Specification for Discoverable Construction Knowledge



This standard was initiated by the Construction Knowledge Task Group (CKTG) to improve access to knowledge by making it more discoverable.

In February 2020, a project commenced to develop an open standard that will allow practitioners to identify the relevant knowledge resources in the contexts in which they are needed.

The project aimed to create a common standard for the way knowledge is described, to make it easier to identify the right knowledge in every situation. This included the type, source, audience and application of the knowledge. 

Overall, the more universal the standard is, the more useful it will be. The principle is that it is an open standard, whether or not the knowledge it is used to describe is released openly. To do this, we have leveraged existing open standards and classification systems, and avoided creating new ones as far as practicable.

The specification is designed to be adopted by anyone, including professional institutions, publishers, research bodies and businesses to descibe knowledge in a consistent way, so that others may build indexes and tools that signpost the most relevant content to practitioners.

The specification is built on the key principles of making knowledge more discoverable and improving access. 

We call it, “Discoverable Construction Knowledge”.

Adopting the Discoverable Construction Knowledge standard will:

  • Improve searchability, making all knowledge more easily discoverable and accessible by practitioners.
  • Enable better curation and management of knowledge, so it can be collated, organised, queried, filtered, integrated into software and systems and pushed to practitioners, whatever its source.
  • Enable the creation of tools to extract the maximum value from all knowledge and integrate it with industry data and information.

Technical Authoring

Technical authoring for version 1.0 has been undertaken by Barbal Limited.

This project was funded by the Lloyd’s Register Foundation with the support of the Open Data Institute.


This specification defines a standard to make construction knowledge discoverable. This reflects the goal established by the Construction Knowledge Task Group (CKTG) whose aim is to make it as easy as possible for practitioners and other industry stakeholders to:

  • Find the right knowledge when it’s needed;
  • Access that knowledge;
  • and extract the maximum value of the knowledge.

The CKTG includes representatives from over 30 construction knowledge organisations in the United Kingdom; including publishers, practitioners, suppliers and professional institutions.

More information about the CKTG and its vision can be found at https://www.designingbuildings.co.uk/wiki/Construction_knowledge_task_group.

Discoverable Construction Knowledge standard:

  • Will make it easier to share and find knowledge resources within the construction industry.
  • Is designed to work with any resource.
  • Will not undermine existing commercial models for publishers.

For the purposes of this specification, “knowledge” is defined as published resources that are used by practitioners to help them do their job.

The scheme is designed primarily for metadata on web pages but can be used for exchanging metadata using other structured data formats.

 Existing Open Standards and Classification Systems

The scheme builds upon well-known and well-used open standards, such as the Dublin Core Metadata Initiative (DCMI) and Friend Of A Friend (FOAF), using the terms most applicable to construction knowledge. The DCMI is a small scale vocabulary term scheme which can be used to describe physical and digital resources. DCMI is widely used in document heavy fields like academia and law, and is recognised by search engines.  FOAF is a defined computer language for defining people-related terms for structured data, it is also designed to work with the Dublin Core. More information on the DCMI and FOAF can be found in Appendix One – Exisiting Open Standards and Classification Systems

To aid consistency existing classification systems are also referred to and recommended for use, such as Uniclass 2015, Thema, Media Type and ONIX Product Form. Uniclass 2015 is a construction industry classification system. Thema is a publishing and libraries industry classification. Both of these dictionaries can be used to define and describe the subject of the resource. Media Type and ONIX Product Form are both classification systems which identify data format e.g., pdf or audio. Media type has been recommended for use when describing a digital format, and ONIX Product Form for describing physical formats. More information on the existing classification systems used in Discoverable Construction Knowledge can be found in Appendix One – Existing Open Standards and Classification Systems.

Discoverable Construction Knowledge extends on these standards by including properties, types and a new vocabulary for classifying knowledge.

