Problem
Contaminants in the welding workshop were not generated at a single fixed point. The welder moved around the workpiece and changed the tool position, so the source of welding fume moved too.
Removing fumes through general ventilation alone would have required flushing the entire workshop with high airflows. For the facility, this would mean larger fans, larger supply air handling units, higher-capacity heating coils and ongoing air heating costs in winter.
Simply increasing ventilation airflow solves the fume problem but creates another: the business starts heating the outdoors.
The brief
The aim was to ensure safe working conditions and prevent fumes from spreading throughout the workshop without specifying excessive general ventilation capacity.
The economics were critical: every additional cubic metre of extract air has to be replaced with supply air and heated during the colder months.
Engineering challenge
For fixed welding stations, local extraction in a fixed area is sufficient. In this workshop, however, the working area changed depending on the size of the workpiece and the welder’s position.
The extraction device therefore had to be mobile as well as effective: it needed to remain close to the fume source throughout the work.
Solutions
Mobile local extraction stations formed the basis of the system. Swivelling extraction hoods on mobile stands were installed above the work areas, allowing welders to move them as they worked.
Fumes were extracted almost immediately at source, before they could spread throughout the production space.
Mobile stations
Swivelling extraction hoods can be moved as the welder’s working area changes.
Local extraction
Most welding fume is captured at source, rather than after it has spread through the workshop.
Main duct
All local extraction stations are connected to a single main duct.
General ventilation
Fresh air replaces the extracted air and removes residual contaminants throughout the space.
How the system works
A main extract duct runs along the workshop. Mobile extraction stations connect to it through individual branches. This arrangement ensures stable operation of the stations, even airflow distribution and scope for future system expansion.
General supply and extract ventilation works alongside local extraction: it supplies fresh air, replaces the extracted volume and removes residual contaminants not captured by the local hood.
Economic benefits
As most contaminants are removed at source, there is no need to specify excessive general ventilation airflow for the whole workshop.
This reduces the required supply and extract airflow, equipment size, heating coil capacity and supply air heating costs. For a facility operating all year round, running costs are a key factor in the economics of the solution.
Result
The client received a system combining local welding fume extraction with general workshop ventilation. Fume levels in the working area were reduced, and contaminants do not accumulate in the wider space.
The system is not based on the principle that more airflow is always better. It removes contaminants where they arise, and this is what reduces capital and operating costs.
The most effective industrial ventilation starts not with high airflow, but with targeted contaminant extraction at source.