Propane Solenoid experiences , good/bad/best

[Bill Seal]

Originally Posted by Claude_Marie

Sorry Dockhead, it is the other way round, 110v has a greater lethal potential than 220v.

Watt = Volt x Amps

if you want : 2200 W
@ 110 you need 20 Amps.
@ 220 you need only 10 Amps.

Amps kill you, not Volts.

Proof : in between your ignition coil and your distributor cap and further to the plugs you find 10 Kv.
Should you touch the cord on a running engine, you are likely to experience a rather unpleasant shock @ 10 000 Volts, but it will not kill you...because there are hardly any Amps in this H.T circuit.



Another example : Electrostatic discharge, this painful ESD on a cold dry (rare in the UK) winter day when you touch your car, plenty of volts but no Amps.

No surprise the rate of electrocution is half in the UK.


110V was the norm on the continent 40 years ago, we switched to 220 for safety reasons.

I guess a little knowledge is a dangerous thing.

The 10KV from the ignition coil is from a very high impedance source; as soon as you touch it, the voltage (and available current) goes to practically nothing. Years ago a friend of mine got across an 8KV 15 amp transmitter power supply, unfortunately he did not survive.

Given the same skin resistance, 220v will push twice as much current through a human body as 110v.

[rwidman]

Originally Posted by Bill Seal

I guess a little knowledge is a dangerous thing..........

Yes and the Internet has helped to spread misinformation globally.

[Claude_Marie]

Originally Posted by Bill Seal

. Years ago a friend of mine got across an 8KV 15 amp transmitter power supply, unfortunately he did not survive.

.

Sorry for your friend.

But was 15Kv AND 15 Amps = 225 KW, poor lad.


If your friend had received a shock of 15Kv and milliAmps, he would have made it.

From Electrostatic Discharge you can receive up to 50 Kv (Fifty, no typo) from a cat with a thick fur.

And I have never heard from anybody electrocuted from their cat.


Edit : Does not kill the cat either.

Again, no Amps.

For a given power @ 110v you need twice has much Amps.


Residual protection switch, circuits breakers are rated at 30 milliAmps, I suppose that this value was not selected at random, and suggest you are at risk over 30mA @220V

[contrail]

Originally Posted by goboatingnow

Sorry , mostly nonsense.

Gas cooking is very common as is natural gas installations and gas installations on domestic systems are highly regulated.

European 220vac safety codes are well in excess of US 110 NEC codes. Whole house rcbs being a case in point.

My kitchen has smoke and Co monitors too.

I would argue European safety codes are ahead of US ones actually

Sent from my IPad using Cruisers Sailing Forum

As the person who made the original comment about Europeans, let me re-state my comment, which was made from the position of being a professional charter captain and instructor (American citizen but half Brit) observing scores of other, professional (and trained and certified) crews from many nations, in a very busy area: I have never seen a European crew pay attention to turning off the gas at the tank, whether by solenoid or manual valve, after cooking a meal on a yacht. And, when having a European chef onboard, without exception I have had to point out the correct procedure. Is this not emphasized in their training? Have they not suffered the spate of accidents that happened in the early days of propane use on boats? I haven't a clue. And I have no opinion about whose safety regulations are stronger, either. I think that, on a professional level, the crews of both countries are equally competent, but I will certainly agree that, among amateurs, there is much more stupidity among US boaters, probably because no training is required and we are a do-it-yourself nation and we routinely deal with less challenging conditions, on the whole. But, I hope this does NOT start a thread drift...just repeating the very narrow statement I originally made.

Sent from my iPad using Cruisers Sailing Forum[/QUOTE]

[contrail]

Originally Posted by wsmurdoch

I've been thinking about putting the solenoid valve in the high pressure propane piping before the regulator rather than in the low pressure piping after the regulator. At first, it seems like a good idea, but after a while I'm not so sure.

The propane locker is designed to safely handle leaky propane. It is sealed from all sources of ignition, vented, and is drained overboard. A leak there should do no harm. The interior of the boat is not. It is full of ignition sources and drains to the bilge. A leak there could destroy the boat.

