NEW ZEALAND STANDARDS FOR CONCRETE MATERIALS AND CONSTRUCTION: 2012 STATUS S. FREITAG 1 , R. GAIMSTER 2 AND D. COOK 3 1 Opus International Consultants Ltd 2 Cement & Concrete Association of New Zealand 3 Fletcher Construction EQR SUMMARY New Zealand Standards for concrete materials, design and construction have been developed by a consensus approach that has to date delivered good quality concrete construction. In recent years, keeping Standards up to date has become increasingly difficult, resulting in many Standards not necessarily representing current understandings of best practice. This paper describes the current status of concrete-related New Zealand Standards, why they are difficult to maintain, what is being done to overcome these problems, and what practitioners can do while waiting for improvements to be implemented. INTRODUCTION The need to revise New Zealand’s construction Standards has been widely discussed in the wake of the Canterbury earthquakes. Understandably, much of the discussion has focused on improving seismic performance. In the context of concrete construction, this means revising NZS 3101 to include findings from investigations into how concrete structures behaved during the 2010-2011 events. NZS 3101 is just one of more than 20 New Zealand Standards relating to concrete materials, design, and construction practice, albeit one of the most important. It is also one of the most frequently updated. Other concrete Standards, although also important, are not updated as often. For example, Standards for aggregates and concrete testing are now over 25 years old. Consequently, some of the materials and technologies represented in the Standards no longer represent current best practice. This paper identifies aspects that need updating in the New Zealand’s principal concrete Standards, and priorities that industry has set for undertaking revisions and amendments. With increasing interchange of materials, products and expertise between Australia and New Zealand, specifications for New Zealand projects are often influenced by Australian experience and practice. And utilising overseas Standards can be more efficient than having our own. This paper describes the relationship between Australian and New Zealand Standards, identifies some AS Standards that contain useful background information to topics covered in New Zealand Standards, and points out similarities and significant differences between some Australian and New Zealand Standards. To date, New Zealand Standards have been developed and maintained by utilising expertise and experience from a wide range of interested parties. This process ensures that Standards are independent and represent practices acceptable to stakeholders, but is no longer sustainable under current funding mechanisms. This paper describes how New Zealand Standards relating to concrete construction are currently managed, and the aims of reviews now underway to not only to improve the process but also the entire regulatory framework for the construction sector.
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NEW ZEALAND STANDARDS FOR CONCRETE MATERIALS AND CONSTRUCTION: 2012 STATUS
S. FREITAG1, R. GAIMSTER2 AND D. COOK3
1 Opus International Consultants Ltd 2 Cement & Concrete Association of New Zealand
3 Fletcher Construction EQR SUMMARY New Zealand Standards for concrete materials, design and construction have been developed by a consensus approach that has to date delivered good quality concrete construction. In recent years, keeping Standards up to date has become increasingly difficult, resulting in many Standards not necessarily representing current understandings of best practice. This paper describes the current status of concrete-related New Zealand Standards, why they are difficult to maintain, what is being done to overcome these problems, and what practitioners can do while waiting for improvements to be implemented. INTRODUCTION The need to revise New Zealand’s construction Standards has been widely discussed in the wake of the Canterbury earthquakes. Understandably, much of the discussion has focused on improving seismic performance. In the context of concrete construction, this means revising NZS 3101 to include findings from investigations into how concrete structures behaved during the 2010-2011 events. NZS 3101 is just one of more than 20 New Zealand Standards relating to concrete materials, design, and construction practice, albeit one of the most important. It is also one of the most frequently updated. Other concrete Standards, although also important, are not updated as often. For example, Standards for aggregates and concrete testing are now over 25 years old. Consequently, some of the materials and technologies represented in the Standards no longer represent current best practice. This paper identifies aspects that need updating in the New Zealand’s principal concrete Standards, and priorities that industry has set for undertaking revisions and amendments. With increasing interchange of materials, products and expertise between Australia and New Zealand, specifications for New Zealand projects are often influenced by Australian experience and practice. And utilising overseas Standards can be more efficient than having our own. This paper describes the relationship between Australian and New Zealand Standards, identifies some AS Standards that contain useful background information to topics covered in New Zealand Standards, and points out similarities and significant differences between some Australian and New Zealand Standards. To date, New Zealand Standards have been developed and maintained by utilising expertise and experience from a wide range of interested parties. This process ensures that Standards are independent and represent practices acceptable to stakeholders, but is no longer sustainable under current funding mechanisms. This paper describes how New Zealand Standards relating to concrete construction are currently managed, and the aims of reviews now underway to not only to improve the process but also the entire regulatory framework for the construction sector.
