INERIS J P Pineauc

Pare Technoiogique Alata

EXCHANGES BETWEEN RESEARCH ORGANISATIONS IN THE FIELD OF INDUSTRIAL RISK Uncerrtified Translation

Since the beginning of the twentieth century, coal mines research institutes have had cooperation in accident prevention and emergency responses in case of catastrophic events. Therefore, it was possible to decrease the number of accidents and the extent of effects. The acquired experience was exchanged during meetings of directors and of experts of Research Institutes.

Mainly owing to the diminution of the number of coal mines, these institutes evolved to become more involved in other fields such as chemistry, oil, metallurgy, agro and food industries where the effects of accidents could be catastrophic. Accidental phenomena, in which these institutes are working, are emissions in air, releases in soil and water, fires and explosions.

After a brief introduction on INERIS, lessons learnt from cooperation between the Central Mining Institute -CMI -, Katowice, Poland, INERIS and the Research Mining Institute -RMI -Ostrava-Radvanice, Czech Republic, will be dealt with. First in coal mine field and then in other industries, such various aspects as prevention and investigation of accidents, knowledge dissemination through technical papers, courses and guidance books for users and exchanges of technical information during experts meeting will be considered. Development proposals will be also mentioned. Needs in industrial risk assessment in Central and Eastern Europe will be dealt with. Finally, suggestion will be given on how to improve the organisation and coordination of the assistance programmes.

As a public organisation, mainly involved in France and European countries, INERIS has an expertise in Industrial Safety and Environment. The proposed services are mainly based on the experience gained through the work performed for the French Ministries of Environment, Health, Industry, Interior, Labour and Transportation and Equipment and Regional Directorates for Industry, Research and Environment. It carried out also lots of work for insurance companies and industrial firms. They are related mainly to petrochemical industries and refineries, mines, metallurgical, chemical, polymer, agricultural and food processing industries.

0) The ideas and opinions expressed in this document are those of the author at the time of the meeting and do not commit the French Public Authorities.

In the field of the hazard identification and risk assessment, INERIS got a recognized experience on phenomenons of fire, explosion and emission in air through experimental tests, modelling and investigations of accidents [START_REF] Pineau | Mavrothalassitis Accident investigations : a need for safety analysis and emergency response, ER'93[END_REF]. Funding is mainly given by French organisations but also at European level (STEP, Prenormative Research for the Bureau Communautaire de Reference, Copernicus, EUREKA, BRITE EURAM programmes).

A long term work is devoted to evaluation of commercially available softwares dealing with the assessment of the effects of major industrial hazards [START_REF] Mavrothalassitis | Use of pertinent softwares in risk analysis SRA-Europe[END_REF]. INERIS is also a member of the Model Evaluation group (Directorate 12 of Commission of European Communities).

In 1990, the author was chosen as an OECD Consultant for a workshop held on Emergency preparedness and response and wrote the document referenced under 3. INERIS is regularly involved in safety cases (and their critical analysis) for the above mentioned industries.

Finally, INERIS has a long experience in the development and use of sensors for toxic and flammable gases in the atmosphere.

COOPERATION IN MINE FIELD

International meetings on safety in coal mines were held, on a regular basis (every two years), since 1931 at the director's of Research organisations level. These meetings were firstly devoted to mining explosives, flame-proof electrical machinery and explosion risk. Then the covered field was extended to the prediction of methane emission and environmental monitoring, to respirable dust, to diesel engines and to the reliability of systems and formal methods for assessment of safety and reliability.

In the risk field, experts meet every year on safety problems arising from mining explosives uses and means to fight the explosion effects. In addition to CMI and INERIS experts, representatives of Belgium, Germany, Spain and United Kingdom are present.

A regular bilateral cooperation exists between CMI and INERIS for many years. For example, in order to avoid the effects of an explosion from pyrolysis gases in mine galleries when fires occur, it is possible to install physical foam barriers able to withstand such an explosion. For the definition of the installation rules for such devices, a joint experimental programme was carried out with a French foam at the CMI Experimental Mine Barbara. The results were analysed by teams of the two institutes and then applied to French mines by INERIS scientists.

Information exchanges on Mine Accidents and Regulations are also dealt with in experts meetings.

For modelling gas emission (air, nitrogen, methane) from coal seams, tests were carried out in the Polish Mine SZCZYGLOWICE in a face and goaf system. This mine was chosen because it was possible to change in a rather large domain the ventilation rate. The performed tests allowed to validate a model previously defined at INERIS. A tracer gas method was used in these experiments.

COOPERATION IN INDUSTRIAL FIELD

Cooperation between CMI and INERIS was until recently dealing with industries (agro and food processing, chemistry, metallurgy, oil...) in which combustible dusts are present and may induce fires and/or explosions.

Until mid 93, this cooperation involved the participation of experts of both organisations in conferences held every two years in Poland on Industrial dust explosions (6) (7) [START_REF] Cybulski | Sliz Suppression of grain dust explosions with triggered barriers Fifth International Colloquium on Dust Explosions[END_REF] and in courses given in France by INERIS for industrialists and insurers [START_REF]Aide a la conception d'installations protegees contre I'incendie et I'explosion CERCHAR, Formation continue[END_REF].

In 1992, for the COPERNICUS European call of proposals, CMI, INERIS and RMI defined and proposed a project dealing with a guidance book on fire and explosion protection in agro and food processing industries. This project was accepted and was initiated in January 94 for a 2 years period.

The first stage of this work is to share previous experience in accident analysis, research results and use of regulations. Various tasks concerning the types of facilities, the processed products, the competent authorities in charge of the regulation, the professional associations, the engineering societies and the collection of accident data are finished.

Three stages are experimental to get new knowledges, either at CMI (on two protection systems : triggered barriers and venting devices) or at RMI (fire risk in powdered material storages).

The last step will be issuing a guidance book defining Safety measures to be chosen when designing, building or managing a facility. This guide will be presented during technical seminars in the three countries.

Since end 1994, in a cooperation project financed by the French Foreign Affairs Ministry, INERIS is dealing with the use of a methodology for safety case as applied in France for plants in which major technological hazards exist. This work is the consequence of a previous one managed by the French Ministry of Environment on Administration Engineering in Czech Republic and Slovakia. In cooperation with the Regional Directorate of the Czech Ministry of Environment, the Economic Development Agency in Ostrava, a plant "Moravske Chemicke Zavody" in which ammonia is stored is concerned by a case study.

