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GLASS & WINDOWS
TECHNICAL
TECHNICAL UPDATE NAYAN DAS Technical Program Engineer, Australian Glass & Window Association
AS 1288 REVISION In response to member feedback on Section 6 - Sloped Overhead Glazing and Section 7 - Balustrades of AS 1288, AGWA submitted a project proposal to Standards Australia in 2019 to revise the Standard. As a ‘Deemed-to-Satisfy’ (DTS) solution, this Standard does not cover some product configurations and the lack of guidance has created confusion amongst suppliers, builders, and certifiers, and an unawareness of many industry stakeholders and consumers. Over the last two years, AGWA has worked progressively with the Technical Committees and Standards Australia to document these issues and revise these sections to provide more detail and to facilitate easier interpretation for endusers. Industry experts representing AGWA collaborated in the AS 1288 committee (Standards Australia BD-007 Committee) to prepare and amend Section 6 and Section 7 and develop new provisions for these sections on behalf of our members.
SECTION 1 The main intention for this section was to update/revise the current definitions, primarily related to overhead glazing and balustrades, to reflect the introduction of new material and configurations. Definitions for aspect ratio for two and three-sided support glazing, spigot-fixed and point-fixed balustrades were added to the draft to further clarify these terms. In addition, ‘balustrade’, as a general term, has changed to ‘barrier’ to be in line with the NCC definition.
SECTION 6 – SLOPED OVERHEAD GLAZING The current overhead glazing tables (Tables 6.1 to 6.4) do not provide a DTS solution for three-sided support glass. In addition, the current DTS tables only provide solutions for glass thickness to 12 mm. The tables included in this section were expanded and new charts were added to include the new criteria/provisions and different glass types with higher thickness. Some of the most important provisions that were added are: • For short-term load duration (wind load with three seconds or less duration), the application area is 0.01 m2. • For a medium-term duration (imposed live load for up to 10 minutes), the application area is 0.02 m2. • For glazed panels inclined at less than 30° to the horizontal, the live load is assumed to be 1.1 kN. • For glazed panels inclined at greater than or equal to 30° to the horizontal, the live load is assumed to be 0.5 kN.
BUILTVIEW
ISSUE 07 AUTUMN 2021
The new tables are more comprehensive and can be applied to a wide range of overhead glazing with varying thicknesses and dimensions. The new table and charts remove the need for an engineer. Reference to other sections of the Standard, to check the strength of overhead glazing for the wind loads, is minimised.
SECTION 7 – BALUSTRADES Based on the project proposal’s scope, the main intentions for this section are to provide additional guidance as to what is, and is not, covered by the Standard; and to revise the current DTS provision for structural barriers that protect a height of more than one metre with an interlinking handrail. The existing provisions for these types of structural barriers have been revised. New requirements and illustrations to clarify the requirement for the end-users have also been added. The main focus is to clarify all ambiguity around the interlinking handrail definition and related provisions. A clause was also added covering the requirements for a structural barrier protecting a height of more than one metre with a non-load supporting handrail or no handrail. This refers to the appropriate test methodologies to provide the industry with simple, accessible and uniform prescriptive measures for barrier product configurations that are not currently covered in the Standard. To reduce the risk of injury from incidental breakage due to impact load, new restrictions for using monolithic toughened glass barriers protecting falls equal to or greater than five metres has been added to this section. Because of the complexity of the post breakage behaviour of glass in a barrier system, only informative requirements were introduced in this revision of AS 1288. As a performance solution to cover the NCC requirements, a testing methodology was proposed for the glass balustrade system to provide a DTS guideline for mechanically fixed balustrades such as point-fixed and spigot fixing. The procedure was separated into two appendixes, Appendix H (normative – must be followed) covers the testing requirement according to the load’s requirements in AS 1170.1. Appendix I (informative – provides information) covers the post-breakage required testing. We received 278 comments and feedback during the Public Comment period between 28 September to 30 November, 2020. The Committee had a weekly meeting from the middle of November until the end of December 2020 to review the comments. In collaboration with the Standards Australia management team, the Committee amended the relevant sections after reviewing and validating all the comments and technically finalising the draft produced by the Standards Australia drafting team. Currently, Standards Australia is carrying out the final editorial revision and preparing the final draft for April 2021 publication.