Thus the paper aims to help designers utilise current New Zealand Standards and other resources to develop sound and practical specifications for concrete construction in New Zealand now, while awaiting changes in the role, governance, and content of Standards. Opinions expressed in this paper are those of the authors and do not necessarily represent those of the organisations they represent. HOW NEW ZEALAND’S CONCRETE-RELATED STANDARDS HAVE BEEN DEVELOPED Standards are agreed specifications for products, processes, services, or performance. New Zealand Standards are currently developed though a consensus process that draws on specialist expertise from practitioners and stakeholders to ensure that Standards address relevant technical and practical considerations as well as strategic industry needs. The Standards Council is an independent crown entity with members appointed to represent a range of community sectors. Standards New Zealand is its operating arm, which administers the Standards development process in accordance with international protocols and the Standards Act 1988. The need for a Standard to be developed or updated is determined by the relevant industry. Interests of the wider concrete construction industry are represented by the Cement and Concrete Industry Advisory Group (CCIAG), convened by Standards New Zealand. It was established to communicate between Standards New Zealand and the stakeholder interest groups at a strategic level, thereby ensuring that stakeholders have input into Standards New Zealand strategic direction and Standards produced are relevant to the cement and concrete sectors. It advises Standards New Zealand on the need for and nature of Standards in the cement and concrete sector, is briefed by Standards New Zealand and Standards Australia on relevant developments, and prioritises, manages, and maintains Standards work programmes in the sector. The CCIAG consists of representatives from IPENZ, Department of Building and Housing, NZ Institute of Architects, Cement & Concrete Association of NZ (CCANZ), NZ Ready Mixed Concrete Association, NZ Concrete Society, BRANZ and Precast NZ. Once the CCIAG has identified the need to develop or update a Standard, Standards New Zealand seeks input from industry on aspects for consideration. Feedback received is used to determine the scope of a new standard, and whether changes to an existing Standard are small enough to be covered by an amendment or whether a full revision is needed. A budget is then set for the project, which proceeds in defined stages:
1. Standards Committee convened. 2. Draft Standard developed by Committee. 3. Draft circulated for targeted comment and for public comment for two months. 4. Comments reviewed and draft updated by Committee. 5. Final draft voted on by Committee (at least 80% of committee members must agree
on the content before the draft is accepted for publication). 6. Standard is approved by Standards Council. 7. Standard is published as an NZS document.
Standards New Zealand and the CCIAG identify appropriate members for the Standards Committee, which typically represents the same organisations as CCIAG plus other interested parties and technical experts. Standards New Zealand and the Standards Committee notify interested organisations individually when seeking targeted comment on draft Standards. Public input is sought via Standards New Zealand’s website and e-zine. See Standards New Zealand’s website www.standards.co.nz for more information about New Zealand Standards.
STATUS OF NEW ZEALAND’S CONCRETE STANDARDS (July 2012) The government ministry responsible for Standards (now the Ministry for Business, Innovation and Employment (MBIE)) reviews all Standards. Standards it deems suitable to be cited in the compliance documents become part of the NZ Building Code and have regulatory standing. Compliance with other Standards is voluntary unless they are called up in Standards cited in the NZ Building Code. Figure 1 shows how New Zealand’s principal concrete materials Standards are related to each other and to the present regulatory framework for building and construction. This framework clearly separates regulation (NZ Building Act, Regulations, and Code), from the mechanisms of delivering compliance. Thus compliance may be delivered by documents such as Standards that constitute Acceptable Solutions and Verification Methods, or by other means such as determinations, product certification or Alternative Solutions (DBH, 2011). In addition to their compliance roles, New Zealand Standards, like many overseas Standards, contain sufficient technical detail to act as guidance documents. Non-statutory guidance documents produced by various other bodies underpin the regulatory framework. Many of the issues related to resourcing their development are the same as for Standards. In the interests of brevity, this paper does not discuss their roles or content. STATE OF NEW ZEALAND’S CONCRETE STANDARDS (July 2012) Table 1 at the end of this paper lists a selection of current1 New Zealand concrete-related Standards, the nature of recent changes to them, and future updates (i.e. revisions or amendments) needed for them to continue to represent best practice2. Following interim recommendations of the Canterbury Earthquakes Royal Commission (CERC) and the CCIAG, during the last 12 months CCIAG and Standards New Zealand initiated the process of reviewing and updating five key Standards related to concrete: NZS 3101, 3109, 3111, 3112.2 and 3121. Outcomes of these reviews to date are presented below. NZS 3101 It is universally agreed that the concrete design Standard is critical to ensuring safer buildings, therefore