Under the Dutch Building Decree (BBL — Besluit Bouwwerken Leefomgeving, formerly Bouwbesluit), the maximum fire compartment size for new construction is generally 1,000 m² for most occupancy classes, though this limit rises to 2,500 m² for certain industrial and logistics functions. These figures represent the absolute minimum regulatory requirement, not a fixed ceiling: project-specific fire safety calculations, sector regulations, insurer requirements, and client specifications frequently produce stricter outcomes. The sections below unpack each factor that shapes the actual limit for your project.
How does the Dutch building code (BBL) define compartment size limits?
The BBL sets a baseline maximum compartment area that depends on the building’s use function. For industrial buildings (gebruiksfunctie industrie), the code allows compartments up to 2,500 m² in new construction. For most other commercial and mixed-use occupancies, the default limit is 1,000 m². These are absolute minimums in the regulatory sense: no project may fall below them without a formally substantiated deviation, but the actual requirement for a specific project may be more demanding depending on the circumstances.
The BBL structures its requirements around use functions rather than building types. A single building with a production hall, office wing, and storage area may therefore contain multiple compartment size regimes within the same structure. Each zone is assessed according to its own use function, and boundaries between them must meet the fire resistance requirements that apply to the more demanding of the two adjacent functions.
It is important to distinguish between what the BBL prescribes and what a completed project requires. The code sets the outer boundary of the absolute minimum requirement. Whether a specific project can actually use the full 2,500 m² depends on additional factors that the BBL alone does not resolve — including project-specific fire safety calculations, sector regulations such as PGS15, insurer requirements, and client or principal requirements.
Architects specifying products for compartment boundaries can find Metacon-Next’s full product range with corresponding classification documentation, making it straightforward to match a certified solution to the applicable requirement.
What factors determine the actual maximum compartment size for a project?
The actual maximum compartment size for a specific project is determined by four overlapping layers of requirement: the BBL baseline, project-specific fire safety calculations (brandveiligheidsberekeningen), sector-specific regulations, and requirements imposed by the client or insurer. Any one of these layers can reduce the permissible area below the BBL default. Which classification is ultimately required can only be determined through a project-specific fire safety calculation carried out by a qualified fire safety engineer or confirmed by the local authority — not from the BBL alone.
- Fire safety calculations: A fire safety engineer may determine that the risk profile of the building, its occupancy load, or the presence of hazardous materials requires smaller compartments than the BBL default. These calculations are project-specific and cannot be generalised. Standards such as NEN 6060 and NEN 6079 provide frameworks for compartmentalisation sizing, but applying them correctly requires specialist expertise.
- Sector regulations: Regulations such as PGS15 (for the storage of hazardous substances) impose their own compartment size limits and may mandate a heavier fire classification than the BBL baseline for the relevant areas.
- Insurer requirements: Industrial property insurers routinely impose compartment limits as a condition of coverage, particularly for high-value or high-risk facilities. These requirements are contractual, not statutory, but they are binding in practice and can require a classification that exceeds the BBL minimum.
- Municipal or environmental permit conditions: Local authorities may attach compartment size conditions to an environmental or building permit, especially for facilities near residential areas or with elevated risk profiles.
For architects, this means the BBL figure is a starting point for a conversation with the fire safety engineer, not a specification value that can be carried directly into a drawing. The actual compartment size and the associated door classification must be confirmed through the project’s fire safety report before boundary products are specified.
How does compartment size affect fire resistance classification requirements?
Compartment size directly influences the required fire resistance duration of boundary elements, including walls, floors, and doors. Larger compartments generate higher thermal loads during a fire event, which translates into longer required resistance periods. The BBL links resistance duration to compartment area and building height, with longer durations required as either variable increases.
For industrial buildings, the Dutch standard baseline criterion for compartment boundaries in new construction is typically EW 60 — meaning the door blocks flames, hot gases, and radiant heat transfer for 60 minutes. EW is the Dutch standard baseline classification: it requires integrity (E) and limits radiant heat transfer (W), but does not impose a temperature criterion on the unexposed face. Other classifications such as EI2-60 are common and fully valid alternatives where the fire safety calculation or other requirements call for them. Taller structures or compartments that exceed standard area thresholds may require 90-minute or longer classifications. When sector regulations such as PGS15 apply, 120-minute classifications are not uncommon for specific boundary elements.
The relationship between compartment size and classification is not linear and cannot be read from the BBL alone. It emerges from the fire safety calculation, which models the expected fire load, the rate of heat release, and the time required for safe evacuation or intervention. The output of that calculation determines which classification the boundary element must carry, and that classification then drives product selection. For project-specific guidance, consult a qualified fire safety engineer or contact Metacon-Next directly.
