Solar Racking Test
March 17, 2021
At SKYLIT we talk a lot about the quality of our hardware – and we can be confident of its quality because we do our own testing. This is something that makes us entirely different from other solar companies, especially here in Nova Scotia. Below is a description of our solar racking test.
We exhaustively test out hardware from alternative suppliers before we consider using it on your installation, because our systems are built to last.
You may hear about the different types of panels and inverter technology, whereas racking doesn’t get a lot of attention; but here in Nova Scotia we get crazy winds and monstrous snow loads. This is only going to get worse as climate change progresses.
So how do we test our racking? We set up a test rig to check out the load bearing capacity of the racking we use, supplied by TerraGen Solar:
A come-along is attached to a scale which in turn is chained to an off-centre cross beam that pulls down on the centre of the racking. The whole structure is supported on 2 saw horses. This enables us to measure racking rigidity and whether it permanently deforms under load. The loads were considerable. Here’s a piece of TerraGen racking with attachments 6’ apart with a 196kg load!
Even under a 196kg load, the racking returned to its original position with no permanent deformation. 196kg is equivalent to about 14½’ depth of new snow on the solar panel. Normally, racking has supports 4’ apart rather than the 6’ apart in the test, giving much greater support and even greater load carrying capacity than we saw in this test.
We tested the racking we use, TerraGen, against an alternative supplier’s CSA-approved racking, and you can see the results in the chart below:
With a 103Kg load, the TerraGen racking gave a deflection of 1.1 cm compared to 2.3 cm for the alternative racking. With loads right up to 196Kg, the TerraGen racking was still deflecting in a linear way, suggesting no loss of structural integrity, whereas the alternative racking was deflecting at an accelerating rate beyond 100Kg (about 7½’ of new snow). 7½’ of new snow is not a frequently occurring event even here in Nova Scotia, and with a regular roof attachment spacing of 4’ rather than 6’, the displacement would be significantly less. However, the glass on solar panels can shatter if the panel is subject to twisting torque so even a relatively small displacement can be problematic.
There are many markets where the alternative racking would be fine (Southern US or California, for example). Nova Scotia can have ferocious weather and after review of the other components of the racking system, we decided to stick to our TerraGen racking given its exceptional rigidity. When we say our systems are built to last – we mean it, and we can prove it too!