How to sample for asbestos in building materials
Use an environmental consultant or asbestos professional if you feel uncomfortable!
1. Control the area
To avoid the possible release of fibres, clear the sampling area of all occupants. Isolate any HVAC (heating, ventilation or air conditioning) sources to minimize air movement within the room. Try turning off the heating and or cooling system, closing windows and doors, and shut down blowers, fans or other ventilation sources as well.
Another crucial containment strategy is using plastic (poly) sheets. Attach one plastic sheet to the floor where possible debris/fibres might land (under the area of sample collection) to keep the plastic in place, affix duct, construction or painter’s tape. Abatement professionals are often mandated to use double 6-mil poly sheeting for added protection to the contained area though for DIY sample collection any plastic sheeting will do.
2. Wear a respirator
Asbestos textures are regarded as friable material. Take care to get the right type of respirator that fits you well. Qualitative or quantitative fit testing is highly recommended (and required for qualified persons working in asbestos identification and removal). I recommend the p100 half-mask respirator, but any respirator with a purple p100 HEPA filter cartridge works as well. Disposable N95 dust masks cannot provide you with the highest level of protection against asbestos despite the level of protection they provide against airborne viruses and bacteria.
Also, if you have facial hair that is preventing an adequate fit of the respirator, you must shave to remove any hair to seal the respirator to your face. Again, this is where fit testing can be your ally. Contact your safety product supplier or google search for fit testing to find one in your area.
More preparation before starting sampling for asbestos
3. Get disposable safety clothing
Most notably, asbestos is known for the damage it causes the lungs, respiratory tract, and pleural cavity, but it can also cause micro-cuts to the skin and causes a condition called ‘asbestos warts’. Remember that gloves can protect the skin from any damage. To keep your skin safe, you need to wear disposable coveralls. Find sizing guides at your local safety supplier. Also, try to wear one that comes with footwear, or covers the feet. If you can’t find disposable coveralls in your size, you can alternatively use a long-sleeved t-shirt and pants that cover as much skin as possible. Be aware that if your results come back positive, you will have to dispose of these or safely launder them without risk of exposure.
Apart from disposable coveralls you can also wear disposable gloves, the most ideal are powder-free nitrile gloves that are made for automotive mechanics. They are thick and durable disposable gloves. Feel free to add a pair of work gloves on top of these to provide more durability, keep in mind that the work gloves should be disposed of or safely laundered if the results are positive. Lastly, because textures are usually located on ceilings, you might look up into falling debris. Wear safety glasses or a full faced respirator for the best protection.
4. Identify locations to collect the samples
Because of the large surface areas of ceilings and walls where textures are most commonly found, be advised that collection of several samples will give court defensible results. Different laboratories have their own recommendations for sample volume but there is a common range for the number of samples to take for a given area.
Initiate sampling of builidng materials
5. Saturate the material
It is best to wet the material with amended water.
Put a mixture of water and a few drops of detergent and place in a hand sprayer bottle. Then mist the area of texture you plan on getting a sample from. Try to make it as wet as you feel comfortable with without damaging surrounding building materials. The high-water content on the plaster will prevent any asbestos fibres from becoming airborne. In the worst-case scenario, they will fall onto the plastic sheet placed below.
6. Cut/scrape your sample
If the texture you plan on cutting out isn’t too delicate, cut through the entire thickness of the material with a sharp knife then work your way to cut out a 2.5cm x 2.5 cm piece (~1-inch square). Keep in mind that different testing laboratories recommend different sample sizes. But 1 x 1 inch is a typically accepted size. A common method for multiple sample collection is to use a triangle shape with a surface area of 1-inch square for your samples as less cutting is required and this can save time.
As for popcorn ceiling and other friable textures, you are better off scraping out a sample. Trying to cut out such material will be very difficult because it easily crumbles, so scraping out a small 5-10 ml volume is best, if possible.
Finishing up with the sample
7. Encapsulate the patch
After you have collected the sample, trap any fibres that may be released from the open sampling area. Lock down the fibres by encapsulation. For textures, the easiest way to do this is by placing a layer of duct or painter’s tape over the hole. A branded asbestos encapsulant (called Fibrelock) or spray glue can also be used to encapsulate; although, from my experience, tape looks much cleaner/pleasing look at than seeing a hole in the wall or ceiling. Mark your sample number on the tape and take a photo. Decontaminate your cutting tool when collecting multiple samples.
8. Double bag your test sample
Put the piece of plaster you have collected in a strong zip lock bag and have the bag sealed securely. After you have the sample in the first zip bag, put the bag into another bag/container. This provides the needed protection for containing an asbestos sample. Make sure you have the outer container labelled. Repeat this process for additional samples if required. Important details to be placed on the label include the date the sample was taken, and which part of the house the sample was collected from (e.g. northeast end of the kitchen ceiling). Many asbestos professionals will use unique sample labelling to avoid bias at the lab and by using alphanumeric codes.
Decontamination and Clean up
9. Clean the working area
Take care to avoid any contamination of other parts of the room. To keep other places safe follow these instructions:
Cautiously fold the plastic drop sheet. When folding the plastic, assume it to have collected asbestos. So, be as careful as possible not to spill any debris.
Do a thorough cleaning of all hard surfaces, such as the floor that was close to the area where the sample was taken. To clean these surfaces, use a damp cloth, disposable wipe, and/or wet sponge. Keep in mind you should be ready to dispose of the cloth and/or the sponges. I should make one major warning: DON’T USE A VACUUM CLEANER unless it’s an asbestos rated HEPA vacuum. It almost always does more harm than good when it comes to cleaning asbestos fibres.
Decontaminate all of your sampling tools by wet wiping and dispose of the cleaning media as above.
10. Prepare contaminated material for disposal
Before leaving the room, find a heavy-duty plastic bag or labelled asbestos waste bag (depending on your local/national asbestos disposal regulations) where you will place all possibly contaminated materials. Materials to place in this plastic bag include:
The drop plastic sheet, and another protective plastic sheet you may have used
Cleaning media (cloth, sponge or disposable wipe)
If the results for asbestos testing come out to be positive, you need to have a sealed heavy-duty bag sent to a landfill that accepts asbestos. Don’t throw it in a regular trash bin; this may be illegal (depending on your location). Legal action can be taken against you and you are putting the lives of others in unnecessary risk. As always, follow your local asbestos disposal regulations.
Sample analysis by accredited lab
11. Send the sample for analysis
Once you have your sample(s), send to a certified laboratory for testing. An accredited, asbestos lab with multiple analytical services is SAI Labs, in North Carolina. Contact them for specific pricing over email or phone as rates vary. They generally offer the lowest pricing for multiple samples.