Asbestos Abatement

Phase 1: Preparation and Planning

Before the first piece of material is touched, robust planning is essential.

1. Hazard Assessment and Notification

• Testing and Classification: You must verify the presence and type of asbestos using Polarized Light Microscopy (PLM) and quantify the material. This determines if the material is friable (easily crumbled) or non-friable.

• Work Scope: Define the Regulated Area and the total square footage/linear footage of material to be removed.

• Regulatory Notification: For projects exceeding EPA NESHAP thresholds (e.g., typically 260 linear feet of pipe insulation or 160 square feet of surfacing material), you must provide written notice to the EPA or state authority well in advance (usually 10 working days).

2. Site Isolation and Containment

The goal is to create a negative pressure environment that physically prevents asbestos fibers from escaping the work zone.

• Critical Barriers: Seal off all doors, windows, and other openings leading from the work area to clean areas using two layers of 6-mil polyethylene sheeting (poly sheeting) and duct tape.

• Negative Air Pressure: Install Negative Air Machines (NAMs) equipped with HEPA filters (High-Efficiency Particulate Air). These machines draw air out of the containment area, filtering it before discharge, which achieves two things:

  1. Air Exchange: Cleans the air inside the containment.

  2. Pressure Differential: Creates and maintains a continuous negative pressure (typically −0.02 inches of water column) inside the work area. This ensures that if there is a breach, clean air rushes in rather than hazardous air rushing out.

• Decontamination Unit: Construct a fully sealed, multi-chambered decontamination facility (Decon Unit) leading into the containment area. This unit consists of a Clean Room, a Shower Room, and an Equipment Room (Dirty Room).

Phase 2: Abatement and Removal

This phase details the steps taken to safely remove the material within the sealed containment.

1. Worker Protection and Entry

• Personal Protective Equipment (PPE): Workers must wear approved respirators (e.g., half-mask or full-face PAPR—Powered Air-Purifying Respirators—depending on air monitoring results) and disposable, non-woven coveralls, boots, and gloves. PPE is donned in the Clean Room.

• Entry: Workers move through the Decon Unit into the containment area.

2. Material Wetting (Best Practice)

• Wetting Agent: Asbestos-Containing Material (ACM) must be kept wet with a wetting agent (water mixed with a surfactant like liquid detergent). This is the single most critical step for minimizing fiber release. The water binds the fibers, preventing them from becoming airborne.

• Removal: ACM is carefully scored, cut, and scraped to avoid breaking the material into small, dusty pieces. The material must be wet throughout the process.

3. Packaging and Disposal

• Immediate Bagging: Removed ACM is immediately placed into heavy-duty 6-mil disposal bags or drums.

• Gooseneck Seal: Bags are sealed using the "gooseneck" method: twisting the top, folding the twist over, and securely taping the seal.

• Double-Bagging: All waste must be double-bagged outside the direct work area but inside the containment.

• Labeling: All bags must be labeled with the official OSHA Asbestos Warning Label.

• Waste Exit: Sealed, labeled bags are cleaned, passed through the Decon Unit, and secured for transport to an approved landfill licensed to accept asbestos waste.

Phase 3: Clearance and Demobilization

The site cannot be released and containment cannot be torn down until clearance is granted.

1. Post-Removal Cleaning

• Gross Cleaning: All large debris and visible ACM are removed. The floor and walls are scraped and scrubbed.

• Detail Cleaning: All surfaces, tools, and equipment inside the containment are HEPA-vacuumed and wet-wiped until visibly clean. This process is typically performed twice.

2. Encapsulation (Lockdown)

• After the final cleaning, a lockdown encapsulate (usually a bridging or penetrating agent like a specialized paint or coating) is sprayed onto exposed surfaces. This binds any remaining microscopic fibers to the surface, preventing them from becoming airborne in the future.

3. Clearance Air Monitoring

• Visual Inspection: An independent third-party industrial hygienist (or accredited inspector) conducts a thorough visual inspection to ensure no visible ACM or debris remains.

• Air Testing: The hygienist then takes air samples using a method like Phase Contrast Microscopy (PCM) or the more sensitive Transmission Electron Microscopy (TEM) inside the containment. The $\text{NAM}$s are usually turned off during this test.

• Clearance: The clearance test must show airborne fiber levels below the regulatory limit (e.g., often below 0.01 fibers per cubic centimeter) before the containment may be dismantled.

4. Demobilization

Only after final clearance is granted can the containment barriers, poly sheeting, and Decon Unit be safely removed, bagged as ACM waste (since they are contaminated), and transported for disposal. The site is then formally returned to the owner.