Structure of this document

This specification is divided into eight main sections:

  1. Introduction – provides a broad overview of the background, scope and aim of this specification.
  2. Using the scheme – provides guidance about how to use the scheme, with answers to our most frequently asked questions.
  3. Descriptive Resource Properties – defines properties that can be used to describe the scope of the resource. Recommended classifications and formats are also provided for consistency.
  4. Publishing Information Properties – defines properties that relate to the publication aspects of the resource. Recommended classifications and formats are also provided for consistency.
  5. Usage Information Properties – defines properties that relate to how the resource is used. Recommended classifications and formats are also provided for consistency.
  6. Roles Properties – defines properties relating to the roles involved in a resource. Recommended formats are provided for consistency.
  7. Knowledge Types – defines a number of Types which can be used to classify knowledge.
  8. HMTL Template – the HTML template to be used when applying metadata to your resources on webpages.

Using the scheme

Discoverable Construction Knowledge provides a standardised way to describe key properties and types so that resources can be identifed, sorted and filtered.

The scheme has two principal elements:

  1. Properties for describing resources (section three, section four, section five and section six), and
  2. A classification of knowledge types (section seven)

Templates are given in section eight to aid implementation.

Can anyone use the scheme?

Anyone can adopt the scheme. It has been designed to be applied across the whole spectrum of knowledge for the construction industry. It can be used by formal and informal knowledge organisations, as well as any company that publishes content that it considers to be knowledge.

Is it only for digital content?

No, the specification has been designed for any type of ‘knowledge resource’, and includes digital and physical resources, events, people, organisations and groups.

Our resources are only available to members, will I have to give access for free?

No, this standard does not change your access models to content. 

However, by using Discoverable Construction Knowledge metadata, we assume that you want your content to be found. There are several strategies to achieve this where access to content is behind a login wall. Primarily, these include having a publicly viewable version of the webpage that contains the metadata, but obscures the content or to publish a separate metadata set using another serialisation format (e.g. CSV or JSON).

Which search engines/tools currently recognise the Discoverable Construction Knowledge standard?

Because we build on existing metadata standards recognised by Google and other major search engines, using the standard should boost your rankings immediately. The CKTG also plans to instigate construction-specific search engines and other tools based on this schema.

Will I have to re-assign metadata to every resource?

Not necessarily. In total, there are 2 Mandatory terms/ metadata fields in the scheme, which when describing a resource must be used – Title and Access Location

Of the four Recommended terms, only Audience, Type, Subject, and Format use standardised classifications, and it is likely you will be able to map these from your existing metedata fields on a broad strokes basis. 

However, like any Search Engine Optimisation effort, the more thoroughly you follow the guidance, the more search tools can help to direct the right traffic to your content. 

What terms are Mandatory, Recommended or Optional?

The below table provides a brief overview of which terms are Mandatory, Recommended and Optional. 

Access Location Access Rights Client
Title Audience Competency Level
  Date Created Continuing Professional Development
  Date Modified  Continuing Professional Development Accreditor
  Description Contributor
  Format Coverage
  Identifier Creator
  Publisher Instructional Method
  Sector Language
  Subject Relation
  Type Replaces
    Replaced By
    Rights Holder

How do I reference Organisations, Groups or People?

Some of the resource properties are about making reference to an organisation, group or person. In each case, Discoverable Construction Knowledge recommends that you use a name or Universal Resource Identifier (URI).

A URI is a rigorous way of referencing a resource by providing a web link (or another unique reference) to the resource. This mitigates the risk of error or inconsistency across datasets. 

For example, The Institution of Engineering and Technology could be correctly referred to by its name as:

  • The Institution of Engineering and Technology
  • Institution of Engineering and Technology
  • The IET
  • IET

And there is also a risk of misspellings. e.g “The Institute of Engineering and Technology”.

Instead, by providing the URL to The IET homepage “https://theiet.org”, it is unique and imutable. The name, and other properties of the organisation, can be resolved automatically by an indexing tool.

