Dust control on construction sites

In the following article, Josh Thomas of international equipment specialist Ashtead Technology, sheds light on the dangers of dust on construction sites, Health & Safety Executive (HSE) guidance, emphasises the role that dust monitoring plays in dust control on construction sites, and discusses the types of dust monitors available.

Background

Although progress has been made in reducing the number and frequency of injuries among construction workers, this industry still poses significant risks and is responsible for a sizeable proportion of major and fatal injuries, but what is less recognised are the long-term health problems resulting from day-to-day construction activities.

Construction workers bear the highest occupational cancer rate compared to all other industrial sectors. The industry is responsible for over 40% of occupational cancer deaths and registrations. Every year, past occupational exposures cause over 5,000 cancer cases and around 3,700 deaths. Asbestos is the primary cause of these cancers, accounting for 70%. Silica dusts follow at 17%, and are also responsible for breathing problems and lung diseases that afflict construction workers, making it the second leading cause of death among this demographic. 

In fact, over 500 construction workers are believed to die from exposure to silica dust every year. However, it is important to note that other dusts containing very little to no silica and wood dusts (created from working on softwood, hardwood and wood-based products) are also a danger to health if they are small enough.

Many construction & demolition processes have the potential to create high levels of dust that can lead to diseases like lung cancer, asthma, Chronic Obstructive Pulmonary Disease (COPD) and silicosis. These processes include, but are not limited to:

– Cutting paving blocks, kerbs and flags
– Chasing concrete and raking mortar
– Cutting roofing tiles
– Scabbling or grinding
– Soft strip demolition
– Dry sweeping
– Cutting and sanding wood
– Sanding taped and covered plasterboard joints

To ensure safety, it’s important to establish preventative measures that limit exposure to harmful levels. These measures should be clearly outlined in the health and safety document, and regular monitoring should be conducted to demonstrate the effectiveness of these controls.

The Control of Substances Hazardous to Health (COSHH) Regulations require employers to ensure that construction workers are protected against the risks from hazardous construction dusts by following the ‘Assess, Control and Review model‘. Guidance is available from the HSE; see document Construction Dust: CIS 36 and Construction Dust: Specific tasks.

The COSHH definition of a substance hazardous to health includes dust of any kind when present at a concentration in air equal to or greater than 10 mg/m3 8-hour time-weighted average of inhalable dust, or 4 mg/m3 8-hour TWA of respirable dust. This means that any dust will be subject to COSHH if people are exposed to dust above these levels. Some dusts have been assigned specific workplace exposure limits (WELs) and exposure to these must comply with the appropriate limits. For example, the WEL for RCS is 0.1 mg/m3 8-hour TWA.

The role of dust monitoring for dust control on construction sites

Dust exposure monitoring plays a key role in checking that dust control measures are working, and it’s the only way to ensure that WELs comply with COSHH guidelines.

To ensure safety, dust exposure monitoring can be carried out both indoors, within building premises, vehicle cabs, etc., and outdoors, in the surrounding environment of the construction or demolition site. Although the technology for monitoring is similar, each application requires different equipment.

Ashtead Technology also supplies personal air sampling pumps when it is necessary to conduct compliance monitoring, or when the identification and measurement (in a laboratory) of a specific dust type, such as RCS, is required.

Once the dust risks at a construction site have been assessed, ongoing monitoring is more often conducted with direct reading instruments that employ optical techniques to measure the different particulate fractions. Portable battery-powered instruments such as the TSI SidePak and the DustTrak are ideal for this purpose and feature heavily in Ashtead Technology’s fleet of equipment for both sale and rental.

The same dust monitoring technology is employed by fixed units such as the TSI DustTrak Environmental (DTE) or TSI BlueSky, which have been developed specifically for continuous outdoor applications such as dust monitoring on construction sites. 

Fully compliant with stringent MCERTS performance requirements, the DTE employs a ‘cloud’ based data management system, which provides users with easy access to real-time data on dust levels, with the optional addition of other sensors.

Alarm conditions can be set by users so that email alerts are issued when threshold levels arise. The DTE monitors PMTotal, PM10, PM2.5 and PM1.0 mass fractions simultaneously, which provides detailed information on the type of dust present, and means that alarms can be set for specific fractions.

BlueSky air quality monitors are popular choices due to their affordability, and they are also lightweight and easy to install. Each monitor can transmit real-time data to TSI Link Solutions, which allows for secure remote access 24/7. 

One or multiple Bluesky monitors can be set up to create a network of sensors that provide accurate, real-time readings of air quality and dust on site. Additionally, the monitors come with an SD memory card for extra data storage. Optional accessories to go with both BlueSky models include the TSI 12 VDC power solar system and TSI cellular system – both of which enable real-time outdoor air quality monitoring in remote locations.

See the below table for a comparison of the parameters that continuous dust monitors measure.

Continuous dust monitor comparison for dust control

It is important to note that dust pollution may be intermittent depending on activity on construction sites, so continuous monitors can identify peaks and thereby assist in the attribution of sources.

Rechargeable batteries and solar panels with the Bluesky or DTE mean that monitors can operate unattended for extended periods in a remote location. With web-based access to the data, site visits are minimised and costs lowered.

Dust control on construction sites summarised

Continuous dust monitoring is the ultimate way of protecting workers as it enables monitoring whilst conditions change significantly on-site and whilst different tools are used, meaning that dust control measures can be reviewed to optimise their effectiveness.

Changes in construction practices and weather can affect environmental conditions on-site, and workplace exposure can be affected by a wide range of factors such as high energy tools which produce a lot of dust, dry weather, not using water to control dust clouds, how enclosed a space is, how long work takes and the frequency.

With a variety of applications for dust monitoring, appropriate technology must be employed, therefore the Ashtead Technology equipment fleet has been developed to meet almost every need, and technical advice is available to help consultants and site managers ensure that dust hazards and effectively managed.