AU Classification Systems

2.1 Classification schemes

In essence, classification simply means the grouping together of like things according to some common quality or characteristic. This automatically implies the separation of the unlike. 1 In order to be able to classify a collection of subjects it is at first necessary to define the purpose of the classification. Then the properties of interest to the classification may be distinguished, and finally the subjects can be sorted into classes with regard to the chosen properties.

2.2 Faceted classification

Here, each item is comprehended from multiple conceptual perspectives, or facets. The Oxford Dictionary defines facet as ‘one side of a many-sided body’. Individual subjects are classified by describing them by the appropriate combination of each facet.1 Facets are usually referred to as ‘Tables’ in most of the classification systems examined later.

2.3 Hierarchical or enumerative classification

A hierarchy, as used in classification, is a series of classes or groups in successive subordination; for example; Literature / English literature / English poetry / Early English poetry, etc. Thus each subject class, (for example, English poetry) falls into a subgroup of a larger group (English literature), which in turn forms part of an even larger group (Literature). Such a classification scheme is created by a process of division, according to certain characteristics. As the process of division continues the hierarchical classification lists or ‘enumerates’ complex subjects. This may be contrasted with a faceted approach, which would list ‘English’ and ‘poetry’ as separate concepts, but not as a complete subject. In a properly designed hierarchical classification each subject should have only one place where it fits into the scheme. 1 Rather than becoming preoccupied with the abstract intricacies of any given scheme, the guiding principle for ordering subjects should always consider how helpful it is likely to be for most of its intended users.

2.4 Consistent terminology

Different people may use different terms to describe the same item, and individuals may use different terms to describe the same item on different occasions. For day-to-day purposes this might not cause any problems, but within a classification scheme this can cause confusion. For this reason, classification schemes usually rely on agreed definitions of terms and consistent usage.

2.5 Notation

Notation is a very important consideration. However, a common error is to think that choice of notation is the first step in the compilation of a classification scheme – on the contrary, it is one of the final steps. Notation provides a classification system with a short, unambiguous subject identifier facilitating quick orientation and navigation of the system. (For fuller coverage of this topic, refer to ‘Principles of Classification’ by John Cann’3http://www.icis.org/siteadmin/rtdocs/images/5.pdf)

2.6 Primary uses of classification systems in the construction industry

Typical items assisted by an information classification system include:

• Organising reference material on construction products, technical matters, costs, etc.

• Structuring the contents of individual documents in a consistent manner.

• Co-ordinating information between individual documents found in sets of documents.

• Facilitating communications between different members of a construction project team.

• Facilitating interoperability of digital systems.

2.7 Existing classification systems for the construction industry

2.7.1 Standards relevant to construction classification systems

See Appendix B for a summary of the relationships between current classification systems and the following standards: •ISO TR 14177 Classification of Information in the Construction Industry: •ISO 12006-2 Organization of information about Construction Works – Part 2: Framework for Classification of Information (an evolution of ISO TR 14177). •ISO 12006-3 Organization of information about Construction Works – Part 3: Framework for Object-oriented Information. In recognition of the need for an alternative ‘object oriented’ approach. (see Appendix A for an explanation of terms). ISO 12006-2 has had the most immediate influence on the development of a number of classification systems currently being implemented in Europe (Uniclass) and North America (Omniclass). This influence is a reflection of the trend away from the separate development of incompatible systems by individual countries and the convergence of systems based on shared standards.

