Page 1 of 33

AAFFSS LLOOGGIICC WWAALLLL

SSTTRRUUCCTTUURRAALL EENNGGIINNEEEERRIINNGG AASSSSEESSSSMMEENNTT

AAPPRRIILL 22001155**** ((RReevviisseedd VVeerrssiioonn)) PPRREEFFAACCEE AFS Logic Wall consists of closely spaced metal channels, 6mm fibre cement sheets glued to the metal channels on both faces, conventional steel reinforcement and concrete infill. Refer Detail ‘A’ on page 6. This assessment originally commenced in the year 2000 and revised many times to incorporate new findings and the changes in the AS3600 Concrete Structures Code. This assessment of AFS Logic Wall considers the following: (A) DURABILITY ASSESSMENT (B) FIRE DESIGN ASSESSMENT THE EVIDENCE OF SUITABILITY, BCA, CLAUSE A2.2 FOR AFS LOGIC WALL HAS BEEN

COMMENTED BY: • The AFS Logic Wall system argues in the (download) Unisearch, UNSW Report dated 5th

May 2014 that AFS complies with the “Deemed to Satisfy” conditions.

• The previous report by the same (download) Unisearch, UNSW Report dated 20th March 2014 states that AFS Logic Wall DOES NOT COMPLY WITH AS3600.

• The later report by (download) Access-UTS dated 23rd May 2014 states that AFS Logic Wall

DOES NOT COMPLY WITH AS3600.

• (Download) Professor Bijan Samali, author of the UTS Report dated 23rd May 2014 stated on 19th December 2014 that AFS Logic Wall DOES NOT COMPLY WITH AS3600.*

THEREFORE, THE CRITICAL QUESTIONS TO ASK WHEN CONSIDERING USING THE AFS LOGIC WALL SYSTEM ARE: (A)(1) Does AFS Logic Wall comply with the “Deemed to Satisfy” conditions? The answer is

‘NO’ since AFS Logic Wall relies on a protective coating without concrete cover. (A)(2) Does AFS Logic Wall qualify to be defined as an ALTERNATIVE SOLUTION with the type

of protective coating described in the AFS Logic Wall documents? The answer is ‘NO’ since the protective coating selected by AFS Logic Wall cannot be used without concrete cover and the render system cannot be relied upon as a protective system.

(A)(3) Why AFS Logic Wall must have concrete cover? (B) AFS Logic Wall Fire Design Assessment. * Added to August 2014 AFS Logic Wall Structural Engineering Assessment ** August 2014 version of this assessment updated to incorporate newly released commentary AS3600, Supplement 1 : 2014 which replaced the 1994 version. For the subject topic referred in this document, the 1994 and 2014 versions are identical.

Page 2 of 33

WHEN CONSIDERING THE USE OF AFS LOGIC WALL THE FOLLOWING SAMPLE STRUCTURAL ENGINEERING CERTIFICATE SHOULD BE REQUIRED BY CERTIFIERS WHO ASK FOR AS3600 – 2009

COMPLIANCE Certifying (Company Letterhead) (Date) (Client’s Name) (Client’s Company) (Client’s Address) Dear Sir RE: (Project Title) AT: (Project Address) CERTIFICATE OF DESIGN – STRUCTURAL FOR AFS WALL SYSTEM Pursuant to the provisions of Clause A2.2 of the current Building Code of Australia (BCA) and the Worker Health and Safety Act 2011, I hereby certify that the above design is in accordance with normal engineering practice and meets the requirements of the Building Code of Australia, Part 7 of the Environmental Planning and Assessment Regulations, relevant Australian Standards and relevant conditions of Development Consent. In particular the design is in accordance with the following: (1) B.C.A. Part B1 – Structural Provisions.

(2) AFS Logic Wall does not comply with the “deemed to satisfy” provision of AS3600 – 2009, i.e. concrete

cover over the metal ‘C’ sections is required to be able to comply with the “deemed to satisfy” conditions. Protective coatings cannot be relied upon without concrete cover.

(3) AFS Logic Wall can be considered as an Alternative Solution provided the conditions given in AS3600 – Appendix B which requires:

(i) Durability testing for a period of 50 years, +/- 20% = 60 years. (ii) The Fire Resistance Level determination test for AFS Logic Wall for the design applied loads, load

eccentricities, wall height, wall thickness and concrete (commercially available – not purpose design concrete) strength. AFS Logic Wall as an Alternative Solution cannot be used above and beyond the Fire Resistance Level Test Limitations.

As Structural Engineers for the above referenced project, I have reviewed the testing and certification provided for the AFS Logic Wall and certify that: • AFS Logic Wall is structurally adequate to satisfy the Durability requirements for a design life of 50 years,

+/- 20%.

• AFS Logic Wall will not be loaded in excess of the Fire Resistance Level test limitation (including load, height, thickness and eccentricity).

I am an appropriately qualified and competent person in this area and as such can certify that the design and performance of the AFS Wall system complies with the above and which are detailed on the following drawings, Nos:…………. I possess indemnity insurance to the satisfaction of the building owner or my principal. Full Name of Designer: Qualifications: Company: Address of Company: Yours faithfully (Company Name) (Certifying Person’s Signature) (Certifying Person’s Name)

Page 3 of 33

((AA)) AAFFSS LLOOGGIICC WWAALLLL –– DDUURRAABBIILLIITTYY AASSSSEESSSSMMEENNTT IINN AACCCCOORRDDAANNCCEE WWIITTHH AASS33660000--

