Recommendations for the types of glass suitable for use in roof or canopy glazing in or around non‑agricultural buildings are given in BS 6262-4 as follows.

If the lower pane is toughened glass or heat-soaked toughened glass, then the upper pane should also be one of the types of glass given in a) 1) below. When insulating glass units are used in sloping glazing, each pane should be assessed for the risk of thermal fracture.

1. Glazing at a height up to 5 m above floor level (covering single storey buildings and conservatories):
1. Single glazing: This should ideally be glass that remains in position post-breakage, such as laminated safety glass, wired glass, adhesive-backed polymeric filmed glass or plastics glazing sheet materials. The following can also be considered: thermally‑toughened soda lime silicate safety glass, heat‑soaked thermally‑toughened soda lime silicate safety glass. Specialist advice should be sought if the glass is more than 3 m² or more than 6 mm thick.
2. Insulating glass units: The lower pane should be one of the types of glass given in a) 1). If the lower pane is toughened glass or heat soaked toughened glass, then the upper pane should also be one of the types of glass given in a) 1).


2. Glazing at a height over 5 m above floor level:
1. Single glazing: This should be laminated glass, adhesive-backed polymeric filmed glass, wired glass or plastics glazing sheet materials;
2. Insulating glass units: The lower pane should be one of the types of glass given in b) 1).

[Reference: BS 6262-4: Glazing for buildings - Part 4: Code of practice for safety related to human impact]