BS EN 12953-11:2003 – Shell boilers — Part 11: Acceptance tests

BS EN 12953-11:2003 - Shell boilers — Part 11: Acceptance tests

6.2 Steady-state conditions
6.2.1 Steam pressure, steam and feed water temperature or, for hot water generator, the flow and return temperatures, together with the relevant flow rates, shall be held as steady as possible and at levels close to normal operating conditions. These measurements shall be taken at the boiler exit or as closed as practical at the (same) test prior. NOTE During the operation of a boiler the various factors contributing to heat losses can vary from their intended values as a result of the absorption of heat by the boiler structure as it acquires the conditions determined for the test and as a result of the operation of automatic controls. The most important variables are the exhaust gas temperature and the CO 2 or O 2 content of the exhaust gases. It is therefore essential that tests are conducted only after steady-state conditions have been achieved.
6.2.2 For the purposes of this standard, steady-state conditions shall be deemed to have been reached for solid fuel fired boilers with continuous fuel and ash flows and for liquid and gaseous fuel-fired boilers, when during the period of the test, variation in exhaust gas temperature remains within 10 C and variation of oxygen content within 0,5 % from the mean value.
6.3 Test procedure
6.3.1 It shall be confirmed that the water treatment is being carried out in accordance with the instructions of the boilermaker and the supplier of the water treatment plant. Where necessary during the preliminary running of the boiler prior to the test, except when testing under ‘as found’ conditions (see 6.3.2), the gas side surfaces shall be cleaned, the fuel input and fuel air ratio shall be set and adjustment of the combustion chamber draught or pressure shall be made to conditions laid down by the boilermakers before establishing steady-state conditions.
6.3.2 When testing under ‘as found’ conditions, e.g. whenever the user wishes to determine the current performance of the plant, no adjustments to the firing equipment shall be made and no cleaning of the gas-side surfaces shall be carried out prior to the commencement of the test.
BS EN 12953-11:2003 – Shell boilers — Part 11: Acceptance tests

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