The fire might be out, but asbestos may still linger.
Flames licking at materials which contain asbestos, can release plenty of asbestos fibres into the atmosphere.
While asbestos materials might be stable and solid in day to day calmness, a fire can be like a tornado or any other natural force that breaks and snaps at the materials, sending fibres into the air. This creates dangers for firefighters and anybody else for many days after the fire might have been extinguished.
In a normal still room, asbestos fibres are so light that they can take up to three days before they fall to the ground. Asbestos fibres are so microscopic that any living species can breathe them into their lungs without sensing any reaction. Once lodged in lung tissue, the carcinogenic effects can take years to evolve. But incurable illnesses such as mesothelioma or asbestosis usually result.
During a fire, building materials that contain asbestos will typically crack or ”spall.” Spalling occurs when flakes of the material pop off due to the build-up of pressure inside the material. Monitoring of air during and after fires has indicated that asbestos fibre concentrations typically are very low. This is likely to be due to the low numbers of fibres actually being released, and the large volumes of air circulated by fires, sweeping the fibres further away from the building. This means the internal environment could be potentially less hazardous compared to the outer area of the property.
On a safer note, asbestos fibres can also become “denatured” when exposed to high temperatures for a sufficient period of time. The recognised melting point for asbestos fibres is 1500 degrees C. This is a little higher than the recognised melting point for steel. Fires in buildings can reach these temperatures. Steel beams, unless insulated – often with asbestos sheeting, have been known to weaken and collapse because of a fire’s temperature. The Twin Towers collapse in the USA is believed by some, to have been caused by aluminium framing being weakened by heat. Aluminium melts at only 630 degrees C.
Heat up to its melting point changes the chemical structure of asbestos. Asbestos, despite its unusual, fibrous character, is actually a naturally occurring rock. Heat can return it to magma. This means the asbestos fibres lose their asbestos qualities and no longer pose the same level of health risk.
But fires have also been known to release large amounts of asbestos dust in a damaged building. Water from fire fighting appliances can help to prevent asbestos dust from accumulating in the atmosphere, but only for the duration of the hoses in actions and while the surfaces of the burning structure remain wet. There is little evidence of how much or how long, watering reduces the danger of asbestos dust.
Asbestos, when exposed to fire, can become brittle and breakable and more likely to allow fibres into the air. For this reason, fire is sometimes considered more dangerous as an asbestos damaging catalyst compared to building weathering. So while asbestos is one of the most heat-resistant substances known to man and was put to good use for fire protection, the same material can be highly toxic when it is confronted by fire.
Professional firefighters are well trained in how to avoid the dangers of asbestos released during fires. It is no coincidence that trained asbestos removal staff are fully protected in a similar way to firefighters. Removing burnt asbestos materials is not a task recommended for the untrained property owner.
Licensed companies such as Chemcare, with qualified Class A removal experts, can undertake the work safely and always under the further safety check an independent assessor.
