Passive fire protection is one of the most overlooked aspects in the design and renovation of industrial, commercial and public buildings. Yet, neglecting it — or entrusting it to uncertified operators — means exposing projects to regulatory penalties, work stoppages, and above all, real risks to people’s safety.
This guide explains when REI fireproofing is required by law, which structures it applies to, and how to choose the most suitable system.
What is REI fireproofing?
Fireproofing refers to the full range of passive fire protection treatments applied to a building’s structural elements. The goal is not to extinguish flames (that is the role of active systems such as sprinklers) but to slow down structural collapse, buying the time needed for evacuation and emergency response.
The REI classification defines the performance of a structural element under fire conditions across three parameters:
- R (Load-bearing capacity): the structure maintains its ability to support loads
- E (Integrity): it prevents the passage of flames, hot gases and vapours
- I (Insulation): it limits heat transfer to the unexposed side
Lastly, the number following the acronym indicates the minutes of resistance guaranteed: REI 30, REI 45, REI 60, REI 90, REI 120, REI 180, up to REI 240. The required class depends on the building’s intended use, its height, fire load and the risk category defined by the fire safety engineer.dal carico di incendio e dalla categoria di rischio definita dal progettista antincendio.
When is fireproofing required by law?
Across Europe and in many international jurisdictions, passive fire protection of load-bearing structures is mandatory in the following contexts. Requirements are enforced through national building regulations, fire safety authorities and project-specific fire strategies: all of which must be satisfied before a certificate of occupancy or operational licence can be issued.
- Industrial buildings and warehouses
Any structure housing production activities with combustible materials, machinery or at-risk systems is subject to REI requirements. Steel beams and columns — a material that can lose its load-bearing capacity at temperatures as low as 500°C — must be treated to guarantee structural stability for the minimum period specified in the fire safety plan. - Commercial buildings and logistics centres
Supermarkets, warehouses, shopping centres and logistics hubs fall within the scope of fire authority controls above certain thresholds of floor area or occupancy. In these cases, exposed load-bearing steel structures must be REI-certified in accordance with the class specified in the fire protection project. - Public buildings and infrastructure
Schools, hospitals, stations, airports, road and rail tunnels: for all high-occupancy or public-use structures, fireproofing is an integral part of the structural design and a mandatory condition for obtaining occupancy approval. - Renovations involving a change of use
This is one of the most common — and most underestimated — scenarios. When an existing building (a former warehouse, an industrial shed, a historic building) is converted to a new use, the entire fire protection design must be reassessed. The original structures, even if in good condition, may not meet the REI requirements applicable to the new function.
The main fireproofing systems: which one to choose
Once the required REI class has been determined, the designer and applicator select the most appropriate system for the structure and its context. There are three main options.
-> Intumescent coatings
The preferred solution when aesthetics matter: on exposed steel structures, architectural beams, commercial interiors or heritage buildings. Applied in thicknesses measured in microns — virtually invisible to the naked eye — they leave the structure fully visible without altering its proportions or design. When exposed to temperatures above 200°C, they react by expanding into an insulating carbon foam that protects the structure from heat for the certified duration. Suitable for classes up to REI 90, in some cases up to REI 120.
-> Cementitious and mineral spray systems
Cement-based or mineral systems sprayed directly onto the structure, with thicknesses measured in centimetres. The typical choice for areas where aesthetics are secondary — plant rooms, warehouses, industrial structures — but where high performance is required. They offer excellent mechanical resistance and are often preferred for concealed columns and beams, or for infrastructure exposed to impact and vibration. Suitable for classes up to REI 120, in some cases up to REI 240.
-> Hydrocarbon fireproofing
The most specialised system, required in high-risk environments such as refineries, petrochemical plants, offshore platforms, LNG facilities and energy infrastructure. Hydrocarbon fires are characterised by significantly higher temperatures and far faster thermal rise rates than standard cellulosic fires: conventional intumescent coatings are not sufficient.
In these cases, epoxy-based intumescent coatings are applied using dedicated equipment designed to mix and spray two fire-resistant components in a controlled manner. Integrated heating technology and electronic control of the mixture ensure precise, uniform application even in extreme environmental conditions, with continuous monitoring of temperature, dosing ratio and applied thickness. The result is a certified and fully traceable protection system that maintains the structural integrity of steel and reinforced concrete even during a hydrocarbon fire.
Certification and documentation
Fireproofing is not just a matter of application: upon completion, regulations require certified documentation to demonstrate compliance. This typically includes material certificates, inspection reports and third-party verification confirming that the treatment meets the approved fire protection design. Entrusting the work to an uncertified applicator means risking the inability to obtain this documentation — and therefore being unable to open or continue operating the facility.
The specific requirements vary by country and project type; FES Global Group works with clients and their fire safety consultants to ensure full compliance with the applicable regulatory framework.
Why choose a specialist applicator
Selecting the right REI system and applying it correctly requires technical expertise that goes well beyond standard painting or coating work. Coating thickness, substrate condition, surface preparation standard (typically achieved through abrasive blasting to Sa 2½ or Sa 3) and the treatment cycle sequence are all factors that directly determine the final performance.
A specialist applicator like FES Global Group manages the entire process: from preliminary technical assessment and surface preparation through to certified application and final documentation. With over twenty years of experience on industrial structures, infrastructure and major projects, FES has the technology and certifications to operate across all three passive fire protection systems — including hydrocarbon fireproofing with controlled mixing and dosing equipment, a specialisation available to very few operators in Europe.