CSR Hebel is 100% owned by CSR Building Products Limited, one of Australia’s leading building products companies. CSR Hebel manufactures and markets a range of lightweight Autoclaved Aerated Concrete (AAC) blocks, reinforced PowerPanels, cladding and lintels for use in the housing and commercial construction industry. CSR Hebel also sells complementary mortars, tools and accessories.

In 1989, CSR became involved with Hebel and established the Australian operation. Since then, Hebel has won wide acceptance as an innovative and environmentally friendly building material due to its speed of construction, excellent thermal/fire/acoustic properties and its design versatility.

1.2 Design Overview

As environmental consciousness and social responsibility increases, CSR Hebel is striving to exceed these ideals and set new standards in building materials and residential living.

Designed for Inner Comfort

With Hebel PowerWall clients can enjoy a comfortable interior in their home, and be comfortable with their choice for the environment.

Manufacture of Hebel materials uses a small fraction of the energy and natural resources used in manufacturing conventional masonry, producing almost no waste or by-products. Hebel’s highly efficient insulation also saves power in heating or cooling the home.

Designed for Inner Peace

Hebel PowerWall helps you create a tranquil inner space. We have worked closely with acoustic experts and testing authorities to engineer inherently superior acoustics from our wall and floor systems. They create a sound barrier to external noise and from other rooms within the home.

Designed for Peace of Mind

Although it’s remarkably lightweight, Hebel is solid and durable. Hebel PowerPanel is reinforced with steel for extra strength. Hebel is also extremely fire-resistant and is not a food source for termites.

Designed to Save

As they’re lightweight, Hebel materials are quick to assemble, saving building time and costs. They also minimise the need for supporting materials, saving budget resources and energy.

1.3 Use Hebel for Better Framed Construction

• Using Hebel PowerPanel for your framed construction provides you with cost savings and greater floor space for the same building dimensions.
• Hebel PowerPanel is faster to install than bricks, saving on building costs.
• Hebel products are lightweight, reducing the structural load on the frame and its design requirements for supporting building materials.
• Their low weight makes Hebel PowerPanels ideal for use in difficult applications such as sloping sites. An external wall of Hebel PowerPanels is steel-reinforced, solid and secure.
• Hebel PowerPanels have better thermal efficiency than brick veneer or even double brick walls, resulting in reduced heating and cooling costs. Further thermal efficiency may be achieved by adding insulation to the frame cavity.
• Hebel is fire-resistant, with a fire rating of up to four hours.

1.4 Hebel PowerWall

Hebel PowerWall for Detached Houses & Low Rise Multi-Residential External Walls has been designed for homes built using either timber or steel framing and can be used in new dwelling construction, extensions or re-cladding. The system consists of 75mm thick, steel-reinforced Hebel PowerPanels, fixed vertically to horizontal battens attached to the load-bearing frame. For quick, clean construction, Hebel PowerPanels can be ordered in the stock lengths of 2400mm, 2700mm and 3000mm and in widths of 300mm and 600mm. The 600mm wide PowerPanels are also available in the additional lengths of 1200mm, 2550mm and 2850mm.

Fig. 1.1 Panel Installation 

• With Hebel PowerWall, your home will reach lockup stage sooner. 
• The installation of Hebel PowerWall is very fast, especially on purpose-designed houses.
• Any competent tradesperson can easily install Hebel PowerWall. Two people can install up to 100m² of external wall in about three days.
• The modular design of the dwelling minimises waste.
• A standard 2400mm Hebel PowerPanel weighs about 74kg when delivered*, which two people can position. No cranes are required.

Space

• Hebel PowerWall gives you great freedom in designing your home and you can customise the style by applying coloured and textured coatings to the PowerPanels.
• A thinner external wall results in greater internal living space and design flexibility. A 50mm reduction in external wall thickness can provide about 2% extra internal space for the same external dimensions.

Solidity

• Hebel PowerWall is a solid choice. It’s extremely strong, and each Hebel PowerPanel is steel reinforced.
• Capable of up to four hours fire resistance for a fire source on the PowerPanel side.
• Hebel PowerPanel does not provide a food source for vermin or termites.

Lower Energy Costs

• As with all Hebel products, Hebel PowerPanel has excellent thermal properties. This feature results in lower heating and cooling costs at no additional building expense.

Fig. 2.1 Hebel PowerWall Installed In Ground Floor

Fig. 2.2 Hebel Home 

Table 2.1 Comparative Wall Thicknesses (mm)

 * Note: Depending on top hat selection.

* Calculated at 30% moisture content. At 4% equilibrium moisture content, the PowerPanel would weigh approximately 60kg.

Structurally, Hebel PowerWall uses Hebel PowerPanel as non-loadbearing external cladding. Each PowerPanel is steel reinforced and installed vertically and secured to steel top hat battens. The top hat battens are secured to load carrying timber or steel stud frames.