URIs for people can be to the their social media profile, a corporate profile page or an email address. These are all valid ways to ensure unique identifiers. However, it is important not to breach the individual’s right to privacy with their personal identifiable information.

Semantic linking using URIs is the foundation of an “Internet of Construction Knowledge” and supports integratation with other systems like the National Digital Twin. Therefore, whilst both a name and a URI are supported, using URIs can provide more value to the discoverability of resources.

Is there a template or guidance I can use?

A template is available in section eight to the standard. The CKTG also plans to publish additional guidance in the coming months. Consultancy to support implementation is available from Barbal.

How do I use the external recommended classification systems?

To aid consistency, the scheme recommends using existing classifications systems for certain resource properties, such as, Uniclass 2015, Thema, Media Type and ONIX Product Form

The plain language version of the terms in these systems should be used, rather than the letter and/or number code provided by the classification systems. This is because the plain language version will help discoverability by search engines that do not support Discoverable Construction Knowledge directly. 

If it is important that you state which system has been applied, the name of the system can be included and displayed like this:

“Uniclass2015: prestressing anchors”

What implications does it have on my Intellectual Property Rights?

Discoverable Construction Knowledge does not affect the intellectual property rights for your knowledge resources, but it could have implications for copyright or database rights for the metadata. 

By using the schema on publicly accessible websites you are granting an implied license for others to store a copy of the metadata in an index and republish the metadata to aid discoverability of resources you hold. The assumption in using the Discoverable Construction Knowledge schema on publicly accessible web pages is that you want third party services to help people find your content without having to grant an explicit permission to each service. However, it does not change permissions for accessing, sharing or amending the content itself, which you should control using your normal procedures.

If metadata is shared using the Discoverable Construction Knowledge schema in any other way, you should state the license under which you make the data available to the receiving party. Typically, a Creative Commons (CC-0 or CC-BY) license is suitable.

Nothing in this specification constitutes legal advice. If you have any concerns or queries, seek independent legal advice.

Is there any ‘authority’ to verify that indexes are correct?

No, however any official implementation will verify the index is not pulling content from a malicious source. 

What if I want to use metadata not included in the standard?

You can extend the scheme by using other Dublin Core fields or any other fields or tags you like, but they might not be recognised by search engines that use Discoverable Construction Knowledge.

My content is more authoritative/ higher quality than my competitors, can I make sure I rank more highly than them?

No. The standard does not attempt to address subjective matters like quality or authoritativeness. 

However, search engines have become adept at identifying bogus claims used to boost search ranking and we expect the same to be supported for construction knowledge.

What data format is the scheme designed to support?

The scheme is designed to support any structured data format and also to be used with intranets and content management system solutions. In this sense, there is no recommendation how the data is stored internally.

In order for resources to be discovered on the world wide web, the metadata should be published in the <head> element of the html page containing or, in the case of non-html content, describing the resource or agent. The recommended formats are to use the html <meta> tags or JSON-LD. Templates for HTML implementations are given in section eight.

What do the properties and types in the scheme mean?

This section defines the layout used for definining the properties of terms, known as ‘metadata’. The list of properties for describing resources are laid out in sections three, four, five, and six.The list of types of knowledge are laid out in section seven. Each of these sections are navigated by the label assigned to each individual term.

For describing resources, the properties are arranged by their functionality, whether they are Descriptive, Publishing Information, Usage Information, or Roles.

Each property has been assigned a status, whether they are a Mandatory, Recommended or Optional property. The Manadatory properties are those which are designed to help a resource be discoverable. The Recommended properties are those whch are designed to help a user to understand how valuable the resource is to them.

For each term, the following properties are given, where applicable. 

Label The human readable name assigned to the term.
Fieldname The computer readable name assigned to the term for use in datasets.
Definition A statement which represents the concept of the term.
Format The recommended practice for the term.
Status Defines the essential nature of the term.
Source Where the term has been derived from.
Note Additional points of note.
Example An illustration of how the term can be used.

