The Dutch Nationale Milieudatabase (NMD) calculates the environmental performance of construction projects in the Netherlands. The latest version, NMD v3.11, introduces significant updates to datasets, methodologies, and standards, ensuring better precision and compliance with evolving requirements such as the MKI A2 standard.
This article answers the following questions:
What sector does the NMD apply to?
What LCIA method corresponds with NMD v3.11?
What are the key updates in NMD v3.11?
How to decide between Bepalingsmethode MKI A1 & MKI A2?
How to use NMD v3.11 in Ecochain Helix?
Feel like you're missing information? This article builds upon the following articles, check them out if you want to learn more:
On LCI Databases: Explained: LCI databases
On NMD Bepalingsmethode: Explained: NMD Bepalingsmethode
On LCIA methods: Explained: LCIA methods
On ECI weighting factors: The updated ECI (MKI) weighting factors
What sector does the NMD apply to?
The Dutch National Environmental Database (NMD) is an LCI database developed by the Dutch National Environmental Database Foundation (Stichting NMD). It is specifically designed to calculate the environmental performance of construction projects within the Dutch context.
Which LCIA method corresponds with NMD v3.11?
When working with the NMD v3.11 database, you must select the "NMD Bepalingsmethode v1.2" as your LCIA method. This ensures compliance with the specific methodology tied to the updated database. For full compliance, see the latest NMD assessment guidelines on their website.
What’s new in NMD v3.11?
Many new/updated cement base profiles (several explicitly conform NL-PCR Cement): Heidelberg Materials, Spenner, Thomas Zement, Wittekind, Phoenix, Cemminerals, Dyckerhoff, plus Megamix (zandcement/mortel). Older ENCI/Heidelberg data were removed/replaced - use the new profiles.
Biobased fibers/materials: flax (long), straw (bales/loose), willow rods, mycelium, hydraulic lime, multiple fiber boards and biocomposites.
Concrete mixes: a broad set of C20/25 → C90/105 mixes incl. CEM III variants and mixes with recycled aggregate and PP-fibers - useful for downstream alignment with updated cement.
Energy carriers & ships: new A1–A4 fuel/energy carrier datasets (diesel, MGO, LNG/Bio-LNG, HFO, HVO, FAME, hydrogen (gas/liquid)) and ship capital-goods/use profiles.
Machines/transport on H₂/HVO/FAME: updated inventories per Bepalingsmethode v1.2; hydrogen carrier data refreshed.
Plastics recycling: revised process now covers sorting through granulation; aligned end-of-waste handling.
Biogenic CO₂ handling: small additions/corrections across wood, coconut, hemp/flax processing; corrected moisture/density values where relevant.
Set-2 coverage & warnings: most Cat-1/2 processes now have Set-1 & Set-2; remaining items without Set-2 are flagged and should be avoided for EN 15804+A2 reporting.
Change log & delivery: 3.11 comes with an Excel change log
Cement-PCR implications
NMD now supplies PCR-conform cement datasets in v3.11. Previously, many cement basics were explicitly marked “not in accordance with PCR”; with v3.11 you can (and should) switch to PCR-conform producer profiles to improve comparability and reduce verification risk.
Dual variants of the database
The NMD v3.11 includes two (ecoinvent) database versions tailored for different applications:
One version based on ecoinvent v3.6.
Used for calculating MKI A1 scores.
Used for calculating MKI A2 scores during the NMD transition period.
Utilizes the "Set 1" indicators.
One version based on ecoinvent v3.9.1.
Designed for MKI A2 calculations.
Aligns with EN15804+A2 standards.
Note - Transition rule: Dutch practice requires reporting set A1 and set A2 in parallel until July 2026; from July 2026 onward only MKI-A2 will remain. (Sector guidance points to A2 becoming the sole reference by 1 July 2026.)
How to choose between Set A1 and Set A2
Use A1 when MKI-A1 is required and model with the Ecoinvent 3.6 variant.
Use A2 when MKI-A2 is required and model with the Ecoinvent 3.9.1 variant (EF 3.1).
Note: Until Jul 2026 deliver both A1 and A2; after that, A2 only.
Deciding between Bepalingsmethode MKI A1 & MKI A2?
Use the following decision tree (Figure 1) to decide what MKI (ECI) score applies to your model.
Figure 1: Decision tree for Bepalingsmethode ECI A1 and/or ECI A2.
How to apply NMD v3.11 – EI3.9.1 (Set A2) in Helix
Go to Settings → Calculation method
Standard database: Dutch – Nationale Milieudatabase v3.11 (obv Ecoinvent 3.6 or 3.9.1)
LCA standard: NMD Bepalingsmethode v1.2 (2025) (obv Ecoinvent 3.9.1)
Presentation of results: Set 2 + MKI A2 (GWP-bio adapted)
Figure 2: Selecting NMD v3.11 in workspace settings in Helix.
How to apply NMD v3.11 – EI3.6 (Set A1) in Helix
Go to Settings → Calculation method
Standard database: Dutch – Nationale Milieudatabase v3.11 (obv ecoinvent 3.6)
LCA standard: NMD Bepalingsmethode v1.2 (2025) (obv ecoinvent 3.6)
Presentation of results: Set 1–2 + MKI A1–2 (GWP-bio adapted)
Pro tip - Parallel modeling: If you need parallel A1 and A2 modeling, keep separate years, or accounts so each points to the correct NMD variant and method in their respective settings.
Figure 3: Selecting NMD v3.11 based on ecoinvent v3.6 in Helix' settings.
Using NMD v3.11 in Ecochain Mobius
Note: Ecochain Mobius will not release NMD v3.11. We’re skipping directly to NMD v3.12, planned for Q1 2026. Continue with your current NMD setup using NMD v3.9.1. in Mobius until v3.12 is available.
Next steps
NMD v3.11 introduces several important changes for environmental performance calculations in the Dutch construction sector. From new and updated datasets to the MKI A2 standard, this version enhances accuracy and aligns with future regulatory requirements.
The sector is currently in a transition period, where both MKI A1 and MKI A2 results must be reported. Starting from July 2026, only MKI A2 will be accepted for compliance. Transitioning to the updated standards and methodologies now will ensure Dutch construction businesses remain fully aligned and ready for the upcoming regulatory shift.