Fire resistance testing is a standardized laboratory procedure in which a door assembly is exposed to a controlled fire according to a defined time-temperature curve, then evaluated against criteria that measure how long the door continues to perform its protective function. The result of that test is expressed as a classification code that tells architects, engineers, and building inspectors exactly what the door can and cannot do. The sections below work through each layer of that system, from the test itself to the documents that prove compliance.
How is a fire door actually tested in a laboratory?
A fire door is tested by mounting a complete door assembly, including the frame, hardware, and any glazing, into a furnace opening and exposing it to a standardized fire curve defined in EN 1634-1. The furnace temperature rises in a controlled pattern over the test period, typically reaching around 900 degrees Celsius within the first hour. Throughout the test, the door is assessed against defined performance criteria at timed intervals.
The test measures three things simultaneously. First, the door must maintain its integrity — no flames or hot gases may pass through gaps, cracks, or joints. Second, the door’s insulation performance is measured: thermocouples on the unexposed face record whether surface temperatures rise beyond the permitted threshold. Third, in some test regimes, radiation through any glazed sections is also measured to assess heat flux on the unexposed side.
The test is conducted on a specific, fixed assembly. This is important for specification purposes: the classification is only valid for the exact configuration tested, including frame dimensions, anchor pattern, threshold design, and hardware. Any deviation from the tested configuration requires either a new test or a documented extended application of test results (EXAP), which must be produced by the testing laboratory. Independent testing bodies such as Efectis carry out these assessments and issue the classification report that accompanies the product throughout its service life.
Metacon-Next products are tested and certified through this process, with full classification reports available for each product line. Architects specifying a fire-rated industrial door can access those reports directly, without having to request them separately after placing an order.
What does the classification number on a fire door mean?
The classification number on a fire door indicates the number of minutes the door maintained its performance during the standardized test, as defined in EN 13501-2. A door classified as EI2-60, for example, passed the test for 60 minutes under the EI2 insulation criterion. The number is always the duration in minutes; the letters before it define which performance criteria were met.
Common classification periods are 30, 60, 90, 120, and 240 minutes, though not every product is tested at every interval. The number reflects a minimum guaranteed performance: a door classified at 60 minutes must hold for at least that duration under the test conditions. It does not mean the door fails immediately at minute 61 — it means the classification is guaranteed only up to that point.
For industrial applications, the 60-minute class is frequently encountered in fire compartmentation between production and storage areas, while 90-minute or 120-minute classifications appear in higher-risk environments or where project-specific fire safety calculations demand a longer resistance period. The classification period must match the fire resistance requirement stated in the building’s fire safety documentation, not simply the most commonly available option.
What is the difference between EI1, EI2, and EW classifications?
EI1, EI2, and EW are three distinct fire door classifications defined in EN 13501-2, each representing a different level of thermal protection on the unexposed side of the door. EI1 applies the stricter insulation limit, EI2 applies a less strict insulation limit, and EW requires only that radiated heat flux stays below a defined threshold — without controlling surface temperature in the same way. In the Dutch context, EW60 is the standard baseline classification for fire-resistant industrial doors; EI2-60 is a common and fully valid alternative, not an exception.
EI1: the stricter insulation criterion
EI1 requires that the temperature rise on the unexposed face remains within a lower permitted threshold. The integrity requirement is the same as for EI2, but the insulation criterion is more demanding, meaning the door must more effectively limit heat transfer to the safe side. EI1 classifications are used in contexts where this stricter criterion is explicitly required by the applicable regulation or the project’s fire safety calculation.
EI2: the less strict insulation criterion
EI2 allows a higher permitted temperature rise on the unexposed face than EI1. The integrity requirement remains the same, but the insulation threshold is less strict, meaning the door surface on the safe side may become significantly hotter than under EI1. EI2 is widely used across European industrial applications. Always confirm with the project’s fire safety report whether EI1 or EI2 is required — never write or specify “EI” without the suffix, as the two criteria are not interchangeable.
EW: radiation control without full insulation
EW doors maintain integrity and limit the heat flux radiated through any glazed areas to below 15 kW/m², but they do not control the surface temperature of the door leaf itself. EW60 is the Dutch standard baseline classification for fire-resistant industrial door openings — it is the typical default in the Dutch regulatory context, not a lesser or non-standard option. Whether EW is sufficient for a specific opening depends on the fire safety calculation for that project; in some situations a higher classification such as EI2-60 or EI1-60 may be required.
