FR3005864A1 - DECONTAMINATION PROCESS. - Google Patents

Abstract

The method for decontaminating a structure comprises: - installing a confinement (3) around the structure (2), - deconstructing the structure (2), which generates inside the containment (3) stale air which comprises contaminating particles from the structure (2) being deconstructed, - is generated inside the confinement a clean air flow (24), by suction of the exhaust air (34) carrying particles contaminating from the interior of the containment (3), and retention of contaminating particles at a filter (11 ') passing clean air (24), and conduction of clean air (24) thus obtained to the interior of the containment (3), - there is generated inside the confinement (3) a mist (21) of liquid droplets by association at the level of a misting nozzle (23) disposed inside the confinement (3). ) an inflow of liquid to be dispersed and the flow of clean air (24) generated.

Description

The invention relates to the field of methods for decontaminating structures. More specifically, the invention relates to the field of asbestos removal. For many structures, asbestos removal requires deconstruction of the structure, which volatilizes in the air around the contaminant particle structure. To reduce the risk of contamination, the regulations impose drastic conditions to remove asbestos from structures, particularly buildings. Such asbestos removal must be done under confinement to prevent the spread of contaminating or harmful particles into the atmosphere. Also, the personnel in charge of asbestos removal carry very restrictive equipment, unfit for deconstruction work.

During deconstruction, stale air is constantly extracted from the containment by powerful air extractors, equipped with so-called absolute filters, which retain all the contaminating particles from the deconstruction and present in the air during this period. extraction, and expel out of the confinement a flow of clean air. No. 5,009,685 describes such a system.

Such an extraction is intended both to recover the contaminating particles, in order to reduce their concentration inside the confinement, and to keep the interior of the confinement in a vacuum with respect to the atmosphere, in order to reduce the risks of dispersion. contaminating particles through containment.

The aim is always to facilitate as much as possible the work of the personnel in charge of deconstruction, without having a negative impact on their safety. A known track for reducing the quantities of harmful dust present in the stale air inside the containment is to use a nebulization of liquid in the confined atmosphere. In fact, the droplets of liquid are charged with the dust of the stale air and drag them to the ground, thus reducing their concentration in the confined atmosphere, and consequently their risk of inhalation by personnel or deposit on tools or equipment inside the enclosure. There is the need to further improve known asbestos abatement processes, both for the safety of personnel, and to increase the efficiency of the process and thereby reduce the cost.

Hereinafter, a description of the invention as characterized in the claims. According to a first aspect, the subject of the invention is a method of decontaminating a structure comprising: installing a confinement around the structure, deconstructing the structure, thus generating inside the confinement a stale air comprising contaminating particles from the structure being deconstructed, a clean air flow is generated inside the containment, sucking the polluted air carrying contaminating particles from inside the confinement, retaining the contaminating particles at the level of a filter passing clean air, and driving the clean air thus obtained inside the containment, is generated inside the confinement a mist of liquid droplets by associating at a misting nozzle arranged inside the containment an arrival of liquid to disperse and the flow of clean air generated. Thanks to these provisions, a clean air flow is used to implement the misting. Thus, it benefits from misting, while avoiding generating a flow of stale air in the enclosure, which could be harmful for the staff. It also benefits from the fact that it generates already, as part of the decontamination process, a clean air flow (however, it is generated outside the enclosure, where the misting would have no effect ). Although the invention has been presented above in relation to a typical implementation in the field of asbestos removal of buildings, it is understood that the invention can be applied to other types of decontamination processes in a confined atmosphere and other structures to decontaminate only buildings, for example vehicles, or objects carried on a mobile conveyor, for example. According to one embodiment, a clean air flow is generated inside the confinement by means of a system arranged entirely inside the confinement. According to one embodiment, the exhaust air is sucked by means of a pumping system housed in a housing, and the inside of the housing is maintained under overpressure.

According to one embodiment, a mist of droplets is generated by combining at a plurality of misting nozzles arranged inside the confinement an arrival of liquid to be dispersed and the flow of clean air. According to one embodiment, the flow of clean air is generated along a supply axis, the flow of clean air is dispersed radially with respect to the supply axis, the misting nozzles having been arranged radially relative to the feeding axis and spaced circumferentially from each other. According to one embodiment, the fog is generated by means of a clean air flow supply channel having a mouth opening inside the confinement, and the mouth is alternately placed in the open state during deconstruction and in the closed state.