Descriptive Resource Properties

This section defines eight properties that can be used to describe the scope of the resource. These are:

  1. Title (mandatory)
  2. Description
  3. Audience
  4. Project Stage
  5. Sector
  6. Subject
  7. Coverage
  8. Type

Resource properties make up the tags which can be applied to each resource to make a resource discoverable.


Fieldname: dcterms:title

Definition: The title of the resource.

Format: Text

Status: Mandatory


Fieldname: dcterms:description

Definition: An abstract or summary of the contents of the resource.

Format: Free text, typically one or two paragraphs long.

Status: Recommended

Note: The description is intended to help a practitioner understand what the resource contains and how it is presented. It supports the Subject and Type properties by giving an account in sentence form. This will often be the “preview” to the resource when served in an external application, such as search engine results. For resource types that are self explanatory (e.g. a news article or wiki entry), it can help to use an introduction to the contents, e.g. the first paragraph of an article.


Fieldname: dcterms:audience

Definition: The intended audience for the resource.

Format: Recommended practice is to use Uniclass 2015 Roles table.

Status: Recommended

Example: Lits the roles the resource applies too.

Note: Uniclass 2015 focuses on project roles, this is sometimes not applicable / appropriate to knowledge. If Uniclass 2015 cannot be used, provide a clear term that could be recognised by search and filtering tools.

Project Stage

Fieldname: ckterms:projectStage

Definition: The stage of the project life cycle the resource is relevant to.

Format: Recommended practice is to use an accepted plan of work. State both the plan used and the project stage.

Status: Optional

Example: Including; RIBA Plan of WorkBSRIA Soft LandingsBS 8536-1:2015CIC Scope of ServicesProCure22Network Rail GRIP.

Note: If the resource relates to an activity that isn’t necessarily coupled with a project stage, state the activity under the Subject property instead.

Example: “RIBA Plan of Work: Concept Design”.


Fieldname: ckterms:sector

Definition: The market sector(s) the resource is relevant to.

Format: Recommended practice is to use Uniclass 2015 Complex and/or Roles table.

Status: Recommended

Example: “Uniclass2015: Quarries”


Fieldname: dcterms:subject

Definition: The topic of the resource.

Format: Recommended practice is to use terms from Uniclass 2015 and Thema.

Status: Recommended

Note: Often resources will need several terms listed to adequately describe its subject matter. If nothing suitable is listed in Uniclass 2015 or Thema, use free text. If the subject relates to building regulations, legislation or another external resource, use the Relation property.

Example: “Uniclass2015: Concrete repair and renovation systems”


Fieldname: dcterms:coverage

Definition: The geographic location and/or time period the resouce is relevant to.

Format: Recommended practice is to use the appliable ISO 3166 code for countries and regions. Where appropriate, named places or time periods can be used in preference to numeric identifiers such as sets of coordinates or date ranges.

Status: Optional

Note: The designated ISO 3166 codes are available for free using the ISO Online Browsing Platform.


Fieldname: dcterms:type

Definition: The type(s) of knowledge contained in the resource.

Format: Must use the most applicable Knowledge Type as listed in section seven.

Status: Recommended

Note: You can list more than one Knowledge Type, this can be helpful to provide more information to the user about how they would use the resource.

Publishing Information Properties

This section defines 13 properties relating to the publication aspects of the resource. These are:

  1. Access Location (mandatory)
  2. Date Created
  3. Date Modified
  4. Access Rights
  5. Format
  6. Identifier
  7. Language
  8. Relation
  9. Version
  10. Replaces
  11. Replaced By
  12. Rights 
  13. Rights Holder

Access Location

Fieldname: ckterms:accessLocation

Definition: The location where the resource can be accessed.

Format: Must provide a URL or name of library.

