Trade Guide to Load Class & Specification
Selecting the correct drainage channel prevents cracking, grate failure and costly remedial work. Specification should be based on traffic load, location, hydraulic capacity and installation method.
1. Confirm the Application
Establish:
- Location of installation
- Type of traffic
- Frequency of vehicle movements
Typical areas include driveways, car parks, service yards, highways and industrial sites.
2. Load Classes (EN 1433)
Load Class Rating Typical Use
A15 1.5t Pedestrian areas
B125 12.5t Domestic driveways
C250 25t Commercial car parks
D400 40t Roads & loading bays
E600 / F900 60–90t Ports, airports, heavy industry
Important: The lowest-rated component (usually the grate) determines the system rating.
3. Channel Materials
Material Best For
- Plastic (HDPE/PP) A15–B125 domestic applications
- Polymer Concrete B125–D400 commercial use
- Concrete Heavy-duty industrial and highway use
4. Hydraulic Capacity
Channel width and depth must suit catchment area, rainfall intensity and surface finish. Incorrect sizing can cause surface flooding even if load class is correct.
5. Installation
Ensure:
- Correct concrete surround
- Proper bedding and haunching
- Channels level and aligned
For C250 and above, follow manufacturer installation guidance.
Quick Trade Checklist
✔ Application confirmed
✔ Correct load class specified
✔ Material suitable
✔ Grate matches rating
✔ Hydraulic capacity checked
✔ Installation detail followed
When in doubt, step up a load class rather than risk underspecifying.
