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A complete guide to fire safety compliance in industrial spray booths for the automotive, aerospace, marine, rail, manufacturing and construction sectors.
1. Why fire safety is critical in spray booths
Spray booths are high-risk environments for fire and explosion. The reason is physicochemical: solvent-based paints, primers and related products release flammable vapours which, mixed with air at certain concentrations, form potentially explosive atmospheres. This critical concentration is defined as the LEL (Lower Explosive Limit) or LFL (Lower Flammability Limit): above it, a single spark is sufficient to trigger an explosion.
Ignition sources in spray booths are numerous: sparks from electrical equipment, electrostatic discharge generated by the spray gun, hot surfaces, stray currents. This is why every electrical component inside a booth — from motors to lighting systems — must be certified for use in potentially explosive atmospheres.
The risk is not theoretical: fires in spray booths are one of the leading causes of serious industrial incidents in the European and North American manufacturing sectors. Consequences range from severe material damage and extended production shutdowns to the most serious outcomes for people.
The complexity increases because spray booths are used across very different sectors, each with its own operational characteristics and additional regulatory requirements:
2. The UK regulatory framework
Regulatory Reform (Fire Safety) Order 2005
The Regulatory Reform (Fire Safety) Order 2005 (FSO) is the primary fire safety legislation for non-domestic premises in England and Wales. It places a duty on the "responsible person" — typically the employer or the person in control of the premises — to carry out a fire risk assessment and implement appropriate fire safety measures. For spray booth operations, this requires specific assessment of the risks from flammable vapours, overspray accumulation and ignition sources, with documented mitigation measures proportionate to the risk level identified. Equivalent legislation applies in Scotland (Fire (Scotland) Act 2005) and Northern Ireland (Fire and Rescue Services (Northern Ireland) Order 2006).
DSEAR 2002 — Dangerous Substances and Explosive Atmospheres Regulations
The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) implement the European ATEX Directives in UK law and remain in force post-Brexit. DSEAR requires employers to eliminate or reduce risks from dangerous substances — including flammable solvents and paints — and to classify zones where explosive atmospheres may occur. For spray booth environments, this means producing an ATEX zone classification document, selecting appropriately rated equipment for each zone, and verifying that all electrical and mechanical components in classified zones carry appropriate certification.
ATEX UK Regulations 2016
The Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 2016 (UK ATEX Regulations) govern the supply of equipment for use in potentially explosive atmospheres following the UK's departure from the EU. Equipment placed on the UK market after Brexit must carry UKCA marking (in addition to or instead of CE marking, depending on the supply route) and meet the same technical requirements as the EU ATEX Directive 2014/34/EU.
HSE Guidance and Approved Codes of Practice
The Health and Safety Executive publishes specific guidance on spray booth safety, including guidance on DSEAR compliance and zone classification for finishing operations. Employers are expected to follow HSE guidance as a baseline standard; departures from it may need to be justified in the event of an incident or inspection.
ATEX zone classification in spray booths
Within and immediately around a spray booth, two classified zones are typically identified:
All electrical and mechanical components installed in classified zones must carry ATEX certification (or UKCA ATEX equivalent for UK market supply) with appropriate group, category and protection type for the zone in which they are installed.
3. The European regulatory framework
EN 16985:2019 — European reference standard for spray booths
EN 16985:2019 is the current European reference standard for spray booths intended for the application of organic liquid and powder coating materials. It replaced the earlier standards EN 13355, EN 12215 and EN 12981, consolidating into a single standard the safety requirements for different types of spray booths and finishing installations.
The standard addresses the principal significant hazards associated with the use of spray booths, covering both intended use and reasonably foreseeable misuse. It defines requirements for:
Conformity with EN 16985:2019 is a fundamental technical reference for demonstrating that a booth has been designed and built in accordance with the state of the art in safety. It supports the CE marking process in relation to the essential health and safety requirements applicable to machinery.
From a legislative perspective, the primary framework until 20 January 2027 remains the Machinery Directive 2006/42/EC. From 20 January 2027, the new Machinery Regulation (EU) 2023/1230 will come into full effect, replacing the Machinery Directive and strengthening safety requirements including those for fire risks.
