Frameless structural glass balustrades: new requirements
Acceptable Solution B1/AS1 now incorporates Amendment 13, which cites the glass barrier requirements in section 22 of NZS 4223.3:2016 Glazing in buildings – Part 3: Human impact safety requirements.
From 1 June 2016, all new structural glass (toughened or toughened laminated) framed barriers complying with B1/AS1 will need to have an interlinking top rail combined with an edge support system. Interlinking rails must be designed to resist serviceability limit state (SLS) loads specified in AS/NZS 1170 Structural design actions and B1/VM1 in the event that a glass pane breaks.
Also from 1 June, frameless glass barriers (no interlinking top rail) must be constructed from laminated toughened or laminated heat-strengthened safety glass with a stiff interlayer designed to retain glass and prevent collapse, if broken. The stiff interlayer must be capable of preventing collapse in the event of a breakage of both panes of glass.
Building consent applications for glass barriers that were accepted before 1 June 2016 may use the old version of B1/AS1 (Amendment 12) to show compliance with the Building Code. Building consent applications for glass barriers made on 1 June 2016 or later must comply with the new barrier requirements in Amendment 13 of B1/AS1 (i.e. section 22 of NZS 4223.3:2016). If an alternative method is proposed, the application should include appropriate documentation to show compliance with clause B1 Structure.
Only section 22 of NZS 4223.3:2016 comes into force in B1/AS1 on 1 June. The other remaining sections of NZS 4223.3:2016 are not part of B1/AS1 Amendment 13 but may be used as part of an alternative method.
Existing glass barriers are not required to be upgraded to comply with the new requirements, although retrofitting structural glass barriers to comply with NZS 4223:3:2016 may be possible.
From BRANZ Guideline, June 2016