22000099 SSEECCTTIIOONN 44 (A)(1) DOES AFS LOGIC WALL COMPLY WITH THE “DEEMED TO SATISFY” CONDITIONS? The prevention of concrete cancer (i.e. corrosion of metals within the concrete) is one of the most important requirements of AS3600 – Concrete Structures Code. Concrete cancer or corrosion of metals occurs when CO2 and chlorides attack the metal. These contaminants are available from ambient conditions or using inappropriate concrete ingredients, such as aggregates containing salt and/or water containing salt (i.e. chlorides), CO2 is available in the atmosphere. For these reasons, AS3600 provides guidance for the concrete mix design specification and requires any metallic embedments to have minimum concrete cover as per AS3600 – Clause 4.10.3.7 (refer Appendix No: 7 for the Japanese Code). Concrete’s own chemical reaction together with having adequate cover on the metallic embedments is the only protection mechanism accepted by AS3600 for durability compliance. AS3600 excludes the prevention of corrosion by protective coating (including galvanising, epoxy coating) of any kind. AS3600 excludes the use of protective coatings because there are too many conditions that are relevant to using protective coatings. For this reason, the current and legal commentary, AS3600 Supplement 1 : 2014, states that “protective coating is outside of the scope of AS3600” (refer Appendix No: 6). Therefore, any concrete wall system having metallic embedments without concrete cover falls outside of AS3600 hence cannot be defined as complying with the “DEEMED TO SATISFY” conditions of the Building Code of Australia. This is the failure of the Unisearch, UNSW Report dated 5th May 2014 for not recognising this fundamental AS3600 requirement of concrete cover. (A)(2) DOES AFS LOGIC WALL WITH THE SPECIFIED PROTECTIVE COATING SYSTEM

QUALIFY TO BE DEFINED AS AN ALTERNATIVE SOLUTION? The answer is ‘NO’ for the following reasons. (a) The fundamental requirement of AS3600 is that CO2 and chlorides must be prevented from

getting in contact with metallic embedments. Assuming that appropriate concrete mix is used, the only remaining alternative for the source of CO2 and chlorides is the atmospheric condition. Therefore, this necessitates AFS Logic Wall to have an impervious protective coating to be qualified as an ALTERNATE SOLUTION. Appendix – Item 5: AS3600 commentary states “No concession is given in the standards for coatings on the steel such as galvanising or epoxy coating”. The same reference also states that “corrosion can be initiated by carbonation or grossly inadequate cover”.

(b) The life of a durable structure is up to 50 years +/- 20% = 60 years as per AS3600. Therefore, the impervious protective coating must have 60 years life or must be renewed (maintained) at regular intervals of 7 to 10 years. There is no Australian law that requires that building owners must maintain their protective coating for durability compliance purposes. This is another reason why AS3600 – Appendix B requires an alternative solution to demonstrate by testing of the required structural life of 60 years condition. Therefore, for any alternative solution the protective coating must be totally impervious and 100% reliable for all conditions. The following conditions describe why the AFS Logic Wall with Dulux Acratex render system as a protective coating cannot be regarded as impervious.

(i) The building walls never come straight. This necessitates a build-up of render material to

achieve a reasonably level finished surface. The render material’s excessive thickness shrinks/expands and cracks.

(ii) The top coat placed over the render system that is intended to reduce vapour transmission

is “breathable” and it is only as good as the workmanship skill of the applicator. If adequate dry film thickness of the top coat is not provided, the top coat will be totally useless.

Page 4 of 33

(iii) The effectiveness of the render and top coat is also dependent on weather conditions.

Render/top coat manufacturers clearly warn that no application shall take place on hot, humid, or rainy days and in windy weather conditions.

(iv) In addition to the above, the cracking in the protective render system can occur due to

foundation/floor settlements, shrinkage and thermal movements of concrete infilled AFS Logic Wall. The concrete infill and fibre cement sheets (which concrete bonds to it) have different coefficients of thermal expansion which is bound to result in movement at the fibre cement sheet joints. The cellulosic fibres of fibre cement sheets are also subject to biological/chemical degradation which normally results in sheet joint movement by curling.

Refer http://www.dincelconstructionsystem.com/documents/Leaky_Buildings_Fibre-Cement_Sheet_Suitability.pdf (v) If protective coatings in the form of a render system are reliable the mould/mildew and

corrosion shown in the following Photo No: 3 would not occur. (vi) The compliance conditions of the Unisearch, UNSW Report dated 5th May 2014 infers that

AFS Logic Wall is not compliant when the approved protective coating is not applied onto the AFS Logic Wall at Zones A and B of the below diagram (e.g. against another building and internal walls in which Clause 4.10.3.7 and Table 4.3 of AS3600 – 2009 require minimum concrete cover).

The following diagram represents a case where there is no protection to the AFS Logic Walls.

(c) Refer to the following Appendix – Item 6: AS3600 commentary which states that when protective

coatings are allowed to be used, a maintenance program is required. It should be noted that the metal channels of AFS Wall are hidden by the glue fixed fibre-cement sheeting (may also have paint/render finishes on them). Therefore, the metal channels cannot be visually inspected and corrosion is allowed to occur behind the fibre-cement sheets with no method of inspection or repair. Refer to the following Photo No: 2. This is against the maintenance requirement of AS3600 if and when protective coatings are used.

The protective coating (in the form of true membranes and epoxy coating – not a render

system) helps to reduce concrete cover requirement. Refer AS3600 – 2009, Table 4.3, Note 9.Refer to the following Appendix – Item 5 which defines what the acceptable coating is on concrete to satisfy the purposes of AS3600. The definition is: “such coatings should be impermeable to carbon dioxide and chlorides and should be durable themselves”.

Page 5 of 33

AFS Logic Wall Certification by Unisearch, UNSW dated 5th May 2014 refers to the Dulux

Acratex System (render and top coat). If this system was totally impervious, the Dulux document titled (download) Dulux Protective Coating Technical Document No: 1:3:8 would not require concrete cover as per AS3600.

Dulux Acratex clearly states that for their “Protective Coating” to be effective, the protective

coating must be applied over adequate concrete cover. In the absence of concrete cover with the Dulux Acratex render system, AFS Logic Wall DOES NOT QUALIFY FOR THE ALTERNATIVE SOLUTION. Therefore, this makes the reports from Unisearch dated 20th March 2014 and AccessUTS dated 23rd May 2014 correct in stating that AFS LOGIC WALL DOES NOT COMPLY WITH AS3600 – 2009.

(A)(3) WHY AFS LOGIC WALL MUST HAVE CONCRETE COVER It is our observation that many engineers do not realise that the critical issue is the permanent gaps against the metal ‘C’ sections which will result in corrosion of the reinforcing bars and the metal ‘C’ sections if the protective coating cannot stop CO2 and chlorides from entering into the AFS Logic Wall.