Hebel PowerFloor is a complimentary system that can be used in conjunction with Hebel PowerWall. Hebel PowerFloor can be quickly installed over timber or steel floor framing using a construction adhesive & screw fixings.

Figure 3.1 shows an example of a typical home that uses Hebel PowerWall for Detached Houses & Low Rise Multi-Residential External Walls.

This section outlines the design process for determining the adequacy of Hebel PowerWall.

STEP 1: Determine the wind category, stud framing layout and PowerPanel height requirements.

STEP 2: Design Criteria. Where required identify the BCA Performance Requirements:

• Fire Resistance Level (FRL).
• Sound insulation performance (R_w values).
• Energy Efficiency (R-Value).

STEP 3: The flowchart below can be used to select a type, spacing and quantity of top hats and fixings to suit requirements.

STEP 4: Select insulation and/or sarking material to suit energy efficiency and condensation requirements.

STEP 5: Check adequacy of sound insulation and fire resistance level.

STEP 6: Complete detailed design and documentation.

4.2 Compliance With the Building Code of Australia (BCA)

All building solutions, such as walls, floors, ceilings, etc. must comply with the regulations outlined in the BCA or other authority.

The BCA is a performance based document, and is available in two volumes which align with two groups of ‘Class of Building’:

Volume 1 - Class 2 to Class 9 Buildings; and
Volume 2 - Class 1 & Class 10 Buildings – Housing Provisions.

Each volume presents Regulatory Performance Requirements for different Building Solutions for various classes of buildings and performance provisions.

These Performance Provisions include: Structure; Fire Resistance; Damp & Weatherproofing; Sound Transmission & Insulation; and Energy Efficiency.

This design guide presents tables, charts and information necessary to design a Hebel PowerWall that complies with the Performance Requirements of the BCA. The designer must check the adequacy of the building solution for Performance Requirements outlined by the appropriate authority.

Hebel PowerWall basically consists of Hebel PowerPanel secured to the framing via horizontal steel top hats. This section provides the basic information on the selection of top hat spacings for a given stud spacing and wind category, as well as considerations to assist the designer in determining the appropriate wall configuration.

The design information presented in Table 5.1 to 5.5 has been determined for the following top hat types:

• Rondo 303 – Rondo Building Services Pty Ltd.
• Lysaght Topspan 22 – Bluescope Steel Ltd.
• FastStud 24TH42.

For other brands or types of top hats, contact the manufacturer for design information. Minimum performance requirements for the metal studs, top hats, fixings and Hebel PowerPanel have been provided to assist the designer.

IMPORTANT
The design and approval of the structural framing (cold-formed steel or timber) is to be provided by the framing product manufacturer and/or project engineer.

5.2 Principles of Design

The principles on which the design is based include:

a) The lateral wind loads applied to the PowerPanels are transferred into the horizontal top hats, then to the stud frame, which should be designed in accordance with the relevant Australian Standards for the imposed loads. The frame should be designed for all bracing and holddown requirements.
b) The design of the stud frame shall consider the weight of suspended PowerPanels (such as the upper storey of two-storey construction).
c) The system is not considered as cavity construction, as the top hat clearly bridges the cavity, hence the details show the necessity of sealing the windows and door frames, as well as applying a water resistant external coating.
d) The system specifications vary with wind load. The notation used in AS1684 Residential Timber Framed Construction has been adopted.
e) The localised effects of wind around corners of buildings have been considered in the design and included in the tables. The extent of this effect is discussed towards the end of this section.

Criteria for Corner Panels

Due to the increase of wind load around the corners of buildings, extra top hats and screws may be necessary (N3 and greater) for a distance of 1200mm in each direction from the corner.

Tables 5.1 to 5.5 identify the installation criteria in these areas, in the columns titled ‘Panel Location – Corner’.

Cyclonic Loading Effects

Hebel PowerWall for Detached Houses & Low Rise Multi-Residential External Walls has been tested at the James Cook Cyclone Structural Testing Station (Report No. T5 444) in Townsville. The pullout capacity of the screw into the back of the Hebel PowerPanel is the critical element in the design. The results from the cyclic testing showed that the system, in particular the pullout load of the screw, is unaffected by the cyclic loading. The detailing presented in this design guide is satisfactory for cyclonic areas.

Earthquake Loads

Earthquake loading has not been considered in this design guide.

5.3 Design Tables

This section presents tables to assist the designer in the selection of the number of top hats and number of screws for securing the Hebel PowerPanel to the framing, for a given wind category.

IMPORTANT
The wind category is to be used as a guide. The designer should check the project wind pressure against the valves given in the tables.

