SECTION 5: PROPRIETARY SCAFFOLDING

This section covers proprietary scaffolds (modular scaffolds). Proprietary scaffolds have been designed by a chartered engineer as reflected in the manufacturer's specifications for the design and use of the equipment. The manufacturer's specifications must be used in the erection, use and dismantling of proprietary scaffolds.

Proprietary scaffolds can be separated into two specific categories.

1. Proprietary systems solely comprised of prefabricated components. Here manufacturer's specifications and instructions for safe erection must be followed.

2. Proprietary systems comprised primarily of prefabricated components, but with additional scaffolding components that are not covered by the manufacturer's specifications. Here the additions to the proprietary scaffold should follow the general requirements of the BPG. If this can not be achieved scaffolds constructed using these systems should be classified as special duty scaffolds.

The industry recommends that all special duty scaffolds be notified to the DOL. There is a template for this in the appendix at the end of these guidelines.

5.1 Modular proprietary systems (prefabricated)

Proprietary equipment has been prefabricated to a unique design for use as scaffolding. Figure 45 shows the node or connection points for four proprietary systems.

Figure 45: Connection systems for four different prefabricated proprietary systems

Ring scaffold node or connection point

Kwikstage or system scaffold node

Rapid scaffold node or connection point

Cuplock scaffold node or connection point

Figure 46 shows a standard system or Kwikstage proprietary scaffold showing some general scaffolding terminology

Figure 46: General scaffolding terms applied to proprietary scaffolding

5.2 Aluminium frame and brace tower systems

Aluminium (lightweight) frame and brace proprietary systems are commonly called aluminium towers or aluminium scaffolds. They are either fixed (static) or mobile.

Aluminium scaffolds are generally comprised of the following prefabricated components:

• Castors or basejacks.
• Aluminium end frames (generally with horizontal rungs).
• Aluminium braces - diagonal, horizontal and plan.
• Prefabricated captive decks and hatch decks.
• Aluminium prefabricated ladders or stairs.
• Aluminium outriggers.

All prefabricated aluminium scaffolds must be erected per the manufacturer's specifications and instructions.

Aluminium systems in use today have an extensive range of products that can be used in most scaffolding applications. While aluminium mobile scaffolds are used more than aluminium fixed or static scaffolds, most of these systems utilise the same equipment.

An aluminium scaffold that is more than one bay long must maintain unimpeded access. Climbing through the scaffold's frame rung is not permitted. Walk through frames or space frames must be used. Ladder or stair access must be provided to all working platforms. Always check the manufacturer's specifications, particularly re:

• Erection instructions.
• Maximum loads permitted per bay.
• Maximum height to which the system can be erected.

In the case of a mobile aluminium scaffold, if the lowest working platform using prefabricated decks is above 3.0m from the supporting structure, then plan bracing must be provided at the base of the scaffold. Please note the aluminium frame must be fully decked (captive) at the lowest working platform or a plan brace must be used. Check the manufacturer's instructions.

Particular attention must be taken to ascertain the intended use of the aluminium scaffold, in particular the designed safe working loads per bay. Aluminium is generally lighter than other scaffolds and is therefore more prone to the impact of uneven loads or wind loads.

When stacked one on top of the other aluminium frames must have a positive connection. This is accomplished by connecting frames with an exterior joiner or locking pin, or by bracing over the frame join on both sides of the frame.

5.3 Proprietary systems with additional components

Proprietary scaffold can be used to create hanging scaffolds, cantilevered scaffolds, bridges, etc. As above, if a proprietary system includes additional scaffolding components that are not covered by the manufacturer's specifications the additional components should be used consistent with the general requirements of the BPG. If this can not be achieved the resulting scaffold must be classified as a special duty scaffold.

5.3.1 Requirements for system combinations

Components from different prefabricated scaffolding systems must not be mixed unless the load capacity of the mixed scaffolding systems has been proved by theoretical analysis or testing in accordance with AS/NZS 1576 and the:

• Components are of compatible size and strength.
• Components have compatible deflection characteristics.
• Fixing devices are compatible.
• Mixing does not lessen the scaffold's strength, stability, stiffness or suitability.

The following system combinations must not be used unless designed in accordance with engineer's requirements or specifications in AS/NZS 1576 or other recognised standards:

• Steel prefabricated scaffolding systems used in conjunction with aluminium prefabricated scaffolding systems.
• Aluminium scaffold tubes used as principal structural members in a steel prefabricated scaffold.
• Steel scaffold tubes used as principal structural members in aluminium prefabricated scaffold. This does not apply to the use of tie tubes or members such as guardrails.

Standards

On a system or proprietary type scaffold (excluding frame scaffolds) standards must be staggered if the top working platform is higher than the longest standard, following the principle of a tube and fitting scaffold. Always follow the manufacturer's specifications for proprietary components.

Ledgers

On a system or proprietary type (tube) scaffold ledgers cannot generally be staggered as they are restricted in length between the standards.

5.3.1.1 Bracket scaffold for tank work or form work

Bracket scaffolds are scaffolds erected from an engineer's designed bracket system designed for the purpose. The brackets are prefabricated and fixed to the perimeter of a tank or vessel. They are usually either welded or bolted to the supporting structure.

Generally a tube and fitting scaffold is erected on the supporting brackets to form a working platform, though this does not exclude a proprietary scaffold system being supported by the brackets. The fixing of these prefabricated brackets needs to be checked as does the suitability of the tank or vessel to support the intended scaffold.

5.3.1.2 Temporary grandstand seating

Temporary grandstand seating is covered under the Building Act and building codes.

Again, if additional components are included in a proprietary system these should be used consistent with the general requirements of the BPG. If this can not be achieved, the resulting scaffold must be classified as a special duty scaffold.

5.3.1.3 Stage platforms

Temporary stage platforms can be erected out of most types of scaffolding. Proprietary stage platforms must be erected per the manufacturer's specifications. Designing and erecting stage platforms to support people and materials generally would be classified as a special duty scaffold and notified as such. These structures may need to withstand considerable loads on a concentrated area and individual bays are difficult to recognise, so all care must be taken in calculating loadings. Temporary stage platforms must also comply with the Building Act and the Resource Management Act.

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