In UK house building and retrofit projects, bathrooms and wet rooms are segmented into distinct zones to assess water exposure risk. These zones guide the selection of safe, compliant electrical and building materials. Traditional bathrooms with bathtubs or shower trays use three zones, while wet rooms (designed for full water resistance) use two.
Definition:
Bathroom zones are three-dimensional spatial classifications that dictate the required safety standards for electrical installations and materials based on proximity to water sources. The zones ensure compliance with UK Building Regulations (e.g., Part P for electrical safety) and IP (Ingress Protection) ratings.
Zones in Traditional Bathrooms:
- Zone 0 (High Risk):
- Area: Inside the bathtub or shower tray.
- Requirements: Electrical fittings must be low voltage (max 12V) and rated IPX7 (protected against immersion in water up to 1m depth).
- Example: Submerged LED lighting in a shower tray.
- Zone 1 (Medium Risk):
- Area: Vertical space from the top of Zone 0 to 2.25m above the floor, extending 1.2m horizontally from the water source.
- Requirements: Minimum IPX4 (splash-resistant). If water jets are used (e.g., power showers), IPX5 is required.
- Example: Showerhead-mounted speakers or extractor fans.
- Zone 2 (Low Risk):
- Area: Extends 0.6m beyond Zone 1 and up to 2.25m height. Includes areas around washbasins and toilets.
- Requirements: Minimum IPX4.
- Example: Shaver sockets near basins.
Zones in Wet rooms:
- Zone 0: Floor area where water pools (entire wet room floor). Requires IPX7-rated materials (e.g., tanking systems).
- Zone 1: Walls up to 2.25m height. Requires IPX4-rated fixtures.
Regulatory Alignment:
- Compliance with BS 7671 (IET Wiring Regulations) and Part P of Building Regulations is mandatory.
- Incorrect zoning can invalidate warranties or insurance and pose safety risks (e.g., electrocution).
Summary:
Bathroom zoning ensures safe, regulation-compliant installations by categorising water exposure risks. Correct application is critical in both new builds and retrofits, particularly in the UK’s focus on energy efficiency and safety in housing.