This report compiles the results from the METRO project. The different parts of theproject – design fires, evacuation, integrated fire control, smoke control, extraordinarystrain onconstructions and fire- and rescue operations – are presented separately.
The most complicated and expensive part of the project was the performance of thelarge scale fire and explosion tests in the Brunsberg tunnel, where the maximum heatrelease rates measured from the metro wagon was 77 MW.
The main results from the project are new recommendations regarding design firesin mass transport systems, identification of key factors for fire and smoke spread in tunnelsand at stations as well as regarding the difficulties for disabled persons to evacuatefrom trains in tunnels, new recommended types of way guiding systems, safer design incase of explosions in trains and evaluation of the fire and rescue services’ possibilitiesand limitations in underground mass transport systems.
In 1983 a “Grand Old Man” of Ballistic Science, Dr. Robert J. Eichelberger, wrote1 : ”Ballistic technology is generally considered a mature technology – as it should be after centuries of intensive attention of some of the finest scientific minds of the world.” He predicted that increased understanding of relevant physics and chemistry and development of mathematical techniques and computer models would be key elements in the future of ballistics and weapon system design. These predictions were very accurate! But to-day’s developments and those of the foreseeable future go beyond this. Warheads and ballistics – interior, exterior and terminal – are very dependent on the use and properties of energetic materials – propellants and explosives – for their functioning. New, potentially very powerful substances such as the N5+ and N5– ions and metallic hydrogen were created in labs. Air-breathing propulsion – ramjets etc. - and efficient use of the high combustion energy of some metals adds to the performance increase potential. Increased use of intelligence, computers, sensors and fuzing in weapons, munitions and armours has added another dimension to the efficiency achievable. New high-performance materials have also meant great increases in effects and protection potential. Developments possible in the next 20 years may have similar effect on warfare as the revolution in weapons, munitions and armour that occurred in the late 19th century. The statement that ”Ballistic technology is generally considered a mature technology” is no longer true. Any nation that will abstain from following the developments closely and exploiting their advances will run the risk both of having weapons, munitions and protection that prove inadequate and of making grave mis-investments.
During the twentieth century, few breakthroughs occurred in energetic materials. Hexanitrobenzene was judged only 25 years ago to be the theoretically best explosive. Hexanitrohexaazaisowurtzitane (CL-20) later proved to be 20% better than octogen and 6% better than hexanitrobenzene. In the early 1990s, FOA (National Defence Research Establishment, Sweden) synthesized CL-20, enabling Sweden to purchase it from the United States. In 1995, an effective synthesis for ammonium dinitramide (ADN) was found. ADN gives much lower signature in rockets than ammonium perchlorate (AP), higher performance, and low environmental impact. Diaminodinitroethene (FOX-7) is a high explosive with lower sensitivity than TNT and similar performance to hexogen (RDX). N-guanylurea dinitramide (FOX-12) has properties similar to NC but is very insensitive and inherently more thermally stable. An FOI effort to synthetize new high energy density materials started with tetrahedral tetraazatetrahedrane (N4), sponsored by the U. S. DoD/DARPA. This nonnatural substance was modeled by numerical quantum mechanics, and promises to have three to four times the energy of octogen. So far, the existence of this molecule has not been verified; but efforts continue. Other nitrogen clusters, such as N8 or polymeric Nx, promise even higher yields. The pentazolate ion (N- 5) was successfully made at FOI by laser synthesis. With the N+ 5 counterion, synthesized by the U. S. Air Force Research Laboratory, it could form a very energetic all-nitrogen molecule. The step in energy density from octogen to N4 is much greater than the change from black powder to high explosives, such as picric acid or trinitrotoluene, occurring in the 1870s. That change most certainly caused a complete revolution in warfare methods and weapons technology.
This report is a literature review which summarizes performed fire and explosion tests in tunnels and underground enclosures. Relevant pictures and graphs have been inserted from the papers reviewed, to illustrate the test settings and the results.
The report also gives a brief introduction to the subject itself. Questions that stillneed to be answered are identified and discussed. Furthermore it includes useful tablesto compare the most common computer modelling and finite element codes AUTODYN, EUROPLEXUS and LS-DYNA used for calculation of blast load and construction response.