The EN 12952 and EN 12953 standards are two key European standards for industrial boilers. Each standard focuses on specific boiler types and provides comprehensive requirements covering design, manufacture, inspection, and safe operation.
1. What are EN Standards?
EN standards (European Norms) are technical standards developed by European standardization bodies such as:
- CEN (European Committee for Standardization)
- CENELEC (European Committee for Electrotechnical Standardization)
- ETSI (European Telecommunications Standards Institute)
These standards are widely recognized and applied across Europe to ensure safety, efficiency, and interoperability of products and services in various industries.
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2. Scope and Content of EN 12952 and EN 12953
2.1. EN 12952 – Water-tube Boilers
This European Standard applies to water-tube boilers with a volume exceeding 2 litres, designed to generate steam and/or hot water at:
Maximum allowable pressure greater than 0.5 bar
Temperature exceeding 110°C
It also covers associated plant equipment.
Main provisions:
- Design and calculation: Requirements for structural design, materials, and strength calculations
- Manufacturing and installation: Detailed requirements for fabrication, erection, and quality control
- Inspection and maintenance: Procedures for inspection, maintenance, and repair
- Safety requirements: Measures to ensure safe operation and maintenance
The objective of EN 12952 is to minimize hazards during the operation of water-tube boilers and to provide effective protection against residual risks.
This protection is achieved through proper application of:
- Design methods
- Manufacturing techniques
- Inspection and testing procedures
- Additionally, appropriate warnings regarding residual risks and foreseeable misuse are provided in:
- Operating instructions
- Training documentation
- On-site equipment markings
2.1.1. Scope of water-tube boiler assembly includes
a) Water-tube boiler system, including all pressure parts from:
Feedwater inlet (including valves)
→ up to and including:
Steam and/or hot water outlet (including outlet valves or first circumferential weld / downstream flange)
This includes:
- Economizers
- Superheaters
- Reheaters
- Associated safety devices
- Piping that cannot be isolated by shut-off valves
Also includes connections for:
Draining
Venting
Cooling
→ up to the first isolating valve downstream
b) Isolable components, including:
- Economizers
- Reheaters
- Associated pipework
c) Heat supply / combustion systems
d) Fuel preparation and supply systems, including control systems
e) Feedwater supply systems, including controls
f) Pressurized expansion vessels and tanks for hot water generating plants
Additionally includes:
Supporting steel structures, insulation, brickwork, and casing
Air supply systems, including fans and air preheaters
Flue gas systems including fans and emission control equipment
All auxiliary equipment required for boiler operation
2.1.2. Exclusions
Non-stationary boilers
Shell boilers (including electric boilers)
Nuclear primary circuit systems
2.2. EN 12953 – Shell Boilers
This standard specifies requirements for the design, construction, equipment, operation, and water treatment of new stationary shell boiler plants, with the objective of ensuring safe operation. It also includes provisions to prevent overheating and unacceptable overpressure conditions.
It covers the following areas:
The boiler shell, including all pressure parts from the feedwater inlet (including inlet valves) up to and including the steam and/or hot water outlet (including outlet valves). This also covers economizers, superheaters, and associated pipework heated by flue gases that cannot be isolated from the main system by intermediate shut-off devices, as well as boiler connections up to the first isolating valve;
- Isolable economizers, superheaters, and associated pipework;
- Expansion vessels and/or expansion tanks for hot water generating plants;
- Thermal insulation and/or refractory lining and cladding;
- Heat generation and firing systems;
- Fuel preparation and supply systems for the boiler;
- Air supply systems, including fans;
- Feedwater supply systems;
- All control and safety systems.
EN 12953 specifies requirements for fired shell boilers and electric boilers, including low-pressure boilers, as well as waste heat boilers with gas-side pressures not exceeding 0.5 bar. These boilers are of cylindrical design, manufactured from carbon steel or carbon-manganese steel using welded construction, with a maximum allowable pressure not exceeding 40 bar.
The boilers covered by this standard are intended for land-based applications for the generation of steam or hot water. Where a boiler incorporates a combination of shell boiler and water-tube boiler design features, the BS EN 12952 series shall be applied in addition to this standard.