A joint Czech-French team was created. Until now, a training course by French partners was performed on the methodology to be used. The Czech partners will then use it for the case study. A critical analysis of the safety case will be done by the French partner. Finally, a joint methodology should be defined.

DEVELOPMENT PROPOSALS

A further step on cooperation between CMI and INERIS is proposed between 1995 and 1997 referring to scientific and technical cooperation between France and Poland. The objective will be the development of protection means on industrial risks particularly for mitigation of gas and dust explosions. This project is directly related to chemical, agro and food, fondries industries. Methodologies for risk assessment and measures to fight the effect of explosions and fires will be developed.

INERIS is also involved for some years in work done in European Safety and Reliability Data Association (ESReDA), the objective of which being the data share in safety, reliability and safe working conditions. For this association, INERIS convenes a working group on analysis of accidents in which dangerous substances are involved in chemical plant and in transport. In a first stage, this working group in which representatives of Finland, Germany, Italy, the Netherlands, Norway and United Kingdom are present, was looking through a questionnaire enquiry at strengths and weaknesses of existing date bases. The results were shared during an ESReDA internal seminar on accident analysis (10). Until now, this work was only dealing with Western Europe databases. In a new stage, to be undertaken in 1995, a Directory of Databases on accidents will be carried out and the integration of Central and Eastern Countries is a necessity. In order to harmonise the chemical risk assessment throughout Europe, harmonised data collection is a prerequisite for the development of common policy on prevention and emergency response.

INERIS is also a member of a consortium dealing with the EUREKA project MEMBRAIN, the objective of which is the development of a standard software integration platform to enhance the capability of Major Emergency Management decision makers. This project began end 1993 with Danish, Finnish French and Norwegian partners. End 1994, LODZ (Poland) voTvodship entered the consortium. The leading of the project is assumed by CAP GEMINI INNOVATION (FRANCE). INERIS has carried out a field research on how to choose reliable and dependable atmospheric sensors to look at the development of accidental scenarios in which flammable and toxic gases are involved. Again, this could be an opportunity to define a harmonised policy and means to manage chemical emergency situations [START_REF] Accorsi | Villeneuve de Janti Reliability and dependability of atmosphere sensors data in accidental situations on chemical sites To be presented to International aspects of emergency management and environmental technology[END_REF].

NEEDS IN INDUSTRIAL RISK ASSESSMENT FOR EASTERN AND CENTRAL EUROPE COUNTRIES

The conclusions given here are based on a long-term, more than 20 years, but limited cooperation mainly with two research organisations in Poland and Czech Republic. Needs were identified respectively for competent authorities, industrial firms, research and consultancy organisations and organisations implied in emergency.

1) Competent authorities :

The Administration reorganisation and the willingness of countries in transition to be competitive in world markets impose, as a prerequisite, to make reference to a safety policy. A stepwise planning must be induced by competent authorities for applying European Directives and Standards related to prevention of chemical accidents (Seveso, Machine, potentially explosive atmospheres, construction materials, transportation of dangerous goods, chemical materials directives) and mandated CEN standardisation technical committees (TC 114, TC 305...) for application of directive requirements. Means for risk assessment in plants with major technological risks are to be defined and used. These means should be extended to all chemical plants.

Collection and Analysis of accident reports is also a mean to verify the fitness for purpose of the safety policy and to define where safety efforts have to be undertaken. These authorities shall rely on teams active in developing knowledge in the field of risk assessment and accident investigations. These teams shall be involved in European Information exchange group on Directives and work in standardisation groups (CENELEC, CEN).

2) Industrial firms

For the development of the chemical sector, a new safety culture is to be considered for the countries in transition. The safety culture, the training of industrialists, the technical situation of the chemical field must be first analysed to define goals. Joint teams from developed an in transition countries need representatives of competent authorities in order to integrate the partnership concept. An evolution of a safety policy relies also on enough financial means for training people in charge of managing plant, and of designing, building and maintaining facilities. These actions have to be adapted in the various industrial domains and imply the participation of consultancy and engineering companies. This aspect could be illustrated by the above mentioned work performed in Ostrava region.

3) Research and Consultancy organisations

These organisations must be involved on a contract basis with industrialists and competent authorities for the definition of projects to increase knowledge. These projects must take into account the exact nature of chemical products and equipment, machine and facilities used. Technical guidance books or codes of practice are to be written jointly between interested parties. This work is complementary to the one devoted to the development of new directives and standards which have very broad objectives.

4) Organisations implied in emergencies

Tools to be used for planning and response emergencies are to be developed considering the current situation, the existing means and the necessary funding for personnel and equipment. Local teams have to be trained during exercises using real case conditions.

HOW TO IMPROVE THE ORGANISATION AND COORDINATION OF ASSISTANCE PROGRAMMES

Note : the conclusion are only based on lessons drawn from cooperation with two countries : Poland and Czech Republic.

Integrating the economy of countries in transition in world economy implies, as an important point, closer contacts with possible partners.

These contacts are to be promoted within various contexts : seminars, working groups on European regulation and standardisation, exchanges of people between competent authorities research organisations, consultancy organisations and industrial firms of involved countries. The philosophy of a network of partners is to be developed.

The success of projects in which INERIS was active, lies on longstanding contacts between such organisations as Central Mining Institute in Poland and Research Mining

Institute in Czech Republic and on the long term common work. Considering the specific action related to safety case methodology for a chemical plant in Ostrava (CZ), the objective of training Czech partners has been reached owing to the fact that a previous regulatory approach was jointly performed by representatives of the Czech and French Ministries of Environment.

The success is also to be related to the financial support of industrialists and governmental and European organisations to the projects. Financial assessment fitted to projects on chemical accidents is to be developed during the discussion of projects ; the possible project leader must be aware of the distribution of various costs in the different countries.

In general, it must be emphasized that the effective development of programmes on chemical accidents is only possible when competent networks allowing regulatory, industrial and financial assessments are in place. A specific action must be focused on creating independent international clearing houses for assessment of projects.

Through this long term cooperation with Czech and Polish Research Organisations, INERIS was also in a position to get knowledge developed in both these countries and to apply it in France.


Didier Lacroix

Full Size Testing of Drainage Systems for Burning Liquids in Road Tunnels

Introduction

Most vehides transporting dangerous substances on road are liquid hydrocarbon tanks. When their passage is permitted in a tunnel, measures should be taken in order to limit risks in case of an accident. Thus, the recent French road tunnels are equipped with collecting Systems for burning liquids spilled on the pavement. The objective is to reduce heat and smoke produced by a fire, to limit fire propagation to other vehides, and to enable rescue teams to approach the fire.