Understanding this dependency is essential for architects who specify fire-rated doors at the drawing stage. A door specified as EI1-60 based on an assumed compartment size may need to be revised if the fire safety calculation changes the compartment layout. Specifying from a manufacturer with a broad classification range reduces the risk of late-stage substitutions. Metacon-Next manufactures fire-rated industrial doors across a wide range of classifications — including EW 60, EW 90, EW 120, EW 240, EI1-60, EI1-120, EI2-60, EI2-90, and EI2-120 — covering the range most commonly required in industrial and logistics projects.
What’s the difference between EW, EI1, and EI2 classifications for compartment boundaries?
EW, EI1, and EI2 are three distinct fire resistance classifications under EN 13501-2, each measuring a different level of performance. EW requires integrity (no flames or hot gases pass through) and limits radiant heat transfer on the unexposed side — this is the Dutch standard baseline criterion. EI1 adds a stricter insulation criterion: the temperature rise on the unexposed face is limited to a lower threshold. EI2 applies a less strict insulation criterion, permitting a higher temperature rise on the unexposed side, but still requires that the unexposed surface does not exceed a defined average temperature rise above ambient. Always specify EI1 or EI2 explicitly — never write “EI” without the suffix, as they represent meaningfully different levels of protection and are not interchangeable. The classification required for a specific boundary depends on the fire safety calculation, not on a blanket rule.
EW: radiation limitation
An EW-classified element maintains its integrity (no flames or hot gases pass through) and limits the radiant heat transfer on the unexposed side to a defined maximum. EW is the Dutch standard baseline criterion for compartment boundaries in industrial applications. It does not impose a temperature criterion on the unexposed surface, which means it may not be sufficient in all situations — for example, where the unexposed side is directly accessible to building occupants or where adjacent materials have a low ignition threshold. Whether EW is adequate for a specific application must be determined by the project’s fire safety calculation.
EI1 and EI2: insulation criteria
Both EI1 and EI2 require that the unexposed face of the element does not exceed a defined average temperature rise above ambient, in addition to the integrity and radiation requirements. EI1 applies a stricter temperature criterion — limiting the temperature rise to a lower threshold. EI2 permits a higher temperature rise on the unexposed side, making it a less strict criterion than EI1. EI2 is commonly required where the unexposed side is accessible to building occupants or where adjacent materials have a lower ignition threshold, but whether EI1 or EI2 is required for a specific boundary depends on the fire safety calculation for that project. Never use “EI” without specifying whether it is EI1 or EI2 in a specification document, as they are not interchangeable.
For architects, the practical implication is that the classification code must be carried through from the fire safety report into the product specification without simplification. A product certified as EI1-60 does not automatically satisfy an EI2-60 requirement, and vice versa, even if the resistance duration is identical.
When does a fire compartment boundary require a certified fire-rated door?
A fire compartment boundary requires a certified fire-rated door at every opening that penetrates the boundary. An opening without a rated door nullifies the compartment boundary at that point, regardless of the fire resistance of the surrounding wall or floor construction. This applies to personnel doors, vehicle access openings, and any other penetration intended for passage or transport.
The door must carry a classification that matches or exceeds the classification required for the boundary element it sits within. If the boundary is specified as EI1-60, the door must be independently tested and classified to at least EI1-60 under EN 1634-1. A CE declaration of performance — issued under both EN 16034 (fire and smoke resisting closing elements) and EN 13241 (industrial doors generally), both of which apply simultaneously to industrial fire doors — and an accompanying classification report from an accredited test body are the minimum documentation required to demonstrate compliance at the permitting stage.
In industrial and logistics environments, compartment boundaries are frequently penetrated by forklift routes, conveyor systems, and wide vehicle access points. These openings require fire-rated doors capable of spanning large clear widths while maintaining their classification under the applicable standard. Standard residential or commercial fire doors are not designed for these dimensions or operational conditions.
Metacon-Next’s fire-rated industrial door range is specifically developed for large and atypical openings in production halls, warehouses, and logistics centres. All products are CE-certified under both EN 16034 and EN 13241, and tested by Efectis, with full classification reports available for download without requiring a sales contact. Architects who need to close a specification file can request technical documentation directly, or reach the team through the contact page for project-specific questions.
The requirement for a certified installer is equally important. Installing a certified fire door incorrectly can invalidate the classification, leaving the compartment boundary non-compliant even if the product itself meets the specification. Metacon-Next supplies exclusively through a network of certified dealers and installers, ensuring that the product’s classification is backed by a warranted installation. For architects specifying fire-rated doors in the Netherlands or internationally, this supply model removes a significant source of post-installation risk. Learn more about the company and its approach on the about us page.
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