What is asbestos? We have all heard of this material. The name is familiar to us; perhaps we associate it with several construction products that can be dangerous. It may even be that we associate it with some disease of the lungs.
- But what else do we know?
- Is it dangerous today or was it dangerous in the past?
- Are there any products that contain asbestos?
- Where is it located?
- How does it affect us?
- Who can it affect?
- Are there rights and obligations in relation to asbestos?
- Do you have what it takes to prevent the exposure?
Let’s go in parts, let’s start by defining WHAT IS ASBESTOS.
“It is known by this term to a family of metamorphic and fibrous minerals, consisting mainly of complex silicates of aluminium, iron, and magnesium.”
Varieties of asbestos
The most popular types of asbestos are chrysotile (crystalline structure sheets originating from the crystallisation of serpentine rock) and amphiboles (irregular fibrous aggregates in metamorphic rocks). Amphibole includes crocidolite, grunerite (amosite), tremolite, actinolite, and anthophyllite.
The crystalline structure, which induces the shape and size of the fibres, is an important differentiating element between the chrysotile and the amphibole.
The crystalline structure of chrysotile occurs naturally in superposed layers or sheets, which may form fibres with a diameter of between 0.02 and 0.03 microns. The length-diameter ratios of the fibres can be as high as 100/1.
Contrary to chrysotile, amphiboles do not present a single fibre as a structural unit. All amphibole fibres are straight and do not show the typical curvature of chrysotile fibres.
In relation to the size of the fibres, the diameter of the amphibole is of an order of magnitude ten times higher than the chrysotile, with important variations from one variety to another.
The most commonly used varieties were chrysotile, amosite and crocidolite. This last one is the first one that suffered restriction in its commercialisation and use, because of its dangerousness.
The physicochemical properties are particular to each of the varieties of asbestos, which has conditioned their use.
However, the most commonly used varieties, chrysotile, amosite and crocidolite, have the following common properties:
• The high temperatures.
This gives it incombustibility, a property already known from the antiquity that has determined one of its main applications like material of high resistance to the fire. It withstands temperatures above 1000 ° C.
Asbestos ore is not electrically conductive and therefore a good electrical insulation.
o Abrasion and traction.
Due to the structure of fibres and fibrils, which gives it flexibility and stability, asbestos presents a high degree of resistance to abrasion. The tensile strength depends on the varieties; this classification is accepted, in descending order: crocidolite> chrysotile> amosite> anthophyllite> tremolite> actinolite.
o Aggressive chemicals.
The amphiboles have, in general, good resistance to acids. Among them are crocidolite and amosite, and the best is crocidolite. On the contrary, the chrysotile (serpentines) is weak against acids, even the weaker ones. All varieties of asbestos are very resistant to alkalis.
Inorganic mineral fibre can not be decomposed by any microorganism, such as bacteria or fungi. This gives it the characteristic of non-biodegradability, which makes the materials do not rot.
• Thermal insulation
Because of the large surface area of the fibers, asbestos has a low heat exchange power and is therefore used as an insulator.
• Acoustic insulation
The large internal volume of the fibrous structure of asbestos facilitates the absorption of sound energy.
Effects on health
Inhalation of asbestos fibres can lead to various disorders and diseases, some benign as pleural plaques and other severe or very serious as asbestosis or various types of cancer.
But not all those who have been exposed to asbestos will end up suffering an illness for this fact. Whether or not a disease develops and the type of disease that is present will depend on factors such as:
- The frequency, intensity, and duration of exposure.
- The type of asbestos and the characteristics of the fibres.
- The time spent since the beginning of the exhibition.
- Continuous exposure to tobacco or other carcinogenic agents.
- The individual characteristics.
Asbestos mainly affects the respiratory system. Any structure of this apparatus can be affected: bronchi, lung parenchyma (alveoli) or pleura (tissue that covers the lungs). That is why we talk about pleuropulmonary pathology for asbestos.
