Understanding the Waterwall vs Dustblocker Discussion

As HSE continues to focus on respirable crystalline silica (RCS) exposure within stone masonry, worktop fabrication and memorial masonry businesses, many employers are reviewing whether their dust-control arrangements remain suitable and compliant.

Recent discussions within the industry have led some businesses to question whether Waterwalls should replace Dustblockers as the preferred supplementary dust-control measure.

The answer is not that simple.

Importantly, HSE guidance does not require the use of Waterwalls, nor does it identify them as the preferred supplementary control for every stoneworking environment. Instead, HSE promotes a risk-based, layered approach using multiple control measures working together to adequately control exposure to stone dust and respirable crystalline silica.

HSE: Controlling exposure to stone dust
HSE: Silica dust in stonemasonry

What Does HSE Actually Require?

The starting point for any discussion must be HSE's hierarchy of dust control.

HSE guidance for stoneworking consistently prioritises:

• Eliminating or reducing dust generation where possible
• Water suppression
• Local Exhaust Ventilation (LEV)
• Process enclosure and segregation
• Good housekeeping
• Appropriate respiratory protective equipment (RPE) where required

The emphasis is firmly on controlling dust at source before considering supplementary measures. HSE also recognises that effective control typically involves a combination of engineering controls, workplace organisation and management arrangements, rather than reliance on any single technology.

For many modern fabrication workshops, this already includes:

• Wet cutting
• Wet polishing
• Water-fed handheld tools
• LEV systems
• M-Class or H-Class extraction equipment

These controls are generally considered the primary means of reducing worker exposure to respirable silica dust.

Where Does a Waterwall Fit?

A Waterwall is a supplementary dust-suppression measure designed to capture airborne dust using a curtain of water. Its role is to reduce dust that has already escaped the immediate point of generation.

Waterwalls can be an effective addition in some environments and may help reduce airborne dust levels within a work area. However, they are not specifically required by HSE guidance, and HSE does not identify them as the universal next step once wet-working and LEV controls are already in place.

In many stoneworking businesses, water suppression is already being applied directly at the cutting, grinding or polishing process. In these cases, a Waterwall may provide an additional layer of suppression, but it remains only one of several supplementary measures that could be considered.

Where Does a Dustblocker Fit?

A Dustblocker addresses a different aspect of dust control.

Even where effective wet-working and LEV systems are operating correctly, businesses can still face challenges such as:

• Dust migration into offices, welfare areas or showrooms
• Exposure of personnel not directly involved in stone processing
• Contamination of clean workspaces and finished products
• Dust spread during housekeeping and maintenance activities
• Segregation of dusty and non-dusty processes

HSE guidance places importance on process isolation, segregation and workplace organisation as part of an overall dust-control strategy. Containment measures that help separate dusty activities from other parts of the workplace can therefore form an important component of a comprehensive control programme.

This is where Dustblockers can provide value by creating controlled work zones and helping to contain contaminants within designated areas.

Why Waterwalls Are Not Necessarily the Preferred Supplementary Control

A common misconception is that because Waterwalls use water, they must automatically be a superior supplementary control.

HSE guidance does not make this distinction.

The guidance does not state that Waterwalls are superior to segregation measures, nor does it require businesses already using effective wet-working and LEV to install Waterwalls as an additional control.

Instead, employers are expected to assess the risks within their own workplace and select suitable controls based on those risks.

The most appropriate supplementary control often depends on the problem being addressed:

• If the goal is additional dust suppression within the work area: a Waterwall may be considered.
• If the goal is preventing dust migration and maintaining separation between dusty and non-dusty areas: a Dustblocker may be more appropriate.

Both approaches can form part of an effective dust-control strategy depending on the requirements of the individual site.

Supplementary Dust Controls Should Be Risk-Based

Once primary controls such as wet-working and LEV have been implemented, businesses should evaluate any remaining risks.

In many workshops, these residual risks relate less to dust generation and more to:

• Dust movement around the building
• Cross-contamination between work areas
• Protection of adjacent personnel
• Maintaining controlled working environments

Dustblockers can help address these concerns through containment and segregation, which are control principles recognised within HSE guidance.

This does not mean that Dustblockers replace water suppression or LEV. Nor does it mean they replace Waterwalls. Rather, they provide a different type of control aimed at a different risk.

A Layered Approach Delivers the Best Results

The most effective stoneworking environments typically combine multiple measures.

Primary Controls

• Wet cutting
• Wet grinding
• Wet polishing
• Water-fed hand tools
• LEV extraction

Supplementary Controls

• Dustblockers
• Segregated work areas
• Process containment
• Controlled access zones

Additional Measures

• Housekeeping procedures
• Air monitoring
• Health surveillance
• Appropriate RPE

This approach aligns closely with HSE's overall philosophy of combining engineering controls, segregation and management controls to minimise exposure to respirable crystalline silica.

Waterwall vs Dustblocker: Which Is Right for Your Workshop?

Waterwalls undoubtedly have a role in dust management and can provide additional airborne dust suppression in certain environments. However, HSE guidance does not require the installation of Waterwalls, nor does it identify them as the default or preferred supplementary control for stoneworking operations.

For businesses that already have effective wet-working methods and LEV systems in place, Dustblockers can remain a legitimate supplementary control measure. They can support containment, segregation and the prevention of dust migration, all of which form part of HSE's broader approach to controlling exposure to stone dust.

The key issue is not simply whether a workplace uses a Waterwall or a Dustblocker. The key issue is whether the overall control strategy adequately manages the risks identified within that workplace and effectively protects workers from exposure to respirable crystalline silica.

That is ultimately the outcome HSE expects employers to achieve.

Further HSE Guidance

• HSE – Controlling exposure to stone dust
• HSE – Silica dust in stonemasonry