On the occasion of the doubling of the Chamoise Tunnel, on the A.40 motorway between Lyon and Geneva, a general study of these sytems has been financed by the French Qovernment and Societe des Autoroutes Paris-Rhin-Rhöne (S.A.P.R.R.), the semi-public Operator. The study was defined and followed up jointly by SCETAUROUTE, contractor to S.A.P.R.R., and Centre d'Etudes des Tunnels (CETU), which ensured the general guidance and conducted the hydraulic tests. The Institut National de l'Environnement Industriel et des Risques (INERIS) was charged with risk studies and fire and explosion tests.

Preliminary studies

Traditionally water running on the pavement in road tunnels is collected through open gutters along the pavement, then discharged into a collector through 50-100 m spaced gully holes. In order to improve absorption for dangerous substances SCETAUROUTE use gully holes at narrower inten/als, about every 10m. For their part CETU drew elements from the

Fig. 1: Schema of a drainage System with continuous slot gutters and Siphons

Swiss facilities and elaborated continuous slot gutters which communicate with the coliector via gully holes with siphons, in order to extinguish burning liquids (figure 1).

Very few literature data are available on the efficiency and possible risks of such Systems, either in tunnel or in other structures, e.g. oil industry. This justified a testing Programme.

The statistics on dangerous substances accidents on open roads and in tunnels have been analysed and allowed to consider representative study cases:

-continuous leakage of 30-70 l/s corresponding to a component breakage or a puncture of 100-150 mm in diameter;

-sudden release of a volume corresponding to the average recorded spillages, i.e. 5 m 3 excluding the extreme cases, or 10 m 3 including the few most important cases.

Hydraulic tests

The first experimental phase was performed in six operated road tunnels, in order to make a hydraulic evaluation and comparison of the various collecting Systems.

Testing methodology

Water was used for obvious reasons of safety and convenience. The continuous leakages were obtained by running water out of the tunnel fire hydrants. A prefabricated 3 x 3 m pool, with one side that could be opened suddenly, was used to simulate the sudden spillages of 5 m 3 and 10 m 3 , undergood reproducibility conditions.

Three camescopes recorded the tests in order to characterize the wet surface during the spillage operations. The pavement was squared by retroreflective, self-adhesive strips and numbered studs which also allowed tö measure the water depth. When allowed by the site, the water height was permanently measured in the gutters.

Test results

The observation with time of the liquid sheet let appear three successive, interacting flowing zones (figure 2):

-A first zone can be qualified äs inertia zone, because it is a function of the liquid release conditions, principally its ejection speed;

-The second zone is determined by the gradient, the transverse slope and the surface characteristics of the pavement; the liquid flows in the general direction of the principal line under the effect of gravity;

-In a third zone, also a gravitation one, the liquid not absorbed into the gutter flows along the sidewalk edge before being removed through the drainage System.

We called them zone B the first two surfaces together: it corresponds to the minimal sheet extension that would be obtained if all water reaching Table 1 presents the characteristics of the tested tunnels, and gives äs an example the main results obtained with the sudden release of 10 m 3 . Figure 3 shows the extent of the wet zones in this case. The continuous leakages and sudden releases of 5 m 3 led to comparable situations, but obviously with smaller wet surfaces and lengths.

Congres

Main conclusions

In all cases it appears that the conventional System -moreover badly maintained -of the Monts Tunnel is particularly little efficient. The wet surface exceeds 1000 m 3 , even for a continuous leakage of 35 l/s ! The comparison of zones A shows that the slot gutters prove to be the most efficient facilities. Among the two tested types of slots (figure 4) those with the opening in the vertical plane benave best: the zone A is non-existent in the Cornil and Siaix Tunnels, even for a sudden release of 10 m 3 . This arrangement indeed allows to utilize directiy the flow dynamics to remove the liquid. In the Grand Märe Tunnel, where the slot opening is in the horizontal plane, the liquid is collected under the action of gravity only and therefore not so well intercepted.

In this last tunnel, the slot gutter is also hindered by its inner diameter of 200 mm, which proves insufficient and forces the liquid back in case of heavy release.

The diameter of 400 mm installed in the two other tunnels is satisfying.

Siphons there also showed a proper hydraulic behaviour: in the Siaix Tunnel, the volume of 10 m 3 was drained through the gully hole within 50 s, which corresponds to an average flow of 200 l/s.

The lower performance of Systems with gully holes at small interval in the Chätillon and Saint-Germain-de-Joux Tunnels can be explained by the very principle of the gully holes and their design, which only allow an insufficient absorption. In addition the presence of small open gutters, 30 cm in width and 3 cm in depth, along each sidewalk (including at the transverse slope top) induces the formation of very long liquid "tongues" on both sides of the pavement.

Other Statements

Except the case of the Monts Tunnel, water needs less than 2 minutes before being removed from the pavement after the end of the continuous or sudden spillage. In the Grand-Mare Tunnel, however, where the pavement is coated with pervious bituminous concrete, some liquid continues to flow below the wearing course for over 15 minutes. Questions may be raised about the risks resulting from this lasting presence of dangerous substances inside the tunnel.

Lastly it must be mentioned the flowing problems noted in certain drainage Systems, which induced liquid to be forced back onto the pavement, thus raising a potential risk. Such phenomena resulted either from a narrower hydraulic section at the gully hole entrance, or from the presence of debris due to insufficient maintenance. Obviously the strict avoidance of such situations must be reached.

Fire and explosion test

As the Systems including slot gutters proved to be properiy operating from the hydraulic point of view, it appeared necessary to test then regarding fire and explosion risks.

The basic purpose of these tests was not only to check the efficiency of the facility for extinguishing and removing a burning liquid, but also to characterize the mechanisms implied in dysfunction situations. This explains that numerous tests have been devoted to such cases, although they are exceptional.

Methodology

The experimental facility

For safety reasons, tests could not be made Underground. The selected site was the INERIS Montlaville open site in Verneuil-en-Halatte.

As no similarities allowing a reduced scale study were available, a section typical of a drainage System was reproduced in füll size. It included two Siphons separated by a 48 m long slot gutter communicating with a collector which crosses the facility from one end to the other (figure 5).

