Glass balustrades and compliance with the Building Code of Australia by Heath McNab

The following is a guide to achieving compliance with the Building Code of Australia Volume II, when incorporating glass within a required balustrade. This information is a guide only and shall not be relied upon. Please consult your glazier or engineer for advice specific to your situation.

Part 3.9.2 of the Building Code of Australia (BCA) pertains to balustrades within Class 1 and Class 10 buildings. A required balustrade is any balustrade or other barrier used to prevent a fall of: 

• 1m or more along the side of any roof to which public access is provided, any stairway or ramp, any floor, corridor, hallway, balcony,deck, verandah, mezzanine, access bridge or the like and along the side of any delineated path of access to a building. 
• 4m or more through an openable window. (It is deemed possible for a person to fall through an openable window when a 125 mm sphere is able to pass through the window opening.)

The requirements of a required balustrade (or other barrier) generally are stated within Part 3.9.2.3 of the BCA, they are: 

• The height must not be less than 865mm above the nosings of the stair treads or the floor of a ramp. 
• The height must not be less than 1m above the floor of any access path, balcony, landing or the like 
• The height must not be less than 865mm above the floor beneath an openable window. 
• Openings shall not permit a 125mm sphere to pass through the balustrade or other barrier (For stairs this is tested above the nosing line) 
• When protecting a fall of 4m or more there shall be no horizontal elements within the balustrade or other barrier between 150mm & 760mm above the floor level that would facilitate climbing. 
• A glass balustrade must comply with AS1288 Australian Standard AS1288-2006 (AS1288) sets out the procedures for the selection and installation of glass in buildings, subject to wind loading, human impact, and special applications such as overhead glazing, balustrades and glass assemblies.

Section 7 of AS1288 provides deemed to comply solutions for required balustrades incorporating glass. AS1288 classifies glass balustrade panels into two categories; 

a. Structural balustrade panels, or

b. Infill balustrade panels.

Glass can form a structural component of the balustrade (this would be option a. above or a structural balustrade panel of glass) or the balustrade may have a structural component provided from another material such as timber or steel, with the glass acting as an infill panel only (this would be option b. above or a infill balustrade panel of glass). 

Whenever glass is relied upon to provide a structural component to a required balustrade a handrail is generally always required.  

Handrails are classified by Section 7 of AS1288 into three categories;

a. Load supporting handrails

b. Non-load supporting handrails

c. Interlinking handrails

Load supporting handrails: the handrail is mechanically fixed to the structure, independent of the glass, but the glass may be connected to it. The handrail supports the loads. This handrail is utilised with infill balustrade panels.

Non-load supporting handrails: either the top edge of the glass acts as the handrail or the glass supports a handrail that is fixed to the glass and relies upon the glass for structural support. This handrail is utilised with structural balustrade panels.

Interlinking handrails: an interlinking handrail is only considered such when it is connected to adjacent panels of glass, or the building, where the adjacent panels are at least 1000mm wide and the balustrade consists of at least three glass panels. This requirement means that if one of the glass panels fails (breaks) the two remaining panels and the handrail must be capable of resisting the defined loads. The handrail must be designed with this in mind. This handrail is utilised with structural balustrade panels.

Therefore as required by the BCA a required balustrade, shall when incorporating glass and attempting to comply with the deemed to comply provisions of AS1288 be either:

a. An infill panel of glass, with thickness selected in accordance with table 7.3 of AS1288 and incorporating a load supporting handrail, or 

b. A structural panel of glass, with thickness selected in accordance with table 7.2 of AS1288 and incorporating an interlinking handrail or load supporting handrail. 

For any other required balustrade incorporating glass to comply, including systems that do not incorporate a handrail, then the requirements of Section 3 of AS1288: General Design Criteria must be satisfied. This is considered an engineered solution. And as such the site specific application of the system (NOTE: the system refers to the glass, the fixings and the handrail as applicable) shall be tested and certified as being compliant with the BCA, AS1288 and AS1170.1. 

Regardless of the means of compliance, be it a deemed to comply solution under Part 7 of AS1288, or an engineered solution under Part 3 of AS1288, the requirement to demonstrate compliance is the same. 

A Certificate shall be submitted that certifies the system utilised as compliant with the BCA, AS1288 and if applicable AS1170.1. 

Within this Certificate must be included:

• the date the certificate was issued
• the address of the subject property
• the credentials of the individual endorsing the certificate
• the means of compliance, i.e. deemed to comply solution or an engineered solution
• a statement confirming that the installed system complies with AS1288, the BCA and AS1170.1 (as applicable)