Status: Mandatory

Note: This is not necessary where the metadata is provided on the same web page that the resource is accessed (i.e. where the web page would be self-referencing). More than one Access Location may be given.

Date Created

Fieldname: dcterms:dateCreated

Definition: Date of the creation of the resource.

Format: Recommended practice is to use ISO 8601, i.e the format YYYY-MM-DD.

Status: Recommended

Date Modified

Fieldname: dcterms:modified

Definition: Date the resource was last modified.

Format: Recommended practice is to use ISO 8601, i.e the format YYYY-MM-DD.

Status: Recommended

Access Rights

Fieldname: dcterms:accessRights

Defintion: Information about who can access the resource or any indication of its security status.

Format: Must use one of the following:

  • Open Access
  • Registration Required
  • Subscription Required
  • Membership Required
  • Purchase Required
  • Limited Access
  • Internal

Status: Recommended


Fieldname: dcterms:format

Definition: The physical or digital format of the resource.

Format: Must use the Media Type (Digital Format) and ONIX Product Form (Physical Format).

Status: Recommended

Note: Often resources are published in multiple formats where the Access Rights and other properties are variable depending on the format. There are two options in this scenario, the first is to define separate property sets for each format. The second is to combine all the options within a single record and leave it to the user to work out what their options are for accessing the resource.

Example: “Media Type: pdf”


Fieldname: dcterms:identifier

Definition: An unambiguous reference to the resource within a given context.

Format: Must use an identifier to state which system has been used, where applicable. For example, ISBN, DOI, URL or Document Number (BS 1234). It is permissible to list more than one identifier.

Status: Recommended

Example: ISBN:1234567891; DOI:https://doi.org/123.45/abc, BS 1234


Fieldname: dcterms:language

Definition: The language of the resource.

Format: ISO 639-2 or ISO 639-3, for example “en-gb”.

Status: Optional

Note: ISO 639-2 is sufficient for most construction knowledge resources. A list of official codes is available from the Library of Congress website.


Fieldname: dcterms:relation

Definition: A related resource that could also be useful to the practitioner.

Format: The recommended value is the URL. The ISBN, DOI or Document Number (BS 1234) are also permitted.

Status: Optional


Fieldname: ckterms:version

Definition: The version number (or similar) for the specific version of the resource.

Format: Number or text.

Status: Optional

Note: To describe the relationship betwen different versions use the Replaces and Replaced By properties.


Fieldname: dcterms:replaces

Definition: A related resource that is supplanted, displaced, or superseded by the described resource.

Format: The recommended value is the URL of the resource being replaced. The ISBN, DOI or Document Number (BS 1234) are also permitted. It is also permissible to provide some notes about the nature of the replacement (e.g. where a resource partially replaces another).

Status: Optional

Replaced By

Fieldname: dcterms:isReplacedBy

Definition: A related resource(s) that supersedes the described resource.

Format: The recommended value is the URL. The ISBN, DOI or Document Number (BS 1234) are also permitted. It is also permissible to provide some notes about the nature of the replacement (e.g. where a resource partially replaces another).

Status: Optional


Fieldname: dcterms:rights

Definition: Information about rights held in and over the resource.

Format: Text. Recommended practice is to:

  1. use the accepted name of a license if it is a publicly available license, e.g. CC-BY for Creative Commons Attribution;
  2. include the URL to a page containing a proprietary license or terms;
  3. use “All rights reserved” for resources that have standard copyright terms applied.

Status: Optional

Note: Creative commons is the preferred licensing format for construction knowledge.

Rights Holder

Fieldname: dcterms:rightsHolder

Definition: A person or organisation owning or managing rights over the resource.

Format: Name or URI of the person or organisation.

Status: Optional

Usage Information Properties

There are four properties relating to how the resource is used. These are:

  1. Competency Level
  2. Continuing Professional Development
  3. Continuing Professional Development Accreditor
  4. Instructional Method

Competency Level

Definition: Describes the educational level of the intended audience of the resource.

