Boiler Feed Water - Chemistry and Impurity Limits

ABMA recommended feed water chemistry limits for steam boilers. Contains maximum recommended limits for Total Dissolved Solids (TDS), total alkalinity, and suspended solids across different boiler operating pressures, as well as maximum allowable impurities in boiler water.

Boiler Operating Pressure (psig)Boiler Operating Pressure (bar)Total Dissolved Solids - TDS (ppm)Total Alkalinity (ppm)Total Suspended Solids (ppm)
0 - 500 - 3.52500500—
50 - 3003.5 - 20350070015
300 - 45020 - 30300060010
450 - 60030 - 4025005008
600 - 75040 - 5010002003
750 - 90050 - 607501502
900 - 100060 - 706251251
ChemicalSymbolMaximum Concentration (ppm)
Sodium sulphiteNa2SO31
Sodium chlorideNaCl10
Sodium phosphateNa3PO425
Sodium sulphateNa2SO425
Silica oxideSiO20.2