Vernon B Posted November 23, 2009 Share Posted November 23, 2009 I see in the December edition of MMM that a strong warning has been given about travelling with your gas cyclinder on - Interchange Page 160 - "Switch Your Gas Off". The warning includes the statement "Some modern motorhomes have a cutout device for the LPG system in the event of an accident, but it's best not to rely on that." Although the piece doesn't mention it by name, do we take it that MMM would advise against relying on a Truma's SecuMotion regulator when travelling? V Link to comment Share on other sites More sharing options...
Brian Kirby Posted November 23, 2009 Share Posted November 23, 2009 I, too, saw that, and it made me wonder if Peter Rosenthal was including the Truma Secu-Motion / Drive Safe systems. Since it has been safety tested and evaluated, and is legally accepted Europe wide for use with the gas "on", it would seem it may have slipped his mind. Maybe he'll pick up and clarify? Link to comment Share on other sites More sharing options...
peterrosey Posted November 23, 2009 Share Posted November 23, 2009 It's also legal to carry passengers without seatbelts in certain motorhomes too. I wouldn't advise that, either... Link to comment Share on other sites More sharing options...
Vernon B Posted November 23, 2009 Author Share Posted November 23, 2009 peterrosey - 2009-11-23 4:52 PM It's also legal to carry passengers without seatbelts in certain motorhomes too. I wouldn't advise that, either... Hi Peter - glad you were able to respond. I'm not sure that the comparison you draw is particularly helpful. In the case of unbelted passengers there is clearly a risk, despite what legislators may or may not choose to do about it. On the other hand, as Brian points out, the SecuMotion device has been tested and meets EU regulations that make it "safe" for the nature of it's operating use. Within that context it is presumably as "safe" as any other safety critical components fitted to a motor vehicle. So would you dispense with the convenience of power steering on the grounds that the hydraulics might fail? V Link to comment Share on other sites More sharing options...
Brian Kirby Posted November 23, 2009 Share Posted November 23, 2009 Hello Peter. Is there a specific risk with the Secu-Motion system you have identified, or is it the whole idea you are uneasy with? Link to comment Share on other sites More sharing options...
tonyishuk Posted November 23, 2009 Share Posted November 23, 2009 I would go down the route and take a pessimstic view that after an accident with my unbelted passengers, I would not like to add further injury by blowing them up. :-) Rgds Link to comment Share on other sites More sharing options...
Tomo3090 Posted November 23, 2009 Share Posted November 23, 2009 Where does that point leave us with a gas tank then? I don't get under the van to turn that off each time I drive off, so is that unsafe too? I am not arguing against the legal and insurance implications of rear seat belts, but..as for getting too uptight about being belted up in the back, you are driving along in what is basically a polyyrene and fibreglass box! If even a medium sized vehicle hits the back end at speed they will be inside your van with you without too much trouble! I am aware of the dangers and inury road accidents can cause and I don't want to give the impression of minimising the issues but I feel we can get too hung up on the hazards of day to day living if we aren't careful. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 24, 2009 Share Posted November 24, 2009 I don't really understand why anyone should have felt it necessary to contact MMM because they were "worried about AES fridges switching to gas and trying to light up when on petrol forecourts" (which is what provoked the warning Vernon refers to). If you've got a fridge that's fully automatic and it's switched on, then that's what it's going to do. If this concerns you, then just ensure that your fridge is always turned off before your motorhome is to be refuelled. Dometic Series 7 AES fridges (and, presumably, the AES Series 8s too) have the option to select gas, 230V, 12V or 'Auto' operation. Selecting 12V prevents the fridge attempting to switch to gas operation if the vehicle's motor is no longer providing 12V power. SecuMotion (and similar systems) were developed to allow gas heaters like mine to be used in a moving vehicle even in those countries like France that had regulations that historically forbade that practice. SecuMotion's 'protection' assumes certain things - that any gas leak downstream of the regulator will be significant and that, if the gas-hose is damaged, the damage will be downstream of the hose's cut-off valve. The system won't react to a very minor gas leak and, if an accident damages the gas hose upstream of its cut-off valve, then full-pressure gas will emerge from the bottle. You don't need to be a rocket scientist to appreciate that SecuMotion cannot offer the level of protection provided by simply turning off the bottles' valves. My Hobby has neither an AES-type fridge nor a SecuMotion-type regulator/gas-hose. It has a Truma C-Series gas heater that is certified for use in a moving vehicle, but I've never employed it 'en route'. When my motorhome is out of use for an extended period I turn off the gas bottles: I also do this when the vehicle is on a ferry and when I'm driving between a ferry-port and my home. Otherwise, I leave the gas bottles turned on simply because it's a nuisance with the type of use we make of the motorhome to be turning the bottles on and off every time the vehicle is driven. I acknowledge that it would be less hazardous if I heeded MMM's Interchange warning and always turned off the bottles before I drove the motorhome, but, although I fully recognise that the advice is 100% valid, I shall ignore it. Cross-comparisons (eg. gas-bottles and seat-belts) are essentially a waste of time. How would you assess the relative safety risks of choosing to drive a motorhome with 'open' gas-bottles or choosing to ride a motorbike in London traffic? Link to comment Share on other sites More sharing options...
