Relevant systems must comply with the requirements of the Medium Combustion Plant Directive which places limits on emissions of NO X , SO X and particulates for all plant with a net thermal input of 1 MW to 50 MW. Some plant may need additional abatement systems in order to meet the Emission Limit Values (ELVs) in which case the abatement system shall be maintained in accordance with the manufacturer’s instructions . All tests shall be recorded on the log sheet and allowable limit data must be readily available. Suitably qualified persons shall investigate any problems and take corrective action. All manufacturers’ tests shall be carried out at recommended frequencies with special attention to: x Testing flame surveillance equipment operation & recording the results. Prove lock- out and manually reset (but see note below). In a process where the burner is firing continuously, a self-checking photocell shall be used; x Testing correct operation of forced ventilation and its interlocks and/or ensure natural ventilation is to design standards and is unobstructed; x On dual fuel installations, it is recommended that the changeover to the stand-by fuel should be tested monthly or as recommended by the burner manufacturer; x Fuel leak and shut-off checks: o Gas - if a significant gas leak is suspected, the gas supply must be shut down immediately and be reported to the Responsible Person. Follow site procedures for any necessary evacuation of personnel and/or activation of audible hazard alarms; o Oil - visually inspect pipework, tanks, bunds and supply lines for leakage. Record and immediately report any leaks to maintenance personnel; bund alarms are recommended, particularly where sites are unattended for 72 hours. Note : Some types of high integrity self-checking photocell need professional adjustment and setting, and the manufacturer’s recommendations and timescales must be followed. Should the Emission Limit Values of any environmental permit be exceeded, the user/owner must notify the relevant authorities as soon as possible. If the plant cannot be brought back within limits in a reasonable time, the plant must be taken offline. Where shell boilers are fitted with new burners to cope with new or additional fuel types, the design, installation and commissioning of the new equipment must be carried out in accordance with all required legislation and guidance. As one example, if changing a heavy oil fired installation to gas firing, a full check of the ventilation requirements will be required and may involve modifications to the boiler house. 8.5 Solid fuel (coal and biomass) and alternative sources of heat Whilst this BG01 guidance is primarily written for oil & gas, much of its contents are relevant for other sources of heat such as biomass and Combined Heat and Power (CHP). In this case, references to burners and fuel systems can be taken to mean the heat source and any associated fuel handling equipment. Where a heat source cannot be completely removed quickly, for example in the case of a solid fuel fired boiler where fuel is already on the grate or in the case of a CHP where it is unsafe to regularly and repeatedly trip the engine, particular consideration shall be given to: x The residual heat left in a boiler after a shut-down condition. The plant shall be designed so as to be able to accept this heat;
BG01 Guidance on the safe Operation of Steam Boilers Edition 2 – © 2019
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