A Practical Guide to Silica Dust Management in UK Construction

Introduction

Managing exposure to silica dust is an important part of protecting construction workers’ health and meeting UK health and safety requirements.

Activities such as cutting, drilling, grinding, chasing and working with concrete, bricks, mortar, stone and similar materials can release very fine dust into the air. Where that dust contains respirable crystalline silica (RCS), particles can travel deep into the lungs and cause serious long-term harm.

This guide looks at the practical steps construction businesses can take to assess, control and review silica dust exposure — from reducing dust at source through to selecting suitable respiratory protective equipment (RPE) and ensuring tight-fitting respirators actually fit the people wearing them.

What is Silica Dust and Why is it a Concern?

Silica is a natural substance found in many rocks, sand and clay, and in common construction products including bricks and concrete. When these materials are cut, drilled, ground, sanded or otherwise disturbed, they can generate dust.

Some of this dust can be extremely fine. The fraction capable of being breathed deep into the lungs is known as respirable crystalline silica (RCS).

Because respirable particles can be too fine to see clearly under normal lighting, the absence of a large visible dust cloud should not be taken as evidence that exposure is adequately controlled.

Long-term or significant exposure to RCS can cause serious health problems including silicosis, chronic obstructive pulmonary disease (COPD) and lung cancer.

For further information, see HSE INDG463 – Control of Exposure to Silica Dust.

Where Does Silica Dust Come From in Construction?

Silica-containing materials are encountered throughout construction, refurbishment, demolition, civil engineering and property maintenance.

The risk increases when these materials are subjected to processes that create fine airborne dust.

Health Risks: The Silent Threat of Silica Dust

The health effects associated with silica exposure normally develop over time, which means the danger can be underestimated in the workplace.

Workers may complete dusty tasks repeatedly without experiencing immediate symptoms while harmful respirable particles are being deposited deep within the lungs.

HSE identifies construction as a significant area of occupational exposure to RCS and estimates that silica exposure is associated with hundreds of deaths each year in Great Britain.

Assess, Control and Review

A sensible approach to silica dust follows the same underlying principles as other hazardous-substance controls: understand the task, identify how exposure can occur, implement effective controls and check those controls continue to work.

HSE’s construction dust guidance commonly uses an Assess, Control and Review approach.

1. Assess the Task

Consider the material being worked on, the activity being undertaken, how much dust is likely to be generated, how long the work will last and who may be exposed.

High-energy processes such as grinding, cutting, scabbling and chasing can generate particularly high concentrations of silica-containing dust.

2. Control the Dust

Controls should focus first on preventing or reducing the creation and spread of dust rather than relying solely on personal protective equipment.

3. Review the Controls

Check that water suppression, extraction equipment, RPE and working methods are being used properly and remain effective. Controls that exist on paper but are not used correctly provide little practical protection.

Applying the Hierarchy of Control to Silica Dust

Silica exposure should be managed using the hierarchy of control, with higher-order controls considered before relying on personal protective equipment.

Water Suppression and Dust Extraction: Control the Dust at Source

Water suppression and dust extraction can make a substantial difference to the amount of airborne dust generated during construction activities.

Water Suppression

Supplying sufficient water to the cutting or grinding point can reduce the amount of dust becoming airborne.

The water supply needs to be adequate for the equipment and task, and the system must actually be used as intended. Simply dampening the area occasionally is not necessarily equivalent to effective water suppression at the point where dust is generated.

On-Tool Extraction and LEV

Suitable on-tool extraction can capture dust close to the point where it is created. The extraction unit needs to be appropriate for hazardous construction dust, correctly connected, maintained and capable of providing sufficient airflow.

Effective engineering controls protect more than just the person operating the tool because they reduce the amount of contamination released into the surrounding workplace.

HSE publishes task-specific guidance covering activities including concrete scabbling, chasing, drilling, cutting paving and other silica-generating construction work. See HSE Construction Silica COSHH Guidance.

Focus on Respiratory Protective Equipment: FFP3 Masks and P3 Filters

There are construction activities where effective engineering controls still need to be supplemented by respiratory protective equipment.

For a number of high-dust construction tasks, HSE guidance identifies RPE with an Assigned Protection Factor (APF) of 20, giving examples such as an FFP3 disposable respirator or a half-mask respirator fitted with a P3 filter.

However, the marking on the respirator is only part of the equation.

RPE must be:

Tight-Fitting RPE Needs to Fit the Individual Wearer

This is particularly important where workers use FFP3 disposable respirators or reusable tight-fitting half masks.

