Access panels should be positioned so the cleaning contractor can reach every grease-bearing internal surface, especially at changes in direction and components—not simply spaced at an arbitrary distance on a drawing.
Installation boundary: This article explains design and coordination principles. Drainage, ventilation, fire, electrical and fabrication work must be designed and carried out by competent people using current project documents, manufacturer instructions and the requirements that apply in the relevant UK nation.
The short answer
There is no useful design that says 'one panel every few metres' while ignoring bends, risers and physical reach. Some council guidance uses intervals such as 3 m, but the governing practical test is whether every section can be inspected and cleaned safely with available methods. Provide access on both sides of obstructions where necessary, near changes of direction, at high-risk horizontal runs, fans and treatment stages, and wherever cleaning equipment cannot pass. The building must also provide a hatch, platform or safe working position outside the duct.
Duct access and building access are different
A well-positioned grease-tight door is useless if it sits 600 mm above a fixed plasterboard ceiling with no hatch, directly over a hot cookline or inside a locked neighbour's flat. Plot each duct door in section and show how a person reaches, opens and works at it. Allow room for the door swing, tools, lighting, protective sheeting and collection of loosened deposits.
Access panels must match the duct's leakage and fire requirements. The frame should not create an internal lip that catches grease, and the gasket must tolerate the temperature and cleaning regime. In a fire-resisting duct or enclosure, use an access-door solution that preserves the tested or assessed performance of the complete system.
Design from the cleaning method backwards
Ask the specialist how far their mechanical equipment can work effectively from an opening, how they manage vertical risers and whether remote techniques need line-of-sight or cable access. A 90-degree bend usually blocks reach; an attenuator, UV section, ESP or fan creates component-specific access. Both sides may require doors even when the overall spacing seems close.
The original route drawing should become a cleaning schematic at handover. Pair this article with DW/144, DW/172 and TR19 Grease explained so the design, construction and maintenance documents are not confused with one another.
What common failures reveal
| Site symptom | Likely installation issue | Practical consequence |
|---|---|---|
| Panel exists but cannot open | Door clashes with ceiling grid, wall or nearby service | Section remains uncleaned |
| Long residue shadow after a bend | No access downstream of change in direction | Hidden grease accumulation |
| Cleaner stands on equipment | No external hatch or safe working platform | Injury and equipment damage |
| Door leaks grease | Unsuitable frame, gasket or distorted installation | Staining, odour and fire load outside duct |
| Fire enclosure is cut open | Access strategy not coordinated with fire protection | Compromised compartmentation |
Installation and coordination checklist
- Draw every bend, transition, riser, fan, attenuator and treatment component.
- Agree the effective reach of the intended cleaning method.
- Provide doors before and after obstructions where one opening cannot reach both sides.
- Show ceiling hatches, riser doors and safe working positions outside the duct.
- Check door swing and tool space against all adjacent services.
- Use grease-tight doors compatible with temperature and duct pressure.
- Preserve any fire-resisting classification at protected sections.
- Number the doors on drawings and physically label them at handover.
Commissioning and handover
Issue a door schedule with unique references, dimensions, locations and the duct section each opening serves. Photograph the inside in both directions before the system operates, then use the same references in cleaning reports. Confirm keys and access rights for landlord or roof areas, and record any section requiring a specialist remote-cleaning method.
Questions to ask before approving the work
- Which internal surface is reached from each opening?
- How does the contractor get to the door safely?
- What lies immediately before and after each bend or component?
- Does the door preserve grease-tightness and fire performance?
- Will access remain after ceilings and fabrication are complete?
Capture the installation detail before it becomes a site problem
Coordinate the installation, testing and handover items before the kitchen is signed off.
Technical sources and further reading
- HSE CAIS10: Ventilation of kitchens in catering establishments
- Bromley Council: Kitchen extraction planning requirements
- TR19 Grease information from BESA
Last technical review: 14 August 2026. Always check the latest manufacturer instructions, statutory guidance, standards and project approvals before installation.