2.7.2 The relationship of classification systems to specifications

ISO 12006-2 is very broad in scope. It sets out a framework of Tables for classifying construction information, and recommends titles for these Tables, but generally does not detail their content or structure. The distinction needs to be made between complete ISO 12006-2 based classification systems, such as Omniclass and Uniclass, and the individual facets or ‘tables’ of these systems, which provide a classification system within the broader framework, for a specific purpose. The ISO 12006-2 Table A.9 Work Results (by type of work) is where the classification system for specification work sections is usually located. Work sections are defined as: ‘One or several parts of a building or other facility viewed as the result of particular skills and techniques applied to particular construction products and/or elements during the construction phase. Work sections are usually executed by particular types of subcontractor or groups of operatives. The class is influenced by both inputs (the construction products used) and outputs (the parts of the building or facility constructed) and thus represents a dual concept’ – ISO/TR 14177: 1994

2.7.3 Australia

NATSPEC, the pre-eminent master building specification in Australia, is based on a classification system developed by its founder, Bryce Mortlock, in 1989. NATSPEC notation consists of numerical codes of up to four digits. The notation is hierarchical – for example 0311 Formwork is a subclass of 031 Concrete, which in turn is a subclass of 03 Structure (see Appendix E for a summary). There is currently no unified construction information classification system, similar to Uniclass or Omniclass, used nationally for a broad range of classification purposes.

The NATSPEC classification system was amended in 2005/2006 when NATSPEC and Masterspec of New Zealand agreed to align their systems more closely. The most recent amendment was in 2007, when a large number of new worksections were introduced following the incorporation of AUS-SPEC, a master specification system used nationally by state and local government bodies for documenting civil engineering, landscaping and infrastructure works, including their maintenance and operation.

2.7.4 New Zealand (NZ)

Masterspec is New Zealand’s default standard specification system, managed by Construction Information Limited (CIL) a company owned by the New Zealand Institute of Architects, Registered Master Builders Federation and the Building Research Association. In 1998 CIL took over the work of a previous construction industry organisation and adopted the Coordinated Building Information (CBI) national classification system as the basis for organising Masterspec. CBI is based on the British Common Arrangement of Work Sections (CAWS) system and Uniclass (See 2.7.10 United Kingdom). CBI modified these systems to take account of local construction customs and practices, and to incorporate a four-level numeric notation that can be used to co-ordinate specification data as well as drawings, product data and research information.

2.7.5 Europe

ISO 12006-2 or its drafts have been applied in the development of the following European classification systems:

2.7.6 Denmark

ISO 12006-2 formed the basis of the Danish DBK system (Dansk Bygge Klassifikation), developed in 2006. Prior to this, a system based on the Swedish SfB system (See 2.7.9 Sweden), called BC/Sfb, was used. The DBK system is part of a wider program called Digital Convergence, which focuses on introducing and implementing shared Information and Communication Technology (ICT) standards in the entire construction sector: email standards, discrepancy lists and web-based project management.4

2.7.7 Finland

The Finnish Building 90 system developed by the Building 90 Group and the Finnish Building Centre was published in 1999. It is widely used in the Finnish engineering community. 5

2.7.8 The Netherlands

The NL/SfB, or ‘Elementenmethode’, is based on SfB, and is used in the Netherlands for the classification of building elements. The Dutch building specification system, STABU2, is produced by STABU, which is the abbreviation (in Dutch) for the ‘Foundation for a National Standard Building Specification’. STABU was founded in 1975 and produced its first specification in 1986. From its earliest stages, the STABU2 system was based on a relational database. In 2005, NL/SfB was connected to the STABU2 system, making it possible to reorganise work sections to building elements and vice versa. The next proposed development is to link the classification of elements to performance specifications, allowing users to start developing their specifications early in the design process. Civil engineering works are specified using the RAW specification system. RAW is the abbreviation for ‘Standard Conditions of Contract for Works of Civil Engineering Construction’, published by the Centre for Research and Contract Standardisation in Civil and Traffic Engineering (CROW). RAW specifications do not use a formal classification system, but are broadly based on work sections and product groups.

