23 May 2018

Different approaches

When a team first comes together to design a project, each member will bring a different approach to the preparation of the documentation required. The time allocated to the project will usually be based on the number of drawings to be prepared, and minimal time will be allowed for the preparation of the supporting information. As a result, specifications are reused from previous projects that contain out of date standards, with little consistency in language, structure or formatting across the varying classification systems used by the respective disciplines. The job of authoring this information is quite often left to a small handful of senior colleagues as this is regarded as a specialist area of work requiring a wealth of technical understanding.

Consistent information structures should not, however, be a problem. The Uniclass system is based on the framework set out in ISO 12006-2:2015 and is specifically designed to work with all disciplines and all types of BIM projects. Uniclass was developed by NBS as part of the UK Government-funded BIM strategy in 2011, and examples of UK Government use are published for buildings and road, rail and water infrastructure. Here in Australia, NBS are working closely with Transport for New South Wales, applying Uniclass across all of TfNSW’s fixed, linear and fleet assets.

Uniclass offers a consistent structure for all disciplines and can classify any scale of item from a huge complex such as a University Campus down to a product such as a Fan. These classification codes can be assigned to digital representations of assets in specifications, BIM objects, databases and spreadsheets.

Figure 1 – The classification of large-scale items
Figure 2 – The classification of smaller scale items

A specification configured to this classification system provides a standard structure across both documentation and modelling. For example, a system such as an External Window can describe: overall performance, such as weather tightness, durability or energy performance; component products, such as window units, sealants and sills; execution, such as preparation, protection and fixing; completion, such as required documentation, verification of performance and spares; and operation and maintenance, such as approved cleaning aids, maintenance requirements and inspection timings.

A common classification to ISO 12006-2 also allows information to be extracted for different audiences. Information can be isolated for, say, a specific type of window system, all window systems, or all sealant products that serve not only windows, but also rooflights, doors and curtain walls. Applying a common classification system across a project or an estate will result in BIM objects and specifications having a consistent structure regardless of which item in the project they describe, and regardless of which discipline or organisation generated the information.


Specification and BIM

With respect to writing and assembling specifications, there are generally a couple of choices for a practice. The most common is to prepare your project specification based on word processing files that are maintained and managed by internal experts. The better method is to adopt a digital master specification system that self manages content updating as standards, codes of practice or the Building Code of Australia are modified, or new building technologies emerge.

By adopting such a master specification system, more time can be spent by staff on fee-earning work as the base reference content is managed centrally by the provider of the master system. In addition, functionality will exist that is particular to specification writing, unavailable in word processing software, such as synchronized technical guidance, linked clauses, contextual insert suggestions and updates on currency.

Figure 3 – A master specification system with template clauses, insert suggestions and contextual technical guidance

Across the world, at universities, aspiring architects and engineers receive hours and hours of training in how to design and prepare drawings, but in general receive little support or instruction on how to prepare a written specification. A master specification system will have template text that is well written, with a consistent editorial style. A good master specification system must follow the principles of the seven Cs:


  1. Clear – Use language that is unambiguous – it should be understandable by the person performing the work as well as the lawyer.

  2. Concise – Use keywords and colons to be direct and succinct. Do not write ‘The Contractor will indicate critical dimensions on all shop drawings’. Alternatively, write ‘Shop drawings: Indicate dimensions’. It’s far clearer in four words than in ten words.

  3. Correct – Ensure that the standards cited are current and any references to the content within the standards are accurate.

  4. Complete – Include all the necessary information. Citing the standard AS 1234 may not be enough information. There may be a critical difference between grades or finishes within AS 1234 that also need to be specified.

  5. Comprehensive – Cover all the components that need to be included. If specifying by brand, potentially the product reference is enough to specify a product. When leaving the product selection to the Contractor, be specific on the precise criteria by which the Contractor must select the product and how this will be verified and accepted.

  6. Consistent – Adopt a coherent classification system and structure across every item specified by all disciplines on the project.

  7. Coordinated – Ensure that any cross references are correct and current, whether cross referencing items within the specification, or items documented in other sources such as drawings or schedules.

A standardized approach to digital objects will also unlock the true value of BIM. Without consistently structured information, any BIM object will only provide value for modelling and drawing generation. With standardized information within BIM, it is possible to quickly generate meaningful schedules, perform data analysis and annotate and colour code drawings to give them greater clarity.

NBS have published a free-to-use BIM Object Standard that unites international standard properties and classifications from sources such as IFC, COBie, Uniclass and OmniClass. The standard is a collection of online resources such as guidance documentation, shared parameter files and software plug-ins for tools such as Autodesk Revit and Graphisoft ArchiCAD.

NBS also have a free-to-use BIM object library with thousands of generic and manufacturer-specific objects authored to the internationally recognized NBS BIM Object Standard.

Figure 4 – A national library of BIM objects authored to international standards

Embedding expertise

A master specification system or a collection of standardized BIM objects provides project teams with the best possible start on a project. In addition to this, practices may gain further advantages through embedding their own knowledge into the information structures that are provided.

It is common for a practice to specify similar items from one project to the next. It is, unfortunately, also the case that a mistake on the first project may also then be repeated on the second due to a lack of communication.

By using a managed office master system, lessons learned (both positive and negative) from previous projects can be captured and shared across a practice. So if a particular ceiling system works well for a high school classroom, then this specification can be turned into an ‘office master’ that can be reused on the next high school.

Every project provides opportunities to learn new methods or techniques: ensure that the lessons learned are captured in an office master system so that colleagues can view these at the point where specification or design decisions are being made on subsequent projects, while also embedding a culture of continuous improvement.

Manufacturers across all disciplines can author standard specification clauses for their products that match the structure that specifiers use across the project specification. A standard structure allows manufacturers and suppliers to insert their product specific information in a way that conforms to the 7 Cs. Equally, manufacturers can create BIM objects to a high quality that will not slow down models but will provide information that can be used for scheduling or data analysis.

For too long the construction industry has produced poorly structured, badly coordinated, convoluted and inconsistent information. With standards for information structures and classification now aligning around the globe, and with technology to guide this trend, all practices may take advantage of these improvements to improve their own productivity at the same time as providing a better service for their clients and improved outcomes for the project.



Further reading