Format: Recommended practice is to state the level of attainment achieved according to the National Qualifications Framework, or provide the equivalent professional career attainment appropriate to the audience.

Status: Optional

Continuing Professional Development

Fieldname: dcterms:educationalLevel

Definition: The resource is appropriate to count towards CPD.

Format: True/False

Status: Optional

Continuing Professional Development Accreditor

Fieldname: ckterms:continuingProfessionalDevelopment

Definition: If CPD accreditation for the resource has been given, state the accreditor(s).

Format: Name or URI of the accrediting organisation(s).

Status: Optional

Note: Can list more than one accreditor.

Instructional Method

Fieldname: dcterms:instructionalMethod

Definition: The method used to teach/train the user.

Format: Free text account describing the method of learning. For example, classroom, self-led, distance learning and so on.

Status: Optional

Note: To be used where knowledge type is Educational and Training.

Roles Properties

There are five properties relating to the roles involved in a resource. These are:

  1. Creator
  2. Client
  3. Contributor
  4. Publisher
  5. Reviewer


Fieldname: dcterms:creator

Definition: The person or organisation primarily responsible for making the resource. For a text-based resource this is typically the author.

Format: Name or URI of the person(s) or organisation(s).

Status: Optional


Fieldname: ckterms:client

Definition: Client name, where the resource relates to a project or asset on behalf of a client (e.g. a case study) or where the resource has been commissioned.

Format: Name or URI of the person(s) or organisation(s).

Status: Optional

Note: Can be used for commissioned work. Do not use if the name of the client is confidential.


Fieldname: dcterms:contributor

Definition: The person(s) or organisation(s) responsible for making contributions to the resource.

Format: Name or URI of the person(s) or organisation(s).

Status: Optional


Fieldname: dcterms:publisher

Definition: The person or organisation responsible for making the resource.

Format: Name or URI of the person or organisation who published the resource.

Status: Recommended


Fieldname: ckterms:reviewer

Definition: Organisation(s)/ working group/ individual(s) who have reviewed the resource content for accuracy and/or completeness.

Format: Name or URI of Organisation(s)/ working group/ individual(s) who have reviewed the resource.

Status: Optional

Knowledge Types

This section provides a list of knowledge types applicable to construction knowledge.


Definition: The law of a country or jurisdication.


Definition: Mandatory requirements for a given situation.


Definition: An official position on a matter.


Definition: A formalised resource defining an expectation. Typically developed through a consensus or governance process and officially adopted by an organisation.


Definition: A resource stating requirements.


Definition:  A resource describing the nature, scope or meaning of a term. Includes disambiguations, synonyms and antonyms.


Definition: A formal resource which provides an account.

Example: Construction labour market in the UK: Farmer review and ICE State of the Nation Report.


Definition: Advice or information to help understand a concept.


Definition: A procedural or instructional resource guiding the user through an activity.


Definition:  A resource that can be used as the basis of another.

Example: Forms and certificates to be adapted and completed.


Definition: An unstructured resource intended to be used as reference material.

Example: A sample BIM Execution Plan or completed certificate.


Definition: Refers to the programs, data and other information that tells a computer how it should work.

Educational and Training

Definition: A learning resource designed to be used in an academic, vocational or applied context.

Research, Development and Innovation

Definition: Knowledge resulting from a research, development or innovation exercise.

Product Knowledge

Definition: Knowledge about the performance, use and specification of products.

Project Knowledge

Defintion: Knowledge pertaining to projects or built assets.

Example:  Case studies and assets in action.


Definition: Newly received or noteworthy information.

Example: A press release, a broadcast or published report of news.


Definition: An account of opinion; a position not policy.

Case Law

Definition: Refering to law that comes from decisions made by judges in previous cases.


Definition: A collection or series of related resources.

Example: The Design Manual for Roads and Bridges is a collection of design standards for highway assets.