2.7.9 Sweden

The first Swedish classification system, developed in the 1950s, was called SfB (Samarbetskommittén för Byggnadsfrågor, Co-ordination Committee for the Construction Industry). The limitations of this system in addressing new developments in the industry led to the introduction of the BSAB (Byggandets Samordning AB, Construction Co-ordination Limited) system in 1972. The Swedish Building Centre (SBC) released the latest revision of the BSAB96 system in 1999. The Swedish national building specification, the AMA, which uses the BSAB96 classification system, was revised and republished by the SBC in 2001. AMA is the abbreviation (in Swedish) for ‘General Material and Workmanship Specifications’ 6

2.7.10 United Kingdom (UK)

The most recent construction information classification system to be implemented in the UK is Uniclass (Unified Classification for the Construction Industry) driven by developments in ICT and international standards for classification systems. The first edition of Uniclass was published in 1997. Uniclass is a faceted system designed within the parameters of ISO TR 14177. [3] A number of pre-existing classification systems, used for specific purposes, were also incorporated into its 15 Tables; for example: •CI/SfB (Construction Index/SfB), a derivation of the Swedish SfB system. It forms the basis for table D. •CAWS (Common Arrangement of Work Sections for building works), developed in 1987, was adopted by the National Building Specification (NBS), the Standard Method of Measurement of Building Works (SMM7), and the National Engineering Specification (NES). Until recently CAWS formed the basis of Uniclass Table J Work sections for buildings. (See Appendix E for a summary of Table J). This Table is currently under review. •CESMM3 (Civil Engineering Standard Method of Measurement) forms the basis of Uniclass Table K Work sections for civil engineering works. •EPIC (European Product Information Cooperation) Construction Product Grouping (CPG) – or EPIC for short, a common European classification system for construction products, was first published in 1994. EPIC forms the basis of Uniclass Table L Construction products. •UDC (Universal Decimal Classification) system, a derivation of the US Dewey decimal classification system forms the basis of Uniclass Table Q Universal decimal Classification (see Appendix D for a list of Tables). [3] Uniclass notation consists of a single capital letter followed by zero or more digits, except Tables J and K, which have two initial capital letters to allow the incorporation of the CAWS and CESMM3 codes. The notation is hierarchical; for example D21, D22, D23, etc. are always subclasses of D2. A number of signs: + / : (colon) < > are used to combine simple class numbers for complex subjects and define relationships of subjects.

2.7.11 North America

The most recent construction information classification system to be implemented in North America is Omniclass. A group of volunteers from organisations and firms representing a broad cross - section of the construction industry recognised a need for classifying construction subjects, the increased use of electronic information technology, and the expanding focus on the complete life cycle of construction. The majority of the 15 Omniclass Tables were published in 2006. Omniclass is a faceted system designed within the parameters of ISO 12006-2 and ISO 12006-3. Also, Omniclass freely adapted and used Uniclass in its development, and therefore shares many of the Uniclass legacy documents – for example, both use EPIC as the basis of their construction product Tables. The most significant points of departure include: •The adoption of Masterformat as the basis of Omniclass Table 22 Work results. In the same way CAWS is used in the UK, Masterformat is the pre-eminent means of organising commercial and institutional construction specifications, such as Masterspec, in North America. It is published in by the Construction Specifications Institute (CSI) and Construction Specifications Canada (CSC). The most recent edition was published in 2004. •The adoption of Uniformat as the basis of Omniclass Table 21 Elements (including designed elements). Uniformat provides a standard method of arranging construction information, organised around the physical parts of a facility called systems and assemblies. These systems are characterised by their function without identifying the technical or design solutions that may comprise them. It is used for formatting documents on project scope, quality, cost and time, such as cost estimates or reports (see Appendix D for a list of Tables). 7Omniclass notation consists of numerical codes, generally of six digits. These can be extended by adding more digits after a decimal point. The notation is hierarchical (see Appendix E for a summary of Table 22).

