Machinery Directive 2006/42/EC: Technical Guide for Boiler and Industrial Thermal Equipment Manufacturers
Analysis of the essential health and safety requirements, conformity assessment and CE marking for OEM manufacturers integrating thermal components —economisers, heat exchangers, heat recovery units— into boilers and industrial machinery assemblies.
For OEM manufacturers of boilers, steam generators and industrial thermal equipment, the Machinery Directive 2006/42/EC is the legal framework that governs the conditions for placing products on the European market. Integrating third-party components —economisers, heat exchangers, heat recovery units— into a machinery assembly is not a minor technical detail: it determines the risk assessment scope, the technical documentation and the liability of the integrating manufacturer.
1. Scope: when does the Machinery Directive apply?
Directive 2006/42/EC applies to machinery, defined as an assembly of linked parts or components, at least one of which moves, fitted with an appropriate actuating system. Industrial boilers with burners, automatic control systems and electrically or pneumatically actuated auxiliary components clearly fall within the scope of the directive.
When a boiler integrates pressure-bearing components, two directives apply simultaneously: 2006/42/EC for mechanical and operational risks of the assembly, and PED 2014/68/EU for pressure-specific risks. The integrating manufacturer is responsible for managing both conformity frameworks.
2. Essential Health and Safety Requirements (EHSR)
- General safety principles (§1.1): Machinery must be designed so that, when used as intended, it does not endanger persons. Safety by design takes priority over protective devices and operating instructions.
- Materials and products (§1.3.2): Materials must be suitable for the working fluids, temperatures and pressures involved. The integrating manufacturer must verify that the materials of external components meet the requirements of the boiler's working fluid.
- Surface temperature (§1.5.5): Accessible hot surfaces capable of causing burns must be insulated or guarded. Especially relevant for high-temperature economisers.
- Design pressure and temperature (§1.5.7): Machinery must withstand the anticipated loads with adequate safety margins, including maximum operating pressures of hydraulic and steam circuits.
- Control systems and emergency stop (§1.2): The boiler must be equipped with control systems enabling safe shutdown in the event of a failure, including integrated components.
- Instructions (§1.7.4): The instruction manual must include information on all integrated components, including maintenance instructions for third-party supplied components.
3. Conformity assessment: applicable procedures
| Procedure | Notified body | Application for boilers | Resulting documentation |
|---|---|---|---|
| Annex VIII Self-assessment |
Optional | Machinery not listed in Annex IV. Standard boilers where the manufacturer applies harmonised standards (e.g. EN 12952, EN 12953). | Internal technical file + CE Declaration of Conformity |
| Annex IX EC type-examination |
Mandatory | Annex IV machinery or where harmonised standards are not applied. High-power boilers or non-standard configurations. | EC type-examination certificate + Technical file + CE Declaration |
| Annex X Full quality assurance |
Mandatory | Alternative to Annex IX for manufacturers with a quality system approved by a notified body. Suitable for series OEM manufacturers. | Approved quality system + CE Declaration |
Applying harmonised standards published in the OJEU confers a presumption of conformity with the corresponding EHSR. For fire-tube boilers, the reference standard is EN 12953. For water-tube boilers, EN 12952. For general machinery risk assessment and reduction, EN ISO 12100 is the central reference.
4. Integrating manufacturer liability for third-party components
If a third-party component does not meet the technical requirements needed for safe integration, liability for the non-conformity of the assembly rests with the integrating manufacturer, not with the component supplier. Supplier qualification diligence is a conformity requirement, not merely a commercial best practice.
- PED Declaration of Conformity (where the component exceeds Article 4 thresholds of Directive 2014/68/EU), indicating risk category and conformity assessment module applied.
- Technical datasheet with design parameters: PS (maximum allowable pressure), TS (maximum design temperature), DN, materials of construction, design fluid and use limitations.
- Installation and maintenance instructions in the official language of the country of commercialisation.
- Material traceability for components in contact with pressurised or high-temperature fluids.
5. CE Marking and Declaration of Conformity
- The CE marking is not a quality mark or an external approval certificate: it is the manufacturer's declaration that the product meets all applicable legal requirements.
- CE marking is mandatory for placing on the European market (EEA). Its absence constitutes a legal violation.
- The technical file must remain accessible to market surveillance authorities for a minimum of 10 years from the date of manufacture of the last unit.
- The CE Declaration of Conformity must accompany each unit and be available in the official language of the destination country.
6. New Machinery Regulation 2023/1230/EU: the upcoming change
Regulation (EU) 2023/1230 will replace Directive 2006/42/EC from 20 January 2027. The shift from directive to regulation means direct application without national transposition.
The most significant changes include: requirements for control systems incorporating artificial intelligence, new cybersecurity requirements for connected machinery, extended scope to partially completed machinery, and reinforced sustainability and ecodesign requirements. OEM manufacturers should begin reviewing their technical files well ahead of the January 2027 application date.
BOIXAC supplies economisers, heat exchangers and heat recovery units to boiler and industrial thermal equipment manufacturers. Our components are delivered with a complete technical datasheet, documented design parameters and, where applicable, a PED 2014/68/EU Declaration of Conformity. Contact our technical team for further information.