Clive Posted November 24, 2009 Share Posted November 24, 2009 How about a poll of how many of us turn our main gast tap off 1) When driving 2) When on the ferry 3) When in the tunnel. My guess is that it might be a bit of an eye opener. C. Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted November 24, 2009 Share Posted November 24, 2009 1) always on 2) ditto 3) off, only because they check *-) Link to comment Share on other sites More sharing options...
rupert123 Posted November 24, 2009 Share Posted November 24, 2009 Ditto Judge Link to comment Share on other sites More sharing options...
Keithl Posted November 24, 2009 Share Posted November 24, 2009 When driving from home to first site it's turned off but then stays turned on until we arrive back home. It's too much trouble to turn off every time we go out for the day and need it on when parked up. And as yet we haven't used the ferry or tunnel. Keith. Link to comment Share on other sites More sharing options...
pagey Posted November 24, 2009 Share Posted November 24, 2009 ditto to keith Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 24, 2009 Share Posted November 24, 2009 It's perhaps worth highlighting that a Dometic AES fridge is potentially much more dangerous when a motorhome is on a ferry than when the vehicle is being refuelled. The delay between 12V operation ceasing and gas operation commencing should be more than adequate for refuelling to have been completed and the motorhome to have cleared the refuelling area. However, if the fridge is left in auto-mode and a gas supply is available (ie. the bottles/tank is not turned off), the fridge will light up on gas while the motorhome is on the ferry's car deck 20 minutes or so after the vehicle goes on board. Link to comment Share on other sites More sharing options...
Brian Kirby Posted November 24, 2009 Share Posted November 24, 2009 This may help. There are two elements to consider. First, there is a cut-off valve at the cylinder connector, with the hose attaching to the cut-off valve. That is the green bit at the end on the hose. The valve is spring loaded closed, and held open by cylinder pressure. A sheared, or damaged, hose results in a pressure drop, and the valve closes, shutting off gas flow. The valves are quite sensitive. For example, if I open a gas tap in the van just after connecting a cylinder, the pressure drop as the downstream system comes up to pressure is sufficient to "trip" the valve. There is no hose on the cylinder site of the cut-off valve to shear. It would be possible for the whole connector to be sheared off, but that seems little more probable than for the main cylinder gas cock itself to be sheared off. So possible, I guess, but improbable.There is a further shut off valve in the regulator. This shuts off gas flow if there is reduced pressure in the system downstream of the regulator, taken to indicate leakage. The valve is surprisingly sensitive in that, although it will pass sufficient flow for several gas appliances all operating together, if I open the valve to the gas heater with nothing else consuming gas, it "trips" as the gas line to the heater re-pressurises.There is no such thing as absolute safety, all safety systems are based on a balance of risks. This system seems to me to offer a reasonable compromise, having regard to the number of risk events that would have to take place before either system would be negated. I do turn off at the cylinders whenever on ferry or in tunnel, because their regs request this is done. Otherwise, the cylinder cocks stay open when we use the van. Link to comment Share on other sites More sharing options...
carioca Posted November 24, 2009 Share Posted November 24, 2009 JudgeMental - 2009-11-24 9:48 AM 1) always on 2) ditto 3) off, only because they check *-) im with you on this guess we are all rebels with a deathwish :$ >:-) Link to comment Share on other sites More sharing options...
Archiesgrandad Posted November 24, 2009 Share Posted November 24, 2009 I'm with The Judge. AGD Link to comment Share on other sites More sharing options...
rupert123 Posted November 24, 2009 Share Posted November 24, 2009 Derek Uzzell - 2009-11-24 3:03 PM It's perhaps worth highlighting that a Dometic AES fridge is potentially much more dangerous when a motorhome is on a ferry than when the vehicle is being refuelled. The delay between 12V operation ceasing and gas operation commencing should be more than adequate for refuelling to have been completed and the motorhome to have cleared the refuelling area. However, if the fridge is left in auto-mode and a gas supply is available (ie. the bottles/tank is not turned off), the fridge will light up on gas while the motorhome is on the ferry's car deck 20 minutes or so after the vehicle goes on board. Do not understand Derek, why is this dangerous. Car decks are very well vented, so no fume buildup, which is only danger I can see. Link to comment Share on other sites More sharing options...
