TRAD Demarcation Barrier System is classed as a form of Collective Protection in accordance with the HSE’s hierarchy of risk management as set out within the Working at Height Regulations 2005 (WAHR). The WAHR 2005 Part 3 illustrate the use of a demarcation system as an “example of taking other additional suitable and sufficient measures to prevent a fall”. The demarcation system is to be placed a safe distance from the fall hazard (normally 2 m).
Health and Safety in Roofwork HSG33 states that “where work is not done at the edge, demarcation barriers can be provided at a safe distance from the edge. (usually at least 2 metres). e.g. work on an air-conditioning unit in the middle of a roof.”
BS6399-2:Code of practice for wind loads. The BRE 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 BRE concludes that a 1:50 year occurrence would be 30m/s (approx 67mph).
