Why a supply system, not just extract
Extract-only ventilation works when air can leak in freely through the fabric. In a sealed or well-sealed building it does not, and the fans end up fighting the building. A supply system gives the air a controlled entry point, filters it and delivers it where people are.
It also lets the building be held at a slight positive pressure, which keeps odours, dust and humid air out of the occupied areas instead of pulling them in.
Where fresh-air supply is essential
Some spaces cannot function without a dedicated supply, whatever else the building has.
- Sealed office floors without openable windows
- Basement offices, gyms and staff areas
- Commercial kitchens requiring make-up air for the extract
- Meeting rooms and conference spaces with high occupancy per square metre
- Change rooms and ablution blocks
Sizing to occupancy
Supply volumes follow the number of people the space is designed for and what they are doing. A call centre desk and a gym floor have very different requirements per person, and a room that changes use between tenants needs a figure that can be adjusted.
We set the design occupancy with you, then size the fan, duct and diffusers so the system meets it at a sensible velocity and noise level.
Operation and control
A supply system should run when the building is occupied. Simple time scheduling, a manual boost for out-of-hours use, or a demand-based control all work — the important thing is that the running pattern is agreed at handover rather than left to whoever finds the isolator.
Included in our scope
- Occupancy and airflow assessment
- Outside-air intake and filtration
- Supply fan and ducting installation
- Diffuser layout and balancing
- Extract coordination
- Controls, commissioning and readings