Panels Supported at Base

Table 5.1 Number of Top Hats – Panel Supported at Base (such as slab edge or shelf angle)

Note:
1 Figures shown in brackets are the top hats required when using RONDO 303 top hats.
2 All top hats to be spaced evenly, with top and bottom top hats installed 150mm (typical) from the end of the PowerPanel.
3 Additional top hats will be required below all window openings and above openings if a PowerPanel or sill block is to be installed in this location.
4 Corner panel location applies to PowerPanels within 1200mm of corners. Permissible wind pressures have been increased by a factor of 2 in these PowerPanel locations.

Table 5.2 Number of Screws Per Panel at Each Top Hat Location – Panel Supported at Base (such as slab edge or shelf angle)

Note:
1 For fire rated construction a minimum of 3 screws per middle top hat is required (FRL 240/180/180 for a fire source from the PowerPanel side of the wall only).
2 Type of screw used is the 14-10x65mm Hex Head Type 17 screw, fixed from inside the building, or 14-10x100mm MP Bugle Head Batten screw, fixed from outside the building (as per Table 5.6).
3 Corner panel location applies to PowerPanels within 1200mm of corners. Permissible wind pressures have been increased by a factor of 2 in these PowerPanel locations.

 Panels Suspended from Frame

Table 5.3 Number of Screws Per Panel at Each Top Hat Location – Panel Suspended at Gable Ends

Note:
1 Top and bottom top hats installed 150mm (typical), and 250mm (max.) from the end of the PowerPanel.
2 Top hats to be installed horizontally with PowerPanels to span vertically. Number of Screw Per Panel Per Top Hat Information is not suitable for soffits or any other areas where the PowerPanel is not vertical.
3 Corner panel location applies to PowerPanels within 1200mm of corners. Permissible wind pressures have been increased by a factor of 2 in these PowerPanel locations.

Table 5.4 Number of Top Hats – Panel Suspended from Framing (such as, second storey construction)

Note:
1 Figures shown in brackets are the top hats required when using RONDO 303 top hats.
2 All top hats to be spaced evenly, with top and bottom top hats installed 150mm (typical) from the end of the PowerPanel.
3 Additional top hats will be required below all window openings and above openings if a PowerPanel or sill block is to be installed in this location.
4 Corner panel location applies to PowerPanels within 1200mm of corners. Permissible wind pressures have been increased by a factor of 2 in these PowerPanel locations.

Table 5.5 Number of Screws Per Panel at Each Top Hat Location – Panel Suspended from Framing (such as, second storey construction)

Note:
1 For fire rated construction a minimum of 3 screws per middle top hat is required (FRL 240/180/180 for a fire source from the PowerPanel side of the wall only).
2 Type of screw used is the 14-10x65mm Hex Head Type 17 screw, fixed from inside the building, or 14-10x100mm MP Bugle Head Batten screw, fixed from outside the building (as per Table 5.6).
3 Corner panel location applies to PowerPanels within 1200mm of corners. Permissible wind pressures have been increased by a factor of 2 in these PowerPanel locations.

5.4 Stud Frame

The stud frame shall be designed by the steel stud manufacturer or appropriate project engineer. Hebel PowerPanel is a masonry product and the support structure should be designed to provide sufficient stiffness.

The steel stud frame shall be designed and constructed in accordance with AS3623 and AS/NZS4600 (BCA Performance Requirement) with performance requirements for the studs of:

Properties:

• Cold-formed steel studs.
• Minimum yield strength 300MPa
• Minimum thickness 0.75mm BMT.
• Coating class Z275 (see Durability).
• The designer shall specify the need for noggings.

5.5 Steel Top Hat

Other steel top hats than those referenced in this design guide shall be designed by the top hat manufacturer or appropriate project engineer. The steel top hats shall be designed and constructed in accordance with AS3623 and AS/NZS4600 (BCA Performance Requirement) with performance requirements for the top hats, of:

Properties:

• Cold-formed steel top hats.
• Minimum thickness 0.42mm BMT.
• Minimum yield strength 300MPa.
• Coating class Z275 (see Durability).

Alternate steel top hats must have an equivalent or better performance than the top hat products outlined in Section 5.1.

5.6 Hebel PowerPanel

Design procedures for the verification of wall systems consisting of Hebel autoclaved aerated concrete (AAC) PowerPanels generally follow the design principles outlined in Australian Standard AS3600 – Concrete Structures, with the exception of cover requirements for durability and development length for reinforcement.

The strength design of the Hebel PowerPanels has been carried out using the Transformed Section Theory, as detailed in the text book, ‘Reinforced Concrete’ by Warner, Rangan and Hall (Longman Cheshire). The load carrying capacity of the Hebel PowerPanel is influenced by several factors, such as:

• Imposed action (wind).
• Lateral stiffness of the supporting structure (lightweight structural (cold-formed) steel framing).

• Stud size and spacings.
• Deflection limit.

• Height of the wall.
• Number and spacing of the top hats.
• Number of screw fixings considered effective.

