Asbestos Surveys & Testing​Water Absorption Testing​

Water absorption testing is a crucial step in determining whether an asbestos-containing material (ACM) is asbestos cement (AC) or asbestos insulating board (AIB). This information is vital as it determines whether it should be dealt with under licensed or non-licensed conditions.

AIB typically contains 15-25% Amosite (brown asbestos) often with a small amount of Chrysotile (white asbestos), in a calcium silicate matrix. Older boards may contain up to 40% asbestos and also contain Crocidolite (blue asbestos). AIB is readily broken and can release significant amounts of fibres.

Asbestos Millboards may contain 37-97% asbestos with a matrix of clay and starch. Millboards have a low density and are easily broken.

AIB and Millboards have a lower density than typical asbestos cement products and will generally absorb more water (≥30%) than asbestos cement products.

To conduct the water absorption test, a sample must be first identified as an ACM using the polarised light microscopy (PLM) method. A representative sample of the material is then dried, and its weight determined. After weighing, the sample is immersed in water for at least 15 minutes and until there are no more visible signs of bubbles being formed. Excess water is removed from the sample, and it is re-weighed. The percentage of water absorbed is calculated using the dry weight and wet weight of the sample.

It’s important to note that samples with one or more surfaces coated or covered with an impermeable layer may take longer to saturate and may not absorb the same amount of water as similar uncoated samples. Age weathered board materials, which have or are starting to delaminate, will absorb more water than they would in their original state, and the results may, therefore, overestimate the true value. It is recommended that delaminated samples are not submitted for analysis if possible.

At G&L, we understand the importance of accurate water absorption testing, and our experienced team can conduct the test within one of our state-of-the-art laboratories. Our water absorption testing method is suitable for use on high-density asbestos cement products and medium-density insulating boards, and we can classify asbestos-containing materials as either AIB or AC. Our strict sample labeling and handling procedures ensure accurate results, and our commitment to providing reliable and professional service, every time, means you can trust us to deliver the best possible service for your asbestos management needs.