design element: g2 - semi-framed steel and glass panel balustrade
DESCRIPTION
The G2 semi-frameless balustrade design is one of the most elegant balustrade formats in the Arden catalogue. Glass panels are surrounded by a full perimeter stainless or mild steel frame, with glazing channel top and bottom. Clear space between glass and frame is maintained laterally on each side.TRANSCRIPT
G2
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design elements
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The G2 semi-frameless balustrade design is one of the most elegant balustrade formats in the Arden catalogue. Glass panels are surrounded by a full perimeter stainless or mild steel frame, with glazing channel top and bottom. Clear space between glass and frame is maintained laterally on each side.
The frame and handrail is supported by stanchions (typically SHS or blade profile stainless / mild steel) interposed between each panel. The vertical frame members may be hard up again each side of the stanchion, or set-back by small off-stands (typically steel rod). The entire balustrade section may be capped with a handrail of any material and profile, and/or combined with an offset handrail. Finally, the semi-framed panels may be fixed to the treads / structural floor, fixed to a stringer such as a PFC, or face fixed to the stringer or treads.
All implementations of the G2 tend to share a sense of luxury and even opulence. This is demonstrated by the some of the featured images, where crisp white stone, American Oak and built-in lights accentuate the effect. Even when the materials chosen are restricted to only stainless steel and glass, the interactions of geometry between the various components create a fine, intricate impression.
design
1A
Timber handrail with stainlesssteel ribbon plate support
Intermediate stanchions
Corner stanchion
Level panel with stainlesssteel framing
Line of stringer
Connecting void edgebalustrade omitted
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F indicated on dimensions denotes a nominal dimension that typically varies according to specific application, engineering requirements or client preferences.
Figure 1. Glass panels semi-framed with stainless steel supported by floor fixed blade stanchions.
1A. Isometric overview of installation on U-shaped staircase.
1B. Front and side elevations. Balustrade panels are set out to achieve maximal coherence in terms of proportion and alignment. To achieve this, glass panels incorporating internal and external angles are applied. Care must be taken to ensure that enough space is nominated to allow a continuous line of handrail and balustrade as it transitions between different raking and level heights (typically ~900mm and ~1050mm respectively). Overall width of flights is determined by the desired traversable width of each flight, the required clear space around the handrail, stanchion and stringer details, as well as the space specified between flights.
1B
A
Clear space between handrails
118. Clear space between handrailand glass panel frame
51 (50 min). Clear space between handrail and stanchion Upper floor void
edge bulkhead
Overall width of flight
EQ EQ
Level panel
Raking panel
Transitional panel
PFC stringer with fascia board
Upper structural
floor
Lower floor structure
Floo
r to
flo
or c
over
ed r
ise
1050 (1000 min) Upper floor level handrail height
1130. Balustrade height at landing
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In this balustrade style, the glass component is infill glass with continuous support on the top and bottom edges. The continuous support of the glass (as opposed to patch fittings, being point loads) allows the specification of the laminated glass as infill glass, although toughened and toughened laminate could also be used. Arden suggests standard methods for approaching both the glazing channel frames and the blade stanchion supports.
Some variation in the specific glazing profile and stanchion dimensions may be made for aesthetic or engineering considerations, depending on the specific properties of each project.
Handrail fixing is always offset from the stanchion, either vertically or horizontally. Handrail profile style may be selected from Arden technical document A.4 ‘Handrail profiles’ or a custom profile may be specified.
technical
1C. Detail of semi-framed glass panel with stainless steel supported by blade stanchions. As the diagram shows, the height of handrail and blade stanchion can be specified at a nominal height below the top line of the balustrade frame. The stainless steel frame incorporates a glazing channel U section top and bottom, with only a minimal width for the vertical sections. We consider a significant gap between the glass and panel sides (nominal 55mm in the illustration) helps create a highly satisfactory detail between panels. Another possible variation to the G2 style is use full height stanchions, with handrail directly positioned above the panels, which has the advantage of increasing the traversable width of the flight.
J-J
J
J
3055 55
3 3
16
Toughened safety glass panel(8-10mm typical thickness)
Timber dowellhandrail
Stainless steelsupport ribbon
Blade stanchion
6mm round connectionsto stanchion
77
18
8
Glass framed top andbottom by 18mm square C-channel
Light gauge vertical frame supports
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1C
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F indicated on dimensions denotes a nominal dimension that typically varies according to specific application, engineering requirements or client preferences.
