Placement of sign channel

I have recently had some signs to diag 878 made. The signs are 625w x 680h and the fixing channel has been placed 200mm from top and bottom of the sign plate giving a distance of 275mm between channels. This gives two issues, 1, if fitting back to back with existing signs it is very difficult to get hands up the back of the sign to fit clips and 2, the top / bottom of the sign is vulnerable to vandalism by bending over the sign plate. The manufacturer has indicated that the channel spacing was specified as part of the proprietary design s/ware. Signs from a previous supplier had channel 50mm from top / bottom edges.

I have looked in 12899-1 2007, Specification for Highway Works 1207 and channel suppliers literature but cannot find any guide / best practice on placement of top / bottom channel. My memory from the old SignFix days was max 150mm from top / bottom and max 600mm for intermediate channel.

Does anybody have thoughts please


  • Hi Phil
    Well, it wasn't our SignLoad software, which defaults to 150mm margin for the top and bottom channels, but can be set to any other value. I agree that 200mm is too high and not in keeping with industry norms or recommendations.
  • Hi, Simon, the software used by the manufacturer was SignPlot v 3.45. I speculate they have not configured it correctly. However I am surprised there does not appear to be national guidance / specification on such a fundamental element of the sign design process.
  • Channel spacing and positioning has always been down to manufacturers' recommendations, perhaps because the different proprietary products available make it difficult to provide national guidance. We were the first to work it out analytically, based upon deflection and ultimate strength of the various channels with each possible substrate, but had to provide separate data tables (built into the software) for each product. The default 150mm margin we took from one company's recommendation on what is common practice, as it was not important structurally (but very important for erection and serviceability for the reasons you mention). In the User Guide where we show how to change it, we use 75mm as an example of what it might typically be changed to.

    This is the same software your sign manufacturer was using, as SignLoad is built into SignPlot, but they must have changed the channel margin to 200mm for reasons known only to themselves.
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