Start with the whole room
Make-up air is the replacement air needed as an extraction system removes air from a space. In a laboratory, the fume cupboard is one part of the room’s overall supply and extraction arrangement.
Record the other cupboards and extraction equipment in the room, as well as the building’s supply-air system. The ventilation designer needs to consider how those systems operate together and how the room is used.
Opening a door is not a design for replacement air. Door movement can also disturb conditions around the cupboard opening, so planned supply and ordinary room access need to work together.
For the equipment sequence, see how a ducted fume hood works. The cabinet-ventilation brief covers a different extraction application that may also need coordination.
Describe the operating scenarios
| Scenario | Information for the project team |
|---|---|
| Normal work | Which cupboards and other extracts run at the same time? |
| Changing demand | Which systems vary their extraction or operating state? |
| After hours | What extraction must remain operating for the approved use? |
| Building changes | Has supply air, room layout or equipment changed? |
| Fault response | How are ventilation faults identified and handled? |
Use the laboratory’s actual procedures when preparing these scenarios. They provide a clearer brief than a single assumed operating condition.
Coordinate variable extraction
Our SashDrive design regulates exhaust fan speed using sash position. The building team needs the proposed operating and control information when assessing the room’s replacement air.
Share the cupboard selection, intended use and any existing ventilation drawings early. Our SashDrive planning guide covers the equipment information needed for that discussion. Any energy assessment should use the actual system and operating pattern.
Collect a useful project record
- Room plan, intended use and typical occupancy.
- Existing supply and extract drawings, where available.
- Cupboard and fan identification for each connected system.
- Normal and after-hours operating procedures.
- Recent ventilation changes, faults and test records.
We can discuss the cupboard, fan and extraction equipment with your project team. The building ventilation design and completed system assessment should address the room and equipment together. Use our installation planning checklist to record who is responsible for each part.