www.highwaysmagazine.co.uk
DECEMBER 2013 Building barriers
New wind-stability requirements in legislative guidance and concerns about the consequences of falling short on safety are prompting contractors to demand higher-specifi cation roadwork barriers, explains Baden Sparkes from JSP
BARRIERS 49
JSP’s barriers are designed to meet certain wind forces
“Roadworks provide increased risk in what is already a very hazardous environment.” It is a seemingly common-sense statement, but, delivered as it was by a Health and Safety Executive (HSE) inspector following the prosecution in November of a road-maintenance fi rm in relation to a serious road accident, it carries certain poignancy.
The incident in 2010 left a motorcyclist paralysed following a collision with traffi c signs on the A12. The fi rst indication of a road closure came just 175 metres on the approach to the roadworks, giving vehicle users little time to slow down.
Following the court hearing, at which Carillion AM Government was fi ned £180,000, HSE inspector Sandy Carmichael explained that had the company complied with the industry’s code of practice and correctly placed temporary warning signs to alert motorists in good time, the incident could have been avoided.
The Safety at Street Works and Road Works Code of Practice has recently been updated and road contractors have just under a year to bring their systems and practices into line with its requirements.
Prosecutions, such as the case highlighted above, and civil claims from members of the public or road
workers illustrate the consequences of non-compliance with the code, raising safety awareness among contractors. Meanwhile, manufacturers of safety equipment have been working to align their products with the code for some time, with new designs incorporating contoured sections to maximise wind fl ow through and around road safety barriers.
Don’t throw caution to the wind
The key change to the code in relation to barriers is its specifi c reference to BS 8442:2006, which considers the wind stability and testing of such equipment.
According to the code, wind force should be calculated in accordance with Annex B of BS 8442, and barriers must be capable of withstanding winds of class C (8.7m/s) blowing from any direction. The code suggests it may be necessary to use ballast or cross-bracing as a means to achieve stability. In Scotland, there is a further requirement: from 1 April 2015, barriers must be capable of withstanding winds of class B (17.6 m/s) blowing from any direction, where a site is unattended for 24 hours or more.
With contractors increasingly seeking specifi cation information of a more scientifi c nature to mitigate the chances, in part, of becoming the subject of litigation or prosecution, JSP commissioned a Formula One aerodynamics testing company to simulate barrier performance of its new
Frontier Cross-Link at different wind velocities and angles.
Various confi gurations were examined: three barriers in a line; two barriers connected via cross bars; four barriers in a square formation; and a T confi guration incorporating a cross member linking another barrier at right angles every two or three barriers – a layout the company recommends when digging long linear excavations. Tests showed that all confi gurations met class C wind speeds, with the two-barrier and square formations withstanding class B; tests in the T confi guration showed the barriers were even capable of achieving class A wind velocity (26.3m/s).
Stability and fl exibility
There are many other accessories that contractors can specify to ensure the barriers meet wind classes C and B and further improve stability for the safety of road workers, pedestrians and road users. Telescopic stability poles, for example, are a relatively new concept. JSP’s conversations with contractors indicate that fl exibility is a key requirement, so it has designed poles that enable barriers to be stabilised between distances of 1m and 1.75m apart, and at various points in between.
As well as connecting to other JSP barriers to increase stability, the poles also allow for connection to a heavy-duty foot cover, namely the ‘Surefoot bloc’ which creates an anchored weight when another barrier is either cost-prohibitive or unsuitable for the space constraints involved. The code specifi cally recommends use
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