2.8 A comparison of existing classification systems

2.8.1 Comparison of Uniclass and Omniclass

While both systems are based on ISO 12006-2; or its precursor, ISO TR 14177; and there is generally parity between the Tables in each system, each places them in a slightly different order, and each splits or combines some Tables differently. Uniclass adds an extra Table Q, based on the UDC system; for classifying subjects not covered elsewhere in the system. There is a high degree of parity between Tables based on the same source documents, for example, Uniclass Table L Construction products and Omniclass Table 23 Products, which are both based on EPIC. With Tables based on different source documents, we see significant differences in their internal order (see Appendix C for an assessment of the relative parity of Tables in the two systems). •Omniclass classifies subjects in more detail and information is more clearly presented. This is probably a reflection of the fact that Omniclass was published 9 years after Uniclass, giving Omniclass the opportunity to build on the work of Uniclass. •Omniclass does not appear to provide an index like Uniclass. •Omniclass is more readily available – the Tables and supporting documents can be downloaded directly from the web at no cost. The Uniclass manual can only be purchased from RIBA bookshops. Also, there is more evidence of on-going support and development for Omniclass, especially in the guise of Masterformat, than Uniclass. Although there have been recent revisions to Uniclass, and a number of Tables are now under review, it has not been republished since the first edition of 1997 – not insignificant considering the changes that have occurred in the construction industry during this period.

2.8.2 Comparison of Uniclass Table J and Table K and Omniclass Table 22

These work section Tables are used as the basis of comparison of the classification systems used by the NBS (Uniclass) and the American Institute of Architect’s MASTERSPEC (Omniclass) specifications, and as potential influences on Australian specification classification systems.

2.8.3 Preliminary assessment

Omniclass groups work sections for buildings and worksections for civil engineering works together. Uniclass splits these into separate Tables J and K (see Appendix E). •Omniclass documents many more subdivisions of each Table than Uniclass. •Uniclass Table J, Work sections for buildings has an internal structure much closer to the Australian approach used by NATSPEC than Omniclass’ Table 22 Work results. Table J more closely matches the overall sequence of items, and grouping of items. Omniclass Table 22; Division 10 Specialties, for example, groups a number of items together which, by Australian conventions, would be located in a variety of locations. This could very well be because Australian construction and subcontracting practices derive much more from English models than North American. •The structure and notation of Uniclass Tables J and K is very simple, making it more readily comprehensible and easier to navigate. The downside is that it would be more difficult to assign a unique place or notation to items being classified. •The structure and notation of Omniclass Table 22 are highly subdivided, which makes it easy to find a unique place for many different items, but also makes it difficult to navigate quickly. Although good reasons are given for the notation system,8 the six digit format is not very user-friendly, though the amended format adopted by Masterformat 2004 has improved legibility. While the difference might not seem that great when viewing Tables in isolation, the larger codes from each Table would become very unwieldy if combined with codes from other Tables – the basis on which faceted systems are designed. •Omniclass Table 22 provides dedicated maintenance and operation worksections at the beginning of each division – a very useful feature that corresponds to AUS-SPEC worksections recently incorporated into NATSPEC. Most of the previous comments have been directed at the intrinsic qualities of each system, but issues such as access and availability, which impact on their adoption, also need to be taken into account. In this regard, Omniclass is more readily available, and appears better maintained and supported. It is encouraging to note that despite the differences between British and North American systems, in broad terms, they have more in common than they have ever had in the past – largely because of the adoption of ISO 12006-2.

2.9 Current trends in the construction industry impacting on classification systems

2.9.1 The impact of information and communication technology (ICT),

ICT has had a profound impact on the working methods of the construction industry. ICT is well suited to the fluid and dynamic environment of design and management processes, compared to traditional paper-based methods. Developments in communications, such as the internet, have also significantly improved the ability to access and distribute information. The concept of Building Information Models (BIM) is one ICT application to emerge recently that is likely to have significant implications for the construction industry (See Appendix A on BIM).

2.9.2 Interoperability

With respect to software, the term interoperability is used to describe the capability of different programs to exchange data via a common set of exchange formats, to read and write the same file formats, and to use the same protocols. Interoperability relies on software developers adopting agreed standards when creating their applications. 9 Interoperability is facilitated by standards being open, their specification public, and without restrictions in their access or implementation. It improves communications, maintains the integrity of data, and reduces the prevalence of conflicting and ambiguous information which leads to construction errors, defects and wasted resources. Interoperability is crucial to realise the full potential and benefits of ICT, including applications such as BIM. The International Alliance for Interoperability (IAI) is the most active organisation promoting interoperability in the construction industry. It is a worldwide alliance of construction industry organisations, comprising 12 international chapters from 21 countries representing over 550 private industry and government organisations. It is dedicated to bringing about coordinated changes for the improvement of productivity and efficiency in the construction and facilities management industry. Australia and New Zealand joined as a chapter in 1997. The IAI now operates under the name BuildingSMART International.