In one embodiment, the flow of clean air is conducted upwards between the suction and the misting nozzle. According to another aspect, the invention relates to a misting system of a structure comprising: a casing which can be associated with a confinement surrounding the structure to be decontaminated, a pump carried by the casing and adapted to suck stale air containing contaminating particles from the structure being deconstructed, a filter carried by the housing and adapted to retain the contaminating particles and let clean air, a conduction channel of a clean air flow inside the containment, a mist nozzle receiving a liquid inlet to be dispersed and disposed in the flow of clean air. In one embodiment, the conduction channel and the misting nozzle are carried by the housing. According to one embodiment, the conduction channel and the misting nozzle are carried by a casing alternately sealingly engageable with the casing and dissociable therefrom. In one embodiment, the misting system includes a check valve between the filter and the misting nozzle, adapted to prevent a movement of contaminating particles in the direction from the mist nozzle to the filter.

According to one embodiment, the housing is maintained in overpressure.

According to another aspect, the invention relates to a decontamination system comprising a misting system and further comprising a confinement adapted to surround the structure to be decontaminated, and at least one air extractor associated with the confinement and having an end of pumping disposed within the confinement, and an extraction end disposed outside the confinement. In one embodiment, the decontamination system is in kit form. The figures of the drawings are now briefly described. Figure 1 is a diagram schematically describing a decontamination process. FIG. 2 is an enlarged schematic view of a misting system that can be used during a decontamination process as shown in FIG. 1. The following is a detailed description of several embodiments of the invention accompanied by examples and reference to the drawings. Figure 1 shows schematically the implementation of a decontamination process. Decontamination herein is a process in which a structure having a material capable of spreading into the atmosphere into harmful or contaminating fine particles is treated, so as to reduce the risk that these harmful and / or contaminating particles pollute the atmosphere and, as a result, lead to contamination problems in the area. Such a method passes for example by a deconstruction of the structure in question. By deconstruction, it is understood that the structure will be disassembled mechanically piece by piece, this disassembly step causing the volatilization of the particles. In particular, we are thinking here of an asbestos removal process. In this context, the structure to be decontaminated and deconstructed is for example a building 1. In a variant, the structure to be dismantled is not necessarily a building. Alternatively, the decontamination process is not necessarily an asbestos removal process. For example, a deblocking method is provided. In an asbestos removal process of a building 1, such as will be described by way of example herein, there is a building 1 comprising asbestos. Asbestos is typically used as insulation material in floors, ceilings and false ceilings, partitions, etc. The deconstruction of the building 1 requires operations of destruction of the floors, ceilings, partitions, ..., which causes a volatilization in the atmosphere of contaminating particles of asbestos. In the remainder of the description, the particles are alternatively described as contaminating or harmful, these two terms being used indistinctly to designate the same type of particles. In particular, the structure to be decontaminated is a region 2 of the building 1. A confinement 3 is placed around 40 the region 2 to be decontaminated. Containment 3 comprises a barrier 4 impervious to contaminating particles, and assembled in a sealed manner on the ground and around the region 2. As shown by way of example in FIG. 1, the confinement 3 is of relatively large size, at the staff scale 5 implementing the decontamination of the region 2. Thus, the confinement 3 comprises a main enclosure 6 delimited by the barrier 4 at least 2 meters high, and one or more meters in each of the two horizontal directions 45. The containment 3 also includes an airlock 7 allowing the personnel 5 to enter and leave the main enclosure 6. The airlock 7 can be made of several different shapes. For example, there is shown an airlock 7 having five chambers arranged in a row with each other, the last chamber being directly connected in a particle-tight manner with the main enclosure 6. In one example, the one and / or the other rooms may include showers, for example the second and fourth rooms. As shown diagrammatically in FIG. 1, the personnel 5 is equipped, in the main enclosure 6, with a protective equipment 8. The protective equipment 8 is used to prevent the harmful particles present inside the enclosure 6 In particular, the equipment 8 includes a filter respirator preventing the personnel 5 from breathing the contaminating particles. The airlock 7 allows the personnel 5 to leave the main enclosure 6 without taking outside 9 contaminating particles. Tools or equipment may also be removed from the inner chamber 6 through the airlock 7, being cleaned.