Definition: An audial, visual or graphical resource.


Definition: Data encoded in a defined structure.


Definition: A person.


Definition: A legally constituted organisation.


Definition: A collection of individuals, implies no formal legal structure.

Example: Committees and societies.


Definition: A resource relating to an event.

Example: A notice of an upcoming event, or a record of an event that has already occurred.


Definition: A knowledge resource not described by other Discoverable Construction Knowledge Knowledge Types

HTML Template 


This template includes all the terms listed in sections three, four, five, and six.

.Use these declarations in the <head> element of your HTML page.

<link rel="schema.dcterms" href="http://purl.org/dc/elements/1.1/">
<link rel="schema.foaf" href="http://xmlns.com/foaf/spec/">
<link rel="schema.ckterms" href="http://purl.org/dck/spec">

Note: Web scrapers will use these tags to identify that there is construction knowledge to be indexed.

Multiple values for a property

Use a semicolon to separate items in a list of values. 

For example:

<meta name="dcterms:contributor" content="John Lennon; Paul McCartney; George Harrison; Ringo Starr">

Specifying naming systems

Use a colon to specify the naming system used for values, particularly when drawing from multiple systems.

For example:

<meta name="dcterms:subject" content="uniclass2015:Solar module roof anchors">
<meta name="dcterms:identifier" content="ISBN:123456789; BS 123-2; DOI:https://102.212.321/1234; URI:https://example.com">

Resource template – HTML metadata

<link rel="schema.dcterms" href="http://purl.org/dc/elements/1.1/">
<link rel="schema.foaf" href="http://xmlns.com/foaf/spec/">
<link rel="schema.ckterms" href="http://purl.org/dck/spec">
 <!-- MANDATORY -->
<meta name="ckterms:accessLocation" content="...">
<meta name="dcterms:title" content="...">

<meta name="dcterms:accessRights" content="...">
<meta name="dcterms:audience" content="...">
<meta name="dcterms:dateCreated" content="...">
<meta name="dcterms:dateModified" content="...">   
<meta name="dcterms:description" content="...">
<meta name="dcterms:format" content="...">  
<meta name="dcterms:identifier" content="...">
<meta name="dcterms:publisher" content="...">  
<meta name="dcterms:sector" content="...">
<meta name="dcterms:subject" content="..."> 
<meta name="dcterms:type" content="..."> 

<!-- OPTIONAL -->
<meta name="dcterms:client" content="...">
<meta name="ckterms:continuingProfessionalDevelopment" content="..."> 
<meta name="ckterms:continuingProfessionalDevelopmentAccreditor" content="..."> 
<meta name="dcterms:contributor" content="...">
<meta name="dcterms:coverage" content="...">
<meta name="dcterms:creator" content="...">  
<meta name="dcterms:educationalLevel" content="...">
<meta name="dcterms:instructionalMethod" content="...">
<meta name="dcterms:language" content="...">
<meta name="ckterms:projectStage" content="...">
<meta name="dcterms:relation" content="...">
<meta name="dcterms:replaces" content="...">
<meta name="dcterms:IsReplacedBy" content="...">
<meta name="ckterms:reviewer" content="...">
<meta name="dcterms:rights" content="...">
<meta name="dcterms:rightsHolder" content="...">
<meta name="ckterms:version" content="...">


Governance of this specification

The Discoverable Construction Knowledge standard is governed by the Construction Knowledge Task Group.

Changes to the standard are proposed in StandardsRepo.

Changes are voted on during meetings of the Construction Knowledge Task Group.

A current list of the CKTG members can be found here: https://www.designingbuildings.co.uk/wiki/Construction_knowledge_task_group

Anyone can apply to join the Construction Knowledge Task Group on an individual or organisational basis. There is currently no membership fee or qualification to join and participate in its activities, including Discoverable Construction Knowledge


We would like to acknowledge our funder the Lloyd’s Register Foundation, and the Open Data Institute who also supported this project.


