7.2.5 Blowdown Blowdown Systems, Guidance for Industrial Steam Boilers (Ref: BG03) is a guidance document intended to provide advice to designers, specifiers, manufacturers, installers and those responsible for the management and operation of steam plant as well as Competent Persons (CP). It is applicable to both new and existing installations of steam boilers and addresses the following issues: x The safe discharge of blowdown from boilers; x The safe use and operation of blowdown vessels; x The safe use and operation of blowdown pits; x Proper maintenance and inspection of blowdown vessels and pits including requirements for regular inspection. Advice was previously provided by Health and Safety Executive Guidance Note PM60 Steam boiler blowdown systems 2nd edition 1998 which has been withdrawn. This new, comprehensive guide deals with all aspects of steam boiler blowdown for industrial steam boilers and why it is necessary to carry out the function of “blowing down” the boiler. It is aimed at the User/Owner, Engineer, Manager and Operator of the boiler plant to help them understand all aspects that affect the boilers and why blowing down is necessary, both from a practical operational performance view and for the legal requirements. It covers who is responsible for the safe and efficient operation of steam boiler plant, and who is responsible for managing the safe operation of this type of equipment. Ultimately the responsibility lies with the user/owner as defined by the PSSR. Where a high TDS alarm is fitted to the boiler system this shall be through a shell mounted probe and not a probe in the blowdown line. 7.2.6 Chimneys and flues The safe handling of the products of combustion from steam boilers must be carefully considered. Poor combustion, and poorly constructed chimneys and flues, can give rise to life threatening accumulations of CO and other pollutants, and the emissions to atmosphere from combustion processes must be managed in accordance with environmental legislation such as the Clean Air Act and the Medium Combustion Plant Directive. All new steam boiler installations will be notifiable under local planning requirements and larger installations (>1 MWth) will be subject to environmental permitting regulations and require a permit to operate. Chimneys will need to be designed to cope with the expected products of combustion under normal and abnormal operating conditions. Structural requirements may require the advice of specialists in supporting the loads, providing safe access to work on the chimneys, and providing access platforms for emissions monitoring activities. Where multiple fuels can be burned in a single furnace or multiple flues enter a single chimney there may be a need for interlocked dampers and interlocked fuel supplies to provide for safe operation under all possible combinations of firing. These should be rigorously tested at appropriate intervals.
BG01 Guidance on the safe Operation of Steam Boilers Edition 2 – © 2019
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