NEN standards in construction: when and how are they relevant?

NEN standards are technical agreements (standards) covering areas such as safety, fire resistance, the load-bearing capacity of structures, ventilation, daylight, noise and energy performance. NEN stands for NEderlandse Norm. These standards are drawn up by the Netherlands Standardisation Institute, with input from market stakeholders and experts. The NEN standards are voluntary agreements, but may become mandatory if the government refers to them in, for example, the Building Decree / Decree on Buildings and the Built Environment (Bbl), or if parties include them in their contracts. The NEN standards may also influence what is considered ‘good and sound workmanship’.

But what exactly is the legal significance of NEN standards?

What are NEN standards and why do they feature in the Building Decree/Bbl?

The government often uses NEN standards to elaborate on legal requirements. There are three reasons for this:

1. Legislation often sets out functional objectives. For example, that a structure must be sufficiently fire-safe. The standard specifies in concrete terms how that building must be designed and how compliance can be demonstrated:

2. The standard can be updated regularly, whereas legislation changes less frequently;

3. Uniform language in the standards helps to minimise disputes during the granting of planning permission, supervision and litigation.

However, if the NEN standard is not a law, what is its legal relevance?

When does a NEN standard apply in construction law?

The three most obvious routes for the applicability of NEN standards in construction law are:

1. Reference in regulations (Building Decree/Bbl);
2. Contractual agreement;

3. As a standard defining ‘sound and proper workmanship’;

If a standard is designated in the Building Decree/Bbl as a method for meeting a requirement, that standard is the standard route for demonstrating that the structure complies. However, even outside the scope of the Bbl, NEN standards can be important for contractors. In such cases, the standards are included in building contracts, in general terms and conditions such as the UAV/UAV-GC, or in the specifications. However, even if no explicit agreement has been made regarding the NEN standards, they can still play a role in the construction industry. In disputes between the contractor and the client, the NEN standards are regularly used by experts to define what the client could reasonably expect and what is customary in the industry. The NEN standards then serve as a good starting point for what the parties may expect from one another.

Incidentally, the NEN standards are not the only standards that can define what constitutes ‘good and sound workmanship’. It is also quite possible that STABU standards, or installation instructions for building materials, may be used for this purpose. Furthermore, the standards for ‘good and sound workmanship’ may be interpreted according to the judgement of an expert, arbitrator or judge.

How do NEN standards play a role in construction disputes and liability?

In disputes, NEN standards often come into play at three key moments:

• When determining whether a defect exists: does the work carried out meet the standard that is relevant under the contract or regulations?
• When interpreting agreements: if a specification or quotation refers to ‘NEN’, is it clear which standard and version is meant? This can be particularly significant in the case of existing buildings.
• Regarding causality and damage: if a deviation from a standard leads to damp, fire hazards, noise pollution or structural problems, this can be a key factor in the presentation of evidence.

In practice, in addition to a discussion about whether the NEN standards apply, there are three key points of contention:

• which standard exactly applies?
• which version applies?
• Is there an equivalent solution?

With regard to the equivalent solution, the following applies: the contractor and client may deviate from the NEN standard, but must then demonstrate that the chosen solution is at least equivalent. This ‘escape clause’ has been included to allow, for example, scope for innovation and bespoke solutions. If the contractor deviates from the building plan, they will have to demonstrate to the client that equivalence has been achieved. The client must then, if necessary, be able to demonstrate this to third parties.

Why do the NEN standards play such an important role if they were not established by the government and were not freely accessible?

The fact that the NEN standards are not simply freely available to everyone has been a subject of considerable debate, right up to the Administrative Law Division of the Council of State.

The status of the NEN standards was the subject of discussion there. The NEN standards are not law and have not been adopted by an organisation with governmental authority. Consequently, they do not need to be made available to everyone free of charge, as is the case for ordinary laws and regulations under the Constitution and the Publication Act.

The Administrative Law Division of the Council of State ruled on this special position in the so-called City Crash judgment. The Division found that the standards are sufficiently ‘accessible’. This conclusion is based on the argument that the NEN standards can be viewed by professional parties for a ‘reasonable fee’. For consumers, the standards are available free of charge at the NNI library. This means that, in the eyes of the Council of State, the standards are ‘known’ to everyone, which is sufficient to classify them as ‘accessible’. It goes without saying that the expansion of free access to the standards is therefore a huge step forward, for both businesses and consumers.

Is it reasonable for technical standards designated in legislation and regulations to be behind a paywall? That is one of the questions posed by the STOER committee – established to make construction faster and cheaper. Consequently, by 2025, a significant proportion of the NEN standards referenced in the Building Decree / Decree on Buildings and the Built Environment (Bbl) will be available to view online free of charge. However, this does not (yet) apply to all NEN standards, so there is still room for improvement here.

In conclusion

The NEN standards play a key role in building regulations, but certainly also in (the implementation of) agreements between parties. This also means that the NEN standards are very important in the event of disputes. This is due both to their direct impact via the Building Decree, but also via contractual references and the standard for good and sound workmanship. The fact that the most important standards are now freely available is a major step forward. It makes the playing field more transparent: both in construction practice and in legal debate, parties can now assess their rights and obligations more quickly and easily.

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