What is BG02?

BG02, titled Guidance on Safe Operation of Hot Water Boilers, was developed by the Combustion Engineering Association (CEA) and the Safety Assessment Federation (SAFed).

It focuses specifically on:

  • Low Temperature Hot Water (LTHW) systems operating up to 110°C 
  • High Temperature Hot Water (HTHW) systems operating above 110°C

If you manage a hot water boiler as part of a commercial process, district heating scheme or plantroom setup, BG02 outlines how to operate it safely and remain compliant with UK health and safety regulations.

At Dunphy, we care about BG02 because it underpins the safe and efficient operation of the systems we supply. Our industrial hot water boilers and electric hot water boilers are built for performance, but their reliability depends on proper operation, supervision and maintenance. BG02 provides the framework our customers need to run their systems safely, meet legal requirements and maximise performance over time.

What does BG02 cover?

BG02 offers practical guidance on several key areas, including:

  • Safe day-to-day operation of low and high temperature hot water systems
  • Identifying risks such as overheating, pressure build-up and water loss
  • Determining appropriate supervision levels based on system risk
  • Implementing effective water treatment to reduce corrosion and scale
  • Planning routine maintenance, inspections and functional testing
  • Keeping records to support safe working practices and legal compliance

Why BG02 matters

BG02 is not a legal requirement; however, it serves as a guidance document, and failure to comply with it may still lead to prosecution.

Following BG02 demonstrates compliance with the Pressure Systems Safety Regulations 2000 (PSSR) and supports adherence to broader legislation such as Provision and Use of Work Equipment Regulations (PUWER) and Dangerous Substances and Explosive Atmospheres Regulations (DSEAR). For operators, engineers and facilities teams, it also provides a useful framework for managing safety, maintenance and training.

Download the latest version of BG02

The current edition of BG02 is Edition 1.3, published in April 2020. The document remains the primary reference for anyone operating LTHW or HTHW boilers in line with UK legislation.

BG02 Edition 1.3 is available to download from the CEA’s official document store and is used by engineers, maintenance teams and site managers across the industry.

For information on steam boiler regulations check out or blog on BG01