Safe and Compliant Overbanding: 5 Best Practice Steps for Potable Water Projects

What is Overbanding?

The process of sealing or repairing cracks and joints in surfaces is known as overbanding. It is a process that is common during highway and water infrastructure projects to prevent water ingress in materials such as asphalt and concrete.

This article is designed to give practical advice and best practice information for the occupational health and environmental challenges commonly associated with overbanding work in the water sector. For specific and additional information around confined space working, you can refer to our introductory whitepaper here >

Overbanding in the Water Industry

When overbanding works are taking place in the water industry, using best practice is essential to:

• Prevent contamination
• Meet strict regulatory standards
• Safeguard worker and public health
• Protect infrastructure integrity (e.g. avoid water ingress)

It involves choosing the right materials, applying them correctly, and ensuring that all work aligns with environmental and water safety guidelines whilst balancing the health and safety risks whilst works are underway. This is especially true when works take place in a challenging environment.

Potable Environments, Regulation and Compliance

Environments involved in making water safe for ingestion, also known as potable environments, or water-sensitive areas must ensure they do not contaminate drinking water.

In England and Wales, works are subject to regulations enforced by the Drinking Water Inspectorate (DWI) under the Water Supply Regulations 2016. These regulations require water quality to be protected at every stage, including materials used during works such as overbanding.

Under these regulations, DWI regulation 31 specifies:

• The management of products and substances used near water intended for human consumption
• Overbanding materials (e.g. bituminous sealants) must not leach harmful chemicals into the water supply
• Only products approved under Regulation 31 should be used

While Scotland doesn't use the same "Regulation 31" system, it adheres to similar principles known as Regulation 33 whereby materials in contact with drinking water must be demonstrably safe.

Best Practice for Overbanding Processes

1. Measuring Air Quality Across Environments

Environments such as service reservoirs can experience the build-up of harmful gasses such as Radon, Chlorine and more. The use of appropriate monitors to measure air quality and forced ventilation is critical to the safety of operators who could otherwise fall victim to oxygen deficiency.

Every project should be assessed on its own merits. Speak to a member of the team at RVT Group to discuss how we can help calculate your requirements >

2. Managing Toxic Hazards During Overbanding Preparation

If the environment requires invasive work such as concrete breaking and grinding, this can create high volumes of toxic silica dust. Some overbanding products will also release toxic gas while curing e.g. Acetoxy based sealant.

Engineering controls such as Local Exhaust Ventilation (LEV) can capture dust and fumes at the source, forcing it through a vigorous filtration process to minimise exposure to harmful byproducts overbanding can produce. Such controls can also give PPE and other last lines of defence the best chance of success.

Speak to a member of the team at RVT Group to discuss suitable LEV options >

3. Meeting DWI Regulation 31 and Scotland’s Regulation 33

Products involved in the overbanding process (such as Sika and other popular brands) typically require temperature and/or relative humidity to be maintained for a given period of time in order to meet regulation standards. Work during the winter months can prove challenging.

Temporary heating or dehumidification during the preparation and curing process with regular measurements logged can prove compliance has been met.

4. Controlling Pollution Risks and Environmental Emissions

Spilled fuel can cause serious pollution to drinking water. Regulators will have their own requirements for bunding and containment of machinery on site and fuel storage is likely to be restricted to a certain distance from any water asset to minimise the risk of damage. Being aware of the standards expected from water regulators can ensure standards are met and works progress smoothly.

Water assets in remote locations may mean that temporary power is required for tools, welfare and heating. If being used, consider more sustainable alternatives such as HVO fuel and hybrid generators.

5. Keep Proximity to the Public in Mind

Water assets are often located near businesses, residents and public areas. The introduction of site works, generators and noisy machinery can create noise pollution that disturbs both people and the environment.

Environmentally sensitive locations may also implement additional noise restrictions to prevent disturbance of the local area, for example near bats or nesting birds at certain times of year.

Acoustic barriers and enclosures can be positioned to break the line of sight between the noise and any sensitive receptor, reducing the noise impact.

Overbanding is a cost-effective and minimally invasive repair, but only when works are carried out effectively. By implementing these 5 steps, you will have elevated your overbanding process, safeguarded your team and met regulation standard.

RVT Group recognise that not every overbanding project is the same, so if you need tailored support, regulatory guidance, or help selecting compliant equipment, get in touch today >