Important engineering questions to discuss when considering the Unisearch Report dated 5th May 2014 are: • What happens if CO2 and chlorides enter into the AFS Wall System? • Is the opinion of Unisearch Report dated 5th May 2014 acceptable by AS3600? (A)(3)(a) WHAT HAPPENS IF CO2 AND CHLORIDES ENTER INTO THE AFS LOGIC WALL

SYSTEM? When CO2 and chlorides enter the AFS Wall System, corrosion of the metal ‘C’ sections at the punched edges, top and bottom end of the metal ‘C’ sections occurs where no galvanising exist and steel reinforcing bars without galvanising will initiate the corrosion of the metal components.

The most important issue to understand is not the corrosion possibility of the metal ‘C’ sections (as stated by AFS Wall they are sacrificial). The main point is that carbon dioxide and chlorides enter into the body of the AFS Walls and directly affect the reinforcement bars when the defined protective coating system of Unisearch Report dated 5th May 2014 (i.e. render system on the fibre cement sheet) becomes ineffective. Therefore, if we follow the Unisearch Report dated 5th May 2014 logic, one would consider that the reinforcing bars should be hot-dip galvanised as well since the penetration of CO2 and chlorides into the AFS Wall system cannot be prevented by the referenced render system.

The permanent gap (refer below diagrams ‘A’ and ‘B’) is defined in the Unisearch Report dated 5th May 2014 as 0.14mm wide. This crack will remain permanently since autogenous healing of concrete cannot happen between concrete and the metal ‘C’ sections.

The limiting crack width in Europe as mentioned in Unisearch Report dated 5th May 2014 is 0.3mm, and in Australia is 0.2mm, for conventional walls, 0.1mm for liquid storage tanks. These crack width limitations are applicable only when a crack occurs between two matching concrete surfaces in which autogenous healing can seal the concrete crack to prevent the entry of CO2 and chlorides through the cracks. These limits are not applicable to the cases when concrete shrinks away from the metal surfaces such as metal ‘C’ channels of AFS Walls where autogenous healing cannot work to close the permanent gaps. When the externally applied protective coating (i.e. top coat of the render system is ineffective, damaged or cracked) as shown in the diagrams below, the 0.14mm crack width for the entire cross section is more than wide enough to allow CO2 and chlorides to enter into the system. (Refer Photos Nos: 2 and 3 to see that the render system of AFS Logic Wall cannot be an effective protection system).

As there is no concrete cover over the flanges of the metal ‘C’ sections as shown in the below Detail A, the contaminants will easily pass through the permanent gap created by the shrinkage of concrete at each metal ‘C’ section for the entire cross section of the AFS Wall and will prematurely corrode the reinforcing bars without hot-dip galvanising. This is the reason why the AFS metal ‘C’ section must have concrete cover.

Page 6 of 33

DETAIL A DETAIL B IMPORTANT NOTES

• Cracks in the walls are unavoidable. • Metal ‘C’ sections shown ensure that crack occurs. • Autogenous Healing cannot occur between the concrete and the metal/plastic sections within the

concrete. • The corrosion problem is therefore unavoidable in the absence of concrete cover. • No concrete cover means NO AS3600 COMPLIANCE. IT IS THEREFORE THE ENTRY OF CO2 AND CHLORIDES THAT MUST BE PREVENTED TO AVOID CORROSION in the absence of concrete cover between the metal ‘C’ sections and fibre cement sheets (as shown in Detail ‘B’ above) and when the acrylic render top coat is ineffective as shown in Photos Nos: 2 and 3. The following can be considered as signs of an ineffective acrylic render top coat as a protective coating; visible rust stains; mould and mildew observations on the walls’ surfaces (refer Photo No: 3). The Unisearch Report dated 5th May 2014 also states that the metal ‘C’ sections’ life significantly increases within an alkaline environment. No doubt this is a statement made without knowing the existence of Photo No: 1. The engineer/certifier needs to consider the following and decide if a total alkaline environment for corrosion protection as referred in the Unisearch Report dated 5th May 2014 is possible to achieve.

Page 7 of 33

(i) Does the glue in the above Detail ‘A’ provide a total alkaline environment at the flanges of the

metal ‘C’ section? (ii) The 0.14mm gap shown in the above details is unavoidable. Does the external protection (i.e.

top coat) prevent CO2 entry as shown in the above details? If this occurs, the alkaline protection along the 0.14mm gap shown in the above Detail A and along the top flanges of metal channels would not exist.

(iii) The potential of concrete honeycombing (refer Photo No: 1). The main causes for honeycombing are: the porous nature of formwork (block walls, fibre cement

sheets), congestion of steel reinforcement (the presence of metal ‘C’ channels may contribute to the congestion of the vertically and horizontally reinforced cross-sections required with the AFS Wall) not having adequate slump and vibration. Honeycombing is exacerbated when the cross sectional area gets smaller in porous materials.

Fibre cement sheets are a porous material. The fibre cement sheets suck the water from the wet

concrete mix when the formwork is filled with concrete. This in turn creates friction between the concrete infill and fibre cement sheets. Very similar honeycombing occur with masonry blocks which are normally saturated with water before they receive the special concrete mix with about 250mm slump in order to avoid honeycombing (AFS documents show 120mm slump). This problem with honeycombing is a well-known problem that exists without depending on the skill of the installer as the majority of problems can be attributed to the material used for the formwork.

The top Photo No: 1 shows “air voids identified and grouted by the installer”. Does this

mean that the installer is aware of the air voids? How were the air voids identified by the installer? – by tapping on the fibre cement sheets?

Do the installer and builder notify the engineers of the air void occurrence? Does the engineer supervise the rectification methodology and work carried out?

