To ensure a safe and secure work environment, it is essential to set up efficient extraction and harmful emissions management solutions. Discover our recommendations to extract welding fumes and to renew the air in this article:
- Extract close to the emission area
- Maximum containment of the pollutant emission zone
- Place the extraction system upstream of the operators’ respiratory tract
- Use the natural movements of pollutants
- Induce a sufficient air speed
- Distribute air speeds evenly in the catchment area
- Recovery of extracted calories
- Waste management and air supply in the building
- Compensate air outlets with corresponding air inlets
1) Extract close to the emission area
Harmful emissions spread and mix quickly with ambient air, which can make them hard to capture. We advice you to extract fumes and other pollutants close to the emission area. This has several advantages:
- Reduction of the extracted air volume: By capturing pollutants at source, it is possible to reduce the air volume to be treated, reducing the energy needs for the ventilation system.
- Optimize network dimensions: Less air volume means that conducts and ventilation equipments can be of smaller dimensions which can also reduce installation and maintenance costs.
- Minimizes heated air losses: By limitating extracted air volume, it reduces also heat losses which contribute to an improved system energy efficiency.
- Higher efficiency: Pollutants extraction close to their source ensure a better extraction efficiency, because the efficiency decrease with the distance. It allows to keep a healthier and safer work environment.
To sum up, capture pollutants close to the source is a key strategy to improve air quality in work spaces while optimizing energy and material resources.
2) Maximum containment of the pollutant emission zone
To limit dilution of harmful emissions in the ambient air and avoid their spread towards other workstations, it is essential to outline emission areas as much as possible. This containment can be done with:
- Protection cabins: use cabins made to isolate emissions sources, to capture harmful particles at source.
- Walls and partitions: set up physical walls to create barriers between work areas and emissions sources, thus reducing pollutants spread.
- Curtains and flexible barriers: set up plastic welding curtains or flexible barriers that can be easily moved or adjusted according to needs, while offering a protection against emissions.
In addition to these solutions, it is important to consider the impact of ventilation and extraction systems. A good containment system must be associated to an efficient extraction to limitate the spread of pollutants in ambient air and thus ensure a healthier air. It contributes to the safety of workers but also to comply with environmental regulations.
3) Place the extraction system upstream of the operators' respiratory tract
The main goal of welding fumes extraction is to avoid inhalation of pollutants by welders and operators. For this purpose, it is important that extraction systems to be set up outside the operators’ direct breathing zone. Here some strategies to do it:
- Integration into work tools: set up the extraction system directly on the used tool, like a grinder or a welding station, allowing to extract fumes when they’re generated, thus reducing their spread in the air.
- Positioning downwards: place the extraction vents below the work zone can help to extract fumes by guiding them towards the extraction system before they reach operators’ respiratory tract.
- System orientation away from operator: positioning extraction équipements away from the operator, while keeping a proper distance, can also reduce exposure to harmful fumes.
By taking these approaches, not only we can protect health operators, but also improve extraction system efficiency. It allows to create a safer and healthier environment in compliance with health and safety standards.
4) Use the natural movements of pollutants
Harmful emissions spread in characteristic patterns, and understanding these dynamics is essential for optimizing extraction systems. For instance, welding-generated particles tend to rise vertically in the workshop, with their ascent speed influenced by temperature, which itself depends on the amperage used. In contrast, grinding emissions follow a circular motion, being rapidly projected horizontally.
To maximize the efficiency of pollutant capture while reducing the required air volumes and extraction velocities, it is recommended to take these natural flows into account when positioning the extraction elements. This includes:
- Strategic placement of extraction inlets: Position the extraction inlets close to the emission sources in order to capture harmful particles before they disperse into the ambient air.
- Optimization of duct diameters: Adjust the diameters of the extraction ducts to minimize pressure losses and improve the airflow rate.
- Fan selection: Select a suitable fan that can provide the required airflow while remaining energy efficient.
- Management of power consumption: Assess the energy efficiency of the system in order to reduce operating costs.
- Minimization of heated air losses: Design the system to limit air leakage, which contributes to better energy efficiency and a more comfortable working environment.
By integrating these considerations, it is possible to optimize the extraction system so that it is both efficient and cost-effective, while ensuring worker safety by reducing their exposure to pollutants.
5) Induce sufficient air velocity
Ensure an appropriate air velocity to capture pollutants
To extract efficiently pollutants, it is important that velocity or air flows are sufficiently high. This helps direct airflow toward the extraction inlets while counteracting unwanted drafts and the initial movement of polluted air.
The specific values to be used depend on several factors:
- Distance from the emission source: The farther the source, the more it may be necessary to increase air velocity to ensure effective capture.
- Type of application: Requirements may vary depending on whether it is an industrial environment, a laboratory, or a public space.
- Toxicity and quantity of pollutants: More toxic pollutants, or larger quantities, require higher airflow rates to ensure adequate safety.
- Surrounding air currents: Climatic conditions and natural air movements can influence extraction efficiency.
