Fumes, vapours, and dust are not just a workplace nuisance. They pose a significant risk to employee health. Did you know? As reported by the Health and Safety Executive (HSE), almost 12,000 people suffer from lung disease deaths caused by past exposures within the workplace.
While HSE continues to identify potential risks at the workplace and make it safer for people, it is the employer’s responsibility to create a safe work environment for its people. That is why choosing the right extraction method is extremely important, not only for compliance with COSHH regulations but also for protecting your people and maintaining efficient operations.
What are the Hazards Caused by Fumes, Vapours, and Dust?
Fumes
Fine particles are formed during the heating of metals or plastics. For instance, fumes are released while soldering and welding.
Without appropriate safety measures, continued exposure to fumes can cause short-term and long-term health risks such as dizziness, nausea, and even critical and life-threatening risks such as stomach ulcers and irreversible lung damage. An efficient LEV system can help extract fumes from the environment before they spread into the wider environment.
Vapours and gases
Solvent-based emissions or process gases released during processes such as cleaning, coating, or chemical handling can cause irreversible damage in a workplace.
COSHH regulations state that it is an employer’s responsibility to create a safe workplace and minimise the risk of vapour absorption via wearable equipment or LEV systems.
Dust
Airborne particles are released during processes such as cutting, sanding, grinding or while handling bulk powders. Whether combustible or not, dust particles can cause long-term harm in the workplace, ranging from fire risks to lung diseases.
In the UK, employers are required by law to control exposure to dust, with COSHH regulations setting clear rules.
Each of these emissions behaves differently in the air, and therefore, their extraction methods also differ. An employer needs to assess which type affects their workplace the most and then choose an appropriate extraction method to create a safe workplace.
What are the Principles of Effective Vapour, Fume, and Dust Extraction?
Capture at the source
Extraction at the source prevents contaminants from spreading, which is more effective than cleaning an entire space.
Match the hood to the process
The hood is the real extractor of an LEV system, so it needs to be designed around how the contaminant is generated and moves in the air for effective extraction.
Go beyond general ventilation
While having a generic ventilation system can be good for dilution and ambient air cleaning, it is not usually effective at eliminating/reducing exposure to harmful substances.
What are some Types of Extraction Methods Used in LEV Systems?
Source capture
Capturing the contaminant right at its source prevents spread to the entire area. It is particularly efficient in areas where harmful fumes/emissions are released in a confined space.
Advantages
- Minimises spread into the wider workspace.
- More energy efficient.
- Especially useful for processes such as soldering, laser cutting, and 3D printing.
Downdraft Extraction
Perforated surfaces draw harmful contaminants downwards, reducing their impact on the air.
Advantages
- Prevents emissions from spreading in the breathing zone.
- Safer for the worker as it extracts contaminants without restricting hand movement.
- Ideal for processes like sanding, grinding, and tasks with heavy particle exposure.
Enclosed Capture
These range from welding bays with canopy hoods to fume cupboards for chemical mixing.
Advantages
- Ideal for heat-intensive processes.
- Reduces exposure to workers by capturing the emissions before they disperse into the environment.
- Ideal for difficult-to-reach areas where an extraction arm is less effective.
Ambient Extraction
This method cleans the air of the entire room rather than just focusing on the source. In most cases, ambient extraction serves as a supplementary solution to maintain overall air quality and worker safety.
Advantages
- Maintains air quality throughout the entire facility.
- Useful in complex work environments.
- It can also be integrated with HVAC systems for enhanced air filtration.
In addition to the extraction methods, it is also important to understand which filter best suits your needs.
What Filter is the Best Choice for Fume, Vapour, and Dust Extraction?
Different filtration techniques are suited for different industries. There are many different types of filters and air cleaners that can be seen in LEV, depending on the nature of the pollutant. A competent LEV engineer can help you to design a system which efficiently fits your needs, not only in terms of placement and sizing, but also in filter type. The type of filter that would best meet your system requirements will depend on the contaminant in the air.
Fabric Filters
A porous fabric layer collects all the contaminants as the LEV system draws the air via the inlet.
Remember: It is most important to keep on top of cleaning for fabric filters, as contaminants over time can block the filter and reduce its efficiency.
Cyclones
Cyclones use a spinning airflow to separate heavier particles, which are flung to the chamber walls and collected below. They are most effective for particles above 8µm, with limited efficiency on very fine dust, and usually need a secondary filter for respirable dust.
Remember: Any particles under 2μm will not be able to fall into the collector at the bottom and will just exit the chamber. Particles around 5μm have a 50% collection efficiency.
Electrostatic Precipitators
These systems charge dust and fume particles so they stick to oppositely charged plates, allowing clean air to pass through.
Remember: While an electrostatic precipitator might be cost-efficient in the long run, it does require specialist cleaning and regular maintenance to prevent sparking.
Scrubbing
Scrubbers trap dust and fumes by mixing them with water droplets, forming sludge that can be removed from the system. They are effective for sticky or hot contaminants and reduce fire risks.
Remember: Wet scrubbers have a 96% efficiency for particles over 5μm and 20 to 80% efficiency for particles under 5μm.
How to Choose the Right LEV System for Your Facility?
- Identify the contaminant (dust, fume, vapour) and review the exposure limits.
- Map how and where it is released during the process.
- Select the capture method best suited for your needs.
- Size the airflow and hood design according to HSE guidance.
- Choose the right filtration for your contaminant types.
- Plan for ongoing maintenance, including LEV testing.
- Or, reach out to Vent-Tech – your one-stop solution for all LEV testing, installation, and design.
There is no one-size-fits-all approach to extraction. The right method depends on what you’re working with, how it’s generated, and the setup of your workspace. By starting with the hazard, then choosing the capture method and filter type that fits, you can design an extraction system that’s safe, compliant, and cost-effective.
Still unsure which LEV system is right for your workplace, or thinking about getting one installed?
We can help you. Book a consultation and let us do the hard work for you.