NZS 3101 is reviewed and updated approximately every 10 years. NZS 3101 is based upon ACI 318 (building code requirements for structural concrete), and is fundamentally based on very sound science. The recent Canterbury earthquakes have presented full scale test data on an unprecedented magnitude. The earthquakes tested not only a full range of reinforced concrete detailing and structural forms, but also tested workmanship and construction norms in dynamic biaxial loading complete with high vertical accelerations. With only a couple of exceptions, reinforced concrete structures performed well. The art of engineering is the ability to get improved performance through cost effective careful detailing. Observations from the Canterbury earthquakes thus provide a potentially useful database on well-considered detail that can enhance performance, and deficiencies that can reduce it. These learnings need to be incorporated into NZS 3101. With this and the age of the current NZS 3101 in mind, in mid-2011, Standards New Zealand sought feedback from the wider engineering community on aspects of NZS 3101 that needed review. In November 2011 it convened a workshop to consider and prioritise the comments received and suggested changes. The principal topics identified for investigating and resolving are briefly summarised below (see Fenwick and Cook (2010) for further details of pre-earthquake topics and SESOC (2011) for post-earthquake recommendations).
1 A ‘current’ Standard is the most recent revision of an active Standard.
2 Standards are not referenced in this paper. For references to NZ concrete-related Standards, see
table 1. For other Standards referred to herein, the topic is indicated in parentheses.
A key consideration is that the content of NZS 3101 must address the requirements of AS/NZS 1170.0 (aka ‘the loading Standard’) and NZS 1170.5 (earthquake actions). Review and updating of these Standards to address aspects relating to redundancy, maximum considered earthquake design actions, curvature ductility, displacement base design, and the effects of vertical accelerations will determine directions for changes to NZS 3101. One specific design issue is minimum reinforcing and detailing for shear walls. There have been calls to increase the minimum reinforcing contents in walls and provide extra confinement reinforcement. Others argue that modifying reinforcement layout may achieve the desired effect of ensuring a well distributed crack pattern in walls. Another is damage control design. NZS 3101:2006 pioneered the integration of Precast Seismic Structural Systems (PRESSS) technology into Standards. Since then, a wealth of research has been conducted on these systems. The Canterbury earthquakes have awoken building owners and insurance companies to the commercial benefits of buildings that sustain little structural damage in an earthquake and are self-centring. Indeed, CERC considered low damage building technologies to offer major benefits, and recommended they be developed further (CERC 2012a). This enhanced interest justifies updating NZS 3101 coverage of topics relating to PRESSS and base isolation, as well as to other aspects of seismic design of ductile jointed precast structural systems, e.g. beam elongation. Although ultimately being driven by the philosophy within NZS 1170.5, the Christchurch experience will force New Zealanders to think about how they wish buildings to perform. More conservatism being required at the serviceability limit state could result in less ductility demand, which would necessitate extensive but mainly editorial changes to NZS 3101. Alternatively, since damage is usually related to deformation, the loading Standard may simply place more onerous drift limits on buildings. Irrespective of the outcome, current ductility detailing needs to clarify curvature ductility. Topics relating to elongation of concrete members also need attention. For example, the requirements for strut and tie with significant penetrations need to be strengthened, detailing for diaphragms needs updating to avoid typical mistakes made associated with topping behaviour, and more information is needed on the ductility of welded ductile mesh. Other design issues needing review include aspects relating to performance of stairs in multi storey buildings, load cases to be considered during and after fire, and the minimum specified design concrete strength (i.e. 20 vs 25 MPa). Several aspects of durability design have been identified as needing attention. For example: provisions for freeze thaw durability may not accurately reflect the observed performance of concrete in some structures and environments; specification of concrete chloride content needs to include tolerances and appropriate test methods; provisions for concrete made with supplementary cementitious materials (SCM) or alternative binders like calcium aluminate cements need revising and including respectively; concrete cover requirements and use of life prediction models need to incorporate recent research findings; and the use of surface treatments needs to be expanded and include non-barrier forming materials. There has also been a call for more information related to bridges. This illustrates the complexity of the Standard development process. The Standard must be able to provide quality information for specialist uses such as bridges, while at the same time being equally relevant for the design of a domestic house foundation – two very different applications! Another outcome of the Canterbury earthquakes has been a suggestion that a new Standard addressing the retrofitting and strengthening of existing buildings should be considered.
