Installation and Rigging
How we put your fabric structure into place
Installing tensioned fabric canopies in their many forms, takes a great deal of experience and understanding of the logic of steel erection, plus a broad knowledge of a large range of fabrics.
For exterior canopies, all our installation work is carried out by our in-house team of riggers, trained in safe and appropriate use of machinery and access equipment and in safe practices on site, and briefed with the agreed details of the risk assessment and method statements. Exterior canopies very often involve the inclusion of a steel or timber supportive frame, the erection of which very often leads the site installation. Foundations may be installed by the main contractor, though we are also able to deal with this where required.
On site, our team will pay particular attention to setting out, checking that all the site details are 100% in accordance with the drawings, and so making sure that everything is in order from the off. Steel erection will then be carried out, manually or with lifting equipment depending on the size. The fabric will then follow, being installed onto the steel structure itself or fixed using brackets where wind conditions require it. Particular care has to be taken when handing the fabric, as although its tough form and lacquer finish give most fabrics upward of 25 yrs life, care must be taken not to damage the surface when it is folded etc.. A sacrificial fabric will often act as a ground layer.
Tensioning is the final aspect of the installation. This must be carried out in a specific order, tensioning in certain directions where particular details or fabric stretch dictates. The final tension is predetermined by the engineering of the structure, as 'pre-tension' levels must be achieved to make sure the canopy is tensioned to the correct amount to prevent excessive fabric movement under wind and snow loads.
For interior and exhibition canopies or structures, the procedure is very often the same. A support structure perhaps forms a frame to fix to, or brackets fixed to walls, where a canopy will be tensioned within a space. The same degree of understanding is required of this frame and the fabric, though due to the environment we are working in and the 'fit out' nature of the space, the rigging team understand exceptionally short install lead times, the 'just in time' nature of the other trades working very closely on site and the requirement for tidiness.
Key to our business, but meaning a lot of different things to different people, we use the term 'rigging' to refer to hardware, usually stainless steel, used for fixing and tensioning canopies into place. The variations in designs, details and sizes are huge, from M5 upward to M36 and beyond, but obviously the size of the rigging section will depend directly upon the load that is being imposed upon it.
For interior applications, rigging is generally smaller than exterior, still being used for tensioning but not being put under anywhere the loads of exterior canopies.
The above image shows a typical M6 'Rigging Screw' or 'turnbuckle' just prior to the nuts being locked into place, fixed to a 'deck plate' screwed to solid block wall. This is typical for many interior installations, where canopy size is not too large and small tensioning devises are appropriate.
For larger interior canopies, where loads are increased (as more tension is required to pull the canopy into shape) the size of connectors will increase. This direct relationship of larger loads requiring larger rigging sizes obviously extends to exterior environments, and more so where higher safety factors come into play. Engineering information gained during the design process will dictate these fixing and rigging sizes accordingly.
The image above right shows a laser cut profile and stainless steel connection element on an permanent exterior canopy.
When cables are used there are a number of methods of finishing the ends. Sometimes this depends on loads and therefore end details, but also based upon costs and aesthetics. Here is a typical example of a small 2.5mm cable, crimped closed with a Nico press. A thimble (lining to loop) is inserted to protect the cable and inserted pin from point loading. This operation is easily carried out on site by hand.
Image shows 2.5mm 7x7 Nico press crimped cable with feral to create a 'hard eye'
Cables can be crimped from around 1mm up to 20mm and beyond, but do require a flexible weave of cable (see later note on cables types). An alternative to the Nico press is the Roller Swage. This uses a tube that has a connection on its end (thread or look etc.) that is crushed onto the cables at tremendous pressure. This involves the local crushing of the terminal onto the cable, compressing all parts to make an extremely strong connection that is also very neat in appearance. This process is best carried out off site as it requires the use of hydraulic machinery due to the huge loads required to crush the section.
Photo shows a machined fork terminal with swage to cable (above) and a threaded stud which again swages to a 6mm cable (below)
The cables used for the rigging again vary in type, size and make up depending on what is required from the cable. The types we commonly use are:
1 x 19 – Meaning the cable is made up from 19 small threads of solid steel, which offers very low stretch and very high strength.
7 x 7 – meaning the cable is made up from 7 clusters of 7 threads of solid steel, which offers medium flexibility.
7 x 19 – meaning the cable is made up from 7 clusters of 19 threads of solid steel, inevitably offering excellent flexibility.
Ultimately the subject of rigging is huge and it would not be possible to provide all the information associated with it, but we hope this small overview assists you in understanding the type of fixings and cables we use. Of course please email or call us to chat through any questions you may have.