This standard specifies the determination method of hardness in boiler water and cooling water. This standard applies to the determination of boiler water and cooling water hardness. The measurement range of the chrome black T method in this standard is 0.01 mmol/L~5 mmol/L. When it exceeds 5 mmol/L, the sampling volume can be appropriately reduced and measured after dilution; the measurement range of the acid chrome blue K method is 1 μmol/L ~100 μmol/L; the determination range of potentiometric titration is 0.25 mmol/L~10 mmol/L (both with Ca2+ and Mg2+ as basic units). This standard is also applicable to the determination of the hardness of natural water, cooling water, demineralized water and boiler feed water.
GB/T 6909-2018 Referenced Document
GB/T 601 Chemical reagent.Preparations of reference titration solutions
GB/T 603 Preparation of preparations and products used in chemical reagent test methods*， 2023-08-06 Update
GB/T 6682 Water for analytical laboratory use.Specification and test methods
GB/T 6909-2018 history
2018GB/T 6909-2018 Analysis of water used in boiler and cooling system.Determination of hardness
2008GB/T 6909-2008 Analysis of water used in boiler and cooling system.Determination of hardness
1986GB/T 6909.1-1986 Methods for analysis of water for boiler and for cooling--The determination of hardness--High hardness