Shawcity Limited

Shawcity Limited

Asbestos monitoring – what monitor should I be using?


Courtesy of Shawcity Limited

Asbestos is the name given to a group of minerals that occur naturally as masses of strong, flexible fibres that can be separated into thin threads and woven. These fibres are not affected by heat and do not conduct electricity. Asbestos is chemically, relatively stable. For these reasons, asbestos has been widely used in many industries. 

These four types are classified as follows: 

Chrysotile, or white asbestos (curly, flexible white fibres and, chemically, talcum powder but in fibre-form, which dissociates, when wetted), which accounts for about 90 percent of the asbestos currently used in industry; 

Amosite (straight, brittle fibres that are light grey to pale brown in colour); {Actinolite is a further type of Asbestos, which has green fibres. It is similar in structure and chemistry to Amosite.} 

Crocidolite, also called BLUE ASBESTOS, is a grey-blue to leek-green, fibrous form of the amphibole mineral Riebeckite. It has a greater tensile strength than Chrysotile asbestos but is much less heat-resistant, fusing to black glass at relatively low temperatures. 

The major commercial source is South Africa, where it occurs in ironstone; it is also found in Australia and Bolivia. Crocidolite is often replaced by quartz, forming the chatoyant semiprecious gems tiger-eye and hawk's-eye. 

Anthophyllite (meaning brittle white fibres). is an amphibole mineral, of magnesium and iron silicate that occurs in altered rocks, such as the crystalline schists of Kongsberg, Norway. 

There are no recorded cases where white asbestos was causal to Mesothelioma but, often, browns are found with white, in small quantity; thus posing some danger should the fibres become airborne. 
In fact; many of the substitute materials, evident since 1969, when the Asbestos Regulations were first invoked, are more dangerous than white asbestos but the Asbestos regulations does not differentiate the wide difference in hazard between the four types

In a variety of applications it is therefore necessary for monitoring to take place in order to determine types of hazardous particulates as well as general air quality. Usually an air quality monitor such as the EVM range of air quality monitors by 3M/Quest technologies can be used.

The EVM range of Air Quality instruments from 3M/Quest Technologies which utilises the MiniPID technology has been used by Erith contractors…. Here is what they think about the EVM…

“The dual functions of the EVM 7 cut down the amount of equipment needed and the fool-proof user interface means that the machines are incredibly simple to set up. The nature of our work on historical gasworks means that both dust and PID monitoring are of the upmost importance due to the presence of hazardous contaminants and toxic gases in the materials being disturbed. The factor which makes the EVMs  invaluable and separates them from the other environmental monitoring units on the market, is that they can be left to run at several locations around the site, to continuously collect data throughout the day with complete confidence. It is the reliability of the EVM 7s battery, PID sensor and dust impactor which allow the unit to be left for extended periods of time without any concern. Though when issues do arise, the speed at which the problem is resolved by Shawcity is definitely in need of mention, be it a talk-through of a procedure over the phone, or the provision of a replacement unit while one goes away for service. The final thing which makes the EVM 7 so beneficial is the ease at which the information can be downloaded and analysed. The software is user-friendly and easily customised meaning the data can be downloaded and presented in the relevant form in a matter of minutes.”

Gavin Craig

Site Office Manager




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