The main enclosure 6 is maintained under pressure at a pressure Pc with respect to the external pressure Pa (Pc <Pa), which is generally atmospheric pressure. For this purpose, one or more air extractors 10 (which are suitable for drawing in the interior air to the main enclosure 6 are provided. Maintaining the main enclosure 6 in a vacuum prevents the contaminating particles present in the it does not volatilize in the atmosphere through the barrier 4. On the contrary, the atmospheric pressure tends to confine the contaminating particles inside the main enclosure 6. As can be seen in Figure 1, the extractors 10 are arranged astride the barrier 4. That is to say that the extractors 10 comprise a pumping end 10a disposed inside the confinement 3, and an extraction end 10b disposed outside the confinement 3. The extractor 10 comprises a peripheral wall 10c extending between its pumping ends 10a and extraction 10b. The barrier 4 is sealed to the contaminating particles at the peripheral wall 10c. The air extractor 10 further comprises a filtering system 11 for filtering the contaminating particles of the sucked air. The filter system 11 is considered absolute when it filters at least 99.995% of the contaminating particles passing through it. It is for example of the type H13, H14 or higher according to the standard EN 1822. Thus, the air extractor 10 sucks stale air at its pumping end 10a, and releases outside the confinement air substantially. clean, that is to say released from the contaminating particles. The contaminating particles are retained at the level of the filtering system 11. This filtering system 11 can also be provided in two successive stages along the airflow, comprising a prefilter 12 and a main filter 13. It will be noted that, for example, for the air extractors 10 which have just been described, the motorization and pumping system, as well as most of the electrical, mechanical and small parts components, are arranged downstream of the filtering system 11 , so as not to be contaminated by the contaminating particles during use. These extractors are for example electrically connected to a power source, such as the sector, a generator, or other. The decontamination system further comprises a misting system 14, which will be described in more detail below with reference to FIG. 2.

In the example presented, the misting system 14 is disposed integrally within the confinement 3. It comprises an energy supply 15 such as, for example, an electrical connector adapted to be connected to the sector. The sector may be accessible inside the containment 3, or as shown outside the confinement 3, in which case a cable 16 is provided connecting the sector to the energy supply 15 of the misting system. The electric cable 16 then passes through the barrier 4 in a sealed manner to the contaminating particles. The misting system 14 also comprises a water inlet 17. The water inlet 17 is adapted to be connected to a source of water 18. The water source can be accessible inside the containment 3, or as shown outside the confinement 3, in which case a pipe 19 is provided connecting the water source 18 to the water inlet 17. The pipe 19 then passes through the barrier 4 in a sealed manner to the contaminating particles . The misting system 14 may also comprise a water pump 20. The water pump 20 is used to transmit water, if necessary at high pressure, from the water source 18 towards the water inlet 17. If the water source 18 is disposed outside the confinement 3, the water pump 20 is preferably also disposed outside this confinement, so as not to be contaminated by the contaminating particles. Then, the pipe 19 passes through the barrier 4 in a sealed manner to the contaminating particles between the water pump 20 and the water inlet 17. The misting system 14 can, when supplied with energy, generate a mist 21 of water droplets inside the containment 3. The liquid described here is water, but another liquid could be used as an alternative, if needed. Thus, the misting system 14 comprises a misting stage 22 comprising one or more misting nozzles 23 each receiving water at high pressure from the water inlet 17. In the case where several misting nozzles 23 are used. these may be arranged radially about a central axis X, and circumferentially spaced from one another in a uniform manner. However, other arrangements are possible. By way of example, it is possible, for example, to provide 12 misting nozzles 23 arranged in a horizontal plane in a circle, and spaced from each other by 30 °. The misting system 14 also comprises a means of bringing a clean air flow 24 to the level of the mist stage 22. For example, the flow of clean air 24 is fed along a supply axis coinciding with the X axis. The example described above also comprises a cap 25 for dispersing the flow of clean air 24 arriving along the supply axis radially and in the vicinity of the misting nozzles 23. The joint arrival a flow of clean air and water at the misting nozzles 23 generates the formation of small water droplets, for example of the order of a few microns which form a mist 21 inside the Containment 3. For example, at 22 ° C, and a relative humidity of 50%, up to 1 meter away from the nozzles, 97% of the water droplets produced are smaller than 8 microns in size. The fog 21 can cool the air inside the main enclosure 6, and the droplets can be loaded with contaminating particles, and drag them to the ground, which reduces their concentration in the air. An embodiment of a means for bringing a clean air flow 24 to the level of the fogging stage 22 is now described. This system comprises, for example, an air extractor 10 'which may be of a similar type. to the air extractors 10 described above in connection with Figure 1. In particular, the air extractor 10 'comprises a pumping system 26 for sucking air from inside the main enclosure 6 through a pumping end 10'a, the air exiting the air extractor 10 'at an extraction end 10'b.

The extractor 10 'may also comprise a filtering system 11' as described above.