ATEX Directive 2014/34/EU
The ATEX Equipment Directive governs the placing on the market of equipment and protective systems intended for use in potentially explosive atmospheres. All electrical and mechanical components installed in the ATEX zones of a spray booth must carry CE ATEX marking, with indication of the group (II for surface industries), the category (2 or 3 for zones 1 and 2) and the type of protection adopted (e.g. Ex d = flameproof enclosure, Ex e = increased safety, Ex i = intrinsic safety).
EN 1839 — Flammability and explosibility limits
EN 1839 defines test methods for determining the flammability limits (LEL/UEL) of flammable gases and vapours in air. It is the reference standard for characterising air-solvent mixtures in spray booths, and its values are used as the basis for sizing ventilation systems and gas detectors.
Machinery Directive 2006/42/EC and future Machinery Regulation
Spray booths are classified as machinery under Directive 2006/42/CE. They must therefore satisfy the Essential Health and Safety Requirements (EHSR) of Annex I, be accompanied by a technical file, declaration of conformity and operating manual. The Machinery Regulation (EU) 2023/1230, which will replace the Directive from 2027, will further strengthen safety requirements including those for fire risks.
4. Sector-specific regulatory requirements
Beyond the general fire safety framework, each application sector introduces additional requirements that influence the design and certification of spray booths.
| Sector | Relevant additional standards | Operational specificities |
| Automotive | ISO 16232, IATF 16949 | Intensive thermal cycles, high productivity, full body finishing |
| Heavy commercial vehicles | ECE-R, ADR regulations | Extra-large dimensions, walk-in booths, integrated handling systems |
| Aerospace | AS9100, EASA Part 21, MIL-SPEC | Zero contamination, precision humidity and temperature control, full traceability |
| Marine | IMO SOLAS, MARPOL, Lloyd's, DNV | Saline environments, heavy epoxy paints, anti-corrosion requirements |
| Rail | EN 45545, TSI, UIC regulations | Approved flame-retardant paints, flame propagation testing, batch traceability |
| Industrial manufacturing | ISO 12944 for steel | Wide substrate variety, serial production, automation |
| Construction and steelwork | EN 1090, ISO 12944 | Large surfaces, anti-corrosion primers, large-format booths |
It is essential that procurement managers and installation designers verify, for each project, the integration between the general fire safety regulations and the sector-specific requirements applicable to their operation.
5. Operational best practices for fire safety
Regulatory compliance is the starting point, not the end point. Organisations operating at the highest safety standards integrate mandatory requirements with a system of operational best practices that further reduces residual risk.
Filter maintenance and replacement
Overspray capture filters are the most critical component from a fire safety perspective. Clogged filters reduce airflow, increase the concentration of flammable vapours and themselves represent a fuel source. Replacement must follow the manufacturer's specifications and reflect actual operating conditions. Exhausted filters must be disposed of as hazardous waste.
Solvent management and storage
Solvents and solvent-based paints must be stored in approved metal cabinets (conforming to EN 14470-1) away from the booth. Only the quantities required for the current work cycle should be present inside the booth.
Electrostatic charge control
Earthing and bonding of all metallic components of the booth and the objects being painted is mandatory and must be verified periodically. Workers must wear antistatic footwear in classified zones.
Operator training
Specific training on fire and explosion risk is a legal obligation under UK health and safety legislation. It must include: recognition of hazardous conditions, use of PPE, emergency procedures, extinguisher use and incident management. Training must be documented and refreshed periodically.
Periodic inspections and maintenance records
Maintaining an up-to-date maintenance log — documenting inspections, filter replacements, electrical installation checks and detection system verifications — is both a legal obligation and a critical good practice in the event of an incident investigation.
Emergency plans and drills
Every facility housing spray booths must have a current emergency and evacuation plan. Emergency drills must be conducted at least annually and documented.
6. How to evaluate the fire safety compliance of a spray booth
Before purchasing or commissioning a spray booth, systematically verify the following:
7. USI Italia and regulatory compliance
USI Italia designs and manufactures industrial spray booths in compliance with all major international regulatory standards. Every installation is developed with the specific regulatory context of the destination country and application sector in mind, ensuring that customers have access to all required certifications.
This approach goes beyond formal compliance: USI Italia integrates fire safety by design from the earliest phases of the engineering process — selecting certified components, sizing ventilation systems with appropriate safety margins, and documenting every construction detail in the technical file.
USI Italia's direct presence in Italy, across Europe, and in North and South America enables local support in managing authorisation processes, liaising with competent authorities, and maintaining compliance over time — including when regulatory updates require installation modifications.