What if the installer cannot identify the air voids? The top Photo No: 1 also show “air

voids failed to be identified by the installer” according to the builder of this project. (iv) Would good workmanship avoid honeycombing? (Shown in Photo No: 1). This problem can only be improved by using about 250mm concrete slump (like block walls water

hosing the AFS formwork should assist). The subject problem is associated more with the material use. It is important to note that the Photo No: 1 is from the construction site of a Grade 1 builder, and the installer/concreter of the AFS Wall was the party who is experienced with the AFS Wall installation and concreting. This problem therefore cannot be attributed to unskilled labour of the installer as the installer for the subject project is a more than skilled installer, and only using 120mm slump concrete in lieu of 250mm slump. It appears that the reluctance of not wetting the AFS formwork prior to concreting must be causing air voids as in the case of masonry block walls.

Why the installer does not wet the fibre cement sheets prior to concrete pouring and does not use

in excess of 250mm slump to minimise the air void issue? This would result in blow-out of the fibre cement sheets being only 6mm thick.

THEREFORE, WHERE HONEYCOMBING AS SHOWN IN PHOTO NO: 1 EXISTS, HOW CAN

THE ENGINEER/CERTIFIER JUSTIFY THE FOLLOWING:

Structural Adequacy/Integrity/Insulation requirement of a FIRE WALL.

Structural adequacy even without fire considerations.

ACOUSTIC performance of the walls with air voids.

Page 8 of 33

IS THE OPINION OF THE UNISEARCH REPORT DATED 5TH MAY 2014 ACCEPTABLE BY AS3600? The reader should refer to the AS3600 Supp1 : 2014 Commentary (Refer to the following appendix of this assessment – underlined. The previous commentary, AS3600 – Supplement 1:1994 for the subject topic is identical with the new 2014 commentary). “Care should be exercised when assessing the ability of a surface coating to protect the surface and continue to do so during the life of the building. Originally it was hoped that a definition of impermeability could be provided to aid in this. However, it proved too difficult to firstly define an appropriate test method and secondly to determine the suitable limiting values. THE CHOICE OF A SUITABLE COATING IS OUTSIDE THE SCOPE OF THE STANDARD, but the designer should be warned that inadequate, poorly maintained coating may lead to more rapid degradation than no coating”. It is clear from the above that AS3600 does not rely on the protective coatings for durability compliance. THEREFORE IT APPEARS FROM THE ABOVE COMMENTARY THAT THE DESIGNER/CERTIFIER ACCEPTING THE INFERENCE BY THE UNISEARCH REPORT DATED 5TH MAY 2014 (i.e. acceptance of protective coating without concrete cover) WOULD NOT COMPLY WITH AS3600. AS THE ABOVE COMMENTARY CLEARLY STATES, THE RELIANCE ON PROTECTIVE COATINGS IS OUTSIDE THE SCOPE OF AS3600. AS3600 non-reliance on the surface coating is also clearly stated in the AS3600 Commentary by Paul Walsh of the CSIRO (refer to the following Appendix 5 of this assessment – highlighted) which states that “No concession is given in the standards for coatings on steel such as galvanising or epoxy coating”. As it is obvious, a thin top coat layer of render system is not a comparison to epoxy coating. AS3600 – 2009, Table 4.3, Note 9, states that “Protective surface coatings may be taken into account in the assessment of exposure classification”. AS3600 exposure classification determines the minimum concrete cover (as per Clause 4.10.3.7) and concrete grade depending on the environmental conditions. This does not mean that the minimum concrete cover can be ignored as there is no exposure classification in AS3600 that exist with zero (0) concrete cover. Table 4.3, Note 1 further states that “In this context reinforced concrete includes any concrete containing metals that rely on concrete for protection against environmental degradation. Plain concrete members containing metallic embedments should be treated as reinforced members when considering durability”. The extract from the Japanese Building Code (refer to the following Appendix 7 of this assessment) states that any metallic frames within concrete is to have 50mm concrete cover (this is similar to the Australian Exposure Classification within 1km of a coastal zone). In addition to the above, the commentary by Paul Walsh of the CSIRO (refer to the following Appendix 5 of this assessment) states that “The note to the clause permits coating on the concrete to be taken into account. Such coatings should be impermeable to carbon dioxide and chlorides and should be durable themselves”. This comment refers to coatings on the concrete hence concrete cover is required, and the coatings themselves shall be durable. This is consistent with (download) Dulux Protective Coating Technical Document No: 1:3:8 which requires concrete cover on the concrete as per Paul Walsh’s commentary. If all of the above on concrete cover is considered together with the statement of AS3600 – 2014, Commentary, “The choice of suitable coating is outside of the standard”, AS3600 is suggesting that minimum concrete cover is required for durability compliance. In fact AS3600 is clearly stating to the designer that the code cannot offer a reliable solution to provide corrosion protection without providing minimum concrete cover. This is the reason for Clause 4.10.3.7 in AS3600 – 2009. Systems relying on the concrete protective coating rather than applying minimum required concrete cover are outside of AS3600 therefore as the AS3600 commentary states, the AFS Wall cannot be considered as a “DEEMED TO SATISFY” condition of AS3600.

Page 9 of 33

PHOTO NO: 1 AIR VOIDS CAUSE CORROSION

(PHOTOS FROM A BUILDER OF A SYDNEY PROJECT THAT HAS USED AFS WALLS)

AIR VOIDS IDENTIFIED AND

GROUTED BY THE INSTALLER

AIR VOIDS FAILED TO BE IDENTIFIED

BY THE INSTALLER WHO GROUTED THE

ABOVE VOIDS

AIR VOIDS

AIR VOIDS

GLUE ON METAL CHANNELS

FIBRE CEMENT SHEET JOINT

FIBRE CEMENT SHEET

REMOVED FOR INSPECTION

Page 10 of 33

PHOTO NO: 2 “PROTECTIVE COATINGS” ARE OUTSIDE THE SCOPE OF

AS3600 – CONCRETE STRUCTURES CODE, BECAUSE WHAT IS SHOWN IN THE PHOTOS BELOW IS HARD TO AVOID

METAL ‘C’ CHANNEL CORROSION

FAÇADE WALL – WINDOW HEAD METAL ‘C’ CHANNELS CORROSION

UNDER “PROTECTIVE COATING”

Page 11 of 33

PHOTO NO: 3

PHOTOS SHOW MOULD / FUNGUS AT A SYDNEY – AFS PROJECT INDICATING THAT RENDERED FIBRE CEMENT SHEETS ARE POROUS HENCE CANNOT BE IDENTIFIED AS