If I turn off a solenoid valve in the low pressure piping just before it passes out through the propane locker bulkhead, the only gas that can enter the interior of the boat is the 0.5 psig gas in maybe 15 ft of 1/4" rubber hose and in the propane stove piping.

If I turn off a solenoid valve in the high pressure piping upstream of the regulator, I still have the 0.5 psig gas in the 15 ft of 1/4" rubber hose and the propane stove piping. But, I also have the 135 psig gas in the piping both between the solenoid valve and the regulator and also in the high pressure parts of the regulator. Each cubic inch of the 135 psig gas downstream of solenoid (and upstream of the valve in the regulator) will will expand to make 270 cubic inches of 0.5 psig gas if there is a leak inside the boat. [PV=nRT and all that]

If there is a leak in the low pressure LPG system inside the boat or if an appliance valve is left open, does that extra volume of gas that will come from a solenoid valve in the high pressure piping constitute a real increase in the risk of a fire or explosion in the boat?

It's not that hard! The correct procedure is to turn the gas off at the bottle (solenoid or manual valve) and let the flame burn out at the stove, which usually takes just a few seconds. That way there is no propane in the line, and it won't matter where the valve is. Your burners are also supposed to have safety thermocouples on them that turn the gas off at the burner, should a burner get blown out while still open. That's why there is a procedure for lighting a burner, often holding the knob in to override the thermocouple, while waiting for the burner to warm up. It's also why a land stove is not appropriate on a boat.

[Claude_Marie]

Originally Posted by contrail

As the person who made the original comment about Europeans, let me re-state my comment, which was made from the position of being a professional charter captain and instructor (American citizen but half Brit) observing scores of other, professional (and trained and certified) crews from many nations, in a very busy area: I have never seen a European crew pay attention to turning off the gas at the tank, whether by solenoid or manual valve, after cooking a meal on a yacht. And, when having a European chef onboard, without exception I have had to point out the correct procedure. Is this not emphasized in their training? Have they not suffered the spate of accidents that happened in the early days of propane use on boats? I haven't a clue.

]

The answer is no, they have not suffered the spate of accidents.

How can you explain this carelessness, otherwise ?

I can suggest an explanation why no accident happened in the past (I am far less optimistic for the future), when you asked a professional to run a gaz installation in old days, you dealt with craftmen who had left school at 14, and started in the plumbing trade as apprentice, the know how was passed on from the old experienced generation to the young one.
The overall level of education was low but the skills were high and COMMON SENSE was tought.
They could make simple arithmetic calculations mentally and get them right 100%.
The new generation uses spread sheets, push the wrong key, get a result 3 orders of magnitude wrong and cannot see it.
Old school craftmen took their time, figured out how to run their pipe between gaz cylinder to cooker in ONE lenght, avoiding excessive radius when bending, if they had to dismantle lockers, they would do so.
Routing of the pipe was done in the way that nothing could rag against them, fasteners were used wisely in just the right number (no overkill), some flexibility was allowed.
Extreme care was taken to keep gas cylinder locker ventilated, cylinder secured in a bullet proof mount, no stress on rubber hose possible.
Same at the other end, between pipe and cooker.
No rocket science, but a lot of thinking and the pride to do a perfect job.
Sounds silly doesn't it : Taking pride into one's job.
Design was simple :
Cylinder-rubber hose-copper pipe rubber hose- cooker.
no welding, no couplings in between.
No accidents.
There was also a knowledge about maintenance : A gas gasket coupling is specific under no circonstance a gasket for water pipe should be used.
Rubber hoses to replaced by new ones on a regular basis, some came with a "change before..." printed.
People knew (how, do not ask me ) that no excessive torque should be applied when tightening a new hose.
In doubt, soapy water and torque adjustments.

I have seen my dad tightening the coupling between cylinder and pressure regulator with his hands, no tool.
In these modern days of single mums with no man arround with muscular hands to screw at proper torque, you can buy a plastic spanner, quite strong, which you use when you change your cylinder.
Despite made of plastic it is strong and is designed in a way that it "jumps" from the bolt when the proper torque is reached.
So no excessive torque applied on the soft rubber gasket.
Using this spanner helps developping a muscle memory, so you end up knowing what torque is required for these gaskets.