2A
2B
G
H
Custom timber and stainlesssteel layered handrail
Full height suspended50.8SHS stainless steel
stanchions
Zig-zag plate stainlesssteel stringer
Treads with non-slip strips
Raking semi-framed glass panel
Full-height semi-framedpanel (forms section ofupper floor balustrade)
4
B
B
C
D
K
Zig-zag plate stainless steel stringer
Raking semi-framed panel
Full height semi-framed panelson opposite site of stair
50.8 SHS stainless steel stanchions
5
Figure 2. Glass panels semi-framed with stainless steel supported by face-fixed SHS stanchions.
2A. Isometric overview of installation on a straight flight with zigzag stringer and connections to upper floor balustrade.
2B. Side elevation. In this illustrative example, the RHS (near side) balustrade is comprised of standard raking panels, with the LHS (far side) balustrade panels extending to the upper floor balcony, creating a virtual internal glass wall. In this variant of the G2, the handrail is supported by custom angled rod connections from the stanchions.
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2C. Detail of panel-to-stanchion fixing at a terminating stanchion illustrating the profile of the G2 installed using 50.8s SHS stainless steel stanchions. A slightly finer nominal margin of 23mm is allowed between the side of the glass panel and the vertical panel section, to balance the wider profile presented by the SHS stanchion.
2D. Front elevation. The use of face-fixed stanchions with the G2 can slightly increase the clear traversable space on the flight.
2E. Plan view. In this example, stanchions and divisions between panels are located centre-of-tread. Stanchions are face fixed and also attached to the upper floor balustrade (excluded from diagram). 50mm clear space is maintained between the side of stanchion and the inner face of the handrail.
2D
F indicated on dimensions denotes a nominal dimension that typically varies according to specific application, engineering requirements or client preferences.
2C
206
10
81
Toughened safety glass (typically 8-12mm) orlaminated safety glass (typically 6.38-12.76)
3
23
15
50.8
16
10
Connection between panelvertical section and stanchion
6
Clear space between handrail
Line of stainless platesteel stringer
Line of handrail
Line of inner faceof stanchions
Semi-framed glass panelsin-line with, and occluded bystanchions
Vertical downturned section of stainless steel handrailplate
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2E
E
Clear space betwen handrails
100
100
Extra-wide handrail profile. Note the exampleshown is a domestic installation and is not1428.1 compliant.
Handrail supports from stanchions
65 clear space between glassface and handrail
50 clear space between handrail and stanchion face (50 min)
Treads with non-slip strips
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F indicated on dimensions denotes a nominal dimension that typically varies according to specific application, engineering requirements or client preferences.
2F
2F. Lower detail of stanchion showing detail of bottom raking corners of panels and connection to stringer. Note that the light gauge connection in this particular diagram is suitable for situations where the raking balustrade has a structural connection to the upper form balustrade. Where the balustrade is supported by the stringer alone, the fixing to stringer will vary.
Light gauge fixing to stringer (heavergrade fixings required when stanchionsare not fixed to upper balustrade
Stainless steel rod connectionsbetween stanchion and glass frame
Treads with inset non-slip strips
Plate stainless steelzig-zag stringer
68 aligned overhangof semi-framed panels
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2G
2H
2G. Detail of intermediate stanchion connection of G2 panels. The right angle handrail support ensures that the staircase complies with AS1428.1 (disability and access). The lines of glass, stainless steel and timber components are judged carefully to present a highly effective detail at the visual connection detail between handrail, stanchion, frame and glass.
2H. Plan detail of stanchion, handrail and semi-framed panel layout. 50mm clear space is maintained between the side of stanchion and the inner face of the handrail. The 30mm stand-off of the face fixed stanchion may be varied to suit installation requirements. The dimensions shown are typical for a domestic installation. The gauge of members and connections would be generally be increased for a commercial project to meet design load requirements.
