The standard applies to all types of boiler water with a chloride content of at least 0.3 mg/l. Bromide and iodide are also determined. Nitrate, sulphate, phosphate, magnesium, calcium and aluminum do not interfere if present in levels lower than 1000 mg/l. Zinc, lead, iron(ll), nickel and chromium(lll) influence the color change; levels lower than 100 mg/l do not cause any problems. If chromate, iron(ll) and sulphite are present in concentrations higher than 10 mg/l and copper(ll) in a content higher than 50 mg/l, the method is not applicable.
NEN 6547-1986 history
1986NEN 6547-1986 Water in boiler plants Titrimetric determination of chloride content (mercurimetric)