“PROTECTIVE COATINGS”

MOULD / FUNGUS

MOULD / FUNGUS

Page 12 of 33

PHOTO NO: 4

PHOTOS FROM CANBERRA – INDICATING THAT THE PROBLEM DOES NOT ONLY OCCUR IN CLOSE PROXIMITY TO WATERFRONT PROPERTIES

Page 13 of 33

PHOTO NO: 4 (cont’d)

Page 14 of 33

((BB)) AAFFSS WWAALLLL FFIIRREE DDEESSIIGGNN AASSSSEESSSSMMEENNTT The following paper explains fire related issues relevant to AFS Wall. These issues are: • The use of CSIRO fire test report. The conditions by CSIRO are clearly ignored. In fact the

deviation from CSIRO conditions are displayed in the AFS website (refer Appendix Item 3). The concern is that structural failure of AFS Wall can occur in the event of a fire, especially at levels allowed beyond CSIRO’s test report and clarification letter attached to this document (refer Appendix Items 1 and 2). The CSIRO issued letter dated 13th September 2011 is shown in Appendix Item 4 requesting AFS to avoid any misrepresentation.

• Safety issue relating to delamination of fibre cement sheets during a fire event. (B)(1) STRUCTURAL ENGINEERING – THE USE OF CSIRO FIRE REPORT OF AFS WALL It is the practising Structural Design Engineer’s responsibility to design and certify that

the structural elements (walls, columns, slabs) have adequate fire resistance level (FRL).

Australian engineers can design structures in Australia to suit the concrete structures code such as AS 3600 (Australian) or ACI 318 (American) or EuroCode. All these codes provide guidance to engineers with tables or empirical formulas for the necessary structural element thickness to achieve the required FRL by the Building Code of Australia (BCA).

The abovementioned concrete codes all refer to conventional reinforced concrete walls. ACI and EuroCode also deal with unreinforced concrete walls. The Australian BCA allows the use of an alternative solution such as AFS Wall provided they produce adequate certification/test report from an approved testing authority. The main variation of AFS Wall from conventional concrete walls is the presence of closely spaced metal channels which will most likely provide different fire spalling characteristics than the conventional concrete walls where the metallic components are protected by adequate concrete cover in the event of a fire. The absence of concrete cover over the metal ‘C’ sections of AFS Logic Wall is the reason why AFS Logic Wall varies from a conventional concrete wall adopted by all engineering codes. AS3600 as explained previously is very clear that walls without concrete cover cannot be referred to as a “DEEMED TO SATISFY” condition. Therefore, it is the structural engineer’s responsibility to ensure that the AFS Walls are designed within the limits of their fire testing report, provided AFS Logic Wall can be classified as an ALTERNATIVE SOLUTION. This assessment has previously explained why AFS Logic Wall with a specified render system cannot be qualified as an alternative solution. This is because paint/render system cannot be relied as a protective system without concrete cover.

It appears that there is an incorrect use of CSIRO’s test report on AFS Wall by some structural engineers who use the AFS Wall’s fire test certification. It is therefore important to explain the following:

(a) The Fire Behaviour of Conventional Concrete Walls

The fire spalling behaviour of conventional reinforced concrete walls when subjected to building fires can be summarised as follows:

(i) Due to Pore Pressure Spalling

The moisture that is available within a concrete wall turns into gas when subject to fire which spalls the concrete with a violent explosion.

(ii) Aggregate Expansion Spalling

Concrete consists of crushed rock pieces called aggregate. The aggregates when subjected to the heat of a fire expand and explode causing spalling to the concrete’s matrix. The denser the aggregate the more expansion occurs when subjected to heat.

Page 15 of 33

(iii) Reinforcing Steel Expansion Spalling

If steel reinforcement does not have adequate concrete cover for insulation purposes, the heat quickly reaches the steel. The steel bars expand under the heat of fire causing spalling to concrete. Refer Figure 2 below.

FIGURE 2

The above are the reasons why concrete spalling occurs in a conventional building fire when a concrete wall or column is exposed to the heat of a fire.

(b) The Fire Behaviour of AFS Wall

The abovementioned conventional concrete fire behaviour occurs with AFS Wall as well. However, AFS Walls are most likely subjected to additional concrete spalling for the following reason: Figure 3 below shows a typical AFS Wall. The metal channels are closely spaced to each other. The flanges of the metal channels reduce the clear distance further between the channels. The metal channels’ surface coverage is 33% at each wall face. The face of the metal channels is covered with 6mm fibre-cement sheets which delaminate and detach from the metal channels in a short space of time (CSIRO fire tests show that this period is 15 minutes) during a fire event. This way, the metal channels are directly exposed to fire. The exposed (i.e. unprotected) flange of the partially encased metal ‘C’ shape channel under the fire’s heat expands and the resultant stress causes “corner spalling” emanating from the face of the metal channel as shown in the figure below. The effect of normal concrete’s spalling behaviour in a fire event is thus further exacerbated by the presence of exposed metal flanges.

Page 16 of 33

PLAN DETAIL OF AFS WALL SUBJECTED TO FIRE

FIGURE 3

It can be argued that the metal channels of AFS Walls are not used for structural purposes. The

main issue is to understand that the presence of metal channels most likely contribute to additional spalling in comparison to conventional concrete which is beyond normal concrete structures codes. Concrete structures codes such as AS3600, ACI318 or Eurocode are specifically written for concrete walls without any built in metal channels of Figure 2 above. This additional spalling may cause structural failure, especially in highly stressed AFS Wall.

This is why AS3600 – Appendix B, Clause B2.3 must be satisfied.

Why is Concrete Spalling Important?

The structural capacity of a vertical load bearing element (wall or column) is directly related to the load it carries and its thickness. The other very important criterion is the water/cement ratio of concrete mix and relative humidity in ambient conditions. The structural element buckles under the load if it does not have adequate thickness hence it fails. This is the case with or without a fire incident.