Povi

Horizontolly opened slot

Verticolly opened slot The gully holes and their siphons were the same äs those installed in the Siaix Tunnel. The internal volumes were numbered from 1 to 4 in the liquid flowing direction.

A second facility, consisting only of two coupled gutter sections (6 m) allowed to characterize more stationary phenomena. The System is sealed at both ends, so that the combustion corresponding to various filling up levels can be tested.

Measuring principles

The facility is provided with a complex measuring equipment including thermocouples, flame detectors, pressure sensors, explosimeters, etc. These appliances are distributed in the sensitive zones according to the expected phenomenologies.

All data are sent back to a collecting Station. This has a completely selfsustaining Operation, since the personnel has to stay beyond a safety limit during most tests.

The visual observations are strengthened by four video cameras focused onto the sensitive points of the facility.

Spillage principles

The product selected for these tests was unleaded gasoline, because this liquid counts among the most dangerous ones which are representative of the risk connected with the transportation of inflammable liquids in tunnels.

For safety reasons, and in order to get a better characterization of the phenomena, the Spillage implying burning gasoline did not use quantities so high äs for the hydraulic tests. All tests were conducted with flows of about 3 l/s.

Survey of the experimental testing series

Two experimental testing series were conducted at an interval of one year.

In a first approach (in 1993) one tried to characterize the behaviour peculiar to each component of the drainage System. It appeared then that the exchanges occuring at the limits of each element were determining for the general phenomenology. The second series (in 1994) therefore focused on more global behaviours.

In total twenty-five tests were conducted. This figure does not include a few preliminary tests made without ignition.

Demonstrated basic phenomena

Fire

The fire developing in a drainage System is submitted to constraints in relation to the confined environment. This latter limits the oxygen quantities available for the combustion mechanisms and hinders the removal of burnt gases. These conditions may lead to self-extinction.

Maintaining the combustion requires a sufficient movement of gases. The mainspring of this System consists in the Archimedean Stresses developed mainly at the fire level. This process of fresh air supply will be called below "respiration".

Explosion

The risk analyses show that gasoline can enter the drainage System without burning. Vapours therefore can develop there. The confined environment generally succeeds in maintaining them at a high concentration.

The explosion risk is a function of gasoline vapour concentration at the instant of ignition. For the unleaded gasoline used for the tests, the atmosphere is made deflagrable by hydrocarbon contents between 1.4 and 7.6 %. It was demonstrated that the phenomena which occur at various points of the facility cannot be dissociated in a global phenomenology. It is possible, however, to describe the response peculiar to each system element to a fire.

All mechanisms described here have been brought out by the observation and analysis of recordings made during the experiments.

Gutter

In a normal Operation Situation the gutter is the only element in the drainage System to have a volume in direct contact with the tunnel atmosphere. All tests show that a gasoline fire in the slot gutter is little violent and does not produce much smoke. In a tunnel the generated opacity will therefore be lower than that could be expected in such an event. This is therefore a rather favourable Situation.

Various observations show that two respiration modes are in rivalry:

-a transverse mode in which fresh air flow and burnt gases flow must cross in the slot thickness (6 cm); -a longitudinal mode which supposes that no combustion exists in a zone near the flame (figure 6).

A number of tests with blocked longitudinal respiration movement (small gutter length, or flame on the whole slot length) lead to self-extinction. They tend to demonstrate that the transverse respiration mode is very fragile.

These tests generally correspond to very particular experimental protocoles. The other tests show that the maintained combustion remains the most probable hypothesis. In other words the fire self-extinction in the gutter, although possible, does not appear äs a probable phenomenon in a realistic scenario.

Siphon a) Firebreak role of the Siphon

In presence of a hydraulic Isolation -even gasoline -the siphon ensures its firebreak role. Tests show that the flame never succeeds in reaching the downstream compartment.

b) Respiration mode in normal Operation

The tests which imply a siphon fire show that the combustion process is being maintained there provided that the longitudinal respiration mode has already settled in the gutter (figure 7). The second condition supposes that the fresh air flow and the burnt gas flow cross in the entrance hole. This movement can be easily disturbed and several cases of self-extinction have been observed. In the general case, where fire lasts, the combustion process is low. The hydraulic Isolation divides the siphon -and more generally the drainage System -into two distinct volumes with respect to the gaseous phase. As soon äs this separating role is altered the System enters a disfunction regime. Several plausible situations have been tested:

-If the Isolation is composed of gasoline its level decreases when combustion is being maintained in the upstream 1-2 compartment. In a test where this isolation has become insufficient to preserve its separating role, it has been observed that the explosible atmosphere developed in the downstream 3-4 compartment was sucked then burnt by the flame, without any explosion phenomenon. This test was conducted in siphon B where the head loss in the collector is low (figure 5).

-For comparable tests conducted in siphon A, the head loss in the collector was higher, and it has been demonstrated that the flame had been able to extend in the counter-direction from the upstream 1-2 compartment to the downstream 3-4 compartment, following the free space under the blade. In the most disadvantageous case an explosion was initialized in volume 4. In the other cases this compartment was the seat of a well-marked flash.

-If placed in Situation of double dysfunction (no hydraulic isolation and cover open on the downstream 3-4 side) the siphon does not play any more its role of firebreak protection towards a burning leakage. In return if the hydraulic Isolation is absent, but the downstream compartment still airtight, the absence of standing flame in the downstream part of the facility is guaranteed, although some ignition has been established during the very first instants during the tests. The contest between the speed of self-extinction and the raise of the liquid which arrives into the retention pool can explain that, before the overflowing, the flame has not found the conditions requirecTfor existing and has extinguished. In the inverse case it is not irrealistic to suppose a collector fire. The firebreak role of the siphon is then limited to maintaining conditions unproper to combustion in the downstream compartment.

d) Layering of gasoline vapours

After spillage, layering of vapours can induce a rapid Variation in explosibility conditions in the same volume and completely change the assessment of risk for the same type of experience. Severa! tests show that this gravitational movement is relatively quick in the siphon, although it appears necessary to relate it to volatility of gasoline which Is likely to vary according to the product manufacture (this depends on the period in the year).

e) Effects of explosion

In the most violent cases of explosion the concrete plates covering the Siphons are slightly displaced under the effect of overpressures. The cast-iron covers are thrown up and a short flame appears. In the other situations only the metal covers are ejected. When the phenomenon is limrted to a flash, this generally goes with a small Jump of covers which fall again in their seats (dang). The airtightness of the siphon is then maintained. The experimental configuration selected for the collector may seem particular, since due to its small length this duct cannot be considered äs representative of an actual facility (especially the aeraulic head losses are underevaluated).