The workshop in 2011 concluded that once NZS 1170.5 has been updated, many of the necessary changes can be addressed in two amendments, to be completed consecutively. At the time of writing (July 2012), no further progress has been made since November 20113. The appropriate course of action can usually only be determined by dialogue supported by research and testing. The answers are unlikely to be found overseas, because NZS 3101 already has far greater detailing information than most other Standards. The debates will be long, but many of the changes required to the Standard will probably be small enough to be covered in amendments. For many aspects, the world will be looking to New Zealand for interpretation and innovation. The most recent revision of NZS 3101 was published in 2006 and amended in 2008. The previous version was 10 years old, and the workload for the few dedicated volunteers to rewrite the Standard was large. Upon completion of the 2006 revision it was universally agreed that never again should the review of such a significant Standard be left for 10 years. Six years have since passed. Rewriting a complex Standard such as NZS 3101 takes about two years, so even if the committee started work now, the current Standard would be eight years old when the revised version is published. The ’to-do’ list for the next revision is even longer than the list for the previous one. Therefore a complete revision may still be several years away, even if the project is given a high priority and appropriately generous budget. Such delays affect all New Zealand Standards, and are discussed later in this paper. NZS 3109, 3111, 3112.2 and 3121 In mid-2012, Standards NZ sought input from the community on aspects of NZS 3109, 3111, 3112.2 and 3121 that needed review. The feedback was due to be considered by the CCIAG in September, and the outcome will be summarised in the conference presentation. It has been proposed that NZS 3111, 3112.2 and 3121 be reviewed and updated together, utilising considerations from the recent revision of NZS 4407 (roading aggregates). In addition, submissions to CERC have highlighted shortcomings of practices relating to core compression testing, which will be considered when NZS 3109 and 3112.2 are reviewed. NZS 3109 (concrete construction) An on-line version incorporating all amendments up to 2011 is now available. Feedback indicated the Standard needs updating to incorporate changes that will be made to NZS 3114 (surface finishes), and to include to review provisions for tolerances, particularly for in situ work. Other comments suggested the Standard needs to support project contracts by providing more detail about acceptable practices for managing situations that contractors and project engineers encounter on site, for example, changes in concrete supply, hot/cold weather, difficulties in placing, compacting, finishing or curing concrete. Similarly, it was suggested that the current method cited for evaluating core strengths (UK Concrete Society’s TR11) should be replaced by a method more in line with New Zealand practices and current international Standards (Gaimster 2007). NZS 3111 (water and aggregate test methods) NZS 3121 (specification of water and aggregates) These two Standards are now 26 years old. The methods for determining aggregate performance in concrete and potential alkali reactivity are widely accepted as being impractical and out of date respectively. Feedback suggests that a combination of NZ Standards for roading aggregates plus concrete aggregate Standards published by other organisations could be utilised to improve the efficiency and outcome of concrete aggregate testing. The Standards also need to incorporate guidance for the use of recycled water and aggregate materials, as detailed in CCANZ TR14 (2011).
3 Part One of CERC’s final report, released as this paper went to press, contains specific
recommendations for changes to NZS 1170.5 and NZS 3101 (CERC 2012a). These will form the basis for updating these two standards.