During a fire event, the structural wall thickness reduces due to concrete spalling as explained above. International engineering codes, including the Australian AS3600, are based on the test results for conventional reinforced concrete walls having adequate cover to steel reinforcements. These tests determine the engineering code recommendations which account for concrete spalling due to pore pressure, aggregate expansion and having adequate cover to the steel. The fundamental difference between AFS Wall and conventional concrete walls is the presence of closely spaced metal channels which has every potential of generating additional concrete spalling in comparison to conventional concrete walls. Additional spalling means reduction in wall thickness during a fire hence reduction in the load carrying capacity. This difference distinguishes the AFS Wall from conventional reinforced concrete walls.

Page 17 of 33

The conventional concrete walls accepted by the Concrete Structures Code do not accommodate the metal channels shown in Figure 3. Therefore, AFS Walls clearly do not agree with the prototype accepted by the Concrete Structures Codes.

If a certifier/structural engineer accepts a test report from an approved testing authority, the test report must be in compliance with AS3600 – Appendix B, particularly Clause B2.3. This is why an engineer can only allow the use of any alternative solution within the limitation of the test report. Therefore, it must be clear to AFS Wall’s specifiers and users that AFS Wall must be used within the limits of CSIRO’s fire test certificate for AFS150 wall system which are:

(i) Concrete specification; 32Mpa, 10mm aggregate, 120mm slump.

(ii) 200 kN/m maximum load carrying capacity.

(iii) 3,000mm maximum wall height.

(iv) 136mm net concrete thickness.

Concrete spalling commonly occurs within the first 30 minutes of fire exposure. As a result, the collapse of the wall with excessive spalling can even occur at around 30 minutes of fire exposure if the wall carries a load in excess of 200 kN/m test load. It is therefore essential for all design engineers to limit their design for AFS Wall within the above parameters as stated in the CSIRO letter dated 24th August 2006 (refer Appendix Item 2).

This means that engineers cannot extrapolate beyond the nominated maximum load that AFS wall is tested for. The load carrying capacity of AFS Wall can only be increased (as stated in the attached CSIRO letter dated 24th August 2006) by increasing the net concrete thickness for 3,000mm high walls with the abovementioned concrete specification. Further load carrying capacity can be achieved by increasing the 32Mpa concrete grade to a higher grade of concrete.

The existence of the metal channels resulting in additional spalling behaviour for AFS Wall is the fundamental difference to conventional concrete walls as defined by AS 3600 and international Concrete Structures Codes.

This is why AFS Wall’s structural load capacity has to rely on fire test certificates, and this is why conventional concrete walls can be fire engineered with the principles of the current Australian Concrete Structures Code AS3600 – 2009 which is based on the EuroCode Concrete Structures Code.

Is it possible to effect fire test results? YES, the major contributing factor is spalling. Apart from the presence of metal channels of AFS Wall, a special mix of concrete can make a significant impact on the fire’s behaviour. This can be achieved by using special aggregates, the use of polyethylene fibres in concrete mix, etc. Therefore, the engineer must also understand what type of concrete has been used when assessing a fire report.

Summary of CSIRO’s Response to AFS Wall The above are the limitations imposed on AFS wall by CSIRO’s fire test report (refer Appendix Item 1). The CSIRO letter dated 24th August 2006 (refer Appendix Item 2) confirms the limitation of fire walls. This is consistent with Appendix B, Clause 2.3 of AS3600. The reports presented by CSIRO are only test reports and they are NOT CERTIFICATES. This is why when structural engineers accept a test report he/she accepts full responsibility for the load cases above the test loads.

Page 18 of 33

The effects of Honeycombing on the Fire Performance of AFS Logic Wall Refer to previous assessment for Durability consideration on page 7 for: • The Potential of concrete honeycombing.

• Would good workmanship avoid honeycombing? If the air voids shown in Photo No: 1 is occurring, the structural engineer should not require any further explanation about the consequences in the case of a building fire. Air voids can transmit smoke and heat to the other side of a fire wall. This may first cause extreme panic from the residents of the adjacent sole occupancy. The extended period of a fire, say 30 to 60 minutes might even cause structural failure, depending on the magnitude of the air voids. (B)(2) SAFETY ISSUE DUE TO DELAMINATION OF FIBRE-CEMENT SHEETS Under Fire Conditions – BCA Fire Resistance/Stability and Exit Requirements

The delamination and detachment of fibre-cement sheets during building façade wall fires due to their glued attachment to metal channels of AFS wall represents safety liability for by-passers and fire fighters (i.e. detached sheets of say 1.2m x 2.7m can be airborne for significant distances) if the fibre cement sheets are delaminated as observed by the CSIRO fire test. The following BCA compliance requirements should be considered: • BCA – 2014 Part C1 – Fire Resistance and Stability Clause C1.12 (f) (i), (ii), (iii) and

(iv), and • BCA – 2014 Specification C1.1 Clause 2.4 (a) (i) and (ii). The delamination of the attachments (i.e. fibre-cement sheets), because of adhesives, should comply with Clause C1.12 (f) (i), (ii) and (iii) so that the delaminating fibre-cement sheets would not make the required exit unusable – (BCA Specification C1.1 – Clause 2.4 (a) (ii)). The subject wall’s fire testing clearly states that fibre-cement sheets delaminate after 15 minutes exposure to fire (no glue can resist heat of more than 80°C). The building fire temperature reaches 400°C within 5 minutes and 800°C within 15 minutes in accordance with CSIRO. It is recognised that delamination of fibre-cement sheets occur within 15 minutes of fire testing of AFS Wall when the temperature in the furnace reaches about 800°C. It has been argued by AFS Logic Wall’s representatives that there will be no people within the building to be affected from delaminating fibre-cement sheets at 800°C fire intensity. However, this explanation in CSIRO’s letter dated 24th August 2006 (refer Appendix – Item 2) does not cover the façade wall fires. Also, it does not address if the fire started at the lower levels where the sheets have already delaminated to prevent the people from escaping. The BCA Clause Specification C1.1 Clause 2.4 (a) (ii) is to eliminate the above or similar incidents. This issue will be particularly important when considering that the fire fighting response time is 20 minutes. Therefore, the delaminated fibre-cement sheets may also interfere with the actions of the fire fighters. The certifying authorities should satisfy themselves about the above fibre-cement sheets delamination issue in the case of façade fires.

