APPENDIX 3 – DIAGRAMS OF TYPICAL BOILER ARRANGEMENTS Arrangement drawings in this Appendix are not associated with any particular level of supervision - they are provided to guide designers and users/owners of steam boiler plant in the direction of possible boiler control and measurement arrangements, and do not represent final solutions for any particular circumstance. A detailed risk assessment is the only way to establish the manning requirements for your plant. Note the definitions used in this Appendix and elsewhere: Competent Boiler operator - Someone appointed by their employer who has attended a training course with assessment, is familiar with the boiler and system on site and has sufficient knowledge & experience to operate the boiler system safely. Suitably Trained and Instructed Person – Someone who has been trained to respond to specific boiler house alarms by taking agreed actions which include contacting the duty Competent Boiler Operator. Check the boiler - carry out all documented tests and inspections relating to the boiler and ancillary plant according to local procedures, recording all necessary readings and actions, and making reports of actions and interventions as appropriate. Typical Arrangement 1 This shows the minimum equipment required for the lowest levels of automation. This level does not meet the requirements of boiler standard BS EN 12953. With typical Arrangement 1 the following factors need to be considered: x Attendance: A competent boiler operator shall be on-site at all times that the boiler is operating and be able to respond immediately to an audible and/or visual alarm condition. x Equipment Integrity: All control equipment shall be fail-safe. x Boiler house fire protection: Fire detection should be provided. For oil fired installations, automatic fuel shut-off must be provided. x Minimum frequency of routine testing: o Low water level devices in external chambers : o Daily checks: External chambers shall be manually blown down at least once per shift (or daily for continuous operation) and the low water cut-out and lock-out tested; o Weekly Checks: In addition, the low water level cut-out and lock-out shall be tested by lowering the boiler water level by evaporation and controlled blow down. Discharge temperature to drain must not exceed permissible limits. o Low water level devices in internal protection tubes in the boiler: o Daily Checks: The low water cut-out and lock-out shall be tested at least once per shift (or daily for continuous operation) by lowering the boiler water level or by an integrated test device, or at the beginning of each shift if a shift pattern is used;
o Weekly Checks: In addition, the low water level cut-out and lock-out shall be tested by lowering the boiler water level by evaporation and controlled blow down. Discharge temperature to drain must not exceed permissible limits.
BG01 Guidance on the safe Operation of Steam Boilers Edition 2 – © 2019
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