5.7 Fixings

Table 5.6 outlines the connection type and requirements for constructing Hebel PowerWall detailed in this design guide. The project engineer or framing manufacturer is responsible for specification of alternative details. The minimum performance requirement of the screw is:

• Minimum screw coating class in accordance with AS3566: Class 3. (Refer Section 6.0 for Durability).

Table 5.6 Screws Types

5.8 Design Considerations

5.8.1 Structural Framing Design

The use of Hebel PowerWall in two-storey construction involves a number of design issues that require attention. In conjunction with the following, refer to the Construction Details in Section 17.3 & 17.7. Note, when PowerPanels are suspended from the stud frame the project engineer shall design the frame to support the weight of the PowerPanels.

Design Tip

In order to reduce the load of the upper storey PowerPanels and make installation easier, the lower storey PowerPanels should be specified as 2700mm/3000mm in length and the upper storey PowerPanels as 2400mm in length. The vertical dimensions can be adjusted to suit.

A garage is considered ‘attached’ when at least one full side of the garage is connected to the main dwelling.

5.8.2 Two Storey Construction

Steel Frame Construction

Two storey construction suits a steel framed dwelling as the weight of the upper storey PowerPanels bear directly on the lower storey PowerPanels. Note, lower storey PowerPanels are to bear on the slab. However, consideration should be given to the sectional size of the lintels over openings on the lower storey. As the details reveal, only an ‘Ableflex’ joint is required at the horizontal PowerPanel junction between the upper and lower PowerPanels.

Timber Frame Construction

In contrast, the upper storey PowerPanels cannot rest on the lower storey PowerPanels in timber framed dwellings, due to the effects of timber shrinkage. Movements in the order of 25mm can occur in a two storey timber frame with a timber first floor. The fixing method used in Hebel PowerWall does not allow for this extent of differential movement between the external skin and the timber frame.

The allowances for shrinkage of timber framing in BCA 2006 Vol. 2, Section 3.3.1.10, by providing gaps between framing and masonry, should be adopted as a minimum.

It is therefore recommended that the upper storey PowerPanels be installed 35mm clear of the lower storey PowerPanels. During construction a temporary packer is used to separate the PowerPanels and is then removed after the PowerPanels have been screwed to the top hats.

The impact of this construction is to load the lower storey frame with the weight of the upper storey PowerPanels. In effect, an extra 51kg/m² (for the weight of the upper PowerPanels) is being added to the load already carried by the timber frame. The load approximates 1.2 kN/m (2.4m PowerPanel).

To simplify the design implications of this extra load, it is recommended to add an extra 1.4m of tributary width for a 90kg/m² Tile Roof load (for 2.4m long upper PowerPanels) for the design of the lower storey frame and timber lintels, when using AS1684.

The support of the full weight of the upper storey PowerPanels can be adequately supported by the top hat system. A full design using a safety factor of five has been undertaken and checked to confirm this. The number of top hats can be determined in Table 5.4 to support the suspended PowerPanels, and the PowerPanels screw fixed as per Tables 5.5.

5.8.3 Secondary Support Framing

There is a need for secondary support framing when:

• The layout of the main structural framing does not allow this framing to be used as a support. In this case a mullion is required to break up the span of the PowerPanel, or cleats provided to act as support and connection points for the PowerPanels.
• Around openings: the PowerPanels adjacent to the opening may not have sufficient capacity or stiffness to resist the additional loads that are re-distributed from the opening and infill PowerPanels.
• In this case angles are required to transfer the loads from the opening (window) and infill PowerPanels back to the main structural framing.

5.8.4 Bracing of the Building

The walls of the dwelling should be braced using steel cross bracing wherever possible, to allow the fixing of the PowerPanels from inside the building, such as Teco Speed Bracing. Ply or sheet bracing should be used on the external wall, if the walls are too short for the steel cross bracing (Refer AS 1684-1999). In this case, the full length of the wall should be sheeted to prevent misalignment of the PowerPanels.

Alternatively, localised strips of the sheeting can be fixed to the intermediate studs, between the areas of full sheet bracing, to maintain the PowerPanel alignment. The PowerPanels to be installed over the areas of full plywood sheeting will need to be fixed from the outside of the building using the 100mm long Bugle Head Batten screw (Refer Table 5.6). The extent of the bracing should be determined by the timber frame designer or project engineer.

NOTE
CSR Hebel does not recommend fixing Hebel PowerPanels from the inside when sheet bracing is installed. If sheet bracing is used over steel or timber frame construction then increase the length of the screw fixing the top hat to the stud by the thickness of the sheet bracing (refer to Section 5.7).

Durability means the capability of a building or its parts to perform a function over a specified period of time. It is not an inherent property of a material or component. It is the outcome of complex interactions among a number of factors, including:

• The service conditions.
• Material characteristics.
• Design and detailing.
• Workmanship.
• Maintenance.

