Ballast dust continues to be a priority issue, with several high-profile campaigns such as ‘No Time to Lose’ and Network Rail’s Ballast Dust Working Group championing and educating the industry for greater control measures on dust.
But the rail industry is not alone in the issue. Construction, quarrying, waste and recycling all face the same challenges. So how can exposure to dust be reduced when it’s an inevitable outcome of heavy construction and engineering works?
Identifying the problem
A survey published by the Construction Industry Partnership and IOSH (Institution of Occupational Safety and Health), which was commissioned to gather information on how the construction sector manages the dust risk, revealed that almost half (44.3 per cent) of survey respondents felt that “very little” priority was placed on how the sector controls the dust risk.
In rail, it is well documented that ballast-handling activities increases exposure to Respirable Crystalline Silica (RCS). Breathing in these harmful silica particles at high concentrations, over long periods, can have a serious impact on a worker’s health.
According to research from the HSE (Health and Safety Executive), it estimates that almost 800 deaths a year are caused from occupational silica exposure, with at least 900 new cases being diagnosed annually according to results from studies by Imperial College London.
With the number of national cases for silica exposure rising year on year, coupled with the growing number of policies on managing air pollution in our towns and cities, of which construction dust and rail repair works are cited as some of the key contributors, it will only be a matter of time before more robust measures and limits are in place; particularly as the government reviews its Clean Air Strategy, which will look at reducing total emissions and protecting health.
Of course, education, collaboration and monitoring are fundamental requirements in creating and implementing a strategy to control and measure any hazard, as well as the burgeoning green agenda. Dust prevention strategies will be critical in reducing exposure to silica dust for workers in rail, but also supporting managers as they look to implement sustainable best practice. Engineering control measures, featuring equipment and technology such as dust suppression, will be key elements of a sustainable dust prevention strategy.
Dust suppression systems offer efficient and portable alternatives to traditional methods such as sprinkler systems, manual water hose operation and water bowser trucks that run alongside the ballast wagons. Often on site, teams can be standing for hours at a time with a hose, or inside the bowser vehicle, waiting for the ballast to arrive.
Dust suppression systems speed-up the control process and manage the hazard. Unlike traditional methods, the suppression systems use nebulized water – water particles between 50 and 150 microns in diameter that can capture dust particles with an average diameter of 80 microns. As such, they hold and drag dust particles to the ground, completely covering the ballast and dust cloud, thereby preventing contamination.
Trials undertaken by primary health and environmental firms have certified a decrease of the dust particles by at least 50 per cent in the worst operational conditions through using dust suppression systems which have been deployed as part of a dust prevention strategy.
Updates to technology have seen many mobile power tank dust suppression units operating through start/stop remote technology. This simple feature means that the suppression system can be activated, by a single operator, when the ballast is there. This reduces the health and safety risk to workers who manually dampen dust with a water hose as ballast wagons move along the tracks. It provides greater control of water and means manpower can be focused on getting the project completed, not waiting for ballast to arrive.
Power technology has also evolved the design and efficiency of dust suppression systems, delivering greater fuel economy and projection range.
Once switched on, mobile power tank dust suppression systems can operate autonomously, as many have their own generator and water bowser unit, making them suitable for almost any site.
They can deliver a projection of between 30 and 120 metres, while the automatic rotation systems of the unit enable managers to direct the coverage, plan and place these mobile power tanks intermittently along the ballast or upgrade routes, providing a consistent flow of dust control at height and at ground level.
On the sustainability front, the advances in technology have enabled site managers to keep OPEX costs in check, as the dust suppression units consume up to 90 per cent less water, resulting in a greener operation as well as greater control over water consumption and reduced waste.
Last year, Skanska implemented a dust control strategy during the upgrade works at Waterloo Station. As a key health and safety requirement, the dust suppression units were deployed to control, cover and reduce dust contamination into neighbouring platforms, across operational train routes and indoor passenger terminals.
Working collaboratively with partners, it was agreed to place different dust suppression products according to the range, strength and volatility of the dust cloud during the works period. For example, all-in-one mobile power tanks were used to dampen down ballast dust being loaded and unloaded into the wagons and covered a distance of up to 40 metres.
Significant steps are already in place to help tackle dust. Yet traditional dust control methods often need to be in constant use for any positive impact on controlling the issue. Even then, it is somewhat resource intensive and inefficient in terms of managing costs and manpower, as well as reducing water use.
Through the evolution of suppression and product technologies, dust suppression brings improvement in these areas helping to manage resource and drive down operational expenditure.
New product technologies in dust suppression will support managers further in tackling the issue and provide them with greater flexibility in managing costs and site sustainability.
Beat Nowrooz is product technical manager with Pramac-Generac UK.