rev. 16.08.2001

Special Equipment

meters

Contents

  1. Preface
  2. Arson K-9
  3. Digital Imaging
  4. GPS-Receiver
  5. GPS-Maps
  6. Hydrocarbon Detectors
  7. Laboratory Equipment
  8. Metal Detectors
  9. Microscopy
  10. Special Measuring Equipment
  11. Special Photographic Equipment
  12. Video Equipment


  1. Preface


    2. The special equipment described herein is certainly not necessary for a fire investigator, but some of this equipment simplifies your work, some makes your work more difficult, but it may enhance the results of your work or enlarges the range of your possibilities.

    At least something is true: The more specialized the equipment is, the more expensive it is. So it is certainly of some use to get information about the equipment, we already used and sampled experiences on. Perhaps this may prevent you from spending money invain, or on the other hand it may give you an idea of what and where to purchase equipment you have been desperately looking for in the past.

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  2. Arson K-9 (Accelerant sniffer dog)

    3. These accelerant sniffer dogs are an excellent tool for the fire investigator. The proof of their utility has been shown quite often, but by no means they are a replacement for an experienced fire investigator, an expert on fire causes, or a laboratory examination. They can indicate places where to take samples for a laboratory examination. They cannot proove the presence of an accelerant.

    Two of these dogs are now also available in Germany. They are located at the Landespolizeischule of Nordrheinwestfalen. These dogs are available for police services nationwide.

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  3. Digital Imaging

    4. As we do not have, at least at the moment, the same problems with digital images in legal cases as in the United States due to their easy alterability by wide spread means, there is actually probably no limitation to the use of digital images.

    Kodak DC4800 Since Spring 2001 we use a Kodak DC4800 digital camera. The image quality of this 3,1 megapixel camera is sufficent for most applications. Only the storage card delivered with this camera limits the number of photos taken at full resolution to 1 (in words: one) at the first compression stage to 15. But this may be changed by the purchase of a larger Compact Flash Card (CF Card). The original equipment contains a 16 MB-CF-Card. These cards are available up to 128 MB which should eliminate these problems.

    What we actually use to digitize our 35-mm-photos is a filmscanner, the QS35 from Minolta, an excellent tool which is largely sufficient for our needs at the moment, except for the fact that there is no driver for Windows 2000 available and that, along to minoltas statements, there never will be one.

    The hard copy production is done by a Hewlett Packard Color LaserJet 4500. The imaging capabilities of this printer are good. Especially the printing speed on standard paper and the fact that there is no image clipping as it was with our old Epson Stylus Pro inkjet printer.

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  4. GPS-Receiver

    5. The Global Positioning System (GPS) is a navigational system consisting of 24 satellites which circle the earth twice a day in a very precise orbit transmitting navigational and time information data, operated by the U.S. government for military and civil purposes. The basic precision of the system is 15 meters for the receiver position. This pecision is only available for military purposes. For civil purposes the precision is degraded by selective availibility (SA) to 100 meters.

    By the aid of a supplemental differential GPS (DGPS) receiver it is possible to the enhance the precision to 1 - 5 meters. DGPS needs a second GPS receiver of which the location is exactly known. As the exact position of this receiver is known, it is possible to calculate the incorrect part from the received GPS data. The difference data will now be transmitted to the DGPS receiver, wich may therefrom correct the data received and displayed by your GPS receiver.

    In Germany DGPS data is broadcasted via several public VHF radio stations within the RDS (Radio Data System) signal. As the DGPS precision is degraded by the actual distance from the GPS reference receiver, it is necessary to know the position of the acutal used GPS reference receiver. The precision degrades by 1 meter for every 250 kilometers distance between your DGPS receiver and the reference GPS receiver. The fee for using DGPS data is 15% of the DGPS basic receiver price, paid with the purchase of the DGPS receiver. Coverage is given for the whole country. An alternative DGPS data source is the ALF service, where DGPS data is transmitted via an LF-transmitter in Mainflingen, Germany near Frankfurt/Main. The coverage of this transmitter is comparable to to the german LF-time-normal-transmitter which is also located at Mainflingen (e.g. 1500 km radius around Frankfurt/Main). The data reception license cost is at the moment (march 1998) DM 200,- for a ten year period. Generally said the ALF system is a bit more precise as the frequency used is reserved for DGPS correction data exclusively, while the RDS system shares the RDS channel between the DGPS data and other data services, so that there may be delays in the transmission of the data resulting from the time slices and the time needed to transmit the data to the originating radio transmitter and from this transmitter to the diverse VHF relais.