This standard applies to the main boiler, from the feedwater inlet connection to the steam outlet connection, including all other connections, valves, and steam and water fittings. Where welded ends are used, the requirements are deemed to begin or terminate at the weld location where flanges, if any, would be attached.
It applies to boilers with:
- A volume exceeding 2 litres
- A maximum allowable pressure greater than 0.5 bar
- A maximum design temperature exceeding 110°C
Within the boiler system, in addition to the boiler shell, all equipment necessary for the intended mode of operation is addressed across the various parts of this standard (typically structured in multiple interrelated parts).
This standard does not apply to:
- Water-tube boilers
- Locomotive boilers
- Marine boilers
It also does not fully cover brickwork and insulation systems.
Similar to BS EN 12952, the individual parts of this standard may be purchased separately; however, they are interdependent. Therefore, proper design and manufacture of boilers require the combined application of all relevant parts to ensure full compliance with the standard.
2.3. Comparison between EN 12952 and EN 12953
| Criteria | EN 12952 | EN 12953 |
| Common features | – Both standards establish stringent requirements for design, manufacturing, inspection, and operation to ensure safety and performance.
– Require high-quality materials and rigorous inspection/testing procedures. |
– Both standards establish stringent requirements for design, manufacturing, inspection, and operation to ensure safety and performance.
– Require high-quality materials and rigorous inspection/testing procedures. |
| Boiler type | Water-tube boilers | Shell boilers (fire-tube boilers) |
| Design and construction | Water flows inside tubes; combustion gases flow outside the tubes | Hot gases flow inside tubes, surrounded by a water-filled shell |
| Applications | Large-scale industrial plants requiring high efficiency and high-pressure operation | Small to medium industrial applications with easier operation and maintenance |
3. Industrial Boiler Assessment Process in accordance with EN Standards
Step 1: Design Assessment
Review of drawings and design documentation
Verification that design drawings and technical documentation comply with applicable EN requirements
Engineering analysis
Performance of engineering calculations to ensure compliance with requirements for strength, safety, and performance
Step 2: Material Inspection
Material selection: Ensuring that selected materials meet the required standards for quality and mechanical properties
Material testing and verification
Application of non-destructive testing (NDT) methods such as:
Ultrasonic testing (UT)
Radiographic testing (RT)
Magnetic particle testing (MT)
→ to verify material integrity and quality
Step 3: Manufacturing Surveillance
Verification of manufacturing processes
Ensuring that fabrication processes comply with EN standard requirements
Quality control surveillance
Conducting inspections at critical manufacturing stages to ensure conformity with specified requirements
Step 4: Inspection and Testing
Pressure testing
Performing pressure tests to verify that the boiler can withstand the maximum allowable working pressure
Performance testing
Evaluating operational performance to ensure compliance with technical specifications
Step 5: Final Assessment and Certification
Final inspection
Conducting a comprehensive inspection prior to commissioning
Certification
Issuance of certification confirming compliance with EN standards upon successful completion of all inspections and tests
4. EN Boiler Assessment and Manufacturing Surveillance Services by PREBECC
PREBECC is proud to be one of the leading providers of boiler assessment and manufacturing surveillance services in accordance with EN standards. We are committed to delivering high-quality services to ensure that your industrial boilers fully comply with safety and performance requirements.
Assessment Services
Design assessment
Review of boiler design, including drawings and technical documentation, to ensure compliance with EN standards
Engineering analysis
Our engineers perform detailed technical analyses to verify compliance with strength and safety requirements
Inspection and Manufacturing Surveillance Services
Material inspection
Provision of material testing services, including NDT methods, to verify material quality and integrity
Manufacturing process surveillance
Close monitoring of fabrication processes (cutting, forming, assembly, etc.) to ensure full compliance with EN requirements
Product quality inspection
Inspection at critical stages of manufacturing to ensure conformity with applicable standards
Inspection and Testing Services
Pressure testing
Conducting pressure tests to verify the boiler’s ability to withstand maximum working pressure
Performance testing
Assessing operational performance to ensure compliance with technical requirements