(‘ABCB Guideline Document – Durability in buildings: 2003’)

The following sub-sections of the durability topic are written in order to provide general guidelines in how best to provide, enhance and maintain adequate durability of Hebel PowerWall.

6.2 Maintenance and Enhancement of Durability

The durability of Hebel PowerWall can be enhanced by periodic inspection and maintenance. Inspections should include examination of the coatings, flashings and sealants. Paint finishes must be maintained in accordance with the manufacturer’s recommendations. Any cracked and damaged finish or sealants, which would allow water ingress, must be repaired immediately by recoating or resealing the effected area. Any damaged flashings or PowerPanels must be replaced as for new work.

The durability of the system can also be increased by using Class 4 fixings throughout, additional treatment of steelwork, and by painting all exposed sealants to the sealant manufacturer’s recommendations.

6.3 Coastal Areas

Hebel PowerWall can be used in coastal areas with additional precautions to ensure salt does not build up on the surface of the wall. For buildings, which are 200m to 1000m from a shoreline or large expanse of salt water, such as, Swan River (west of the Narrows Bridge), Sydney Harbour (east of the Harbour Bridge or Spit Bridge), one of the following is required:

• All horizontal and vertical movement joints must be appropriately caulked; or
• All walls must be sufficiently exposed from above so that rain can perform natural wash-down of the wall; or
• Walls, which are protected by soffits above, must be washed down twice per year, to remove salt and debris build-up, particularly at the joints.
• In all cases, Class 4 screws must be used. 
• For buildings less than 200m from the shoreline as defined above, CSR Hebel does not recommend that Hebel PowerWall be used without project specific consultation with CSR Hebel Engineering Services.

6.4 Hebel PowerPanel

Hebel PowerPanel has many characteristics which make it a very durable product, including:

• Will not rot or burn. 
• Is not a food source for termites.
• Unaffected by sunlight.
• Not adversely affected over normal temperature ranges.
• One quarter the weight of conventional concrete.
• Solid and strong with corrosion protection coated steel reinforcement.

6.5 Durability of Components

It is the responsibility of the building designer to ensure that the components, such as screws, top hat battens and other steel components, have the appropriate corrosion protection to be able to maintain their strength and integrity to suit the required design life of the project.

IMPORTANT
The top hat section specified in this guide can ONLY be used on untreated and dry timber frames. CCA treated pine or green timber frames have a deleterious effect on the top hat coatings, which can lead to corrosion. Where timber is CCA treated, provide a barrier between top hat and timber member. Refer to screw manufacturer for appropriate screw specification for this application.

When assessing durability the following documents can be referred to for guidance:

• ABCB Guideline Document – Durability in buildings: 2003.
• AS/NZS 2312: 2002 – Guide to the protection of structural steel against atmospheric corrosion by the use of protective coatings.
• ISO 9223: 1992 – Corrosion of metals and alloys – Corrosivity of atmospheres -Classification.
• AS3566: 2002 – Self drilling screws for the building and construction industries.
• AS2331 Series.

Reference to AS3566 should always be adhered to when selecting the screws corrosion resistance classification.

6.6 Wall Frames

6.6.1 Steel Frames

The designer needs to ensure that the steelwork and Hebel AAC products have adequate protective systems to ensure that durability is maintained. The durability of the stud frame can be enhanced by the provision of a membrane, such as sarking. The manufacturer of the steel stud frame can provide guidance on the appropriateness of this solution on a project-by-project basis.

IMPORTANT
The steel frame requirements outlined in the BCA Vol. 2, Part 3.4.2 should be considered in conjunction with steel frame design and construction advice from the steel frame manufacturer. These requirements consist of minimum protective surface coatings with restrictions on the location of the building and exposure condition of the steel frame.

6.6.2 Timber Frames

Information on the durability design of timber structures and components can be obtained from documents such as:

• AS 1720.1 Timber Structures, Part 1: Design Methods.
• AS 1684 Timber Framing Code.
• State timber framing manuals.
• AS 4100 Metal Connectors: Corrosion.
• AS 3600 Subterranean Termites.

Fig. 6.1 Hebel Home

Hebel PowerWall can be subjected to a fire loading as the result of either an external fire source, or an internal fire source. When the wall requires a fire resistance level (FRL) rating, CSR Hebel provides the following guidance.

External Fire Source

For an external fire source, the excellent fire resistance qualities of the Hebel PowerPanel cladding protects the structural support framing, and provides a high fire resistance level for Hebel PowerWall.

NOTE
The FRL rating of the wall can be affected by the penetrations and the method adopted to protect these penetrations. A fire collar with a –/120/120 FRL rating will govern the FRL of the wall, even if the wall configuration has a FRL rating of –/180/180. Where required, the performance of the external coating when subjected to a fire loading shall meet the appropriate performance requirements outlined in the BCA. Joints & gaps need to be appropriately fire rated. Eg. vertical control joint will need fire rated sealant & horizontal joints must be blocked with compressible fire rated material.

