Collecting carbon footprint data in Collaborate:

GWP and GWP IOBC Requirements

A guide for Cobuilder Collaborate users, part of the Collaborate Sustainability service.

Across the construction industry, the sustainability conversation has narrowed to one question above all others: what is the carbon footprint of what we build? Regulators, clients and value chain partners increasingly ask for it in numbers, and those numbers have to be traceable back to their source, whether that source is a product-specific EPD or a recognised generic LCA database.

To help you meet that demand, we have added two new libraries to Cobuilder Collaborate: GWP Requirements and GWP IOBC Requirements. Both are built to gather, in one structured place, the product data you need to calculate the carbon footprint of a project. This guide explains what each library collects, how the two differ, and how they connect to the reporting frameworks that apply in Norway today.

This page builds on our overview of how EPD and LCA data work in the Cobuilder platform. If you are new to how we source and prepare environmental data, we recommend reading that guide too.

Global Warming Potential (GWP) expresses a product’s contribution to climate change, usually in kilograms of CO₂ equivalent (kg CO₂ eq). It is the single most requested environmental indicator in construction, and it sits at the centre of both project level climate accounting and company level sustainability reporting.

Because the industry is so focused on this one measure, we decided to give it dedicated homes in Collaborate rather than leaving it inside broader environmental datasets. The result is two libraries that share the same purpose, collecting the product data required to calculate a project’s carbon footprint, but that use two different GWP indicators.

Whichever library you use, the goal is a complete, calculation-ready picture of each product’s climate impact. Both libraries gather:

• The GWP value from the product’s EPD (Environmental Product Declaration), where one exists. Where an EPD is not available, a generic GWP value from a recognised generic database is used instead. You can read how these generic values are sourced and mapped in our EPD and LCA data usage guide.
• The declared unit for which the GWP value is given (for example per kilogram, per cubic metre or per linear metre). This is essential, because the same indicator can be reported against very different units.
• The weight of the product per the EPD’s declared unit, which allows the declared value to be converted and scaled to the actual quantity used in the project.
• The weight of the F-pak (the consumer or sales packaging unit), so that packaging can be accounted for alongside the product itself.

Together these fields let Collaborate move from a declared indicator result to a usable, project specific carbon figure, including the necessary unit conversions and scaling.

The difference between the libraries is the GWP indicator each one is built around.

Because the GWP-IOBC indicator is not always stated directly in an EPD, the GWP IOBC Requirements library also collects two further values that make it possible to calculate it when needed:

• The biogenic carbon content in the product
• The biogenic carbon content in the packaging

These are the inputs required for the calculations set out in the Norwegian Building Authority’s (DiBK) guideline for preparing greenhouse gas accounts under the Building Technical Regulations (TEK17) § 17-1.

The difference between the libraries is the GWP indicator each one is built around.

Since 1 July 2022 (with a one year transition period, so effective for applications from 1 July 2023), TEK17 § 17-1 has required a greenhouse gas account from materials for the construction and major renovation of residential blocks and non-residential buildings in Norway. The account is based on the method in NS 3720:2018 and, as a minimum, covers life cycle modules A1 to A4, B2 and B4 for the specified building parts. DiBK recommends using third party verified, standardised, life cycle based documentation, such as an EPD, as the basis for the account.

The GWP-IOBC indicator is the one used for this material level climate accounting, which is exactly what the GWP IOBC Requirements library is designed to support. For details of the requirement, see DiBK’s § 17-1 provision and guidance and their guide to preparing greenhouse gas accounts.

Beyond project level accounting, the EU Corporate Sustainability Reporting Directive (CSRD), now transposed into Norwegian law, is progressively extending structured sustainability disclosure across the construction value chain. Even where the direct obligation sits with larger companies first, it creates a ripple effect for manufacturers, contractors and suppliers who are asked to provide the underlying product data. Having reliable, traceable GWP data organised in Collaborate puts you in a strong position to respond, whichever framework is driving the request.

The value of a carbon figure depends entirely on the quality and traceability of the data behind it. In Collaborate:

• EPD based values are linked to the corresponding EPD’s registration number, so they can always be traced back to the original declaration and its indicator results.
• Where generic data is used, its source and version are clearly indicated in the system, and generic values are selected using a consistent, documented mapping approach.

As always, the EPD data itself is owned and provided by manufacturers. Cobuilder’s role is to apply the conversion and scaling steps that make it usable, not to warrant the underlying figures. You can read the full detail of both processes in the EPD and LCA data usage guide.

The Sustainability service focuses first on the product categories that matter most for carbon impact and regulation: high embodied carbon materials such as concrete, cement, steel and other metals; high volume materials such as insulation, gypsum, glass, windows and doors; strategically important materials such as timber; and chemical products. The scope of applicability is described in more detail in the EPD and LCA data usage guide.

If you already collect sustainability data in Collaborate, the GWP Requirements and GWP IOBC Requirements libraries slot into the same familiar workflow. Choose GWP Requirements when you need a total carbon figure, and GWP IOBC Requirements when you are working towards TEK17 material level climate accounting.