This pathology has been known for some time, and there is no doubt about its relationship with asbestos. At the beginning of the 20th century, the first cases of asbestos-related pulmonary fibrosis (asbestosis) were described in spinning workers.
ACM removal protocols
The Work Plan is a document that includes the planning of the works with asbestos that must be done to ensure that these are done in a way that does not compromise the safety and health of the workers who perform these tasks, nor the of other people who are in the place where the work is carried out or in its vicinity.
The employer must prepare a Work Plan before beginning each job with the risk of exposure to asbestos.
Points to be provided for a Work Plan for activities at risk of exposure to asbestos
- Identification data.
- The work description to be carried out specifying the type of activity: demolition, removal, maintenance or repair, work with waste, etc.
- Types of material to be intervened indicating whether it is friable (projected asbestos, heat-insulated, insulation, etc.) or non-friable (asbestos cement, asbestos-vinyl, etc.) and, Indicating the quantities to be handled of asbestos or materials containing it.
- Location of the place where the work should be done.
- The commencement date and the scheduled duration.
- List of workers directly involved in work or in contact with the asbestos-containing material, as well as professional categories, trades, training and experience of said workers in specified jobs.
- Procedures that will be applied and the peculiarities that are required for the adequacy of the procedures in the concrete work that is wanted to realise.
- The preventive measures envisaged to limit the generation and dispersion of asbestos fibres in the environment, and measures taken to limit workers’ exposure to asbestos.
- Equipment used for the worker’s protection, specifying the characteristics and number of decontamination units and the type and mode of use of personal protective equipment.
- Measures taken to avoid the exposure of others in and around the place where work is carried out.
- Measures to inform workers about the risks they are exposed and the precautions they must take.
- Measures for disposal of waste according to current legislation, indicating management company and landfill.
- Preventive resources of the company indicating, in the case that they are extraneous, the concerted activities.
- The procedure established for the evaluation and control of the working environment as provided in the corresponding Royal Decree.
Individual protection equipment
In relation to Personal Protective Equipment, workers must have FFP3 self-filtering masks or masks with P3-type particulate filters and single-use working hoods. The other possible risks caused by the activity and the environment where the work is carried out must also be foreseen.
- Handle the material with asbestos as little as possible and with care.
- Avoid breaking the material with asbestos.
- Avoid dispersion of friable materials by injection techniques with wetting liquids that penetrate the entire mass.
- Use tools that generate the minimum amount of dust. Manuals are preferable.
- To work in wet, avoiding the use of pressure in the application of water that can cause the dispersion of fibres.
- Work with localised air extraction systems using absolute filters.
In order to remove these old ACMs, it is first necessary to soak their surface with an aqueous solution of encapsulating liquid, in order to avoid the emission of asbestos fibres due to the accidental movement or breakage of the contaminated materials.
The method of work consists of disassembling the entire fibro-cement sheets and avoiding breakage. The anchor points must be removed with great care, starting with the highest area. If the fasteners have to be cut, the rotary machines must be avoided due to the high dust emission they cause.
Packaging and Identification
The plates shall be packed with a plastic of sufficient strength to prevent breakage and shall be marked with the asbestos label.
Once the sheets have been removed, the entire support structure of the cover will be cleaned by suctioning with HEPA vacuum.
The Work Plan should contemplate that once the demolition or asbestos removal in Adelaide tasks are completed, it must be ensured that there are no risks due to asbestos exposure in the workplace.
At the end of the dismantling, the asbestos cement sheets will be considered as asbestos waste. Asbestos waste will always be collected separately from other waste that can be generated in demolition, repairs and removal work with asbestos.
It should be specified that all asbestos-contaminated material (filters, work appendages, masks, wet rags, etc.) must be disposed of as asbestos waste and should be managed as such.
For the transfer of asbestos waste, it must be taken into account that the transporter:
- must be authorised by the Environment Protection Agency.
- must have the corresponding generic plan of asbestos approved by the Labor Authority.
- must apply what is specified in the regulations for road transport of dangerous goods.
The final destination of asbestos waste is the hazardous waste landfill.