Australian Capital Territory Current Regulations

SCAFFOLDING AND LIFTS REGULATION 1950 - SCHEDULE 3

Schedule 3     Method of treatment of silica paint for the purpose of ascertaining the percentage of free silica present

    1     take 10g of paint and extract with successive portions of a suitable solvent until the residue is free from vehicle

    2     take 0.5g of dry residue and boil for 5 minutes with 50mL of 20%, acetic acid containing 5.0g of ammonium acetate, then cool, centrifuge, decant off the supernatant liquid, and wash the residue with 50mL of 20% acetic acid

    3     treat the residue with 50mL of 1:2 hydrochloric acid, boil, cool, centrifuge, decant, and wash with 50mL of 1:2 hydrochloric acid

    4     treat the residue with 25mL of concentrated sulphuric acid containing 5g of sodium sulphate, then heat to fuming, cool, centrifuge, decant, and wash with 25mL of concentrated sulphuric acid, decant and wash with 25mL of water

    5     boil the residue for 5 minutes with 50mL of 10% sodium carbonate, cool, centrifuge, decant, and wash with 50mL of 1:10 hydrochloric acid

    6     transfer residue to a platinum dish, evaporate to dryness, ignite, and weigh (residue A)

    7     treat the residue with 5mL of hydrofluoric acid, containing 0.5mL of concentrated sulphuric acid, then heat on water bath for 1 hour, evaporate to dryness over flame, ignite and weigh (residue B)

    8     free silica equals residue A minus residue B