- Rise of hot gases: Hot gases tend to rise, which may require adjustments in the design of the extraction system to capture these pollutants effectively.
In short, proper management of air velocities is essential to maximize the efficiency of pollutant capture systems, thereby helping to improve air quality and protect workers’ health.
6) Evenly distribute air velocities across the capture zone
The ventilation criteria are often defined by minimum values of the average extraction velocities at the capture zone. To ensure optimal efficiency, it is crucial that these extraction velocities are distributed as evenly as possible, which helps prevent leakage of polluted air from areas where the extraction velocity is lower.
Uneven velocity distribution can cause disturbances in airflow, creating vortices that may carry pollutants back toward the operator. To prevent this, several strategies can be implemented:
- Use of air distribution devices: Installing equipment designed to homogenize airflow, such as diffusers or adjustable grilles, can help ensure a uniform distribution of extracted air.
- Extraction ductwork design: Adapting the design of the duct network to minimize pressure losses and ensure smooth airflow throughout the entire capture zone.
- Monitoring and adjustment: Implementing control systems to monitor air velocities in real time and adjust the extraction flow rate if necessary to maintain optimal conditions.
In summary, a uniform distribution of air velocities at the capture zone is essential to maximize the efficiency of extraction systems and protect operators’ health, while also contributing to a safer and more comfortable working environment.
7) Heat recovery from extracted air
Whether local (source capture) or general, ventilation in industrial premises requires a supply of fresh air to compensate for the extracted air volumes, even when cleaned air is partially recirculated. The resulting air movements can create significant discomfort, which often leads to ventilation systems being switched off and, in turn, compromises air quality.
To address this, it is essential to provide a preheating system for the supply air. Mechanical introduction of air into the building is recommended, as it allows the air to be treated so that it is clean and at an optimal temperature before being distributed to the appropriate areas.
In addition, part of the heat contained in the exhaust airflow can be recovered by installing a heat exchanger. The role of this exchanger is to transfer part of the heat from the exhaust air to the fresh air, which makes it possible to:
- Improve energy efficiency: By recovering heat, heating demand is reduced, which can lead to significant savings in energy costs.
- Maintain a comfortable working environment: Preheated air contributes to a pleasant indoor climate, reducing discomfort caused by cold draughts.
- Optimize ventilation system performance: By integrating heat recovery systems, the overall efficiency of the ventilation installations is improved, which benefits the health of occupants.
In short, recovering heat from extracted air is an effective strategy to improve air quality while optimizing energy resources in industrial environments.
8) Management of exhaust and supply air in the building
When extracting welding fumes, the polluted air should be filtered by a treatment unit (central filtration system or extraction unit) before being discharged outside the building. The outdoor discharge requires particular attention. The height of the stacks and the location of the extraction duct outlets must be considered according to the building layout and its surroundings.
To avoid recirculating pollutants, it is essential that polluted air is discharged away from the fresh air intake zones. The following recommendations help optimize this management:
- Stack height: Stacks must be tall enough to ensure that pollutants are dispersed at an altitude where they cannot be drawn back in by the ventilation systems. Adequate height also helps reduce the impact of air currents on pollutant discharge.
- Orientation and location: Extraction outlets should be positioned strategically, taking into account wind direction and nearby obstacles such as buildings or trees that may disrupt airflow.
- Environmental considerations: Local topography and weather conditions must be taken into account, as they can influence pollutant dispersion. For example, in hilly areas, pollutants may accumulate in low-lying zones, increasing exposure risks for occupants.
By integrating these aspects into the design and operation of ventilation systems, indoor air quality can be improved while minimizing environmental impact, thereby creating a healthier and safer working environment for all.
9) Compensating air outlets with corresponding air inlets
In an enclosed space, maintaining a balance between incoming and outgoing air volumes is essential. When an air extraction system is installed, providing a corresponding air supply system to replace the extracted air is imperative. Key considerations for implementing this system include:
- Efficiency of extraction and supply systems: Ensuring optimal operation prevents building underpressure, which could reduce extraction efficiency and lead to pollutant buildup.
- Reducing air currents: A well-designed supply system minimizes high-velocity drafts from openings (doors, windows, cracks, etc.). This helps:
- Prevent thermal discomfort for personnel caused by temperature variations.
- Improve capture device efficiency by avoiding pollutant dispersion in the workshop.
- Avoid resuspension of settled dust on surfaces, which worsens air quality.
- Protecting clean zones: Avoid drawing air from adjacent polluted areas (e.g., parking lots or high-traffic roads) into clean work zones by strategically placing air inlets.
- Operation of combustion appliances: In areas with toxic or asphyxiant products, a slight underpressure is often needed. For adjacent spaces with varying pollution levels, separate ventilation systems may be required, using airlocks maintained at positive fresh air pressure to prevent cross-contamination.
In summary, proper management of air supply and exhaust is essential to ensure a healthy and comfortable working environment. It not only contributes to employee safety but also enhances the efficiency of ventilation systems.
Would you like our team to recommend a customized welding fume extraction solution for your facility? Contact us!
