers the economic solution for the larger, Multi Span type building.

Sleeve Assembly and Cleat Details

For more information see Albion’s Sigma Purlin Technical Manual (pages 5, 7-8) or contact Albion’s Technical Team.

Download Brochure

Albion Sigma purlin technical manual
To combat rising material costs, Albion has developed a lighter, robust section – the Albion Sigma purlin.

Download PDF (PDF 5.05mb)

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Sigma purlin features:

Reduced section size by a gauge – using S450 materials grade as opposed to S390.
Improved strength to weight ratios of up to 11% against some S390 popular Zed Profiles.
Less accessory components required, such as Anti Sag Bars and Sleeves.
Vastly improved speed and ease of erection, due to reduced component requirement.
The use of M12 bolts (Grade 8.8) in sections up to and including 240mm deep.
Meets forthcoming Eurocodes; BS EN 1993-1-3:2006.
Practical Sleeve solution providing additional support to purlin prior to fixing.

Development behind the Albion Sigma beam purlin has been to assist in combatting rising materials costs with a lighter more efficient product.

Whilst providing a cost effective solution, the Sigma purlin is also designed in accordance with BS EN 1993-1-3:2006.

Albion Sigma purlin offers:

Material grade S450 as standard.
Requiring less accessory components e.g. anti sag bars and sleeves when compared to zed sleeved systems.
Vastly improved speed and ease of erection.
14 dia holes to suit M12 bolts (sections up to 240mm deep).
Practical sleeve solution providing additional support to purlin prior to fixing.

Section Dimensions Table

Click Here to enlarge