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851 Silica Dust Safety in Construction
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Best Practices When Milling

  • Small drivable milling machines (less than half-lane): Use a machine equipped with supplemental water sprays designed to suppress dust. Water must be combined with a surfactant. When this requirement is met, respiratory protection is not necessary.
  • Large drivable milling machines (half-lane and larger): For cuts of any depth on asphalt only, use machines equipped with exhaust ventilation on drum enclosures and supplemental water sprays designed to suppress dust. For cuts of four inches in depth or less on any substrate:
    • Use machines equipped with exhaust ventilation on drum enclosures and supplemental water sprays designed to suppress dust, or
    • Use a machine equipped with a supplemental water-surfactant spray system designed to suppress dust.

Best Practices When Crushing

  • Use equipment designed to deliver water spray or mist for dust suppression at crusher and other points where dust is generated (e.g., hoppers, conveyers, sieves/sizing or vibrating components, and discharge points).
  • You may also use a ventilated booth that provides fresh, climate-controlled air to the operator, or a remote control station.

When the above methods for crushing are used, no respiratory protection is required.

Knowledge Check Choose the best answer for the question.

4-8. When crushing, use equipment designed to deliver water spray or mist for dust suppression _____.