How to reduce dust by applying the STOP principle

dust reduction

Following on from our “Why you should care about dust” article, we'll now be looking at what can be done to reduce dust exposure.

We'll begin by discussing Workplace Exposure Limits and risk assessments, before delving into the main focus of this blog - the STOP principle.

Exposure to dust is highly regulated

Please enter alternative text here (optional)

Since some dust particles can be potentially harmful, national authorities have set so-called Workplace Exposure Limits (WEL). These values are upper limits that define the acceptable concentration of hazardous dust in the workplace, based on a time-weighted average throughout an 8-hour workday. WEL values exist for specific dust types and depend on their hazard level.

For example, if you're processing materials that contain silica by drilling, chiselling, sawing or grinding, the dust will most likely contain respirable crystalline silica (RCS). These particles are especially dangerous as they can go deep into the lung and reach the lung alveoli, where long-term overexposure can cause damage to the respiratory system. In worst-case scenarios, this may result in a disease called silicosis, which is currently incurable.

Because the health effects of dust can be dramatic, WEL values were established to protect workers. They vary amongst different countries, so you should always check with your local authority to get the WEL values that apply to you.

Do you know what these limits mean in practical terms? It's a tiny amount - like a small pinch of salt - and weighing less than a penny.


A reliable way to assess the amount of dust in your workplace is by systematically measuring it. Dust particles can be measured by using specific sampling equipment - the HSE published a variety of suitable samplers for such an undertaking.

It can be time and cost intensive to implement and execute air monitoring, so another possibility is to refer to previous measurements and investigation reports. Tool manufacturers, raw material suppliers or research organisations may publish this data. However, when referring to such data, bear in mind that it's always an average and taken in a laboratory - which is different to your everyday site conditions. Therefore, caution is required as it can easily result in overexposure.

The German BG BAU provides task-based measurement data as an aid to assessment. Similarly, US-based Occupational Safety and Health Administration (OSHA) has published a list of 18 recommended product solutions reflecting common silica-generating construction tasks, with corresponding control methods that they deem effective.

Once you've assessed the dust exposure at your workplace, you can then carry out a risk assessment to define appropriate protective measures.

general advice on risk assessments

A risk assessment is the process of evaluating risks to workers' health and safety and defining what preventive measures are - or should be - in place to control the risks. The OIRA provides several resources with the aim of supporting companies in conducting risk assessments.

We can also apply the STOP principle to help reduce dust in the workplace. This principle is in accordance with the prevention methodology of leading European institutions and authorities. It's also the principle that Hilti uses when considering health and safety!


stop principle

STOP defines the sequence of controlling risk:

Substitution is the elimination of the risk by using safer alternatives. By doing so, the root cause of hazards can be avoided (e.g. for some applications, we recommend diamond drilling or direct fastening to minimise dust and HAVS exposure).

Technical measures are machinery, tools or technologies that reduce the amount of dust in the air (e.g. Hilti Dust Removal Systems (DRS) and Active Vibration Reduction (AVR) are practical harmonised systems designed to reduce the risk. We’ve also introduced NFC tags in our tools that connect to the Hilti App, allowing operatives to access safety information, training videos and safe exposure information at the click of a button).

Organisational measures lead to improved work organisation (e.g. Hilti ON!Track software allows users to manage employee certifications and access health and safety information such as EAVs).

Personal protective measures are required when the risk can't be removed, so Personal Protective Equipment (PPE) must be worn.

As the conversation around construction dust continues to gain momentum, it's your responsibility to make your business as safe as possible. Want to become virtually dust-free? Check out our Hilti dust management solutions, or visit our dust page for more in-depth reading.