Fire Certificates & Reports

Copies of the test reports and/or opinions can be obtained by contacting CSR Hebel. A certificate of test FSV0356 is provided in Appendix D of this guide. Hebel PowerWall achieves a FRL of 240/180/180.

Internal Fire Source

For an internal fire source the studs must be protected by the internal wall linings. Refer to CSR Gyprock Red Book for specifications.

External Walls in Fire – BCA Provisions

Where necessary, the designer and builder should ensure the structural support framing, its connections as well as the Hebel PowerPanel installation are satisfactory when subjected to fire conditions. The BCA Vol 2 (Part 3.7.1) outlines provisions for external walls for fire resistance in a residential building where the external wall is less than 900mm from an allotment boundary or 1.8m from another building on the same allotment. If this occurs an FRL of not less than 60/60/60 is required from the outside.

7.2 Fire Performance of Hebel PowerWall

Hebel PowerWall was tested at the CSIRO, North Ryde and a Fire Resistance Level (FRL) of 240/180/180 was achieved (refer to Appendix D). Note, the fire source was on the PowerPanel side. This excellent result enables Hebel PowerWall to be used in the following applications:

• Walls on zero line allotment blocks.
• Multi-storey residential dwellings – external walls.
• Commercial developments.
• Infill PowerPanels.

NOTE
In the above applications, each PowerPanel should be screwed as specified in this guide, except a minimum of three screws should be installed through the middle top hat into each PowerPanel (refer to the fire test certificate in Appendix D).

Fig. 7.1 Bushfire Area

7.3 Bushfire Areas

BCA 2006 Vol. 2 Part 3.7.4 describes the provisions applicable to construction in bushfire prone areas. The reference code is AS3959. Hebel PowerPanel is non-combustible and suitable for all bushfire exposure levels (refer to Appendix A.6).

7.4 Design Considerations

Fire Stop Penetrations

Penetrations through Hebel PowerPanel to accommodate pipework, electrical cabling or ductwork will have to be protected (fire stop), to prevent the spread of fire through the penetration. The penetration can be protected with proprietary products, such as:

• Fire rated sealants.
• Fire collars and intumescent wraps.
• Fire rated mortars.
• Fire rated pillows.
• Fire rated switch boxes.

CSR Hebel recommends contacting the manufacturer to obtain the appropriate product/solution and installation method for the application and wall configuration.

The BCA is available in two volumes which align with two groups of ‘Class of Building’:

Volume 1 - Class 2 to Class 9 Buildings; and
Volume 2 - Class 1 & Class 10 Buildings – Housing Provisions.

Each volume presents the Performance Requirements for the efficient use of energy for internal heating and cooling in buildings. The majority of changes have been associated with the Housing Provisions.

The Performance Requirements for energy efficiency ratings are dependent upon the form of construction (i.e. walls or floors), Class of Building, and the type of areas being separated. The performance requirement is a value that is the Total R-Value, which is the cumulative total of the individual R-Values of the building system components.

8.2 Hebel PowerWall

One of the primary design objectives in planning a building is to provide a cost effective comfortable living/ working environment for the building’s inhabitants. Exploiting the inherent thermal mass and insulation qualities of Hebel enables the designer to achieve this objective.

Several international comparative studies have been conducted to investigate the benefits of incorporating AAC walls in place of conventional wall systems. A common trend was the lower heating and cooling energy consumption and smaller mechanical equipment required to maintain a comfortable living environment, especially with regards to regions of mainly cold weather. The excellent performance was the result of the three characteristics – thermal mass, thermal insulation, and the air tightness of the construction.

The level of insulation provided in a wall is determined by the required Total R-Value. The higher the required Total R-Value the greater the insulation provided. Hebel PowerWall incorporating CSR Bradford insulation can provide the R-Value ratings outlined in Table 8.1.

8.3 Thermal Insulation

It is recommended that insulation materials be installed to enhance thermal insulation properties and occupant comfort. Insulation also improves the acoustic performance of the wall against outside noise.

The BCA provides Deemed-to-Satisfy Provisions for compliance and installation of the various types of insulation. The insulation should be installed in Hebel PowerWall such that it forms a continuous barrier to contribute to the thermal barrier. All insulation installed in Hebel PowerWall must comply with: AS/NZS4859.1; or AS2464.3 for loose fill insulation.

8.4 Air Tightness

As outlined in Section 8.1 the thermal performance can be influenced by many factors. Most of these are related to the design decisions and properties of the adopted materials. Construction practices can also significantly affect the performance with poor sealing, resulting in drafts. The tight construction tolerances of AAC provide a wall with low air infiltration rate. Testing at the CSIRO (Test Report DTM327) on Hebel blockwork with thin bed adhesive joints has determined an air infiltration rate of 0.3L/s (0.014% of internal volume). For PowerPanels having fewer thin bed adhesive joints, a rate less than this could be achieved.

