Recommended Feed Water Chemistry Limits

Steam boilers and ABMA recommended feed water chemistry limits

 according to ABMA - American Boiler Manufacturers Association - are given in the table below:

Boiler Operating Pressure (psig) (bar)	Total Dissolved Solids - TDS - (ppm)	Total Alkalinity (ppm)	Total Suspended Solids (ppm)
0 - 50 0 - 3.5	2500	500
50 - 300 3.5 - 20	3500	700	15
300 - 450 20 - 30	3000	600	10
450 - 600 30 - 40	2500	500	8
600 - 750 40 - 50	1000	200	3
750 - 900 50 - 60	750	150	2
900 - 1000 60 - 70	625	125	1

Maximum Allowable Impurities in Boiler Water

Chemical	Symbol	Maximum Concentration (ppm)
Sodium sulphite	NA2SO3	1.0
Sodium chloride	NaCl	10.0
Sodium phosphate	NA3PO4	25.0
Sodium sulphate	NA2SO4	25.0
Silica oxide	SiO2	0.20