50
217 17
3 3
23 23
20
6
10
Right angle handrailsupport
Welded connection withraking handrail plate
20 15
10mm inset of glassinto glazing channel
Stainless steel rod connectionsbetween stanchion and glass frame
Laminated or toughenedglass panel
9
B
B50
50 3
30mm clearance between stanchion and stringer
50mm clearance between stanchion and handrail
Glazing channel C-sections topand bottom of panel
17 17
20
11infill glass panels
Notes1. These tables are to be used as a general design guide only.2. Individual project requirements will dictate final glass specification and thickness.3. All spans nominated are indicative of normal internal conditions. In some exposed situations, wind loads may exceed design load and thicker glass or smaller spans may be required.
This table shows the recommended maximum glass span (mm) depending on design load.
Design load
Annealed laminated safety glass (mm)
Toughened monolithic safety glass (mm)
Toughened laminated safety glass (mm)
6 8 10 12 8 10 12 10 12 16
Domestic/Residential 910 1210 1490 1770 1640 2000 2300 1980 2290 2830
Offices/Commercial stairs
640 850 1050 1250 1070 1650 1930 1630 1920 2380
Retail/Restaurant 520 690 860 1020 1140 1430 1730 1420 1720 2150
C5 high loads Special glass engineering: designed as required
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2I. Isometric detail of stanchion and handrail connection location.
2J. Isometric detail of stanchion and stringer connection location.
2I
2J
Cantilevered structural. Glass panels supporting an interlinking handrail cantilever from an appropriate floor fixing.
A
B
C
E
F
G
H
Fully framed. Glass panels are provided with four-edge support and are therefore rated as infill only.
Two-edge clasp. Glass panels are supported on two opposite edges by clasp-style mechanical fixings. The bearing of point loads influence the required grade of glass.
Two-side patch-fitting. Glass panels are supported on two opposite sides by through-glass mechanical fixings. The bearing of point loads influence the required grade of glass. Stanchions may be located between, or at intermediate locations within, each panel span.
Semi-framed lateral channel. Glass panels are fixed via proprietary or custom channel system on the bottom rail and underside of handrail.
Hybrid. Glass panels are provided with a combination of the above methods so as to comply with safety requirements.
glass balustrade styles
Glass balustrade panels must satisfy engineering requirements as specified in AS1288, and the Arden balustrade styles shown here are defined and specified with regard to the relevant design standards.
Of particular importance in the initial design stage, it is critical to maintain an awareness of the designation of glass panels as structural or infill, and the classification of handrail as load-supporting, non-load-supporting, or interlinking. Combined with other considerations (e.g. whether or not mechanical point-fixings are specified, span is cantilevered or supported on both sides), this determines the grade of glass (e.g. laminated annealed, toughened safety, laminated toughened) and type of handrail that satisfies the code.
As in other aspects of stair and balustrade design, Arden will advise with respect to the practicability of preliminary designs with respect to Australian standards.
design standards for glass panels
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complianceArden is a BSA licensed contractor for carpentry, joinery, glass, glazing and aluminium as well as structural metal fabrication and erection. Arden supplies a Form 16 (Licensed Contractor) on all projects. In design and construct contracts, a Form 15 (Design Engineer) certification is supplied upon request. For products and services incorporating the G2 system, this table shows compliance with relevant codes and standards.
full compliance with the code
not applicable to this element
Key
Code Title Applicability
BCA The Building Code of Australia
AS NZS 1170.1-2002 Structural Design Actions – Permanent, imposed and other actions
AS 1288-2006 Glass in Buildings. Selection and installation.
AS NZS 1554.1-2004 Structural steel welding - Welding of steel structures
AS 1554.6-1994 Welding stainless steels for structural purposes
AS NZS 4586-2004 Slip resistance classification of new pedestrian surface materials
AS 1428.1-2009 Design for access and mobility
AS 1657-1992 Fixed platforms, walkways, stairways & ladders. Design, construction and installation
For all commercial applications, it is important that sufficient space for the stairwell cavity be allowed to satisfy Australian Standards and BCA requirements.
The footprint is primarily driven by the floor to floor rise, as well as the staircase configuration chosen. However, stringer and balustrade style design may increase the amount of space required. Allowing too small a cavity can restrict the design options of the staircase. Also, points at where the staircase interacts with other structures are best addressed early in the design cycle.
Consultation with Arden early on will help ensure that these design issues can be addressed in a cost-effective manner.
design note
About this document
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