# EN 1090: what is it and when do you need it? > EN 1090 in plain language: what the standard covers, who needs an EN 1090 certificate, what execution classes mean and how certification works. Source: https://dehaasprojects.com/en/knowledge-centre/what-is-en-1090/ Updated on: 2026-11-05 EN 1090 is the European series of standards for the execution of load-bearing steel and aluminium structures, and the basis for the mandatory CE marking of those components. Anyone who makes and supplies beams, columns, trusses, platforms or other structural parts will run into it sooner or later, through the client, the structural engineer or the notified body. This article explains what the standard covers, who it applies to and how a company obtains an EN 1090 certificate. For direct help with the programme, see [EN 1090 certification support](/en/services/en-1090-support/). ## Which parts make up EN 1090? EN 1090-1 sets out how you demonstrate that your structural components comply, and is the part on which CE marking rests. EN 1090-2 contains the technical requirements for executing steel structures: materials, cutting, welding, bolting, tolerances and inspection. EN 1090-3 does the same for aluminium. On the shop floor part 2 matters most, for certification part 1. - EN 1090-1: conformity assessment and CE marking - EN 1090-2: technical requirements for steel - EN 1090-3: technical requirements for aluminium - EN 1090-4 and -5: thin-gauge, cold-formed components ## Who needs an EN 1090 certificate? Every manufacturer placing structural steel or aluminium components on the market as a construction product needs certified factory production control under EN 1090-1. That includes a workshop producing only to order for a contractor, as soon as the part leaves the door as a load-bearing part of a structure. Erection on site and non-structural products are generally not covered. In doubt about a specific product? Read [when CE marking of steel structures is mandatory](/en/knowledge-centre/ce-marking-steel-structures/) or use the [standard selector](/en/standard-selector/). ## What do the EXC classes mean? EN 1090-2 has four execution classes, EXC1 to EXC4, and the higher the class, the stricter the requirements for welding, inspection and documentation. The structural engineer sets the class based on the consequences of failure, the loading and the production method. For most buildings it is EXC2. Your certificate covers up to a given class: a company certified for EXC2 may not supply EXC3 work. A full comparison is in [the EN 1090-2 execution classes](/en/knowledge-centre/en-1090-execution-classes/), and the required weld quality per class in [ISO 5817](/en/knowledge-centre/iso-5817-quality-levels/). ## What needs to be in place for certification? The core of EN 1090-1 is a working factory production control (FPC) system: documented procedures that show every component meets the requirements. For welded structures this includes a responsible welding coordinator, qualified welding procedures and qualified welders. - A documented FPC system, see [factory production control under EN 1090-1](/en/knowledge-centre/factory-production-control/) - A responsible welding coordinator to ISO 14731, in-house or [hired in](/en/services/welding-coordinator/) - Qualified welding procedures ([WPQR to ISO 15614-1](/en/services/wpqr-qualification/)) and a [WPS](/en/knowledge-centre/wps-in-welding/) per application - Welders qualified to [ISO 9606-1](/en/knowledge-centre/welder-qualification-iso-9606/) ## How does EN 1090 certification work? An EN 1090 certificate is issued by a notified body after an initial inspection of your factory and your FPC system. Periodic surveillance follows. A gap analysis beforehand pays off: what is already there, what is missing and which qualifications still need testing. Welding procedure qualifications take longest, because test pieces must be welded, examined and tested. Start there. DEHAAS is not a notified body and does not issue certificates. We prepare the programme, handle the welding side and stand beside you during the audit. ## Our advice First establish which execution class your clients ask for, because that sets the scope of the whole programme. Do not certify higher than you actually need, but take into account the projects you want to do in a few years. Want to know where you stand? [We support EN 1090 certification](/en/services/en-1090-support/) from gap analysis to audit, throughout the Netherlands. ## Frequently asked questions ### Is EN 1090 mandatory? Yes, for structural steel and aluminium components placed on the European market as construction products. They must carry CE marking, and that marking rests on certified factory production control under EN 1090-1. ### What is the difference between EN 1090-1 and EN 1090-2? EN 1090-1 describes how you demonstrate compliance and how CE marking works. EN 1090-2 contains the technical execution requirements for steel, such as welding, tolerances and inspection. ### Which EXC class do I need? The structural engineer decides per project. For most buildings it is EXC2. Certify for the highest class you actually want to supply. ### Does DEHAAS issue the EN 1090 certificate? No. The certificate comes from a notified body. DEHAAS prepares the programme, arranges welding coordination and qualifications and supports the audit. --- DEHAAS Inspection, Manufacturing & Welding Consultancy, Rypsterdyk 2, 9036 JG Menaam. Phone 06 29 72 37 91, e-mail cdehaas@dehaasprojects.com, https://dehaasprojects.com.