Appendix One – Existing Open Standards and Classifications Systems

Dublin Core Metadata Initiative

At the base of this scheme, is the Dublin Core Metadata Initiative (DCMI). The DCMI, otherwise known as Dublin Core, is a small scale vocabulary term scheme that can be used to describe physical and digital resources. Dublin Core was developed in 1995, out of an Online Computer Library Center/National Center for Supercomputing Application Metadata workshop in Ohio, USA. Initially, 15 established metadata terms, known as the Dublin Core Metadata Element Set (DCMES) were established, and endorsed in 3 standard documents. These being; IETF RFC 5013, ISO Standard 15836-1:2017, and NISO Standard Z39.85.

Dublin Core metadata can be used for various functions, including, describing simple resources to amalgamating the vocabularies of diverse metadata standards. The Dublin Core standard originally incorporated two levels, Simple and Qualified.

In 2012, both Simple Dublin Core and Qualified Dublin Core were incorporated into the DCMI Metadata Terms. The Dublin Core Metadata Terms lists the current Dublin Core vocabulary, known as the Dublin Core terms for short. The current vocabulary includes the original 15 elements, and the 3 qualified elements.

More information about the DCMI Metadata Terms can be found at https://www.dublincore.org/specifications/dublin-core/dcmi-terms/.

This specification reproduces the aspects of the DCMI Metadata Terms that are part of Discoverable Construction Knowledge and provides additional guidance to encourage consistency across the industry.

Friend Of A Friend

The Friend of a Friend (FOAF) project is devoted to linking people and information using the Web. Regardless of whether information is in people’s heads, in physical or digital documents, or in the form of factual data, it can be linked. FOAF integrates three kinds of network: social networks of human collaboration, friendship and association; representational networks that describe a simplified view of a cartoon universe in factual terms, and information networks that use Web-based linking to share independently published descriptions of this interconnected world. FOAF does not compete with socially-oriented Web sites; rather it provides an approach in which different sites can tell different parts of the larger story, and by which users can retain some control over their information in a non-proprietary format.

FOAF is designed to work with Dublin Core and there is a formal agreement of support between the two projects.

The full FOAF specification can be found here: http://xmlns.com/foaf/spec/.

This specification reproduces the aspects of FOAF that are part of Discoverable Construction Knowledge and provides additional guidance to encourage consistency across the industry.

Uniclass 2015

Uniclass 2015 is a unified classification system for the construction industry, which covers all sectors, and is maintained by the NBS. It comprises 12 tables, which can be used to categorise a wide range of information, including costings, briefings to production documents. The table allows project information to be defined from both a broad and narrow perspective.

For more information and to search and browse the Uniclass 2015 tables, please click here.


Thema is a multilingual category scheme used to classify book content via subject. It was designed to meet the needs of publishers in all sectors of the global book publishing industry, in both digital and physical products. It consists of hierarchically-arranged subject categories and qualifiers, each with a descriptive heading, available in multiple languages, and a language independent code. 

Thema aims to enhance discoverability by simplifying the communication of accurate and detailed subject information across international markets.

The complete scheme is available in various languages, as well as versions in Excel, XML, HTML and JSON.

Thema subject categories can be found here.

Basic user instructions for the current version of Thema can be found here.

ONIX Product Form

ONIX Product Form Issue 36 is an international standard for representing and communicating book industry product information in electronic form. It is an XML-based standard which provides a consistent way for publishers to communicate rich metadata about their products. It has been designed for global use, and is not limited to any one language.

ONIX Product Form Issue 36 is a codelist, consisting of a controlled vocabulary of descriptive items; including resource format. The ONIX Product Form Issue 36 List 7 for resource format can be found here


Creative Commons License
The Discoverable Construction Knowledge specification by the Construction Knowledge Task Group is licensed under a Creative Commons Attribution 4.0 International License.