NZS 3112.2 (concrete strength tests) This Standard is also 26 years old. Feedback from testing organisations indicates a need to update requirements for capping, and for compressive strength testing of cores. Additional information on measuring strength of Special concretes such as self compacting, fibre reinforced and shrinkage compensating could also assist in ensuring test results reflect actual performance. UTILISATION OF AUSTRALIAN AND OTHER OVERSEAS STANDARDS Adopting the same or similar Standards to those in other countries facilitates trade by reducing compliance costs. It also frees up resources to develop Standards that address needs specific to New Zealand. Thus AS and other Standards or joint AS/NZS standards have replaced some New Zealand Standards when New Zealand needs are not unique, such as AS 1478.1 (chemical admixtures), the AS 3582 series for SCMs, and the AS/NZS standards for reinforcing and prestressing materials. When AS and NZS Standards are similar but need to retain elements particular to local manufacturing processes and commercial environments, AS and NZS committees may collaborate, exchange ideas, or co-ordinate the development of corresponding AS and NZS Standards under an agreement between the two Standards organisations. For example, this was done when AS and NZS Standards for cement were revised in 2009, and New Zealand is represented on the current AS 5100 (bridge design) committee. Resources such as overseas Standards may provide useful background information to augment information and requirements in New Zealand Standards, for example when shortcomings in New Zealand Standards as described above have been identified but not addressed. Specifications developed by overseas consultants sometimes refer to overseas Standards. Thus other Standards can provide practical solutions for individual projects, but the requirements of current New Zealand Standards always take precedence for demonstrating compliance with the NZ Building Code unless they can be shown to be unsuitable for the application. Examples of alternative Standards that can be utilised in this way follow. AS 5100 (bridge design) is currently under review. Some aspects of the concrete design section AS 5100.5, based on AS 3600 (concrete structures), may be relevant to New Zealand applications. AS 5100.5 currently has nothing in common with New Zealand bridge design practice as defined by the NZTA Bridge Manual, but some content may improve on our present methodology. For example, its method for managing concrete creep and shrinkage may be adopted once appropriate default creep and shrinkage data for NZ conditions and materials have been identified. NZS 3101 and AS 3600 are similar in some ways, thus AS 3600 may provide some insight where NZS 3101 lacks detail, as long as differences between the two Standards are taken into account. The durability provisions are an example. Both Standards use the same nomenclature for exposure classifications. AS 3600, however, separates classifications for residential and non-residential members in interior environments or in contact with non-aggressive soils to reflect the greater risk associated with non-residential structures. AS 3600 also has separate classifications for exposure to sea spray (C1) and tidal/splash (C2) to reflect the more aggressive tidal/splash exposure, and its default demarcation between coastal perimeter (B1) and coastal frontage (B2) exposures is 1 km inland compared to up to 500 m inland in NZS 3101. AS 3600 uses the same A1-U classifications for exposure to aggressive soils and groundwater. Its provisions for this type of exposure are more detailed than NZS 3101, and include requirements for saline soils, reflecting the greater frequency of these conditions and experience in managing the associated risks.
Similarly, NZS 3106:2009 (liquid retaining structures) is based on the equivalent AS 3735-2001, but the exposure classifications it specifies are based on the NZS 3101:2006 exposure classifications and are slightly more rigorous. AS 3735 and its commentary, however, give more detailed guidance about how to protect concrete, reinforcement and other components. The provisions for chemical attack from aggressive soil and groundwater introduced to NZS 3101 in 2006 were kept relatively simple to encourage people to actually use them. More detailed approaches such as those now used in the UK (BS EN 8500) and Australia (e.g. AS 3600 and AS 2159 (piling)) give more detailed guidance for specific conditions. NZS 3122 and AS 3972 (cement) were both revised in 2009 to allow type GP cement to contain more than 5% of mineral additions, but the availability of various cement constituents and SCMs in Australia and NZ resulted in the two Standards differing in many details. These are described in NZS 3122’s Foreword and commentaries. NZS 3104 and AS 1379 both prescribe requirements for the production and delivery of fresh concrete. Other aspects are covered to different extents. Parts of AS 1379 that may be useful in the absence of up to date appropriate clauses in current NZ Standards include the provisions for sampling and testing mixing water, sampling and testing concrete for chloride and sulphate content and drying shrinkage, and chemical requirements for admixtures. AS 1379 Appendix B compares typical attributes of Normal and Special concretes, which may help specifiers decide whether their project requires Normal or Special concrete. WHAT DOES THE FUTURE HOLD FOR NEW ZEALAND STANDARDS? The Problem: How to develop Standards that represent current market needs and best practice, and keep them up to date? The present method of developing and maintaining Standards by an open and transparent formal consultation process involving practitioners and stakeholders has worked well for a long time. But times have changed, and although the process is robust, it is now too slow and expensive to keep the entire suite of cement and concrete related standards up to date. More sustainable regulatory and funding systems are needed for Standards to remain relevant in today’s regulatory and commercial environments. Several barriers to the effectiveness of the current Standards process need to be addressed, as follows. Firstly, adequate funding is needed. Standards are currently funded by the industry that develops them, via direct sponsorship covering project management costs (typically around $50,000), and committee members or the organisations represented paying the costs associated with their participation. This model cannot provide sufficient funding to maintain all standards. Government funding is clearly appropriate for managing Standards that are in the public good, such as NZS 3101, but needs an appropriate framework to support it. Secondly, there is also a shortage of human resources with appropriate technical expertise. In a small country such as New Zealand, relatively few people are willing and able to provide specialist input into Standards. In particular, the experts required for engineering design Standards are currently in high demand for forensic reviews, and evaluation and strengthening of existing structures, and don’t have the time to give all Standards the attention they deserve. Although end-users value participation in Standards committees because it ensures their interests are met, other businesses and research institutions who employ technical specialists no longer consider contribution to Standards a core business activity. Consequently, Standards committees now rely largely on practitioners willing to invest personal time and money to achieve what needs to be done. This is not sustainable. Obtaining expertise from overseas can help, as can commissioning individuals to write Standards. But these are no substitute for local specialist knowledge, particularly when it is world-leading. A compromise is needed to encourage participation from local technical experts without placing unreasonable demand on their own and their employers’ goodwill.