2.9.3 IFC, IFD, IDM and MVD

One of the key strategies of BuildingSMART is the promotion of the Industry Foundation Classes (IFC), a specification for a neutral data format to describe, exchange and share information typically used within the building and facility management industry sector. BuildingSMART have developed and maintained the IFC and facilitated its implementation through mission programs which offer industry-wide forums to identify, test, review, recommend and implement ways delivering quality buildings and services to the facility owner. The IFC data model consists of definitions, rules, and protocols that uniquely define data sets which describe capital facilities throughout their lifecycles. IFC is the only non-proprietary, open global data model specification available, and in 2002 it became the international standard, ISO/PAS 16793. Software applications supporting IFC are able to exchange data with other applications that support IFC. See http://www.iai-international.orgBuildingSMART has been working with its member organizations and major CAD vendors to put the standard in place. The latest release of the standard, IFC 2x specifies over several hundred object types and related concepts, which support the core exchange needs of the building industry.10Two of the world’s largest CAD vendors, Autodesk and Bentley, have both developed BlM solutions (Revit Architecture and Bentley Architecture respectively), which support IFC. Many BIM-associated applications, like those for thermal or structural modelling, are appearing with IFC capability.11Another important interoperability program is the development of the International Framework for Dictionaries (IFD) Library, an object terminology library for the building construction industry. The name is used both for the IFD Library and for the organisation running and maintaining it. The simplest description of IFD Library is that it is a kind of dictionary of construction industry terms that must be used consistently in multiple languages to achieve consistent results – this will enable reliable automated communications between applications. The structure of IFD is given in ISO 12006-3, which is an EXPRESS model with a short explanation of its purpose and use. (See Appendix A) The first implementations of this standard were the Norwegian BARBi library and the Dutch LexiCon by STABU. Other implementations include EDIBATEC in France. In 2006, on behalf of BuildingSMART, STABU and BARBI combined their efforts on the IFD. The IFD Library is compatible with IFC. See http://dev.ifd-library.org/The three pillars of the BuildingSMART initiative are IFC, IFD and the Information Delivery Manual (IDM). While IFC is about HOW data is exchanged and IFD defines WHAT is exchanged, IDM is about information requirements, defining WHICH information to share WHEN. The IDM/MVD (model view definition) approach (also an ISO standard in development) forms that specification. IDM regulates the controlled flow of information in and out of a BIM. It’s like a contract defining which information will flow, defined by whom, and when. A MVD is more like a subset of the IFC model representing the information of interest to a user, or user group, for a particular purpose.

2.9.4 The continued relevance of classification systems

The need for information classification systems within the construction industry is more pressing today than ever. The information-rich environment of the construction industry increasingly demands appropriate classification systems. 12 Some might argue that full text search and keywords make classification obsolete, but data needs to be organised somehow, and it is very convenient if the supplier and user of the data can use the same structure. 13Robust industry classification systems have the potential of forming the firm foundations necessary for realising the full benefits of BIM. There are already many existing, widely used computer applications whose full potential could be realised by the adoption of uniform classification systems.

2.9.5 Implementation of classification systems

ICT will have a fundamental impact on the way any new or amended information classification system will be implemented, compared to the implementation of previous paper-based systems of the past. Any classification system is now likely to be created on a computer, distributed by digital means, and used in a digital environment. It would be unrealistic to expect someone working most of the time in a CAD or word processing environment, for example, to refer to a large printed classification manual or index. The nature of classification systems suggests a database platform as their natural vehicle.

2.10 Classification systems for the Australian construction industry

(Refer Appendix A for some definitions)

8.1 UNICLASS TABLES