8.5 Sarking

As well as controlling condensation and acting as an air barrier, a sarking can be used to significantly improve the thermal insulation and energy efficiency performance of a building solution. Sarking layers can alter the performance of the cavity by providing a reflection side. The design of the sarking arrangement is complex and should be performed by the appropriate project consultant.

Where the sarking layer provides a weatherproofing function, the sarking material must comply with AS/NZS4200 Parts 1 and 2.

Where sarking is installed in the PowerWall, panels must be fixed from the outside.

Table 8.1 Energy Efficiency

The following tables show the performance levels required for walls and floors under the BCA and the thermal performance of the Hebel PowerWall system.

Notes:
• Refer to BCA for state & territory variations.
• Refer to BCA for alternative means of satisfying the required performance levels.
• Refer to CSR Bradford product literature for design & installation requirements for the nominated reflective foil laminates and insulation.

Energy Rating Software

Energy legislation (5 stars) is changing every year and ratings software is changing to keep up. Combine this with all the variable elements in a house such as window sizes, floor space and house orientation and you have a moving landscape. Hebel provides a great springboard for walls and floors in these rating systems due to its unique thermal properties of insulation AND mass. When rating in FirstRate, AccuRate, BASIX and BERS select AAC as the wall and floor option and see why Hebel is fast becoming the all star performer. Hebel can help your project achieve 5 stars and beyond.

Current BCA Sound Transmission and Insulation Requirements

Hebel PowerWall is primarily used in buildings that have a domestic type of activity purpose. The BCA generally classifies these buildings into class 1 or 10. The acoustic performance requirements for external walls in these buildings or their building elements are not currently stated in the BCA. If a building using Hebel PowerWall was required to provide acoustic performance, then the performance level requirements for a building envelope and elements would be set by the relevant authorities (i.e. Local Councils, client specific requirements and etc).

Design Recommendations

Acoustic design is a complex science, and there will be instances where a specialist acoustic consultant is required.

For walls requiring acoustic performance CSR Hebel recommends:

1. Engaging a reputable acoustic consultant on a project-by-project basis to provide design advice and installation inspections.

2. When selecting the appropriate components for Hebel PowerWall, the designer or specifier must be aware that the laboratory Rw values are almost always higher than the field measured values. Therefore, allowances should be made for the lower expected field values during the selection of the system.

3. Separate advice from a specialist acoustic consultant should be sought to determine the effect on acoustic performance due to any changes to Hebel PowerWall, and any required modification of the installation details pertaining to the systems.

4. Increasing cavity widths, using higher density or thicker insulation or plasterboard, will generally maintain or increase the acoustic performance of Hebel PowerWall.

9.2 CSR Sound Control Systems

The CSR External Sound Control Systems guide provides solution for various external sound environments, the home can be designed so the interior noise is reduced to a selected level. The purpose of this guide is to provide solutions for the design of new residential buildings subject to certain types of external noise.

External Noise

External, or environmental noise in urban areas is pollution that can intrude into homes. It has many sources and can have a number of undesirable impacts.

Common external noise sources include:

• Road, air and rail transport.
• Industrial operations.
• Entertainment venues.
• Sporting activity.
• Pool and garden equipment.
• Neighbourhood noise such as television, parties.
• Barking dogs and lawn mowers.

Noise Source

Noise levels from various sources have been divided into four bands measured as LAeq (see GYP 572 August – 2005):

• Quiet suburban, 50 – 55dB(A).
• Medium suburban, 55 – 60dB(A).
• Noisy suburban, 60 – 65dB(A).
• Inner city, 65 – 70dB(A).

Interior Noise Levels

The noise levels within a home that result from external noise are measured as LAeq in the same way as the noise source. The term is a measure of the loudness of a sound, with units dB(A). The A weighting indicates that the value has been filtered to focus on the frequencies to which the ear is sensitive. Note the noise levels experienced in a home are affected to some extent by the interior furnishings. An interior noise level of LAeq 35dB(A) for road, train, industrial and neighbourhood noise, selected from Australian Standard AS/NZS2107.

Acoustics – Recommended Design Sound Levels And Reverberation Times

For Building Interiors, is considered the upper limit for sleeping areas in houses near minor roads and within the range recommended for houses near major roads.

Note the noise level 35dB(A) is very quiet. Occupants could expect to hold a conversation without raising their voices, listen to TV at low volume, and sleep unaffected. Windows and doors must be closed to achieve the stated result.

It is possible to choose a lower level of internal noise, however, the designer should consider the ability of a system to reach the level, the higher cost to achieve lower noise levels, and the sensitivity of the occupants to noise.

Fig. 9.1 Interior Noise Level Reduction Through CSR Sound Control System

Hebel PowerWall requires an appropriate external coating system and sealant detailing to ensure a water resistant and vapour permeable building envelope is achieved.