Thirdly, it takes time. All technical matters are complex and require sound dialogue to determine the correct course of action. To be incorporated into a national Standard, each aspect needs to be tested and peer reviewed by people with different viewpoints and from different practice backgrounds to challenge ideas. It is also important that appropriate research is identified and carried out to provide good scientific data to support Standard requirements. Even with sufficient resources, it takes time to do all this well! The future technical rigour of Standards may be challenged by a fourth barrier: lack of awareness4. This is demonstrated by the low number of responses Standards New Zealand received to its recent calls for feedback on NZS 3101, 3109, 3111, 3112.2 and 3121: 13 for NZS 3101 (all individuals), two for NZS 3109, and three for NZS 3111, 3112.2 and 3121. The latter responses represented institutions, and the number of individuals providing input to them was not stated. Such a low level of stakeholder participation puts further pressure on those updating the content to ensure they identify and address all shortcomings. The lack of awareness reflects a general lack of interest in the content and development of Standards, perhaps borne from a belief that the development process is still effective. It also reflects the cost and difficulty for users to access current Standards — the current user-pays model and means of publication means many users cannot keep up to date with all Standards related to their business and therefore are not familiar with them. In response to these problems, a trend has developed of regulators carrying out functions traditionally undertaken by the Standards Council, including developing their own de facto Standards. In the building and construction sector, this is evidenced by a likely shift in approach by the Department of Building and Housing. Industry should be concerned about this trend, because regulators do not have access to the diversity of experience and practice knowledge required, particularly in the cement and concrete sector. Furthermore, they may dispense with the transparency and substantive consultation that are major advantages of the present Standards development process. Compliance documents developed in this way will need underpinning by detailed guidance documents such as those produced by CCANZ and BRANZ. Such documents need to be produced by technical experts, and thus share some of the same difficulties inherent in Standards. Thus Standards that are paid for by users and largely based on consensus of experts volunteering their labour have limited ability to respond promptly to changes in technology and stakeholder expectations. This and wider issues associated with the overall building and construction regulatory framework have been brought to public attention recently by the Canterbury earthquakes. The challenge for the future will be to maintain a high level of user and expert input in a timely, cost effective, and sustainable method. The Solution: What is being done to improve the situation? In recognition of the difficulties associated with Standards and with regulators taking matters into their own hands, in July 2012 MBIE initiated a review of New Zealand Standards conformance infrastructure, focussing specifically on the Standards system. The aim of the review is to develop proposals for a system of Standards that meets the current and future needs of business, regulatory authorities and consumers. It sought input from stakeholders on how they use and value national Standards, their use of overseas Standards, and issues associated with the use and development of national Standards. The NZ Concrete Society and CCANZ submitted feedback to this review. In October MBIE will present its findings for Ministerial approval, including opportunities and pressures facing the current New Zealand Standards system, options for addressing these opportunities and challenges, assessment of these options, and recommendations. If the Ministers agree, MBIE will submit a paper to
4 This lack of awareness also results in Standards not being used effectively. Thus specifications
often rely solely on Standards to achieve the desired performance, irrespective of whether the Standards specified are relevant, current, need updating, or contain sufficient detail required to meet the project’s needs. The practice of recycling specifications from previous projects increases the risk. For common types of construction, tried and true approaches generally work well, but for projects with unique needs, Standard specification clauses should be augmented with appropriate additional clauses.