In the absence of inflammable vapours already present in the collector the fire can last there only under the form of a front flame which follows the progression of a gasoline runnel. Behind this front extinction is imposed by the concentration of combustion products (figure 8).

The speed of this displacement depends on the speed of the gasoline runnel at the collector bottom. The existence of the flame therefore depends on the competition between this speed, the collector cross section and the production of burnt gases. Unbalance in these parameters can lead to self-extinction.

The inside surtace of the collector -a PVC pipe in the experimental facility -warped on the occasion of a temporarily stationary fire. This incident resulted in the complete sealing of the duct and the outage of the whole drainage System, which can hardly be repaired. Obviously such a material must be avoided, even äs a lost formwork.

b) Explosion

This phenomenon is expressed by a deflagration along the collector. It supposes that explosible conditions first grow up, äs those generated by the presence before the ignition of a gasoline runnel at the collector bottom. The demonstrated propagation speeds are higher than in the previous case and reach several metres per second (figure 8).

Although the explosion regime never exceeded that of deflagration, the collector is an element in which the flame front speed is likely to speed up, not at the scale of a collector section but rather at the scale of a complete facility. This risk remains at the state of assumptions, but it shows that it is wishable to break the continuity of this duct on the total length of the System.

Analysis of the risks raised by the collecting System

The previous experimental results allowed a comprehensive analysis of risks that may raise in the investigated facility, for all assumable scenarios. It appears from this assessment that a very high safety level is brought in case of accidental spillage of an inflammable liquid:

-The vertical slot gutter allows the very quick removal of the hydrocarbon sheet and therefore reduces the potential fire to a gutter fire, often little violent and which -in addition -does not produce much smoke.

-Very quickly, maximum after several tens metres, the hydrocarbon flow, burning or not, reaches the siphon. In presence of a hydraulic Isolation the siphon proves to be an essential safety factor by stopping the possible flame, also by isolating the flow from the tunnel environment, äs the hydrocarbon pursues its way in the collector. In some cases a little violent fire characterized by a low combustion speed may settle down in the upstream part of the siphon. Its effects remain small during several hours and extinction with foarn is easy.

The study of risks also considered the dysfunction situations of the System, such äs partially damaged siphon covers, or the absence of hydraulic Isolation. Most of time the effects are limited in their gravity.

The most severe scenario occurs.in case of hydrocarbon and inflammable vapours associated in the collector. The starting and propagation of an explosion in this part of the facility can lead to projected covers and flames coming out. These effects will then regard the immediate environment of the Siphons, and their gravity will depend on the collector length affected by the explosion development.

Such dysfunctions must be prevented by adapted supervision and maintenance, in order not to affect the safety potential provided by the System.

Conclusion

The experimental results summarized above are closely related to the geometry peculiar to the tested System, and extrapolating them to other layouts requires a lot of precautions.

Reflections are still necessary for drawing maximal advantage from the experimentation and optimizing the drainage Systems. Among the items to be examined, one can mention the design of siphons in order to reduce their volume (nearly 2 m 3 at present) without altering their qualities, their Installation so that they can "break" the way of a possible explosion in the collector, the minimal inside diameter for the slot gutters, the design of vertically opened slots consistent with low sidewalk edges, etc.

This work is in process and will result in guidelines to be applied to French tunnels. It already becomes obvious that these guidelines lead to generalize the use of slot gutters and Siphons for all tunnels of a certain length permitted to the transport of dangerous substances. A special care must be brought to the maintenance of these Systems, which have an essential role in case of severe accident.

Summary

Tests in six road tunnels have permitted to compare the hydraulic efficiency of several Systems planned to drain possible burning liquids spilled on the pavement after an accident.

Fig. 2 :

 2 Fig. 2: Diagram of flowing zones

Fig. 3 :

 3 Fig. 3: Wet zones A and B for a sudden spillage of 10 m 3

Fig. 4 :

 4 Fig. 4: Possible schemes for continuous slot gutters Fig. 5: Diagram of the experimental System

Fig. 6 :

 6 Fig. 6: Combustion or self-extinction mechanisms in the slot gutter

Fig. 7 :

 7 Fig. 7: Diagram offlows between the gutterand the siphon

Fig. 8 :

 8 Fig. 8: Combustion process in the collector

/ Resumes Versuche im Maßstab 1 : 1 mit Ableitsystemen für brennende Flüssigkeiten in Straßentunneln Eine

  Moreover an experimental, füll size facility of 50 m in length including slot gutters, gully holes with siphons and a collector has been subjected to twenty-five fire and explosion tests. Lessons are drawn on the interest and safety of such a System. zunehmende Zahl von französischen Strassentunneln genehmigen den Transit von gefährlichen Gütern. Diese betreffen hauptsächlich flüssige Kohlenwasserstoffe in Tanklastwagen. Im Fall eines Unfalles mit Leckage muss unbedingt das Abwassersystem die rasche Ableitung dieser Flüssigkeiten erlauben, um die Entwicklung eines möglichen Feuers zu vermindern und seine Ausbreitung zu vermeiden. Verschiedene Ableitungssysteme wurden seit mehreren Jahren in Frankreich in neueren Strassentunneln installiert und untersucht: Sie sind entweder klassische Wasserrinnen den Gehweg entlang mit Sinkkästen in geringem Abstand, oder kontinuierliche Schlitzrinnen, die von den Sammlern durch Siphons getrennt sind, um die Übertragung von Bränden zu verhindern. Bevor solche Systeme zu verallgemeinern sind, schien es notwendig, die Wirksamkeit jeder Lösung experimentell zu vergleichen und die Feuer-und Explosionsrisiken, die von der Einrichtung ausgehen konnten, zu analysieren. Eine erste Versuchsreihe betraf die hydraulische Wirksamkeit der Sammlungssysteme. In sechs betriebenen Strassentunneln wurden Ver-suche mit einer kontinuierlichen Strömung von reduzierter Leistung (20 bis 30 l/s) und raschen Freigaben von 5 und 10 m 3 durchgeführt. Wasser wurde verwendet, um den gefährlichen Stoff zu simulieren. Ein zweiter Versuchstyp betraf eine experimentelle, mehr als 50 m lange Einrichtung in natürlicher Grosse, die mit einer kontinuierlichen Schlitzrinne, Sinkkasten und einem Sammler versehen wurde. Bleifreier Superkraftstoff wurde verwendet, um die verschiedenen Feuer-und Explosions-Ausbreitungsphänomene in der Einrichtung zu analysieren. Zahlreiche Versuche wurden durchgeführt, u.a. auch unter Bedingungen, für welche das Ableitungssystem fehlerhaft war. Die Ergebnisse wurden verwendet, um die Risiken der Einrichtung zu analysieren, und daher die Betrachtung aller möglichen Betriebsfälle des Ableitungssystems zu erlauben. Der Vortrag stellt die Resultate dieser Untersuchungen vor und die Schlußfolgerungen, die für Tunnelprojekte über die Rinnengestaltung, die Knienutzbarkeit und -gestaltung, die Sammler, Einrichtungsunterhaltung, usw. gezogen werden können.