Page 19 of 33

(B)(3) IS BONDEK / CONDECK USE SIMILAR TO AFS WALL

Metal floor forms (i.e. partially embedded metallic continuous sheet) such as Lysaght/Bluescope (Bondek) and Stramit (Condeck) are commonly used for floor slab construction. Refer Figure 4. Why AFS Wall metal channels cannot be considered in the same way? The fundamental differences between the two (2) systems are:

Bondek/Condeck are for floor slabs with a dominant action is flexure and the metal forms

are partially embedded into concrete without concrete cover on it. AFS as a wall is predominantly under compression and the metal channels penetrate the

entire wall cross section without concrete cover on them.

Floor slabs consisting of forms such as Bondek/Condeck have been tested by their manufacturers under fire for 100% of their real life load conditions as required by AS3600 – Appendix B. The important point is that the AFS 150mm wall is only tested for 200 kN/m loading and not for full loading where a multi-storey wall can be subjected to.

AFS WALL BONDEK SLABS FIGURE 4

AS3600 – Appendix B refers to all conditions, including fire and serviceability. The serviceability requirement of Appendix B includes durability compliance. Bondek (or Condeck) provides maximum 15 years life for their product against corrosion protection. AS3600 requires that structural elements must have a life for 50 years, +/- 20%. It is clear from the Bondek (Condeck) documents that the designer must consider that the metal form can be inspected within 50, +/- 20% years required by AS3600. The AFS Wall is covered with fibre cement sheets hence the corrosion of its metal channel sections (in the absence of concrete cover to the metal channel sections) unlike the Bondek form cannot be inspected at all. This is the fundamental difference between the metal floor formwork Bondek (Condeck) and AFS Wall. Engineers can also use Bondek (Condeck) for sacrificial formwork only without relying on the structural capacity of the sheeting itself. This way, engineers can ignore the structural presence of the Bondek sheeting and design the concrete slab based on conventional reinforced concrete principles. This way, Bondek acts as a sacrificial formwork only. However, the engineer/trades must ensure that the reinforcement required for the floor slab has the required concrete cover in accordance with AS3600 – 2009, Section 4. This is commonly done by engineers, especially in inaccessible conditions where corrosion of metal sheeting cannot be inspected. This way, the

Page 20 of 33

Bondek sheeting can rust away without adversely affecting structural integrity. However, in the case of AFS Wall this is different, particularly in the presence of metal channels penetrating the entire cross section and not having concrete cover on both ends and metal channel sections without concrete cover cannot be inspected due to the presence of the fibre cement sheet coverage. The fundamental durability difference between Bondek/Condeck and AFS Wall is that the AFS metal channels penetrate the entire cross section of the concrete cross section. This will allow a gap due to concrete’s shrinkage between the metal channel surface and concrete extending to the inner parts of the cross section where AFS Walls’ horizontal and vertical steel reinforcement is placed. This is a direct corrosion path to the vertical and horizontal steel reinforcement in addition to concrete degradation. This mechanism is explained in Item A, page 3 of this document. It is also important to note that Bondek/Condeck corrosion protection is not offered without limitations (i.e. maximum life is 15 years for Z450 Zinc coating) in accordance with the manufacturer’s literature. The Bondek document also has a clear disclaimer that the product must be used 1 km away from marine or industrial influences.

As described above, engineers can always have the option of designing Bondek/Condeck as sacrificial formwork.

Bondek also clearly state that the ends of the sheeting are protected by special detailing. Can AFS wall explain how they protect, particularly the bottom end of the metal channels at the wall – floor junctions. This would also be interpreted as a clear corrosion initiator in accordance with Bondek’s information. The type of boards used as formwork will affect the degree of the corrosion problem. The use of MgO Boards, particularly known as a corrosion initiator (American ACI386 and IBC Section 2502 recommend MgO Boards to avoid water contact), if any is used for concrete formwork purposes, would result in increased corrosion problems. In the case of the current AFS wall use which consists of fibre-cement sheets may hide the corrosion of metal components for a significant amount of time (rust stains if observed would be a clear indication that the corrosion process is occurring). However, this can be difficult to detect in the presence of fibre-cement sheets, particularly when it is covered by a membrane or a similar type (i.e. less porous) of coating system. The important point is that structural engineers must always consider the durability requirements of AS3600. After all, the structural engineer provides a certificate for a minimum life span of 50 years +/- 20%.

The Lysaght document states: “Bondek sheeting is partially effective during a fire event of up to two (2) hours”. Bondek’s (similar to Condeck) fire design principle is based on one way slabs, reinforced with fire reinforcement. The presence of steel reinforcement (with adequate concrete cover) avoids the catastrophic failure of the slabs even if the metal sheeting loses its structural integrity under fire conditions.

Walls are much more critical than floor slabs with Bondek/Condeck which are only in flexure and further to that they are reinforced to avoid a sudden failure under fire conditions. This is quite the opposite in the case of walls which are mainly in compression. The structural capacity of a wall is dependent on its slenderness ratio. The slenderness ratio can significantly increase due to concrete spalling under fire conditions and even durability conditions (i.e. corrosion spalling). Therefore, high stress levels can easily lead to sudden structural buckling failure, particularly in the case of a fire. This is because concrete’s behaviour during a fire event will be different at low and high stress levels. Also, 33% of the wall face metal coverage of AFS Wall should make a difference to the concrete spalling value. Unless AFS Wall is tested for 1,195 kN/m there is no way of knowing if this load can be safely resisted. The other criterion such as design eccentricity must be considered since fire tests do not impose eccentricity on the test panels.

AFS 150 version has a fire report from CSIRO and tested for 200 kN/m (refer Appendix, Item 1). If AFS wishes to advise its users that AFS 150 can be used for 1,195 kN/m (refer Appendix, Item 3) load capacity, the CSIRO test report should show 1,195 kN/m, not 200 kN/m. Otherwise this would be contrary to AS3600, Appendix B and CSIRO’s letter dated 24th August 2006 (refer Appendix, Item 2). Alternatively, BCA Specification A2.3, Clause 3 can be considered for each and every project. However, this will not be considered practical by a practicing design engineer as this methodology will be extremely time consuming and most likely commercially not viable.

