BS EN 303-5:2021

What is BS EN 303-5 about?  

BS EN 303-5 is the fifth part of a multi-series of standards that  specifies the requirements for test methods for safety, combustion performance, operating characteristics, marking, and maintenance of heating boilers for solid fuel.

The guidance in BS EN 303-5 covers all external equipment that influences the safety systems of heating boilers (e.g. back burning safety device, integral fuel hopper). It  also  specifies the necessary terminology for solid fuel heating boilers, the control and safety-related requirements, the design requirements, the technical heating requirements (considering the environmental requirements), and testing, as well as the marking requirements. 

For those involved in the manufacturing of heater boilers, this standard is crucial for ensuring your products meet the necessary performance requirements, so that they are safe for use. 

Note: BS EN 303-5  covers only boilers that include burners as a unit. The document applies to the combination of a boiler body with a solid fuel burner according to EN 15270:2007 as a unit only when the whole unit is tested in accordance with this document. 

Note: BS EN 303-5  does not apply to: 

• Boilers that are within the scope of the Machinery Directive 2006/42/EC or outside of the scope of the Machinery Directive 2006/42/EC. 
• Heating boilers and other heating appliances that are also designed for the direct heating of the place of installation, also according to the European regulation 2015/1185/EU. 
• Cooking appliances. 
• The design and construction of external fuel storage and transportation devices prior to the safety devices of the boiler. 
• Manual stoked straw bale boilers. 
• CHP appliances (combined heat and power). 

Who is BS EN 303-5 for? 

BS EN 303-5 on heating boilers for solid fuels can be adopted by:  

• Heating boiler manufacturers 
• Solid fuel users  
• Industries using heating boilers  
• Industries using solid fuels 

Why should you use BS EN 303-5?  

Traditional solid fuel boilers are stoves that can be connected to a central heating system.  BS EN 303-5 covers test methods for safety, combustion performance, operating characteristics, marking, and maintenance of heating boilers.

As a user of this standard, your business can ensure the safety and reliability of its heating boilers and, in turn, build trust and confidence in your products. It does this not only through providing guidance on performance testing, but by establishing the standardization on heating boiler terminology, which can avoid misinterpretation and miscommunication between manufacturers, installers, and users throughout the supply chain.

Crucially, BS EN 303-5 helps you reduce the risk of hazardous situations that may occur with the use of heating boilers, by recommending performance tests. These tests ensure that your heater boiler performs as it should and are required for the marking of heating boiler products.

What’s changed since the last update?  

BS EN 303-5:2021 supersedes BS EN 303-5:2012, which is withdrawn. BS EN 303-5:2021 includes some technical changes with respect to BS EN 303-5:2012. These include:  

• The scope was extended to condensing boilers with a heat output of ≤ 500 kW. 
• The scope was extended to boilers with an outside combustion air supply at a heat output of ≤ 100 kW. 
• Requirements for materials, weld joints, and wall thicknesses have been revised and adapted to condensing and room sealed operations. 
• General and electrical safety requirements have been revised and adapted to condensing and room sealed applications. 
• Tests were revised and new tests for condensing boilers, outside combustion air supply, secondary emission reduction systems, and safety requirements were added.