Safe use of biomass boilers

A biomass boiler burns non-fossil fuels such as wood fuel (pellets, chips, logs, and forestry material). It produces energy to heat water that is distributed via a low-pressure water system around the building.

Biomass generates power, produces heat, and can be used in combined heat and power plants.

• When using wood chips, there is a potential risk of spontaneous ignition, causing a fire if microbial activity occurs.
• When using wood pellets, they can produce dust during delivery, transport, and storage periods. This can enhance the explosion risk.
• Carbon monoxide poisoning can be caused by poor ventilation or improper use of biomass boilers.

Due to the explosive nature of wood dust used in biomass boilers, you may need to meet legislative requirements for use in a workspace. This is called the Dangerous Substances and Explosive Atmospheres Regulations (DSEAR).

• Wood chip needs to be turned regularly to reduce the risk of spontaneous ignition occurring.
• Use good-quality pellets with a low dust content and good mechanical durability.
• Areas associated with the biomass boiler equipment, including fuel storage areas and the boiler house, need to be swept out and cleaned down at least weekly, and all combustible waste removed.
• Dust build-up must be kept to a minimum, and you must ensure no ignition sources (for example, smoking, fires, or naked flames) are used near the storage areas.
• Ensure zones are created to contain dust within the fuel store so that it cannot escape between the fuel store and the boiler room. In some situations, an explosion relief panel may be appropriate.
• All plant and equipment must be inspected, serviced, and maintained as per the manufacturer’s recommendations.
• All work must be undertaken by an approved and qualified engineer. For example, HETAS or Micro Generation Scheme (MCS) approved installers.

You should take steps to make your biomass boiler safe for both employees and visitors.

• If possible, the boiler should be located in a self-contained external building of non-combustible construction.
• Only trained personnel should be authorised to access the area.
• Appropriate signage should be used to warn people of the danger and access restrictions.
• Adequate ventilation should be provided in the storage area.
• A dry powder fire extinguisher should be present at all times.

For detailed guidance on how to manage risks from biomass boilers, read our biomass boiler guidance notes.