Sigma Purlin System Roll Forming Machine
It offers solutions from 120mm to 400mm with gauges from 1.2mm to
3.2mm, all fully supported by Strucad and Tekla Structures
detailing packages, which also generate
Cam Data to reduce the risk of potential errors, and remove the
need for the time consuming creation of drawings.
Our new Sigma Beam Purlin generates excellent strength to weight
ratio improvements, not to mention the reduction of accessory
requirements in common design criteria, saving the additional cost
of components and erection time on site. This product has been
launched using S450 material rather than the existing industry
standard S390, and the Sigma Beam Purlin used with our standard
range of C sections as side rails offers practical, flexible and
economical solutions for all your purlin and rail needs.
Product Range
Here is a profile for your reference:
The system is designed primarily for use, on roofs, as secondary
sheeting support. Bay widths up to 15m and maximum roof slope of 25
degrees.Sigma sections are manufactured by cold roll forming
pre-hot dipped galvanised steel, grade S450, having a minimum yield
stress of 450N/mm2 Section properties have been 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.
Sleeve Assembly and Cleat Details
Sleeves are required to provide structural continuity of the purlin
section across the supporting rafter. All sleeves are of similar
length and longitudinal drillings consistent. Sleeve thickness is
dependent on purlin thickness - see table.
The most cost effective purlin system, in terms of material content
and number of components to erect, is the double span butt system.
Purlin Cleat Details
Standard Sleeve Dimensions
Note: Where Albion standard cleats are not provided, take care to
ensure that sufficient clearance is provided from the underside of
the purlin to the top of the rafter for the installation of the
sleeve.
Sigma Standard Drillings
Standard drillings are shown below for the sigma purlin range.14mm
diameter sleeve and cleat connection holes, to suit M12 bolts, are
used for the 200, 225 and 240 series sigma, whilst 18mm
diameter, for M16 bolts, are used for the 265 and 300 deep sigmas.
All connecting bolts to be grade 8.8. Speed fix holes, where
required, are 14mm wide * 20mm rectangular. Holes to suit
intermediate span angle struts are 14mm diameter for M12 grade 4.6
bolts. 14mm diameter flange holes provided if required. Maximum
section length 16m.
Sigma Purlin System Roll Forming Machine
Sigma Purlin Systems and Joining Layouts
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).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
Use with 200, 225, and 240 Series
The most popular purlin system combining double span lengths with a
minimum of jointing sleeves. The sleeved system can be used for
buildings with two bays or more and combines a cost effective
solution with ease of detailing. Bay widths are limited to 8m
(Maximum purlin lengths 16m)
Sigma Purlin Systems and Joining Layouts
Single Span Sleeved System
Heavy End Bay System An alternative to the double span system and
suitable for all bay sizes.May be used with all Sigma Sections.
Where purlins are required to be single spanning, but still
maintaining continuity over the rafters, the single span sleeved
system can be employed. With additional sleeves, as shown, the
ultimate capacities of the double span sleeve system can be
realised. Use also where access may be limited, i.e. purlin lifted
in from below.
Heavy End Bay System
Suitable on buildings of 5 bays or more Single span arrangement
(All Sigma Sections)
Speed Fix Anti-Sag Bars
Albion speed fix sag bars provide an effective restraint to the
purlin both during the cladding operation and under wind uplift
(reversal) conditions. The spring loaded clip fixing system makes
installation quick and easy. Speed fix should be fixed as shown
below
Anti-Sag bars serve two main purposes:
• To stop the purlin twisting during erection. (Once sheeting is
fixed the purlin derives a large measure of stiffness from the roof
membrane).
• To provide lateral restraint to the bottom flange under uplift
conditions.
Note:These details apply to roof slopes up to and including 25º. For
roof slopes greater than 25ºconsult our Technical Department.
Speed Fix are manufactured from 1.6mm thick pre-hot dipped
galvanised mild steel and cold formed into a channel section 15mm
deep * 12mm wide.Each end is notched to locate in the standard pre
punched rectangular holes at mid span or third points.Alternative
apex ties are manufactured from 12mm diameter allthread, zinc
plated finish.
Angle Strut Purlin Restraints
For larger spans or deeper sections, angle struts are used to
provide stability during the cladding operation and under wind
reversal conditions. Angle struts are manufactured from 45*45*2mm
pre-hot dipped galvanised angle. Holes in the struts are all 14mm
diameter to suit M12 bolts.
Anti-Sag Minimum Requirements
Apex ties must be used on all spans over 4m on duopitch roofs.
Long Roof Slopes
Where roof slope exceeds 20m, intermediate span restraint is
required to resist down slope loadings. This is provided by a strut
and tie system as shown.
Anti-Sag Minimum Requirements
Mono Pitch Roofs
On mono pitch roofs, strut and tie system is required at the apex,
to resist down slope loadings
Flat Roofs
(Slope less than 3º)
For very low pitch or flat roofs the Sigma purlins are installed in
facing pairs, as shown below Angle struts provided at mid span for
spans in excess of 4m and third span positions for span in excess
of 7.1m.
Cleader Angles & Rafter Stays
Rafter Stays/Column Stays
Rafter Stays are manufactured from pre-hot dipped galvanised mild
steel and cold roll formed into angle section 45mm x 45mm x 2.0mm
thickness.
Typical Details
Purlin Gable Overhang/Cantilever Detail
Gable Verge Detail
Further applications of Albion Sigma beams
Mezzanine Floors
The Sigma profile is ideally suited to provide structural support
to lightweight floors.
Sigma Purlin System Roll Forming Machine