Specifying the wrong classification is one of the most common documentation errors in fire door procurement. If you are unsure which criterion applies to a particular opening, the answer lies in the project’s fire safety report. Consult a qualified fire safety engineer or contact Metacon-Next directly rather than relying on a general rule of thumb.
Why does the same opening sometimes require a higher fire class than the minimum?
The minimum fire resistance class set by the BBL (Besluit Bouwwerken Leefomgeving, formerly the Bouwbesluit) is an absolute floor, not a ceiling. It sets the lowest permissible requirement; it does not define what a specific project needs. A particular opening may require a higher classification than that statutory minimum for a number of distinct reasons — none of which represent the BBL “changing” its requirements, but rather situations in which a heavier classification is warranted.
Several factors can drive a higher requirement in practice:
- Project deviates from standard building regulations: When a building’s configuration falls outside the standard scope of the BBL, a project-specific fire safety calculation may determine that a heavier classification is required to achieve an equivalent level of protection.
- Sector-specific regulation: Certain industries operate under additional rules. Facilities storing hazardous substances, for example, may fall under PGS15 guidelines, which can impose fire resistance requirements beyond the BBL minimum.
- Insurer requirements: Industrial property insurers frequently set their own fire compartmentation standards as a condition of coverage. These requirements are contractual, not statutory, but they are binding for the building owner.
- Client or developer specifications: A project developer or end client may specify a higher class to reduce risk, support a sustainability rating, or align with internal corporate standards.
This is why it is not possible to state, as a general rule, that a warehouse requires EI2-60 or a production hall requires EI1-90. The correct classification for any opening is determined by the fire safety documentation for that specific project. Architects carry responsibility for specifying the correct class, which means they need a manufacturer capable of supplying the documented performance that the fire safety report demands. For guidance on which classification applies to your project, consult a qualified fire safety engineer or the local authority — or contact Metacon-Next directly for technical support.
Metacon-Next’s product range covers classifications from EW60 through to EI1-120 and EW240 across multiple door types, including configurations for large industrial openings where standard products cannot meet the dimensional or performance requirements. Custom dimensions and higher classifications are part of the standard offering, not exceptions that require special negotiation.
Which documents prove a fire door has passed testing?
A fire door’s compliance is proven through a set of specific technical documents: the classification report issued by the testing laboratory, the CE declaration of performance, and where applicable, the extended application of test results (EXAP). Together, these documents form the evidence base that an architect, contractor, or building inspector can use to verify that a door meets the specified requirement.
Each document serves a distinct purpose:
- Classification report: Issued by an accredited testing body such as Efectis, this document records the exact test conditions, the assembly configuration, and the classification achieved under EN 13501-2. It is the primary technical proof of performance and forms the basis for the CE certificate.
- CE declaration of performance (DoP) and CE certificate: Required under the Construction Products Regulation (CPR) for products sold in the European market, the DoP states the declared performance of the product against the relevant harmonized standards. For industrial fire doors, two CE standards apply simultaneously: EN 16034 (fire- and smoke-resisting closing elements) and EN 13241 (industrial doors generally). Both must be covered — they are not interchangeable and neither alone is sufficient.
- Extended application of test results (EXAP): When a door configuration differs from the exact assembly tested, an EXAP document, prepared by the testing laboratory under EN 15269, extends the classification to cover the variation. This is common for custom dimensions.
- Environmental Product Declaration (EPD): Not a fire performance document, but increasingly required for projects pursuing BREEAM or LEED ratings. An EPD provides independently verified environmental data about the product over its full lifecycle, based on ISO 14044 and EN 15804. Metacon-Next has published EPDs for eleven product lines as of 2025.
A common problem in specification practice is receiving incomplete documentation after placing an order, when it is too late to change suppliers without disrupting the project programme. The professional standard is to verify that all required documents are available before specifying a product, not after.
Metacon-Next publishes classification reports, CE declarations, and EPDs openly on its website, without requiring a purchase order or a formal request. This is not standard practice across the industry, and it reflects a deliberate commitment to transparency. Architects working to close a permit-ready design file can access the full documentation set at Metacon-Next’s website at any stage of the specification process, including early design, without waiting for a dealer to respond to a documentation request.
If you are specifying fire-rated industrial doors for a project and need to verify classifications, review technical drawings, or understand which product type fits a specific opening, the Metacon-Next team can provide technical support directly. For projects that are further along, a quotation request will connect you with a certified dealer in your region who can confirm product availability and handle installation with full warranty coverage. For background on the company and its manufacturing approach, the about us page provides an overview of the production facility, R&D process, and certification programme.
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