01 August 2018

Some projects begin with a simple question. In this case, it was ‘Once we have a BIM, how are we going to know which construction products are in it?’

The answer too seemed simple – you’ve got descriptions of products in the BIM, so you know what you’ve got. But:

  • How do you know that the description is current?
  • Is that product still available?
  • If it isn't, what is its 'equivalent'?

Also, it seems fine to initially identify things by their attributes, but it’s not the best way. Attributes can be very similar. Products can be almost the same (or ‘equivalent’). If you don’t know exactly which products are in a design, and exactly which products are in the subsequent completed building, there can be significant trouble ahead.

If even only a small number of the specified products have been substituted or ‘value engineered’ out of the final constructed building then the performance of that building could, and may often, be significantly affected.

Other industries suggest another way: it is better to have a simple identifier for products that references a ‘single point of truth’, maintained centrally by the true owner of that information – the manufacturer.

This led to BSI, the NBS and the CPA (Construction Products Association) coming together to work on a project, part-funded by Innovate UK, to research and develop an identifier for construction products.


We found that there are many different kinds of identifier currently in use. Most belong to a firm or system, like SKU codes: they identify products, but not publically, and not consistently.

Others make data publicly accessible, like barcodes or QR codes, but the information is not standardised or centrally held. This means that during its journey through the supply chain, any typical product will be issued with a number of identifiers by different stakeholders and systems. For anyone using those identifiers, it won’t be clear which ID is the most useful, and of course there’s no assurance that the data behind those identifiers will always be there in the future (e.g. if websites, or systems, change over time).



If the object in your model isn't available, how do you find its 'equivalent'?


There was one identifier that seemed to do a number of things better than others: the Digital Object Identifier (DOI). For us, DOIs have three key features:



All DOIs have set, standard metadata associated with them. The data is all the data that is needed to show the uniqueness of a thing, and to provide some core services. But no more than that.



DOIs are persistent both by design and culture. Once a DOI is created, people will always be able to use it to get to the core metadata. This is very useful when thinking about the supply and use of information throughout the lifespan of a building.



The DOI is a fixed, standardised, machine - and human-readable identifier.


No other identifier has all these features. DOIs offer permanent and unambiguous identification of construction products. They also clearly identify the manufacturer.

DOIs also have a pedigree. In use since the 1990s, DOIs are extensively used in the publishing and film industries. There are millions of DOIs in the world, and they are used hundreds of millions of times each month. They are proven to be reliable. They are also governed by an International Standard, ISO 26324:2012.



Having established which is the right identifier, the project moved on to piloting its application.

At this point, we’d like to mention the kind assistance of the project’s steering group, made up of a range of industry experts and representatives from the International DOI Foundation (consisting of those existing agencies who already issue DOIs), who gave much knowledgeable help and advice.

We implemented DOIs through a web-based application. This application allowed:

  • Manufacturers to upload data about their products to create DOIs;
  • Users to get metadata about a product from its DOI;
  • DOIs to take you to the relevant information on a website, when they are clicked on.

Putting together the website was, however, only the first stage. By working with industry, we were able to develop a wide set of illustrative use cases for DOIs. Or, to put it another way, once we had the website, we could see that DOIs could be readily used to solve some long-standing issues in the construction industry.

Below are some examples.



As BIM moves into the life of a building, there is an increasing risk that data within a model may go out of date. By including a DOI in a BIM, current product information (like availability or compliance) can be directly accessed from the centrally held metadata. Indeed, where information is part of the DOI metadata, it will always be centrally available.


DOI outputs at each design stage

It’s not always clear which products that formed part of the design make it into the final building. By having a list of DOIs at each relevant RIBA stage (as a minimum, stages 4 and 6, generated from a specification), changes in products can be programmatically detected, and, through the available metadata, details of substitution/value engineering given.


DOIs with other identifiers

DOIs can both embed and be embedded in other forms of identification. DOIs complement, rather than rival, other IDs. Equally the DOI’s metadata can capture other IDs, so can act in future as a central ID lookup across the product supply chain.

DOIs can also be embedded within existing documents, assets or identifiers. As an example, we have successfully embedded DOIs in radio-frequency identifications (RFIDs). This means that an RFID can be attached to a product (RFIDs are now small and cheap). By using a reader, or just a mobile phone, the RFID can be read to give the persistent information about the tagged product – invaluable, for example, to a facilities manager looking to identify and replace an in situ product within their building.


DOIs and compliance

Quality and legal compliance are obviously critical for product manufacturers. The safety and performance of buildings are determined by the products that they are composed of. These attributes are key differentiators in the market for construction product manufacturers. This means that they are keen to find ways to demonstrate their compliance with schemes and standards to those using and selecting their products. The DOI metadata collected through this system allows a manufacturer to display information and evidence around compliance, including details of specific standards or schemes, plus any supporting certification. This helps the user or customer with product comparison and selection, and also helps the manufacturer differentiate their superior quality product from others.


Project Completion

At the start of the research programme, we said that ‘the DOI for construction products must be a system that is of real use to the sector’. During the programme, we found not only that the technical implementation of DOIs for construction products is feasible, and that the DOIs are useful and attractive to the market, but also that more and more potentially valuable applications are being identified, as awareness increases and as we speak to more people throughout the construction supply chain. 


This article was written by Adrian Malleson and Simon Powell, Director, Product Management, BSI and originally appeared in the 2018 NBS National BIM Report. Download the report for free here