Lead lights are a popular traditional form of decorative glazing which adds distinctive character to windows and doors.
Below are the general guidelines for lead light glazing:
New Zealand Standard Glazing In Buildings NZS 4223 Part 3:1999 Human Impact Safety Requirements allows lead lights to be used wherever annealed or safety glass can be used.
In the case of locations subject to human impact, there are special requirements for leadlight as detailed in clause 314:
Each individual glazing piece within the lead light shall not exceed the following maximum areas (taken from column 2 of table 3.2) as below
Glass Nominal Thickness (mm)
Maximum Square Metres per individual piece of lead light
NZBC Clause H1 allows traditional lead light glass to be used up to a total area of 2.6 square metres where the total area of glazing is less than 30% of the total wall area and either the schedule or calculation method is used. There is no legal requirement for the 2.6 square metres of lead light glass to be double glazed.
Large areas of lead lights may need mechanical support to protect the glazing from deformation under wind load.
Consult your GANZ ArtGlass Supplier for a copy of this datasheet which includes guidance on supporting newly constructed leadlights.