    There are more precise systems available, reaching the subcentimeter range. These systems are used for surveying and are certainly too expensive to be discussed here.

    A GPS receiver is an ideal tool for the aquisition of geographical coordinates of a fireplace, which are for example necessary, if you want to request a lightning tracking and positioning report for this location.

    The GPS-Receiver we are using is the new Garmin GPS II Plus, which was introduced into the market in may 1997. It is a general purpose GPS-receiver for land navigation. Other GPS-receivers for special purposes as aeronautical or maritime navigation are also available, but regulary they are more expensive as they contain huge databases for these purposes.

    Garmin GPS II Plus

    Garmin GPS II+ A real 12 channel parallel GPS-receiver. With excellent reception qualities, which make it possible to get position data even in urban regions, so that there are practically no restriction in use and operation.

    The receivers capabilities are really astonishing, even dashboard-mounted with the directly attached antennea there are practical no restrictions in operation to remark. In most cases 5 to 6 satellites are captured even under difficult conditions. Up to now we could not achieve a 'poor satellite coverage' message on the road. The receiver may be powered by four AA cells for independant operation up to 24 hours, or via an optional power/data cable from any DC-source between 10 and 32 volts. It is waterproof to IPX7 standards and may be operated from -15° to 70°C. Data storage is maintained by an internal lithium battery for approximately 10 years.

    Supplemental features you will get with such a GPS-receiver are, a precise clock, a trip counter, a speedometer and a compass as long as you are moving, and a moving map system, if you connect the the GPS-receiver to your notebook computer, as far as it is equipped with a moving map software. There are some freeware moving map systems availble on the net, but most of these systems have some restrictions in use. (most of them need maps in Mercator projetion.) The best thing we found was the FUGAWI moving map software. This software also allows the use of maps and charts with other projections, as for example Lambert Cone. (Used on aeronautical charts.)

    As these GPS-Receivers are relatively expensive in Germany, it may be recommended to get these devices directly from the US. We bought our device at James Associates in Boulder, Colorado, USA.

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  5. GPS-Maps

    6. ----- Cut - Skip to next ----------
    A major problem with the use of GPS-navigation-systems has to be mentioned. This is the availability of sufficient precise maps. Basically for Germany there are three kinds of maps available. First there are road maps. The most spread and known maps are those from MarcoPolo, 1 : 200 000 scale road maps formerly known as Shell General Karte. These Maps are produced by Mairs Georaphischer Verlag. These maps do not have a projection datum, as none was used (available) when they have been pubished the first time. Since then only the information shown on these maps have been updated, not the projection. These maps have been tested and found very imprecise and not usable with GPS-navigation. Further there are the topographical charts of Germany. These are official charts produced by the state authorities. They are precise, but use the Gauß-Krüger-Projection which is not offered by most moving map systems and the information shown is sometimes more than outdated (~1980). They are available in many different scales as there are 1 : 5 000, 1 : 25 000, 1 : 50 000, 1 : 200 000, 1 : 1 000 000, and more. Then there are the ICAO aeronautical charts. These maps use the Lambert-Cone-Projection, are quite actual and precise, but they are only available in 1 : 500 000 scale, which limits their use in land navigation. All of those maps are available as digitized maps (scanned at >500 dpi), but as far as free usable formats are offered, the prices are incredible high. Probably an other 5 years have to pass until somebody in this industry remarks that there might be a huge market for moderate priced digitized maps scaled at 1 : 200 000, scanned in PC-usable resolutions (100 - 125 dpi) using the WGS84 format. The following discussion whether this should be launched will take another 5 years plus the five year realization time. So I'll have to be patient...
    ----- Cut - Continue ------------

    Two years after I wrote the last passage, the solution for Germany is available:
    (May be some of the officials had an open mind for my complaints).

    Top200 Since early spring 1999 a series of CD-ROM's for Germany is, at reasonable cost, available. One CD-ROM for each of Germanys states except Bavaria, which spreads its maps on two CDs. The maps contained on these CD-ROMs have a scale of 1 : 50 000. Supplementary there is a map of the whole country available with a scale of 1 : 200 000. These CD-ROMs contain an GPS-interface for some popular GPS-receivers which can enhance them with the help of a notebook to a real moving map system with tracking capabilities. No supplementary software is needed. I really wonder that official german institutions are capable to offer such an interesting and technical sophisticated thing at a price that is affordable for practical any computer user; congratulations to them. You can get get more information via the image on the left.


