What is BG11?
BG11, formally known as Guidance on the Safe Operation of Water Tube Boiler Installations, was developed by the Combustion Engineering Association (CEA) to support duty holders, designers, operators and maintainers responsible for high-pressure water tube boiler systems.
The guidance outlines best practices for ensuring that water tube boilers are correctly specified, safely installed and competently operated throughout their lifecycle. Covering everything from feedwater control to combustion management, BG11 helps organisations prevent incidents and ensure efficient, stable performance.
Water tube boilers present unique operational challenges due to their design characteristics, including rapid steam-raising capability, higher heat flux, complex control systems and the risk of catastrophic failure if not properly managed.
What does BG11 cover?
BG11 provides practical recommendations across all phases of water tube boiler usage:
Design and Specification
- Boiler and pressure part design to recognised standards
- Material selection, tube arrangement and drum construction
- Design of combustion systems, burners and air supply
- Heat flux management and circulation considerations
- Integration with superheaters, economisers and reheaters
Installation and Commissioning
- Foundation and structural requirements
- Piping systems for steam, feedwater, blowdown and fuel
- Correct installation of safety valves, gauges and instrumentation
- Commissioning procedures including hydraulic testing, chemical cleaning and combustion tuning
- Verification of protective devices, interlocks and control systems
Operation and Monitoring
- Maintaining proper water circulation and drum level control
- Combustion management to prevent flame instability and thermal stress
- Monitoring of pressure, temperature and heat transfer surfaces
- Managing load changes safely, especially rapid demand fluctuations
- Routine boilerhouse checks and operator supervision
Feedwater and Water Treatment
- Feedwater quality requirements
- Monitoring dissolved solids, oxygen and hardness
- Preventing tube scaling, corrosion and overheating
- Deaeration and chemical dosing best practices
Inspection and Maintenance
- Tube integrity inspection (NDT, boroscopes, thickness checks)
- Detection and management of cracking, pitting and erosion
- Sootblower operation and heat surface cleaning
- Maintenance of fuel, air and control systems
- Regular testing of safety valves, alarms and shutdowns
Safety and Compliance
- Hazard identification: tube failures, flameouts, water carryover, overpressure
- Emergency shutdown procedures and safe isolation routines
- Compliance with PSSR, PUWER, DSEAR, EAWR, and other UK regulations
- Documentation, record keeping and operational logs
Decommissioning and Out-of-Service Procedures
- Controlled cooling and depressurisation
- Safe isolation of fuel, steam and electrical systems
- Inspection during outages and planned shutdowns
- Preparation for re-commissioning and statutory inspections
Why BG11 matters
Water tube boilers operate under extreme conditions, with large volumes of pressurised steam and high heat fluxes. If poorly managed, risks may include:
- tube rupture or explosion
- overpressure events
- water level excursions
- thermal shock and fatigue
- unstable combustion
- uncontrolled energy release
BG11 provides a comprehensive safety framework to minimise these risks, ensuring boilers are operated within design limits and in accordance with regulatory requirements.
Following BG11 helps organisations safeguard personnel, maintain equipment reliability, optimise efficiency and demonstrate compliance with UK safety legislation.
Download the latest version of BG11
The current edition of BG11, Safe Operation of Water Tube Boilers, can be downloaded here.
At Dunphy, we support safe and efficient boiler operations across all industrial sectors. Through advanced combustion control systems, technical support and training, we help organisations apply the BG11 framework effectively. Get in touch to find out more.
For more information, see our blogs on:
BG01: what’s new for steam boilers regulations?
BG02: what hot water boiler operators need to know?
BG03: safe operation of blowdown systems for industrial steam boilers
BG04: industrial boiler water treatmentÂ
BG05: safe design and operation of Biomass systems
BG06: safe operation of boiler feed water de-aeration systems
BG07: safe operation of thermal fluid systems
BG08: safe operation of temporary steam and hot water boilers