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Design & Reference Tools

Lighting design calculations and IP rating / bathroom zone reference for BS 7671.

Lighting Lux Level / Downlight Spacing Calculator

Calculate number of luminaires and optimal grid spacing

Room length (m)

Room width (m)

Room height (m)

Mounting height above work plane (m)

Room type

Luminaire output (lumens per fitting)

Maintenance factor (MF)

Utilisation factor (UF)

Formula: N = (E x A) / (F x UF x MF). Room Index RI = (L x W) / (Hm x (L + W)). Results are indicative — always verify with manufacturer data and a detailed lighting design.

IP Rating & Bathroom Zone Reference Guide

IP code decoder, bathroom zones (Section 701), and location-based IP lookup

A IP Rating Decoder

Enter IP code (e.g. IP44)

OR select digits below

First digit (solid protection)

Second digit (water protection)

B Bathroom Zones (BS 7671 Section 701)

Cross-section view (not to scale)

Ceiling

Floor level

Zone 0

Zone 1

Zone 2

Outside Zones

0.6m

Bath/Shower

2.25m from floor

Click a zone in the diagram above, or select equipment below, to see requirements.

Select equipment to see zone requirements

C Quick IP Lookup by Location

Select a location

Study for the 18th Edition Exam

Complement your practical calculations with exam prep. Our app has 800+ practice questions with detailed explanations covering all parts of BS 7671.