	Kurzfassungen / Abstracts

Füll Size Testing of Drainage Systems for Burning Liquids in Road Tunnels

The transit of dangerous goods is permitted in an increasing number of French road tunnels. Most of these substances are liquid hydrocarbons in bulk. In case of spillage, the drainage System must discharge these liquids very quickly, in order to reduce the severity of a possible fire and prevent its propagation. This is the reason why various drainage Systems have been studied for several years and applied in recently built tunnels in France: they are either conventional water gutters along the sidewalk, provided with gully holes at short inten/als, or continuous slot gullies separated from the collectors by Siphons aimed at extinguishing the burning liquids. Before generalizing such Systems it appeared necessary to make an experimental comparison of the efficiency of the various solutions and to examine the fire and explosion risks that may be generated bythe facility.

A first testing Programme concerned the hydraulic efficiency of the drainage Systems. In six road tunnels under Operation, tests have been performed with a continuous limited flow (from 20 to 30 l/s) and a sudden release of 5 and 10 m 3 . Water was used to simulate the dangerous goods.

A second series of tests was conducted on an experimental füll size facility exceeding 50 m in length, provided with a continuous slot gully, gully holes with Siphons and collector. Unleaded super fuel was used to study the various phenomena of fire propagation and explosion risk in the facility. Numerous situations were tested, including malfunctioning of the drainage System. The gathered data have been used to analyze the risks of the facility, allowing the consideration of all possible scenarios for operating of the drainage System.

The paper presents the results of all these studies and draws conclusions for tunnel projects, regarding the design of gullies, the usefulness and design of Siphons, the collectors, the maintenance of the facility, etc.

Essais en vraie grandeur de systemes de recueil des liquides enflammes en tunnel routier

Un nombre croissant de tunnels routiers francais est autorise au passage des matieres dangereuses. Celles-ci sont majoritairement constituees d'hydrocarbures liquides en citerne. En cas de deversement accidentel, il est indispensable que la Systeme d'assainissement puisse evacuer tres rapidement ces liquides, afin de reduire l'importance d'un eventuel incendie et d'eviter sä propagation.

C'est pourquoi depuis plusieurs annees differents systemes d'evacuation ont ete etudiees et mis en oeuvre dans les tunnels recents en France : il s'agit soit de fils d'eau classiques en bordure de trottoir, comportant des regards avaloirs ä intervalles rapproches, soit de caniveaux ä fente continue, separes des collecteurs par des Siphons destines ä eteindre les matieres enflammees. Avant de generaliser de tels systemes, il a paru necessaire de comparer experimentalement l'efficacitö de chaque solution et d'examiner les risques d'incendie et d'explosion que l'installation pouvait engendrer.

Une premiere campagne d'essais a concerne l'efficacite hydraulique des systemes de recueil. Dans six tunnels routiers en exploitation, des essais ont ete realises avec un ecoulement continu de debit limite (de 20 ä 30 l/s), et avec des relächements brutaux de 5 et 10 m 3 . De l'eau a ete utilisee pour simuler la matiere dangereuse.

Un deuxieme type d'essais a ete realise sur une Installation experimentale en vraie grandeur de plus de 50 m de longueur, comportant caniveau ä fente continue, regards munis de Siphons et collecteur. C'est du supercarburant sans plomb qui a ete utilise pour examiner les differents phenomenes de propagation d'incendie et de risque d'explosion dans l'installation. De nombreuses situations ont ete testees, y compris des conditions oü le Systeme d'evacuation presentait des defauts. Les donnees ainsi obtenues ont ete utilisees pour faire une analyse des risques de l'installation, permettant d'envisager tous les scenarios possibles de fonctionnement du Systeme d'evacuation.

La communication presente les resultats de l'ensemble de ces etudes et les enseignements qu'on peut en tirer pour les projets de tunnels quant ä la conception des caniveaux, l'utilite et la conception des Siphons, les collecteurs, l'entretien de l'installation etc.


A, LIZEUR, M. BENNANI, T. FELT INERIS P Bigarre

SYTMIS: SOFTWARE FOR REAL-TIME MICROSEISMIC MONITORING SYSTEMS

In order to apply the microseismic monitoring concept to study mechanical instabilities of rock masses, INERIS developed SYTMIS, a comprehensive Software package to design very low-cost but high performance, digital, monitoring and back-analysing Systems, based on Standard PC and/or Werkstation technologies. Designed to fulfil most field situations, SYTMIS also permit multiple monitoring from an unique central site, whether äs a standalone Computer or local area network. The paper describes in more details how controlling seismic regime of rock masses is important, how SYTMIS works and some of its current applications.

-INTRODUCTION

Any redistribution of Stresses (of mechanical, triermal, hydraulic origin) in a rock mass can result in irreversible deformations of the rock matrix and in anelastic readjustment of pre-existing discontinuities. It is possible to draw a distinction between quasi-static (or aseismic) deformations and dynamic deformations for which part of the elastic energy released by the fracture is propagated in the form of transient waves detectable over a very broad frequency spectrum usually ranging from 10 Hz to 200 kHz. We speak then of microseismic or seismo-acoustic activity. The microseismic activity of rocks is a phenomenon which, typically, can be observed in unstable rock masses or those under high stresses. Checking alone of measurements of quasi-static deformations cannot then be considered to be sufficient (see Fig. 1).

Remote microseismic or seismo-acoustic monitoring in real time is a fundamental approach in such varied fields äs: the monitoring of rock masses and local subsidences: extractive industries, hydrocarbon fields; Underground gas-storage reservoirs, radioactive waste; studies of seismic risks, monitoring of reservoirbasins; engineering of geothermaf fields and fluid injections; monitoring of unstable slopes and embankments; laboratory tests.