The air extractor 10 'comprises a casing 27 carrying the pumping system 26 and the filtering system 11'. The casing 27 comprises a small number of openings, in particular openings defining the pumping ends 10'a and extraction ends 10'b of the air extractor 10 '. The air extractor 10 'may differ from the air extractors 10 described above in that it is a positive positive pressure system. That is to say, when it is supplied with energy, the pumping system 26 generates inside the housing 27 a pressure greater than the pressure prevailing in the surroundings, that is to say in the 6. It should be noted that, if necessary, such guaranteed positive pressure air extractors can also be used to replace the extractors 10 described above. The clean air generated by the air extractor 10 'is conducted to the misting nozzles 23. For this purpose, it is possible, for example, to provide a channel 28 having a first end 28a sealingly connected to the contaminating particles at the same time. extraction end 10'b of the air extractor 10 ', and an opposite second end 28b forming a mouth disposed at the level of the fogging stage 22. The channel 28 may have any suitable geometry. For example, it can be provided that, if the extraction end 10'b of the extractor 10 'is substantially horizontal, the channel 28 comprises a vertical chimney 29 opening at the level of the fogging stage 22, and an intermediate portion 30 of a ramp deflecting the air expelled horizontally from the extractor 10 'towards the vertical chimney 29.

If necessary, check valves 31 are provided to prevent air flow from the mist stage 22 to the outlet of the air extractor 10 '. The check valves 31 may thus have an open state in which they let the air pass from the air extractor 10 'towards the fogging stage 22, and a closed state in which they prevent any passage of contaminating particles. in the opposite direction. The check valves 31 naturally take their closed state under the action of an air flow from the fogging stage 22 towards the air extractor 10 '. In the embodiment shown, for example, there are two stages of check valves, one at the outlet of the air extractor 10 ', and one at the entrance of the vertical stack 29. However the number and arrangement of the check valves may be different.

The system that has just been described is represented as a monobloc machine. However, the box 32 comprising the channel 28 could alternatively be made as a separate part of the air extractor 10 ', and connected to that in a sealed manner to the contaminating particles if necessary. Such an arrangement could facilitate the decontamination of the misting system.

Furthermore, it is possible to provide a shutter 33 making it possible to close off the outlet of the channel 28. The shutter 33 can be arranged in obturator configuration, in which it closes the outlet of the channel 28, or in an open configuration, in which case it allows the passage of the clean air 24 from the air extractor 10 'to the fogging stage 22. The shutter 33 can be placed at will by a user in its closed or open configuration, depending on whether or not it is used the misting system. In FIG. 2, the shutter 33 is represented in a shutter configuration by way of example, even if, in order to understand the invention, the air flow 24 is also represented as if the shutter 33 was in an open configuration . Hereinafter, an example of implementation of the system is described.

It is desired to decontaminate a region 2 of a structure 1. A containment 3 containing region 2 to be decontaminated is installed. The misting system is associated with confinement by placing it inside the containment. It is connected to a source of water / liquid and energy. The installation can therefore be very simple.

Staff 5 equips with equipment 8, and enters from the outside 9, through the airlock 7, inside the main enclosure 6. The air extractor 10 is started, in order to place in depression the main enclosure 6 with respect to the atmospheric outside pressure Pa. The misting system 14 is supplied with water as well as with energy via the water inlet 17 and the energy supply 15 , respectively. The misting system 14 begins to generate a mist of liquid droplets from the air present in the chamber 6 sucked by the air extractor 10 ', and leads to the fogging stage 22, where it disperses the air. water arriving in fine droplets. The staff 5 begins the deconstruction process. In doing so, it generates inside the main enclosure 6 stale air carrying contaminating and / or harmful particles. This stale air is sucked by the extractors 10, which retain, at their filtering system 11, the harmful particles, and expel out clean air. This contributes to keeping the interior of the main enclosure 6 in depression with respect to the atmosphere (Pc <Pa). Moreover, a clean haze is generated in that the extractor 10 'also sucks stale air 34, and generates a clean air 24 which is directed towards the fog stage 22. The harmful particles are retained at of the filtering system 11 '. The mist generated can be charged with harmful particles, and drag them to the ground, and / or cool the interior atmosphere of the containment 3. For example, one can realize a system having one and / or the other the following characteristics: - Fog range: 5 to 15 m, - Fog area: 100-200 m2, - Fog volume: 400-800 m3, - Carter and channel made of plastic or other material, - Autonomy: 30-1001 water consumed per hour More powerful machines are possible, which would achieve a much greater range, area, fog volume. Alternatively, the channel 8 may exist in several forms and / or dimensions, or be telescopic, for example. The elements of the misting system can be separated and sealed together, or integrated into a single device more or less compact.