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  6. Hydrocarbon Detectors


    7. There are three different kinds of hydrocarbon detectors on the market:

    1. Flame Ionisation Detectors
    2. Photo Ionisation Detectors
    3. Semiconductor Detectors

    Each type of these detectors has its own advantages and disadvantages.

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  7. Laboratory Equipment


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  8. Metal Detectors

    9. Metal detectors may be used to find remains of lamps or ballasts in hay barns etc., they need a comprehensive training for an efficient use. Their effectivity depends on the local circumstances found on the fire place. They are useless if many metal connections have been used in the building construction, or if machines are located in the building.

    We use a White's Spectrum XLT. The functionality of the user interface is not ideal, as the setup of this instrument is very complex and by an accidental misinterpretation of the menue or misoperation it is possible to dealign the system. This counts especially for the display lighting, which cannot simply be turnd on or off. It is nearly impossible to turn the display light back on, if it was accidentially turned off in the dark. We would recommend to use instruments with analogue display and and potentiometer knobs for the instrument adjustment. This is easier and more reliable than this digital display with function keys, and these analogue instruments are definitely cheaper. So, here you can certainly economize.

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  9. Microscopy

    10. Leica MZ12 Sometimes you will find the need of an optical enlargement of destruction traces on evidence to be able to determin the origin and nature of the destruction. Further, you will want to be able to document, what you could see through your optical enlargement device. Microscopy is an high priced task, as the instuments are regular not sold as complete consumer products. So, for a correct solution you need a certain knowledge to compile the necessary equipment from all the parts that belong to the microscopy system you have choosen. The available information material should be studied extensively and finally you should ask your sales representative of the manufacturer you have choosen all those things that are not clearly understood.

    There are different kinds of microscopes available, first there is the simple standard microscope a monocular with fixed magnification, then there are those microscopes with selectable magnifications via a lens revolver system (sometimes you can see them in those old movies from the 50s and 60s), or zoom microscopes which allow variable magnifications. All these types are also available as stereo microscopes, which give you a three dimensional picture. The criterium to judge the worthyness of a microscope is not the maximum magnification. Far more important is the optical and mechanical quality.

    Presumed you already have a camera system, it is important, that this system may be connected to a phototube suitable for the selcted microscope, preferred at the same magnification factor as your eyepieces you intend to use. This way you need not to spent money for a separate photo documentation system for the microscope.

    You can find more information on the system we use by following this link, or the link provided by the small picture on top of this article.

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  10. Special Measuring Equipment


    11. Return to top of page

  11. Special Photographic Equipment

    12. markro photo equipment

    Macro Lenses

    Close-up Lenses

    Close-up lenses are the first step if you want to make photos from shorter distances as provided by your lenses focal range. Probably close-up lenses are the better way to start as those so called macro-lenses. This is because macro-lenses are always a compromise in optical quality and maximum aperture. So is you use close-up lenses, you still have a standard lens with maximum quality which may be enhanced if necessary by the lens.

    Extension Rings

    Extension rings are the first step into real macro photography. These rings are mounted between the camera body and the lens. A normal set of extension rings consists of three rings of different lengths. Extension rings do not contain any optics as lenses, etc. Though it is possible to combine these extension rings with each other, it is not advised to do so, as the mechanical stability is degraded, which may degrade the optical results due to out of focus faults related to the mechanical tolerances. Extension rings are used to cover the range of shorter extensions which cannot be achieved with a bellows, or the application of a bellows seems to be a technical overkill. The field use on location for the documentation of smaller details is an example

    Bellows

    This is a tool which makes it possible to have variable extensions up to extreme values. The bellows is needed for the extreme macro photography. The bellows is mounted on a rail which makes it possible to shift the camerabody mount and the lens mount. An automatic bellows also allows the automatic function of the aperture mechanism. More luxury models allow a certain rotation angle for the camera and lens mounts as well as their side shift for special effects. Magnification values of up to 7:1 may be achieved with such an equipment.

    Reverse Ring

    The reverse ring is used to mount wide-angle lenses in retro position to the bellows, which results in larger working distances.

    Macro Stand

    A macro stand is used to hold the complete camera, bellows, lens, and focusing rail in a vertical upright postion.