maggyd Posted November 24, 2009 Share Posted November 24, 2009 Always OFF 1. 2. &3. Link to comment Share on other sites More sharing options...
bob b Posted November 24, 2009 Share Posted November 24, 2009 rupert123 - 2009-11-24 10:22 PM Derek Uzzell - 2009-11-24 3:03 PM It's perhaps worth highlighting that a Dometic AES fridge is potentially much more dangerous when a motorhome is on a ferry than when the vehicle is being refuelled. The delay between 12V operation ceasing and gas operation commencing should be more than adequate for refuelling to have been completed and the motorhome to have cleared the refuelling area. However, if the fridge is left in auto-mode and a gas supply is available (ie. the bottles/tank is not turned off), the fridge will light up on gas while the motorhome is on the ferry's car deck 20 minutes or so after the vehicle goes on board. Do not understand Derek, why is this dangerous. Car decks are very well vented, so no fume buildup, which is only danger I can see. If a vehicle nearby has a petrol/gas leak, then the fridge running on gas could start a fire.I leave the gas on when using the motorhome, but would turn it off on ferries and in the tunnel. Link to comment Share on other sites More sharing options...
Brian Kirby Posted November 25, 2009 Share Posted November 25, 2009 bob b - 2009-11-24 11:28 PM .......... Do not understand Derek, why is this dangerous. Car decks are very well vented, so no fume buildup, which is only danger I can see. If a vehicle nearby has a petrol/gas leak, then the fridge running on gas could start a fire. Just to add a bit to the detail, on both ferries and the tunnel shuttles, although the vehicle itself is stationary, its transport is in motion, and hence fuel in the tank is sloshing around. Add that many fill before boarding, and there is a risk that the motion, coupled with a over filled tank, might cause spillage onto the vehicle deck. The decks are vented, but petrol fumes are heavier than air and scavenging at low level isn't easy, so a local build up is possible. Fridge flues are warm when the fridge is running on gas, so there is a through flow of air which, if there are fumes in the vicinity, will contain fumes. Since the fridge has an open flame the risk is real. Fires on car decks at sea ain't much fun, and we all know about fires in the tunnel! Both types of carrier are, therefore, by degrees nervous about the dangers. Link to comment Share on other sites More sharing options...
Lord Raindrop Posted November 25, 2009 Share Posted November 25, 2009 The gas is never on unless I'm on site. Having worked with gas all my life I know how dangerous it is for it to be free to air Just two weeks ago I was stationary on a fast road and had someone aiming for the side of the M/H just where the bottles were. Had there been a collision and the bottle connections broken then propane gas would have enveloped the vehicle and us immediately. One spark would have set the whole lot alight including us, and as the cylinder begins to heat it can explode like a bomb. Not fancifull talk but a very serious fact. Anyone driving with the gas on is risking their life. Link to comment Share on other sites More sharing options...
AliB Posted November 25, 2009 Share Posted November 25, 2009 Always off 1,2 & 3 Turning off the gas on longer overnight ferries, Hull- Rotterdam, is a problem as anything in the freezer compartment goes soft. This year we were directed on to the lorry deck and parked beside a big refrigerated truck. How do they keep their merchandise cool? Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted November 25, 2009 Share Posted November 25, 2009 Lord Raindrop - 2009-11-25 12:15 AM The gas is never on unless I'm on site. Having worked with gas all my life I know how dangerous it is for it to be free to air Just two weeks ago I was stationary on a fast road and had someone aiming for the side of the M/H just where the bottles were. Had there been a collision and the bottle connections broken then propane gas would have enveloped the vehicle and us immediately. One spark would have set the whole lot alight including us, and as the cylinder begins to heat it can explode like a bomb. Not fancifull talk but a very serious fact. Anyone driving with the gas on is risking their life. Not if you have refillable STAKO bottles. You can apparently knock the valves off with a hammer and another internal valve stops gas escape I believe. Not 100% on this though:-S Link to comment Share on other sites More sharing options...
rupert123 Posted November 25, 2009 Share Posted November 25, 2009 We can all make a case for something being dangerous but if a company assures me it is OK to run with gas on that is what I will do. I accept their may be a very small, millions to one chance, it may all go wrong but that is life. As to ferries I take on what Brian has said but while the tunnel may check the ferry companies never do or even ask if your bottles are turned off, so they have no concerns. A small petrol leak from another vehicle setting of a fire because your fridge turns on is so remote personally I would not even consider it, so if you see me on your ferry best catch the next one because my gas will be on. Link to comment Share on other sites More sharing options...
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