These types of RPE depend on creating an effective seal between the facepiece and the wearer’s skin. Different people have different facial shapes and dimensions, so one make, model or size of respirator will not necessarily fit everyone.

For tight-fitting RPE, employers need to ensure that the selected facepiece has been face fit tested to the individual wearer using an appropriate fit-testing method.

The fit-test result relates to the particular make, model, type and size of respirator tested. Changing to a different respirator can therefore mean further fit testing is required.

Workers using tight-fitting RPE also need to be clean shaven in the area where the respirator sealing surface contacts the face.

For detailed guidance on fit testing, see HSE INDG479 – Guidance on RPE Fit Testing.

What About Powered or Loose-Fitting RPE?

For longer-duration or particularly demanding work, powered RPE may sometimes be more appropriate than relying on a disposable tight-fitting respirator. The choice should be based on the hazard, required protection, duration of the task and practical suitability for the wearer.

Do Not Forget Cleaning and Housekeeping

Silica exposure does not necessarily stop when cutting or grinding finishes.

Dust that has settled on surfaces can become airborne again when it is disturbed. Dry sweeping and uncontrolled brushing can therefore create another significant exposure.

Suitable industrial vacuuming and wet-cleaning methods should be considered instead of simply pushing settled dust back into the air.

Health Surveillance and Silica Exposure

Control measures should always be the priority, but employers also need to consider whether health surveillance is required.

Where workers are regularly exposed to RCS and there is a reasonable likelihood that silicosis could develop, appropriate health surveillance may be required under COSHH.

Further information is available from HSE guidance on health surveillance for workers exposed to respirable crystalline silica.

Practical Example: Effective Dust Management in Sunderland

A construction activity involving silica-containing materials should not rely on one control measure in isolation.

For example, a sensible control strategy for cutting or grinding work on a Sunderland construction site could combine effective water suppression or dust extraction, suitable working methods, restricted exposure and correctly selected RPE where residual risk remains.

If tight-fitting RPE such as an FFP3 respirator is selected, the worker should also have been appropriately face fit tested for the specific respirator they are expected to wear.

The important principle is that each measure supports the others: engineering controls reduce the amount of dust entering the workplace, while correctly selected and fitted RPE provides additional protection against the residual exposure that remains.

FAQs on Silica Dust Management

What is respirable crystalline silica?

Respirable crystalline silica (RCS) is the very fine fraction of silica-containing dust that can be breathed deep into the lungs. It can be generated when common construction materials such as concrete, brick, mortar and stone are cut, drilled, ground or otherwise disturbed.

What is the hierarchy of control and how does it apply to silica dust?

The hierarchy means prioritising methods that eliminate or reduce the hazard before relying on PPE. For silica this can include avoiding unnecessary dusty work, using water suppression or extraction, improving working methods and then using suitable RPE where residual exposure remains.

Why are FFP3 masks commonly used for silica dust?

For a number of high-dust construction activities, HSE identifies an APF 20 as appropriate RPE protection and gives an FFP3 disposable respirator or half mask with P3 filter as examples. The exact RPE required should always be selected for the particular task and exposure.

Does an FFP3 mask need face fit testing?

Yes, where an FFP3 respirator is a tight-fitting facepiece, it needs to fit the individual wearer. An appropriate face fit test should be carried out for the specific make, model and size the worker will use.

Can workers have stubble when wearing an FFP3 mask?

Not where facial hair or stubble crosses the respirator’s sealing surface. Tight-fitting RPE relies on contact between the seal and the wearer’s skin.

Is an FFP3 mask enough on its own?

Not necessarily. RPE should not be used as a substitute for reasonably practicable dust controls. Water suppression, on-tool extraction, working methods and other controls may still be required depending on the task.

Does every respirator need face fit testing?

No. Face fit testing applies to RPE that relies on a tight-fitting face seal. Loose-fitting powered hoods and helmets operate differently and do not rely on the same type of facial seal.

How Safety Inspectors UK Can Help With Silica Dust Management

Silica dust management involves more than selecting a mask. Safety Inspectors UK can support businesses with the wider arrangements needed to control workplace exposure and demonstrate that appropriate health and safety measures are in place.

Conclusion

Effective silica dust management is not about choosing between extraction, water suppression or RPE. In many construction activities, effective protection comes from combining the right controls in the right order.

Start by preventing unnecessary dust. Control what remains at source. Organise the work to reduce exposure. Then, where RPE is required, make sure it is adequate for the hazard, suitable for the wearer and used correctly.

And where that RPE relies on a tight-fitting face seal, do not stop at issuing the mask — make sure it actually fits the person wearing it.