What To Expect from an Asbestos Abatement


Understand the Rules

If asbestos containing building materials to be removed exceeding 100 square feet and/or contain a bearing wall, a professional asbestos abatement contractor should be hired.

Some counties now require a lead-based paint inspection certificate, also, before issuing a building permit.


Asbestos Testing is First

A pre-removal inspection of probable asbestos-containing materials will determine the square footage of asbestos to be removed and provide you with a J-card number. Your contractors will usually need this number for a San Francisco Department of Building Inspection building permit. The Bay Area Air Quality Management District will also need this number for their required 10-Day Notice permit.

The hassle, stop-work orders, fines, lawsuits from neighbors or tenants, etc., etc., etc. is not worth it. The cheap can turn out expensive very quickly.

Asbestos Abatement Procedures

When asbestos-containing materials are disturbed or removed asbestos fibers are released into the air. The first thing your contractors will do is to contain the project area with plastic. This plastic should be air-tight. All plastic walls should have a slight bow inward towards the project area. This is called negative air or neg air.

A professional abatement contractor will put machines in place to safely remove asbestos fibers from your air. These machines are large, noisy air purifiers or air scrubbers. Because they push more air out than is taken into the project area, this makes sure the asbestos fibers don’t migrate into living or working areas. 

Your asbestos removal contractor will also attach a plastic duct from an air scrubber to a window so the cleaned air can be blown out and the negative pressure maintained inside the work area.

All workers inside the work area will be appropriately dresses with masks that filter asbestos and other dust particles. These masks require a medical doctor to confirm a workers’ lungs are healthy. Additional white work suits are used by all workers or anyone entering the contained area. 

There may be an attached shower for exiting workers.

There may be separate chambers to provide additional protection of the uncontaminated areas.

Do Not Enter the Contained Area

No one except your asbestos removal contractor or his employees should enter the contained area. Trained asbestos testing professionals can also enter this area. 

Even after your asbestos contractor tells you the job it finished, DON’T ENTER THE CONTAINED AREA.

I know those big air scrubbers are noisy and disturb your work or your sleep. The backflow from turning them off may affect your entire building. It is extremely expensive to clean up an “opps” that contaminated an entire home or office building. Because there are hooks on the ends of asbestos fibers, all soft contents (beds, fabric furniture, clothing, rugs, some types of HVAC ducting) are required to go to a toxic dump site because soft surfaces cannot be successfully cleaned. Consider how expensive it could become to remove all the contents including the HVAC ducting.

You may want to consider a temporary work space or an AirBnB.

Asbestos Clearance

How do you know all the asbestos fibers are out of the air? Air testing. Asbestos fibers are not visible to the naked eye.

There are several types of asbestos clearance testing. 

Asbestos PCM Analysis

Asbestos PCM air sample testing analysis is a method that follows a prescribed standard called the NIOSH 7400 Method.

Asbestos PCM samples use a light microscope to detect all fibers visually. The microscope can be hand carried; one of the advantages of this method is mobility. Samples can even be analyzed on-site, which decreases the turnaround time required for obtaining results. The microscope magnifies objects approximately 400 times their actual size. Yes, a phone can also magnify 400 times. This is not the preferred method, as fibers from other building materials may also be present. There is no separation of asbestos fibers from other building material fibers.

The main disadvantage of the Phase Contrast Microscopy methodology is that it is not asbestos specific. The analyst counts any fiber that falls into a field of view that is greater than or equal to 5 μm in length, with a 3:1 aspect ratio (three times longer than its width).

PCM asbestos analysis is intended for Worker Safety use, not asbestos clearance.

Asbestos PCM air samples with results <0.01 f/cc (fibers per cubic centimeter) are acceptable for worker safety in accordance to OSHA’s PEL for worker safety.

Asbestos PCM air samples with results >0.01 f/cc (fibers per cubic centimeter) are not acceptable for worker safety in accordance to OSHA’s PEL for worker safety. These samples are shown as FAIL.

Asbestos TEM Analysis

Asbestos TEM (Transmission Electron Microscope) air sample testing uses electrons to create images, fine crystal patterns and analyzes the chemical makeup of fibers or structures encountered in the air sample.

The machinery required is not mobile and is very sophisticated.

It magnifies objects at least 20 times their actual size. This method also is asbestos-specific; so specific that it can indicate the type of asbestos fibers in the air sample. 

This method is most appropriate for final clearance samples either due to regulation (AHERA) or liability issues. By law, schools, public buildings, hospitals, etc., must, by law, use this method. This is also most appropriate for litigation and real estate transactions.

Asbestos TEM air samples with a result of <70 s/mm² (structures/millimeter squared) have achieved final clearance. Lab results show asbestos fibers to be non-detect.

Asbestos TEM air samples with a result of >70 s/mm² (structures/millimeter squared) indicate asbestos abatement is necessary. 

Asbestos Tape Lifts

Scotch-type clear tape is gently pressed on hard surface contents that have been cleaned of asbestos fibers. This is a presence or absence only test.