    Focusing Rail

    The focusing rail is needed to focus the complete system without changing the magnification.

    Angle Finder

    The angle view finder makes it more comfortable to work with the complete set in an upright positon. This is the same for extreme low camera positions. An expensive but extreme useful accessory.

    Lighting

    For lighting purposes you will need a cold light source with flexible glasfibre arms. There are actually only two manufacturers I know of that that produce such devices in sufficient quality. These are Gossen and Schott. The unit made by Gossen is available with integrated flashlight. The unit made by Schott is sold by Leica and uses a controlable 150 watt tungsten lamp, to be able to use daylight film, a conversion filter may be placed in front of the lamp. As the main task of our light source is microscopy and not photography, we choose the unit from Schott.

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  12. Video Equipment

    13. Standard Video Systems

    Sony TR 555 The basic equipment you should have is a VHS-videorecorder to be able to view videocassettes for education purposes published by several organizations and enterprises. More desireable is a multistandard VCR, to be able to playback at least NTSC and PAL videos.

    For recording purposes an S-VHS or Hi8 camcorder should be regarded as the minimum necessary, as standard VHS or Video8 systems are outdated due to their limited recording capabilities. A Hi8 system seems to me more desirable, as it is possible to use the same cassettes on the camcorder as on your home VCR, while S-VHS camcorder use special cassettes with reduced recording capacity, which need to be placed in an adapter to be able to use them with your home S-VHS-VCR. Supplementary Hi8 cassettes are much smaller than VHS or S-VHS cassettes and need as a consequence less storage capacity in your office. You are lucky, if this isn't a point of view for you!

    One thing has to be added: Avoid those camcorders without standard viewfinders, which have only a little LCD-monitor. This may look very impressive in the dealers store, but under daylight conditions these monitors are useless, as you can't see anything on them, especially on sunny days.

    Digital Video Systems

    Sony DC 7 Far better as the above mentioned camcorders are digital camcorders. The first big advantage is that you don't have to make a decision between different systems. As far as I know all manufacturers of digital video camcorders use the same system. Finally, though they needed nearly twenty years to understand. But now back to the real needs. The smaller the unit is, the better, as the quality the smallest units offer, is sufficient for our purposes, though the bigger units with three-chip-optics reach the performance of professional tv equipment, which cannot be achieved with the small single chip units, but we are not tv camera men, we are fire investigators. The images you will get from these digital camcorder are are of an incredible good quality compared to the older systems and the versatility of the supplemntal functions of those systems are already so far advanced, that you will rarely find something you whish to be added to them.

    To be able to take full advantage of these digital systems you will need some supplemental hard- and software for your computer for postprocessing your videos. This is, what you will hear from the dealers. The reality is still a bit different. THe supplementary hardware you will need is at the moment still very expensive. For example the price of a FAST DV-Master exeeds the price of the whole PC. And no one garantees you, that your PC is suitable for operation with the DV-Master. Certainly your PC, you bought around the corner some months ago, does not meet the necessary standards.

    Miniature Color Video Cameras

    Sony XC 999 P These miniature video cameras are very useful as inspection devices that grant a view into areas which are not accessible in other ways. A very important disadvantage of these devices is their extremly high price. (You'll get two ordinary camcorders for the price of such a unit.) Equipped with a 12V-battery and a small short range tv-transmitter you will have a cablleless handy spy unit. The camera unit on the picture is a Sony XC-999P. The unit is complete and needs for operation only a 12V power supply and a video monitor plugged into the connector on its back. Its dimensions are 22 mm x 22 mm x 120 mm and the weight is 99 g (without lens). It is equipped with a 1/2-inch-CCD-sensor. There is an other model available, the XC-777P. This one is equipped with a 1/3-inch-CCD-sensor. Its dimensions are 22 mm x 22 mm x 89 mm and the weight is 75 g. Five different lenses, a C-mount adaptor, and four extension rings are available for these camera modules (f1.8 / 3.5 mm, f2.0~f128 / 7 mm, f1.4 / 6 mm, f1.4 / 12 mm, and f2.0 / 8.9 mm).

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Ingenieurbüro Frank Markmann
Gottfried-Blum-Weg 4
D-88639 Wald
Germany

Phone: +49-(0)-7578-933141
Fax: (on request)

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Fire Investigation in Germany / webmaster / revised 16.08.2001