Wind Tunnel Testing - Demarcation System
Wind Tunnel Testing - Demarcation System
B.S.6399-2:Code of Practice for Wind loads
The Building Research Establishment (B.R.E.) confirms that buildings are generally designed for wind speeds with an annual probability of exceedance of 0.02 i.e. a 1:50 year wind speed. If your demarcation system is intended to be left on the roof for one year or more, it should meet the same design parameters.
The D-marc has been wind tunnel tested by the BRE (test report 240857) on single ply, bituminous and concrete roof surfaces resisting wind speeds in excess of 105 mph.
Given that traditional demarcation systems become unstable at wind speeds of 50 mph, it is worth taking a look at the likely incidence of such an occurrence in the UK. If you take atypical UK urban location e.g. Coleshill in the Midlands, figures from the Met office show that over the past 10 years there have been 77 such events.
The lattice structure and base ensure the system cannot be blown over and will not oscillate