29Standards of gypsum

29 Standards of gypsum

(1)  Gypsum is phospho-gypsum if it contains not less than 17% sulphur and not less than 21% calcium.

(2)  Gypsum is grade 1 gypsum if it contains not less than –

(a) 15% sulphur but less than 17% sulphur; and

(b) 19% calcium but less than 21% calcium.

(3)  Gypsum is grade 2 gypsum if it contains not less than –

(a) 12.5% sulphur but less than 15% sulphur; and

(b) 15.5% calcium but less than 19% calcium.

(4)  Gypsum is grade 3 gypsum if it contains not less than –

(a) 10% sulphur but less than 12.5% sulphur; and

(b) 12.5% calcium but less than 15.5% calcium.

(5)  Gypsum is by-product gypsum if it contains not less than 14% sulphur and at most 20% of the weight of the gypsum as moisture.