Page 21 of 33

((CC)) CCOONNCCLLUUSSIIOONN SSUUMMMMAARRYY FFOORR AASS33660000 All of the above explains that embedded metallic components of AFS Wall require: • Minimum concrete cover of 20mm even for internal walls (AS3600 Section 4). • Protective coatings (membranes, epoxy coatings, galvanising) do not provide concession for not

having concrete cover. • Paints/renders are pervious hence they cannot be used as protective coating to satisfy AS3600. • The subject system is commonly used against another structure without even treating the joints

between the fibre-cement sheets over the metal channels (i.e. no access is possible to treat the joints and place the membrane system referred to in Appendix – Item 3, standard detail). This case would be the worst of all since it cannot even have a membrane system required by the manufacturer. The manufacturers of AFS provide shop drawings for every project. Therefore, they are aware (so is the structural design engineer) that the AFS system does not have any durability protection whatsoever when it is built against another structure.

• Even if the metal components have protective coatings they are required to be subjected to

ongoing maintenance (refer Appendix – Items 4 and 5 and AS3600). This cannot be satisfied in the case of AFS Wall since the metal channels are hidden behind the fibre-cement sheets hence visual inspection is not possible.

• When an engineer accepts a test report for an alternative solution, Appendix B – AS3600

will be required to be complied with for all ultimate loads, including strength, fire and serviceability conditions.

• AS3600, Clause 4.1 requires a minimum design life of 50 years +/- 20% (i.e. up to 60 years).

The structural engineer must satisfy this requirement. ((DD)) AAFFSS WWAALLLL –– IISS IITT AAPPPPRROOPPRRIIAATTEE TTOO AASSSSEESSSS AANN AAFFSS WWAALLLL IINN AACCCCOORRDDAANNCCEE WWIITTHH

AASS33770000 –– 22001111?? AS3700 – 2011 Requirements For A Wall 1. AS3700, Section 1 – Scope and General “sets out minimum requirements for design and

construction of “masonry” of the following type.

(a) Unreinforced, reinforced and pre-stressed masonry using manufactured units of clay or concrete “laid in mortar”.

2. AS3700, Clause 1.5.2.23 – Masonry

This clause defines masonry as: “Assembly of masonry units properly bonded with mortar. The term includes the following: (a) Plain Masonry (masonry not grouted, reinforced or pre-stressed).

(b) Grouted Masonry.

(c) Unreinforced Masonry.

(d) Reinforced Masonry.

(e) Pre-stressed Masonry.

(f) Special Masonry.

Page 22 of 33

3. AS3700, Clause 1.5.2.24 – Masonry Unit

This clause defines a masonry unit as: “A preformed component, intended for use in bonded masonry construction (see figure 1.1). The term covers the following: (a) Categories (b) Types

(i) Solid unit. (i) Calcium silicate masonry unit. (ii) Cored Unit. (ii) Clay masonry unit. (iii) Hollow unit. (iii) Concrete masonry unit. (iv) Horizontally cored unit. (iv) Autoclaved aerated concrete masonry unit (AAC). (v) Special purpose unit. (v) Natural store masonry unit.

(c) Dimensions

(i) Height (refer Figure 1.1) (ii) Length (refer Figure 1.1) (iii) Width (refer Figure 1.1) (iv) Face Shell width (refer Figure 1.1) (v) Full bed width (refer Figure 1.1)”

4. Construction and nature of AFS Wall

An AFS Wall is essentially a permanent stay-in-place formwork system comprising two faces of fibre cement sheet that are interconnected by vertical galvanised steel ‘C’ channel components. The fibre cement sheets are connected to the ‘C’ section by a glue bond only. The AFS components are generally delivered to site as a full height component (i.e. floor to floor) and are placed in position and secured with bracing elements. After erection on site, reinforcement is placed within the AFS Wall and concrete is poured to form a reinforced concrete Wall.

((EE)) CCOONNCCLLUUSSIIOONN SSUUMMMMAARRYY OONN AAPPPPRROOPPRRIIAATTEENNEESSSS TTOO AASSSSEESSSS AANN AAFFSS WWAALLLL IINN AACCCCOORRDDAANNCCEE WWIITTHH AASS33770000 -- 22001111

The construction of the AFS Wall does not comprise masonry units that are laid/placed in a bonded arrangement utilising mortar and therefore does not conform to the masonry or masonry unit definition of AS3700 – 2011. The AFS components do not conform to the category, type and dimension requirements of AS3700 – 2011. AFS Logic Wall does not comply with the requirements of AS3700 Masonry Code and therefore should not be designed in accordance with AS3700 – 2011.

Page 23 of 33

APPENDIX 1. AFS WALL CSIRO TEST CERTIFICATE. 2. CSIRO LETTER DATED 24TH AUGUST 2006. 3. AFS WALL PERFORMANCE OVERVIEW AND AFS FAÇADE WALL

STANDARD DETAIL. 4. CSIRO LETTER DATED 13TH SEPTEMBER 2011. 5. AS3600 COMMENTARY – PAUL WALSH, CSIRO. 6. AS3600 SUPPLEMENT 1 : 2014 COMMENTARY.

7. THE BUILDING CENTRE OF JAPAN (BCJ) – THE BUILDING STANDARD LAW ENFORCEMENT ORDER NO: 338, NOV 4, 2008 – SECTION 6.2, ARTICLE 79-3.

Page 24 of 33

Appendix 1 – AFS Wall CSIRO Test Certificate

Page 25 of 33

Appendix 2 – CSIRO Letter Dated 24th August 2006

Page 26 of 33

Appendix 3 – AFS Wall Performance Overview and AFS Façade Wall Standard Detail

Page 27 of 33

Appendix 4 – CSIRO Letter Dated 13th September 2011

Page 28 of 33

Appendix 5 – AS3600 Commentary – Paul Walsh, CSIRO

Page 29 of 33

Page 30 of 33

Page 31 of 33

Appendix 6 – AS3600 – 1994 Commentary

Page 32 of 33

Page 33 of 33