The study of acoustic Signals provides unique information on the damage to rocks and Underground workings, providing a iot of interesting material not accessible by observation. The recording and analysis of seismograms takes account of: the location and intensity of the fracturing produced; the behaviour of the pre-existing discontinuities; the transfers of stresses in the zone concerned; damaging mechanisms; the prevention of instability phenomena.

FMGM 95 -4th International Symposium, Bergamo, 10-12 avril 1995, p. 407-414

-REMOTE MICROSEISMIC MONITORING NETWORKS

In practice, a remote microseismic monitoring System usually comprises (see Fig. 2): 1-A network of Vibration transducers of the geophone, accelerometer or hydrophone type, characterised by two parameters, impedance and sensitivity, and whose Output Signal is proportional respectively to the velocity, acceleration or pressure of the transducer concerned.

The choice of a particular type of transducer depends mainly on the amplitude and frequency of the signats expected. 2-A Signal conditioning and transmission unit comprising elements such äs preamplifiers, amplifiers, filters for the conditioning part, insulators, modulator/demodulator,cable, transceiver for the transmission part. 3-A digital data acquisition and processing centre. Depending on the type of application the interpretation may comprise a simple record of measurements of particular velocities produced at a temporary Station (studies of vibrations/blasts).

For the most complex applications the System must be able to handle complete and real-time processing of the seismograms recorded by a network of several dozen stations distributed on one and the same site, including analyses of location, amplitudes and management of afarm criteria. In this case, the management of the database äs well äs the Optimum distribution of the automatic or interactive processing tasks on the data-processing network shall permit industrial integration of the Software in Standard hardware environments.

In order to satisfy all the objectives and quality requirements of remote seismic monitoring in real time, INERIS has developed the SYTMIS Software System. The main characteristics of SYTMIS are äs follows:

1-Because it is compatible with the Windows 3.1 (16 bits)/ NT (32 bits) and UNIX/X11 environments, SYTMIS makes it possible to convert any compatible PC Computer into a powerfui microseismic acquisition centre which is fully programmable and able to be adapted for any type of transducer and Vibration measurement networks. 2-SYTMIS provides Optimum modularity for the automatic processing of microseismic events.

It enables the automatic printing out of personalised graphic reports (any type of evaluation of measurements and seismic activity for the zones of interest, real-time alarm reports, . 3-SYTMIS offers every graphic faciiity for interpretation of the measurements, caiculations and results for a back-analysis of the seismic regime of the zones of interest. 4-SYTMIS makes it possible to manage several remote monitoring networks from a central site. The automatic management of the databases permits Optimum utilisation of these resources from a central Computer in the local data-processing network.

-MAIN CHARACTERISTICS OF SYTMIS

SYTMIS is a package of integral and modular Software based on the very latest data-processing architectures (C and C++ programming languages, Windows 3.1, Windows NT (32 bits), Unix-XH environments). SYTMIS has been designed for total portability to electronic hardware whose Standards, in tenns of performances and costs, are in a constant and rapid state of evolution.

SYTMIS comprises eight modules, namely : SYTMIScop : data acquisition. Driving one or more A/D boards depending on PC slots available, number of channels to be linked, and sampling frequency, it allows for «intelligent» response of seismic network, thanks to a complete, triggering Controller. SYTMIScop is fully featured for high reliability, digital seismic monitoring for most field situations, ranging from laboratory testing to macroscale networks. SYTMISauto : automatic waveform and seismic event processing. Integrating many built-in, easily adjustable functions, it offers all conventionnal caiculational procedures such äs P/S arrival-time pick-up, location and errors estimates (multilayered, inclined velocity model integrated), amplitude, mägnitude, energy, power and spectral analysis for both «on-line» or «off-line» processing. SYTMISview: interactive waveform and seismic event processing. It offers a high level graphic interface for displaying and analysing waveforms, for fast validation of caiculated parameters or more specific in-depth studies. SYTMIScom: easy-to-use command and computing language for automatic batch processing of seismic data and generating graphic reports. SYTMIScom gives access to selected störed events and user's own procedural caiculations using SYTMIS predefined variables. SYTMISbase: scientific and statistical analysis of seismic data. It incorporates a füll ränge of interactive functions for searching, extracting and displaying data related to seismic events, and proves to be a powerfui assistant for most routine investigations or in-depth research in seismic event parameters and sequences. SYTMIS4D : space-time graphic display of hypocentres with representation of structures probed. It constructs multi-windowed, space-time dynamic animations you need to understand interactions between rock mass and industrial/experimental activity. SYTMISpair: detection and processing of seismic doublets. SYTMISnet: remote control of monitoring Systems and microseismic sub-networks. It allows you rational contro! of on-site stations and collected data from central site.

Since SYTMIS ensures dynamic loading/tracking of network, processing and caiculated parameters from both database and event files, only two configuration files are needed for the whole environnement to be run : one for the acquisition unit, and the other for automatic processing. This architecture ensures safety and easy retrieval of used parameters at any time (report printout, parametric studies, reprocessing of data on standalone Computer,...).

-EXAMPLES OF SYTMIS APPLICATIONS

4-1 Real-time seismic monitoring of deep coal mining

The seismic network of the Provence U.E. mine consists of 9 seismic stations (geophones, 15 channels) distributed at the surface and Underground over a radius of about 2.5 km around the central site. The remote seismic monitoring makes it possible to track, in real time, the tremors generated by the advance of the working fronts located more than 1000 metres Underground. Depending on the rate of advance, more than 100 seismic events of a local magnitude between 1.4 and 3.2 may be recorded every day. To compensate for the Saturation of the Signals for events of magnitude less than 2.7, several stations are equipped with dual-gain channels providing better dynamics of the network (15 channels in total).

The automatic data acquisition and processing System is based on the .SYTMIS Software environment (see Fig. 3). The acquisition centre consists of two PC/386 compatible type Computers, situated in parallel, which in their turn perform the data acquisition in a master/slave logic System. The Master/Slave communications protocol, integrated in SYTMIScop offers Optimum reliability in the event of a breakdown or disruption of one of the two PCs. Each acquisition unit is equipped with a 16 channel/12 bit card. Triggering is initiated when the threshold is exceeded in at least three stations in a time window of 1.5 seconds, with a sampling frequency of 155 Hz per channel.