So everything would be perfect, Hell no !
Modern (cough, cough) Education put on the market so called professionals without a single hint of common sense, the know how does not pass on from the old salts to the rookies.
It seems that they cannot used their hands anymore, cordless drill for everything, would not use a screw driver..."fuxing" threads does not cross their mind, adjustable spanners instead of the spanner for the right size, how can they figure out how much torque they apply ?
At the end of the day, more regulations for gas detectors, safety valves and so forth to overcome poor design and even poorer crafmanshift.
Are we any safer with all these bells and whistles....I am not even sure.
I wonder how our parents and grand parents survived in days when these electronic and safety gizzmo did not exist ?
Still accidents were rare.
Go figure....

[Claude_Marie]

In old days, we could buy cookers which came with a nice flag and a sticker that read Made in USA, GERMANY, FRANCE, ITALY....no longer the case, hence the solenoïd valve, gas leak detector ?
Just askin'

[goboatingnow]

Modern gas codes , including the RCD ( CE ) in Europe, means that todays gas installs are to a far higher standard then previously . The " good old days" actually weren't that good at all.


Dave

[goboatingnow]

Edit : Does not kill the cat either.

Again, no Amps.

For a given power @ 110v you need twice has much Amps.

true,

but the human being is basically a fixed resistance, not a fixed power sink, apply ohms law to see what happens, in 220VAC twice as much current will be pushed through a given resistance ( the human body ) , this makes 200VAC twice as lethal.

dave

[Claude_Marie]

Originally Posted by goboatingnow

Modern gas codes , including the RCD ( CE ) in Europe, means that todays gas installs are to a far higher standard then previously . The " good old days" actually weren't that good at all.


Dave

Does RCD refers to gas grid or to gas cylinder ?

[goboatingnow]

Originally Posted by Claude_Marie

Does RCD refers to gas grid or to gas cylinder ?

The whole gas installation aboard a european boat is governed by the RCD ( recreational craft directive) ISO standard 10239, being the standard to apply to achieve conformance

The cylinder itself is covered by a different standard

dave

[Claude_Marie]

Thanks, I struggle with unfamiliar acronyms.
And thanks also for indicating the exact ISO std.

I am left to find out how ISO 10239 translate into an EN std if it does.


Edit : 10239 would be (I am lost) BS-ISO-EN

[rwidman]

Originally Posted by goboatingnow

true,

but the human being is basically a fixed resistance, not a fixed power sink, apply ohms law to see what happens, in 220VAC twice as much current will be pushed through a given resistance ( the human body ) , this makes 200VAC twice as lethal.

dave

1) Human skin has less resistance when wet. See my post about the electric chair above.

2) Lethal is lethal. I don't think anything can be "twice as lethal".

[rwidman]

Originally Posted by Claude_Marie

........... I can suggest an explanation why no accident happened in the past (I am far less optimistic for the future), when you asked a professional to run a gaz installation in old days, you dealt with craftmen who had left school at 14, and started in the plumbing trade as apprentice, the know how was passed on from the old experienced generation to the young one.
The overall level of education was low but the skills were high and COMMON SENSE was tought. ..

I worked with some of those "old school" people. The problem is, technology changes and they often don't or can't because they lack a basic understanding, they were just taught how to do things.

I was at a demonstration of a new school's computerized heating/cooling system. At the end of the demonstration, the installer asked if there were any questions. The maintenance electrician asked "How do you bypass it?"

Then there was the plumber who never learned how to solder copper pipe. He could work with iron pipe just fine but not copper or plastic.

There was an oil burner mechanic who could not read or write. He could work on things if someone had previously showed him what to do but he couldn't read a service manual.

[Claude_Marie]

Originally Posted by rwidman

2) Lethal is lethal. I don't think anything can be "twice as lethal".

I considered mentioning this also, but, did not sound fairplay.

more dangerous ?

That said, I cannot find a definite answer, I was convinced that 110 was more dangerous (and NOT twice lethal), now, I do not know anymore.
Figures showing that there were more accidents in 110V days prove nothing, as safety standards do not compare with today 220V.
If it is a myth, it probably finds its origin here...