Generally, the external face of Hebel PowerWall is coated with a skim coat render, texture coating and waterproofing paint system, in accordance with the recommendations of the coating manufacturer.

Performance Requirements

The following are items to be considered when selecting a coating system:

Manufacturer approved:

• All coating systems applied to Hebel external walls should be approved by the coating manufacturer as being appropriate for coating an AAC substrate.

Surface adhesion:

• The substrate preparation and coating application should be in accordance with the coating manufacturer’s specification.
• Before applying finishes in coastal areas (refer to definition), all PowerPanels must be thoroughly washed with fresh water to remove any salt residue. Refer to coating manufacturer for additional requirements.

Water resistant:

• The primary objective of the coating system is to prevent water ingress through it, yet allow vapour in and out of the AAC substrate.
• The effectiveness of the coating can be specified by the manufacturer.
• Acrylic resin coating materials have a proven water-proofing capability.

Vapour permeability:

• For the coating to allow vapour to pass through it, the coating must be vapour permeable.

The coating system should exhibit the following performance requirement::

w . sd ≤ 0.2 kg/(m² . h0.5) where, coefficient of water absorption, w ≤ 0.5 kg/(m² . h0.5);
equivalent air layer thickness of water vapour diffusion, sd ≤ 2m.
The coefficient of water absorption w ≤ 0.5 means that minimal dampness has been absorbed regardless of the time factor.
A coating with a sd = 2m has the same diffusion characteristics as a 2m thick air layer.

Compatibility:

• Ensure the coating system is compatible with the substrates. That is, acrylic resin dispersion-based coatings may not adhere to silicone sealants.

Durability:

• The coating must be durable and not deteriorate with exposure to light (UV) and weather.

Elasticity:

• The coating must be able to bridge a 1mm minimum crack width.
• The coating manufacturer can specify the minimum design specification (thickness), so that the coating is serviceable.

IMPORTANT
This list of performance requirements indicates that a specific fit-for-purpose coating system must be adopted, and that a simple paint coating would most likely be an inadequate coating system. Variations to the coating system must be approved by the coating system manufacturer or representative.

10.2 Coating

Hebel coatings have been specifically formulated and engineered to match the thermal and physical characteristics that are unique to AAC.

Easy to work with, Hebel coatings are designed to help you achieve the perfect finish to any Hebel project, including the highly sought after smooth, Monolithic look.

CSR Hebel has worked closely with Dulux AcraTex to develop a total system for the Detached Housing & Low-Rise Multi-Residential market.

Given the variability of some coatings – not all are what they claim to be – customers can be confident that when they choose Hebel coatings they have been correctly formulated to a consistent recipe. CSR Hebel does not recommend cement based site mixed renders be applied to Hebel PowerWall.

Hebel coating systems have been formulated with a special acrylic polymer and combined with washed, graded silica sand, cement and selected additives to enhance the application and workability of the mix, ensuring a consistent finish.

The addition of acrylic polymers provides Hebel coating systems with many advantages over traditional cement based renders:

• Increased flexibility
• Improved adhesion to Hebel substrate
• Matches thermal properties of Hebel substrate
• Faster curing
• Improved crack joint resistance

CSR Hebel now has three coating systems to cover all applications:

• Hebel PowerBase & PowerFinish
• Hebel SkimCoat
• Hebel HighBuild

For further information on Hebel Coatings refer to the publication ‘High Performance Coating Systems’.

10.3 Cladding System

Proprietary cladding systems can be fixed to Hebel PowerWall. Where Hebel PowerWall acts as the structural backing for the proprietary cladding. The designer must ensure the structural performance of Hebel PowerWall is adequate. Contact CSR Hebel Engineering Services for assistance.

10.4 Sealants

All movement joints and gaps between the PowerPanels and infill framing or penetration framing must be filled with an appropriate polyurethane sealant. The sealant should be designed and installed in accordance with the sealant manufacturer’s specifications. The specifications will provide information regarding priming the surface, geometry of sealant (width/depth ratio with width greater than depth), sealant surface profile (concave), substrate preparation, etc.

NOTE
Where different types of sealants come in contact, the designer must ensure the sealants are compatible. Typically a backing rod is used to control the depth of sealant and ensure the sealant is bonded on two sides only.

Note, the surface may require some preparation depending upon the type of sealant. CSR Hebel recommends the use of an appropriate polyurethane sealant.

For fire rated walls, an approved fire rated sealant should be used.

10.5 Wall Flashings

In general, flashings shall be designed and installed in accordance with SAA – HB39 1997 - Installation Code for Metal Roofing and Wall Cladding.

10.6 Sarking

For Hebel PowerWall, sarking is only required for insulation and condensation control. Sarking must be designed and installed in accordance with AS/NZS4200 Part l – Materials, and Part 2 – Installation. When sarking is installed in the PowerWall system, panels must be fixed from the outside.