HSE estimates that 4000 construction workers die from occupational disease every year; most of it lung-related. And each year construction is responsible for 5500 new cases of occupational cancer.

 

Executive Summary

Healthier Highways is our programme aimed at improving health protection across the M25 supply chain, where we work in partnership with health protection and occupational hygiene specialists, Steve Perkins Associates.

Working with Tarmac and Skanska, planing contractors and a planer manufacturer, we've been able to make a great step forward in controlling dust exposure on asphalt planing operations which will result in significantly improved health protection for colleagues working in this area.

The results of a static exposure dust monitoring assessment showed unacceptably high levels of inhalable and respirable dust was created during planing operations, that was at or above the current recommended exposure limits. Further monitoring then concluded that the systems for water suppression and dust extraction on the planers (the main engineering controls for dust in planing) were not being operated as per the manufacturers’ instructions, leading dust levels to more than double.

These findings have been shared across the M25 supply chain and the necessary process and procedural changes are being made to ensure planing dust levels are controlled to as low as reasonably practicable.

Aims & Objectives

The Healthier Highways leadership team suspected that dust levels were likely to be high during surfacing works. During December 2019, exposure assessments were carried out by a chartered occupational hygienist on a number of M25 sites. It was found that asphalt planing activities gave rise to significant personal dust exposures for planer crews. Although silica dust levels were relatively low, respirable and inhalable dust levels were found to be at or near the advisory limits. It was concluded that there was a need to formalise existing control measures, as well as take further steps to reduce dust exposures.

Solution

At a supply chain working group formed by all the partners, discussions revealed that there was a perception in the industry that operators should minimise water use during planing. To objectively assess the impact that water suppression and extraction fan conditions have on the generation of dust during planing, we undertook further static exposure dust assessments during August and September 2020. These assessments were carried out during planing works with both Skanska and Tarmac.

We found that dust levels were significantly reduced when the controls were operated as per the manufacturer’s instructions (i.e. with 100% water spray volume on both the drum and belt of the planer, and a properly maintained and clear fan). Dust levels were found to more than double when water was removed from the belts or when the overall water flow was reduced. This difference in dust levels could even be observed visually between the unrestricted water case (image below, left) and the restricted water case (image below, right).

Following further discussion and investigation by the supply chain working group, we concluded that there was no need to minimise water usage during planing on the M25 works, as the working window for planing is relatively short. As a result, we've been able to more than halve dust levels through the proper use of existing engineering controls, providing a much safer working environment at little or no additional cost to the job.

Unrestricted water

Restricted water

Plans and progress

Connect Plus/Connect Plus Services are considering introducing checks on the use of water for planing to ensure that it is carried out in accordance with the manufacturer’s recommendations. Tarmac and Skanska are looking at how they will ensure checks are made with their planing crews and contractors on water spray usage and fan maintenance. Wirtgen are considering the guidance they can provide for planer operators to ensure the Local Exhaust Ventilation (LEV) system of the planer fan and ducting is adequately maintained and tested to satisfy the requirements of the COSHH regulations

The Supply Chain Working Group has been a great example of how cooperative working can achieve a positive health change for our workforce.

The supply chain working group has agreed that all planing contractors working on the M25 will ensure that water flow and extraction fan speeds are operated in accordance with the manufacturer’s recommendations. This means water will be supplied to all belts, as well as the cutting head, at 100% and that the fan will be set at 100% extraction.

Contractors will also ensure they have adequate checks, maintenance, thorough examinations and tests in place for the extraction fans to satisfy the requirements of  COSHH regulations.

Measuring success

We are now considering introducing checks on the use of water for planing, to ensure that it's carried out in accordance with the manufacturer’s recommendations. Tarmac and Skanska are looking at how they will ensure checks are made with their planing crews and contractors, on water spray usage and fan maintenance. Wirtgen is considering the guidance they can provide for planer operators to ensure the Local Exhaust Ventilation (LEV) system of the planer fan and ducting is adequately maintained and tested to satisfy the requirements of the COSHH regulations

The Supply Chain Working Group has been a great example of how cooperative working can achieve a positive health change for our workforce.