In variants, it will be possible to use several misting systems distributed around the structure to be decontaminated. As a variant, the misting system could not be placed entirely inside the confinement 3. For example, it would be possible to connect the channel 28 at the outlet of one of the air extractors 10, the channel 28 thus extending between a first end out of the confinement and a second end inside the containment. The channel 28 then passes through the barrier 4 sealingly to the contaminating particles. In such an embodiment, the air extractor 10 connected to the channel is not necessarily guaranteed positive pressure. If necessary, the implementation of the misting system is programmed. For example, the misting system operates according to a pre-defined program. Alternatively, the implementation of the misting system can be controlled according to one or more parameters. The parameter (s) in question may be parameters of the decontamination. A parameter sensor may be arranged to measure the parameter. A central unit can process the detected information and control the fogging system accordingly. For example, the parameter or parameters may comprise a parameter representative of the air inside the enclosure. A parameter is for example hygrometry at one or more places inside the enclosure.

In this example, the sensor comprises a hygrometer.

Claims (14)

REVENDICATIONS1. A method of decontaminating a structure comprising: installing a confinement (3) author of the structure (2), the structure (2) is deconstructed, thus generating inside the confinement (3) a vitiated waste including contaminating particles from the structure (2) being dismantled, a flow of clean air (24) is generated inside the confinement, by sucking the contaminated air (34) carrying contaminating particles from inside the containment (3), retaining the contaminating particles. at the level of a filter (11 ') passing a clean air (24), and driving the clean air (24) thus obtained inside the confinement (3), is generated inside the confinement ( 3) a mist (21) of liquid droplets by associating at the level of a misting nozzle (23) arranged inside the confinement (3) an inlet of liquid to be dispersed and the flow of clean air (24) generated. 2, A method for decontaminating a structure according to claim 1, wherein inside the confinement (3) a clean air flow (24) is generated by means of a system (14) arranged integrally with the inside confinement (3). 3. A method of decontaminating a structure according to claim 1 or 2, wherein the exhaust air is sucked by means of a pumping system (26) housed in a housing (27), and in which the air is maintained. inside the housing (27) under pressure. 4. A method of decontaminating a structure according to one of claims 1 to 3, wherein a mist (21) of droplets is generated by combining at a plurality of misting nozzles (23) disposed at interior of the containment (4) an arrival of liquid to disperse and the flow of clean air. 5. A method of decontaminating a structure according to claim 4, wherein the flow of clean air (24) is generated along a feed axis (X), the flow of clean air (24) is dispersed radially by relative to the supply axis (X), the misting tricks (23) having been arranged radially with respect to the supply axis (X) and circumferentially spaced from one another. 6. A method of decontaminating a structure according to rune claims 1 to 5, wherein the fog (21) is generated by means of a channel (28) for supplying clean air flow (24) having a mouth (28b) opening into the confinement (3), and in which the mouth is placed alternately in the open state during deconstruction and in the closed state. 7. decontamination process according to one of claims 1 to 6, wherein the clean air flow (24) is conducted upwardly between the suction and the fogging nozzle (23). 8. System for misting a structure adapted for implementing the decontamination process of claim 1, comprising: a housing (27) associated with a confinement (3) surrounding the structure (2) to be decontaminated, a pump (26). carried by the housing (27) and adapted to suck stale air (34) comprising contaminating particles from the structure (2) being deconstructed, a filter (11 ') carried by the housing (27) and adapted for retain the contaminating particles and let a clean air (24), a channel (28) for conducting a flow of clean air (24) inside the containment (3), a misting nozzle (23) receiving an influx of liquid to be dispersed and disposed in the flow of clean air (24). The misting system of claim 8, wherein the conduction channel (28) and the misting nozzle (23) are carried by the housing (27). 10. A misting system according to claim 8, wherein the channel (8) of conduction and the mist nozzle (23) are carried by a box (32) alternately sealingly engageable with the housing (27) and dissociable thereof. this. Misting system according to one of claims 8 to 10, comprising a non-return valve (31) between the filter (11 ') and the misting nozzle (23), adapted to prevent a displacement of contaminating particles in the direction from the misting nozzle (23) to the filter (11). 12. misting system according to one of claims 8 to 11, wherein the housing (27) is maintained in overpressure. 13. A decontamination system comprising a misting system according to one of claims 8 to 12, and further comprising a confinement (3) adapted to surround the structure (2) to be decontaminated, and at least one air extractor (10). ) associated with the containment (3) and having a pumping end (10a) disposed inside the confinement (3), and an extraction end (10b) disposed outside the confinement (3). 14. Decontamination system according to claim 13 in kit.