RF hazard from mobile phones.

Discussion in 'Royal Signals' started by EX_STAB, Jun 28, 2009.

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  1. I got pulled up by the shop staff in the petrol station the other day for "looking" at my mobile phone.

    Even if I was using it or it was just updating its position, is there really enough of an RF hazard from it to be a danger on the forecourt of a petrol station?

    Put this in R Sigs because I thought it was more appropriate than QMs etc.
  2. the Mythbusters programme on discovery tried really really hard to cause an explosion on a garage forecourt with a mobile phone and failed pretty dismally. there is very chance of a mobile phone causing a fire/ explosion
  3. Missed out 'little' :?
  4. indeed i did!
  5. Did you see the "mythbusters revisited"; where they revisited past myths where people had wrote in with their own theories and ideas?

    They tried it again, and they even took the cover off and played about with the battery if I remember rightly! They did a really comprehensive test and nothing happened.
  6. There is no RF hazard from the phone to cause a fire.

    Slim to none chance that you drop the phone and it causes a spark thus causing vapours to catch fire.

    Not really sure where or when it started but every person working a till in garage forecourt is an expert.
  7. Was it on Mythbusters or another programme? Anyway, I recall seeing a video clip of the scenario that led to use of mobile phones on forecourts being banned.

    The driver (female?) got out of the car, put the nozzle in the petrol tank and flipped the little catch that allowed the nozzle to operate without continuing to hold it. (UK nozzles still have the catch but the bar it engages against has been removed since the 1970's). She went back into the car and came out with a mobile phone. Suddenly, the petrol vapour at the nozzle ignited.

    Subsequent examination of the footage showed that the mobile phone wasn't responsible for the ignition - it was static electricity causing a spark, the static believed to have been induced by clothing and seat contact.

    So now you have the situation where actions have been taken to prevent fire resulting from an event that has never been shown to cause a fire, yet no precautions are in place to prevent a fire resulting from circumstances which have been shown to be hazardous - perhaps because it would be difficult to eliminate static.

    Not the clip I saw, but a similar result (with no mobile phone): http://www.liveleak.com/view?i=7d144757ef
  8. I saw that one, they used literally more than 100 phones i dont see why it is even classed as a hazard, if they just completely proved it safe.
  9. I concur that there is little risk from mobile phones at filling stations, however whilst there is any hint of risk the rule will remain. Anyone seen with a mobile phone anywhere near a petrol pump will naturaly attract the attentions of the nearest jobsworth.

    Last year I was working in Vietnam with a seismic survey crew. I used to give them a wide berth when they were charging the shot holes with explosives as their training in the use of explosives was fairly minimal and the HSE guys involved were all masters of the rules with no understanding of the reasons for the rules. On the one occasion I got close to a seismic team which was charging shot holes I was censured for wearing a watch. Apparently some watches contain batteries. Batteries are not allowed near seismic charges (which is fair enough). But, I was wearing my Rolex s/mariner which is not battery operated. And, no one could give me a safety distance for watch / seismic charge proximity safety. I suggested that the HSE guys write a safety rule for site safety marking whilst shot hole charging was in progress, and incorporate a minimum safety distance for watches / batteries. I was blanked and the geophycisist in charge would only say: "batteries and explosives dont go together".
  10. It's ruling that came in when mobile phones had a bit more "grunt". And the country was running amok with safety this and safety that, due to Piper Alfa going up in flames. THat is why no one really said "er hold on, isn't this getting daft?" becaues they would have been crucified on the backs of all those killed on Piper Alfa.

    Anyone remember the old fashioned ones, that were about 10Kg? And had to get to a tower up to 5 or 10km away?

    modern phones don't kick out half as much power, the towers have been built with greater sensitivity in their Receivers. Conversely the towers kick out more. The trick being tomake the hand set as small/cheap as possible.

    The science is that metal can be "charged" via the RF of the phone or other transmitter. In exactly the same way as the antenna on the phone or receiver, except the charge has no receiver to go to.

    If this metal hasn't been "earthed" correctly there is no where for this charge to go. So either the metal charges until enough charge is amassed to "jump" to earth causing a spark. Or in the case of a swing bit of metal, it may touch an earthed bit, and again a spark leaps across the gap.

    Igniting any fuel vapour (vapour is the problem not the liquid). If the air/fuel mix is right also.... boom.... or perhaps not.

    See the vid below, to see what it would take, and also bear inmind the amount of earthing that goes on in a petrol forecourt... everybit of metal is joined to its neighbour and earthed, for this reason.

    Given that today garages deem it acceptable to put the masts inside their own forecourt signs, I'd imagine the danger from fuel explosion is VERY fcuking small.....

    Petrol stations "hide" phone towers in forecourts

    another article about the same thing.

    For your viewing pleasure

    <embed src="http://www.metacafe.com/fplayer/572992/gas_stations_and_phones.swf" width="400" height="345" wmode="transparent" allowFullScreen="true" allowScriptAccess="always" name="Metacafe_572992" pluginspage="http://www.macromedia.com/go/getflashplayer" type="application/x-shockwave-flash"> </embed>
    <font size = 1>[url="http://www.metacafe.com/watch/572992/gas_stations_and_phones/"]Gas Stations And Phones...[/url] - [url="http://www.metacafe.com/"]The funniest videos are a click away[/url]</font>

    Daftly, the best people to ask about this sort of caper would be the POL ops in the RLC. They'd probably know the thinking behind the ban, even if on the Scaley side the reasons were all debunked.
  11. maninblack

    maninblack LE Book Reviewer

    There was a story doing the rounds a few years ago about the transmissions from a mobile phone interfering with a petrol pump so that it didn't meter correctly and didn't shut off causing a spillage.

    I would stress that it was just a story and I have no evidence.
  12. The RF could affect the counter (it would have to be a pretty meaty transmitter mind) but to prevent a spillage you just take your hand off the pump.

    And of course the counter would have to be electronic, not like the old clunky ones that turn.

    Although it is worth noting that ALL pumps now have electronic counters in them to tell the kiosk how much you've taken... unless you use one of htose stations where th ebod operates the pump.

    Some of these counters could be wireless, in which case the phone signals could mess up the transmissions, but the frequencies would have to be purchased and cleared for use by the relevant governing bodies. Ofcom in the UK.

    The shut off valve works (in Germany for example where it is still fitted) by sucking air thorugh the small tube that runs along the top of the nozzle.

    When the level of liquid reaches the nozzle it blocks this small tube, which causes a change in air pressure in the system and fires the handle. A malfunction on the vacum pump in the "pump" or a blockage in the line would have the same affect so there is little or no chance of malfunction.
  13. Lol, Choccy frog.... is there no subject that you do not have an in depth answer for? I know what you mean about the older mobile phones though! Years ago i was lucky enough to drive General Ramsbottom about Salisbury Plain for a couple of weeks. Aside from being as mad as a bucket of frogs, he had allocated to him the first ever "mobile" phone i had ever seen. The bloody thing was a two man lift and lowered the Rover suspension by a good 4 inches.

    "Feel free to use the phone" he remarked one day, "as long as you don't kick the backside out of it"! ONCE i tried it.... on completion of the call i noticed that all the hair on one side of my head had fallen out, the two metal halves of me stable belt had fused together and me underpants had dissolved. Now THAT was RF! :lol:
  14. I've also heard that there is another reason for not using a phone on a forecourt - many poeple chatting away into their handsets will not be not paying attention to what's going on arround them and as trucks and cars will be manouvering in the same area the risk of collisions will be very very high!