Cabinet in November reflecting these recommendations. MBIE has agreed to consult with industry before finalising its recommendations. At the same time, CERC initiated a review of the overall regulatory framework, roles and responsibilities underpinning the building and construction industry, and other issues stakeholders may raise regarding earthquake performance of buildings (CERC, 2012b). It considers issues relating to the development and role of Standards, and takes into account previous recommendations from IPENZ, Standards Council and the New Zealand Construction Industry Council. The NZ Concrete Society submitted feedback to this review. A public hearing to present the issues raised was due to commence in September 2012. The reviews may result in changes to the way Standards are developed, maintained and used. Once the desired changes to their role and governance have been identified, some may be implemented sooner than others. Whatever they may be, the content of current Standards and other guidelines is unlikely to be updated as quickly as industry might like. If the regulatory framework changes before supporting technical documents are updated, then the convenient habit of simply quoting familiar Standards may no longer be sufficient to ensure compliance or acceptable construction quality. Organisations and individuals need to keep themselves aware of these changes, so they can adapt their practices accordingly. If the findings of the MBIE and CERC reviews are available at the time of the conference, we will summarise them briefly in the conference presentation. At the time of writing, we can only speculate on what they might be, and what changes might implemented as a result. Until the findings are implemented (and Standards updated accordingly), specifiers should inform themselves of shortcomings in current Standards, and address them in ways appropriate to individual project needs and within the regulatory framework applicable at the time. This will ensure construction quality meets both statutory and project requirements. Until Standards are updated or replaced, users should advise Standards New Zealand of matters not adequately covered by current New Zealand Standards. This will help to ensure that compliance documents address recognised issues. Industry and professional organisations and their members should make the effort to participate in consensus processes relating to Standards or the wider regulatory framework. This will ensure that all relevant aspects are considered in determining appropriate solutions, and will demonstrate to regulators that industry values the consultation process. WHAT DOES ALL THIS MEAN TO YOU? In their current form, the content of New Zealand Standards represents:
agreed methods of achieving a minimum quality of performance in products, process or service by practical and economic means in New Zealand, developed by a consensus of stakeholders and technical experts;
best practice at the time they are published, but relying on regular review to remain up to date.
As well as providing technical guidance, many construction-related Standards fulfil compliance roles, providing Acceptable Solutions or Verification Methods to NZ Building Code requirements, and thereby provide a basis for payment and acceptance/rejection of products and services. Standards are not necessarily:
best absolute practice – you can set the bar higher for your application;
solutions to all applications – you may have to think beyond the Standard for your application;
up to date – recent knowledge and requirements may not yet have been added to the current version.
The present means of developing and maintaining New Zealand Standards is unsustainable in today’s regulatory and commercial environment. Therefore to ensure the future of safe, high quality, sustainable concrete construction we foresee:
both the role and the process of developing Standards may change;
the need for consensus documents representing local best practice will remain;
the need for participation by the wider concrete community in consensus processes will become even more important.
WHAT SHOULD YOU DO ABOUT IT? To ensure that all relevant aspects are considered in determining appropriate solutions for individual projects and in compliance documents, and thereby help to ensure satisfactory quality is achieved in concrete construction, we recommend that: 1. While waiting for improvements in the governance and content of Standards to be
identified and implemented:
specifiers inform themselves of shortcomings in current Standards, and address them in ways appropriate to individual project needs and within the regulatory framework applicable at the time;
suppliers and specifiers advise Standards New Zealand of matters not adequately covered by current New Zealand Standards.
2. Individuals and organisations keep themselves informed of changes in the building
regulatory framework and Standards, and adapt their practices accordingly.
3. Industry and professional organisations and their members participate in consensus processes relating to Standards or the wider regulatory framework now and in the future.
ACKNOWLEDGEMENTS J. Lumsden (Standards Council) and D. Chin (Standards New Zealand) for encouraging submissions to MBIE’s review and for supporting the presentation of this paper. CCIAG for supporting the presentation of this paper. G Beattie, D. Chisholm, and J. Ellis, for input to table 1. REFERENCES For more information on any aspect of New Zealand Standards, see www.standards.co.nz . CCANZ (2012). Best Practice Guide for the Use of Recycled Aggregates and Materials in New Concrete. CCANZ TR 14. CERC (2012a). Final Report – Part One (Volumes 1, 2 and 3). June 2012. CERC (2012b). Discussion Paper: Roles and Responsibilities. GEN.CERC.0005.1. July 2012. Department of Building and Housing (2011). The New Zealand Building Code Handbook, 3rd edition, Wellington, NZ.