The real-time transmission of the fifes to the Server machine provides access to the data on the local data-processing network (Ethernet type). Complete automatic processing of the seismic event is executed immediately, making it possible to carry out location, magnitude and energy caiculations. The sedimentary basin is fixed by means of a digital velocity model with four main layers (Senfaute et ai" 1994).

All configuration parameters, seismograms and results of Signal amplitudes and spectra are recorded in the event file. The caiculation parameters and the results are updated in the database.

Interactive processing from any terminal of the local network can be connected a few moments after acquisition for verification of the caiculated parameters. Rapid identification of the quality of the automatic pickups of wave arrival times is based on the evaiuation of an indicator comparing the results by STA/LTAand neural networks, integrated in SYTMISauto [START_REF] Bigarre | Neural net applied to automatic locating of mine induced seismic events[END_REF].

The advantages of this configuration are many. We can note in particular: the acquisition of data from a dual centre (Master/Slave protocol) ensures Optimum reliability, the centralisation of the data, in real time, on the Server machine permits instantaneous response to the characterisation of each event, the centralised access to the database broadly meets the Information distribution requirements for the different operators.

A similar configuration is being developed for the Houilleres du Bassin de Lorraine mine for a remote seismic monitoring System of 15 stations (21 channeis) located at the surface and Underground.

4-2 Seismic monitoring of open pit slopes

Since 1987 the coa! at Carmaux, Tarn has been mined by open-cast methods. The purpose of the working of the Sainte-Marie find is to recover the coal from the barrier of the former main pits which would open up the former Underground mine with 9 main seams whose thickness varies from 0.5 to 8 metres (see Fig. 4).

Apart from the presence of former Underground workings underlying the current pit, the complexity and size of the local fracturing of the basin, äs well äs the heterogeneity of the mechanical characteristics of the carboniferous materials encountered have been the main factors causing a number of instability Problems observed with slopes with a mean height of 12 metres.

The development of certain flanks of the pit requires therefore an overal! method for the monitoring and inspection of configu rations liable to slippage -a method in which instrument surveying assumes considerable importance. The various surveying methods used are: topographical surveying by theodolite, breakable surveying tubes, «Tensmeg 70» strain gauges, inclinometer tubes, multi-point extensometers with «WR-FLEX» rods.

4-2-1 Trials with remote microseismic monitoring

During the end of 1994, in dose collaboration with U.E. Tarn mine, INERIS installed an experimental seismo-acoustic monitoring network making it possible to obtain an accurate answer to the following questions:

does mechanical degeneration of the local zones situated in the rock masses give rise to seismo-acoustic activity ? what impact do mining explosions have on the stability of the flanks in terms of dynamic Stresses and particular velocity ?

The aim of this methodoiogical approach is to evaluate the potential contribution which remote seismo-acoustic monitoring can make to the surveillance of slumps and to assess its complementarity with the operational devices described above.

4-2-2 Description of the experimental network

In the North-East corner of the Saint-Marie pit, underlying the main fault 220, three seismo-acoustic stations have been installed: two vertical monoaxial stations and one tridirectional Station A supplementary vertical Station of the low frequency (2 Hz) type was added to the network to record the low frequency vibrations induced by daily blasting (see fig 4 & 5).

Each cabled Station (coaxiat screened) is connected to an Algeco (mobile cab) positioned at the apex of the sounded zone (approx. 350 metres); this is air-conditioned and equipped with three telephone lines. The Algeco accqmmodates the conditioning hardware and the signa! detection and acquisition centre. The entire equipment forming the acquisition unit is suppiied by an insulating transformer connected downstream from a mains filter.

Because the particular velocities expected are very !ow, the Signals issued by the transducers have to be electrically amplified for them to be compatible with the +-5 V input of the acquisition card inserted into the PC compatible Computer. Six two-stage pass-band amplifier filters are used. The filtering thresholds are controlled over a 60-950 Hz band for the 100 Hz stations and over 2-50 Hz for the low-frequency transducer.

The Outputs pass through a terminal board equipped with electrical insulators, connected to the acquisition PC. The latter, which is of the portable 486 DX2 66 type with 16 MoRAM, 130 MoDD, is equipped with the following features: a RTI 860 12-bit analogue-digital conversion card, 16-channel •< Fig. 4a :triaxial probe to be cemented in vertical borehole.

Fig. 3 :

 3 Fig.3: Automatic data acquisition and processing System in Operation at the Provence U.E. mine: 1) Event detected, 2) Acquisition, changeover into slave mode, pre-processing of data, 3) Transmission to multitasking machine, 4) Wave pickup, locating and amptitude caiculations, 5) Automatic storage and updating of database-oriented files, 6) Interactive processing and validation of the data, 7) Printing of reports.

Fig

  Fig. 4b : dose view of "Pajari" device to recover azimutal orientation of3D probe after Installation. Fig.

5 V Analog Devices, DOS/Windows 3.1, and the SYTMIScop Software which drives the card, i.e. the scanning of the input Signals, the detection, recording, storage and transmission of the files. The sampling frequency is 5000 Hz per channel, with an acquisition time of 2.5 seconds for complete recover of Signal from blasting. An automatically operated modern (9600 bauds) permits daily transmission of the data to the processing location at Nancy via the Standard telephone network.

CONCLUSIONS

Microseismic monitoring is used in many natural or industrial fields concerned with rock mechanics and rock mass failure. However, design and cost of installations, äs well äs lack of human resources to process and analyse seismic data is of the utmost importance in most projects.

SYTMIS represents the state of the art microseismic measurement sortware applied to digital, real-time monitoring. Fully compatible with very Standard Computers, it is developed in several, modular, integrated modules based on recent environments äs Windows NT, offering a major technologica! advance compared to Standard applications.

SYTMIS permits fast adaptation for a wide ränge of macro/microseimic applications, while providing all features needed to analyse in-depth, [arge seismic data banks. SYTMIS accomodates from one to dozens of stations, subdivided into one or several subnetworks. Stations might comprise one or several sensors, each of them providing one or several channels with selected sensitivites for high dynamic ränge. All caiculation procedures are programmable. It manages remote control of on-site acquisition units from host Computer, even from Standard phone iines, which is a very key point for low-cost, remote operating Systems.

SYTMIS is already installed on different sites, ranging from routine analysis in the mining industry to hydraulic fracturing acoustic emission or rock slope instabiiity problems. SYTMIS is a Software technology that benefits constant efforts in improvement and Upgrade.