Silica Dust Abatement

Phase 1: Containment and Air Control

Before starting any aggressive cleaning, you must isolate the contaminated area to prevent the silica from migrating into clean zones (e.g., HVAC system, adjacent rooms).

1. Establish Containment

• Critical Barriers: Seal off the affected area from the rest of the building using 6-mil polyethylene sheeting and duct tape. Seal all doors, windows, and non-essential openings.

• HVAC Isolation: The heating, ventilation, and air conditioning (HVAC) system in the contaminated area must be shut down and sealed at the registers and returns to prevent drawing dust into the ductwork and distributing it elsewhere.

2. Implement Negative Air Pressure

• Air Filtration Devices AFDs / Negative Air Machines NAMs: Install AFDs fitted with HEPA (High-Efficiency Particulate Air) filters within the containment zone.

• Purpose of HEPA: The HEPA filter is essential as it is tested and certified to capture 99.97% of all particles at 0.3 microns—well below the size of respirable silica dust or RCS.

• Negative Pressure: These machines must be configured to create a continuous negative pressure differential inside the work area (e.g., −0.02 inches of water column). This ensures that if any breach occurs, clean air rushes into the contained area instead of contaminated air flowing out. This is essential for preventing cross-contamination.

Phase 2: Cleaning Protocols 

Never use dry sweeping, standard household vacuum cleaners, or compressed air for silica cleanup. These methods will re-aerosolize the fine RCS particles, greatly increasing exposure risk.

1. Primary Collection: HEPA Vacuuming

• Required Equipment: Use only HEPA-filtered vacuums. The vacuum must be certified as HEPA—not just "HEPA-like"—and should have a sealed HEPA filter system to prevent leakage of bypassing air. (basically contaminated air going around the filter)

• Technique: Use a slow, deliberate, and methodical cleaning approach. Vacuum all non-porous surfaces (floors, walls, machinery, countertops) multiple times, working from the highest surfaces down to the floor. Use brush attachments to loosen particles without kicking them airborne.

• Filter Integrity: Monitor the vacuum's filter status. Filters must be changed using manufacturer-prescribed engineering controls to avoid exposure during disposal.

2. Secondary Cleaning: Wet Wiping

• Procedure: After thorough HEPA vacuuming, all non-porous surfaces must be cleaned using a wet-wiping method. Use damp cloths and a minimal amount of water mixed with a mild detergent.

• Rationale: The detergent helps the water capture and hold the silica particles. The wet cloth physically lifts and removes the dust residue that the vacuum may have missed.

• Rinsing: Rinse the surface with a second pass using a clean, damp cloth.

Phase 3: Treatment of Porous Materials

Porous and semi-porous materials, such as upholstery, bedding, and certain furniture, are difficult to completely decontaminate and must often be handled based on cost-benefit analysis.