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Operations were divided into 6 phases/working steps, for a total of 3 months and an average of 35 specialised workers, all of them holding an asbestos training certification.
The intervention was demanding, as the reclamation had to be carried out without interrupting the activities in the plant.
It is worth mentioning how this reclamation has been organised, as this shows an important difference from the Italian regulation: a risk analysis was mandatory for asbestos powder emission during the realisation of reclamation operations in the worksite. In Italy, modifications to the law have been discussed for a long time; something similar could be decided in our country too.
The obligation to assess dustiness levels (the measurement of the concentration of asbestos fibres per litre of air) caused by the activities in the work site was introduced in France by the Decree no. 2012-639 of 4th May 2012. Before starting the reclamation of the site, a testing worksite should be set up to allow the classification of every process which will be used for the reclamation of materials containing asbestos into 3 dustiness levels defined by the law, according to article R. 4412-98 of the above-mentioned decree.
There are 3 levels:
- level 1 - less than 100 fibres/litre in the workstation (analysis carried out using the META method)
- level 2 - between 100 and 6,000 fibres/litre in the workstation (analysis carried out using the META method)
- level 3 - between 6,000 and 25,000 fibres/litre in the workstation (analysis carried out using the META method)
Each level corresponds to a reclamation method which is more and more complex according to the level of exposure.
The remediation process of materials contained in the Isoroy plant correspond to the code M 05_T 01_ME 04a_C 02_A 03_H 01, which is specific for asbestos-containing materials, such as felt and cardboard. The assessment in our Working Plan shows an expected release of fibres of level 2 (on the basis of previous experiences).
The test carried out in the worksite, specific for one out of the six areas the operations are divided into, resulted in a level 1 exposure situation, with the release of less than 100 fibres/litre in the workstation. This would have entailed a modification of the work plan and a simplification of remediation activities, but the Client decided to keep the higher safety level and confirmed the method defined in the existing work plan.
In short, all the areas not containing asbestos - such as walls, offices, machineries and pipes - were confined and covered with a double 200 micron polythene sheet. Linoleum was laid on the ground to allow higher soil resistance. Openings and air leak points in the roof were sealed with polyurethane foam. 3-phase decontamination unit for waste and materials taken out of the contaminated area. 5-phase decontamination unit for the staff. two to eight 50,000 m3/h air extractors to ensure at least 6 exchanges/hour in each one of the six work site sub-areas, according to their dimension.
The Saint Joseph prison in Lyon was built in the 19th century. Last century, it was closed down because it did not meet contemporary standards; the strong mobilisation of associations for the defence of the French artistic heritage led to its reclamation. By 2014, new offices and social houses will be created and a campus will be built to accommodate 5,000 students. TIA was entrusted with the reclamation, on behalf of an important real estate asset manager.
The reclamation of this building included the removal of large quantities of asbestos and lead from the old prison. In order to protect this unique example of the French 19th-century prison architecture, some walls were kept unmodified, under the supervision of the chief architect of the French Historical Monuments. The size of the building and the difficult intervention showed TIA's ability and expertise in managing complex situations. The careful and meticulous conservation work in this historical building was particularly appreciated.
The risk/threshold of 0,1 mg/m3 required the interventions to be realised in confined spaces and the use of assisted-breathing masks. Lead removal was carried out by means of:
- scraping
- high-pressure jet
- sandblasting
The main lead-containing elements, which were subject to decontamination works:
- stairs
- plasters
- windows
- plinths
- doors
- frames
Données
Client: OGIC
Localité: Lyon
Chantier: Ancienne prison de Saint Joseph
Fin des travaux: 2013
Critical aspects
Safety is surely the main critical point, for the following reasons:
- handling of dangerous materials
- railway sector (trains, electricity)
- night work
Limited working time is another critical aspect: the time the line is stopped has to be as short as possible, therefore it is fundamental to plan in detail the completion of some work phases before reactivating the line, so as not to damage the quality of interventions already completed.
Description of works
TIA’s work includes excavations to place foundation blocks for phone poles; the surface ballast and the underlying polluted soil are removed.
These operations usually require setting up an area in the station for the following items:
- train equipped with a decontamination unit;
- temporary ballast storage site;
- worksite shed and changing room;
- chemical toilet.
Tools and equipment commonly used are:
- 2-bar low-pressure airless pump with rain-effect nozzle;
- Electrical extractor fan with absolute filter;
- Manual tools;
- Excavator;
- Light tower;
- Iron sledgehammer;
- Bogie with locomotive.
In addition to the previous list:
- worksite electrical system, including a power generator and a certified switchgear compliant with Law 37/08. The worksite switchgear located near the working area includes switches fitted with magnetic and thermal protection and residual-current devices to guarantee a safe power supply to users.
- Personnel Decontamination Unit
2 bogies are drawn to the worksite before the start of decontamination operations. They contain:
- onboard the first bogie - UDP, water tank, WC, power generator and light tower.
- onboard the second bogie - excavator, big bag holder and new crushed stones.
Before starting the excavation operations, our staff - equipped with specific PPE - should:
- set up the fencing around the worksite;
- start the wetting operations on the ballast using water and incapsulant within the excavation area and the surrounding areas; this operation will be repeated during all ballast handling phases by airless pump.
- carry out airborne fibres sampling: 1 background sampling in each excavation and plinth laying area, to be repeated daily during the removal of ballast.
For more information:
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