Fenwick R. and Cook, D. (2010). Suggested Changes to NZS 3101:2006 with Amendments 1 and 2. Journal of the Structural Engineering Society New Zealand, Vol.23, No. 2, September 2010. Gaimster, R. (2007). The cause for cores or a cause for concern? Concrete Conference, Wairakei, 27-29 September 2007. NZ Concrete Society TR 36. MBIE (2012). Standards and Conformance Infrastructure Review: seeking input from stakeholders. Trade Environment Team, Ministry of Economic Development, July 2012. SESOC (2011) Design of conventional structural systems following the Canterbury earthquakes. SESOC Practice Note version 4 December 2011.
Table 1 New Zealand Cement/Concrete Standards – priorities for updating are shaded
Standard Title (includes amendments)
Last amended / revised
Status
NZS 3101.1 & .2: 2006
Concrete Structures 2008 Scoping Committee has proposed priorities (see text)
NZS 3104:2003 Specification for concrete production.
2010 Minor changes needed to align with changes in other documents.
NZS 3106:2009 Design of concrete structures for the storage of liquids.
2009 May need review after NZS 3101 and loading standards updated.
NZS 3109:1997 Concrete construction 2004 Cut-in version published on-line in 2011. Needs updating (see text).
NZS 3111 :1986 Methods of test for water and aggregate for concrete.
1988 Needs updating (see text).
NZS 3112.1: 1986
Methods of test for concrete - Tests relating to fresh concrete.
2007 Most recent amendment added clauses for self-compacting concrete. Needs further review to consider current methods and materials.
NZS 3112.2: 1986
Methods of test for concrete - Tests relating to the determination of strength of concrete.
2000 Needs updating (see text).
NZS 3112.3: 1986
Methods of test for concrete - Tests on hardened concrete other than for strength
1986 Needs review to consider current methods.
NZS 3112.4: 1986
Methods of test for concrete - Tests relating to grout
1986 Needs review to consider current methods.
NZS 3114:1987 Specification for concrete surface finishes
1987 Needs revising to include current practices.
NZS 3116:2002 Concrete segmental and flagstone paving
2009 Most recent amendment incorporates flagstones.
NZS 3121:1986 Specification for water and aggregate for concrete.
1986 Needs updating (see text).
NZS 3122:2009 Specification for Portland and blended cements (General and special purpose)
2010 May need further amendment depending on outcome of AS 3972 review in 2012.
NZS 3123:2009 Specification for pozzolan for use with Portland and blended cement
2009 Now covers pozzolan, not Portland-pozzolan cement.
NZS 3124:1987 Specification for concrete construction for minor works.
1987 Needs review and updating. Not widely used.
NZS 3125:1991 Specification for Portland-limestone filler cement
1991 May eventually be subsumed by amendment to NZS 3122.
Standard Title (includes amendments)
Last amended / revised
Status
NZS 3151:19741 Specification for precast
lightweight concrete panels and slabs.
1985 Needs review and updating. Not widely used.
NZS 3152:19741 Specification for the
manufacture and use of structural and insulating lightweight concrete.
1985 Needs review and updating. Not widely used.
NZS 3604:2011 Timber framed buildings
2011 Report on engineering aspects being prepared by BRANZ, more guidance documents to follow.
NZS 4206:19921 Concrete interlocking roofing
tiles 1992 Needs review and updating.
NZS 4229:1999 Concrete masonry buildings not requiring specific engineering design
1999 (2012)
Update (due to be published in 2012) aligns with current loading standards, and includes requirements for wall tie spacings.
NZS 4230:2004 Design of reinforced concrete masonry structures.
2006 Needs review and updating to align with revised NZS 3604.
HB 4236:2002 Masonry veneer wall cladding
2002 Needs review and updating to align with changes in NZS 3604 & 4229 and NZBC E2/AS1&3.
SAA/SNZ HB 84:1996
Guide to concrete repair and protection
1996 Superseded by SAA/ACRA/CSIRO HB 84-2006.
1. These are examples of NZ Standards for specific concrete products. Many such Standards exist. They tend to be developed primarily by local manufacturing industries and product specifiers to reflect industry needs of the time, and are therefore less likely to be updated as needs and products change. Depending on NZ Building Code requirements, AS or other overseas Standards may provide satisfactory alternatives.
Figure 1 Hierarchy of controls for New Zealand concrete materials. (Statutory controls are in bold type. Means of compliance are in normal type.)
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