Steam-based pressure vessel: Café boiler
© Getty Images/Jatuporn Amorntangsati

Risk control for small, steam-based pressure vessels

Café boilers, bench-top autoclaves, and miniature steam engines

    alt txt



    Technical Bulletin: March 2023

    The UK's Health and Safety Executive (HSE) has issued a research report on risk control for both users and manufacturers of small pressure vessels. This followed a prior lack of engineering evidence about the potential for failure of certain types of steam-based pressure vessels.

    Their research specifically refers to café boilers (such as espresso machines), bench-top autoclaves and miniature steam engines. These vessels are widely used in the hospitality industry, service industry, and in schools and other education settings.

    The HSE-funded report(1) describes experimental research carried out on a sample of new and second-hand small steam pressure vessels in order to determine proportionate risk controls. The report identified that overheating and/or overpressure could result in catastrophic vessel failure and an explosive release of energy; with flying fragments, and scalding steam and water. This has the potential to cause significant injury or death to people in the vicinity.

    Effective risk control measures

    Duty holders must have effective risk control measures in place to prevent vessel failure and protect the public and employees. The HSE research considers that if effective control measures are in place, catastrophic vessel failure is unlikely.

    Under the current statutory requirements, control measures include correct operation, regular inspection, testing and maintenance. Legal requirements are in the following regulations(2):


    Bench-top autoclave
    © Getty Images/Aleksandar Jankovic

    This technical bulletin contains public sector information published by the Health and Safety Executive and licensed under the Open Government Licence.

    1) Health and Safety Executive: Research Report Risk control for small pressure vessels: café boilers, bench-top autoclaves, and model steam engines (RR1177 - 2022) 2) For Northern Ireland, similar statutory equipment legislation is applicable.