Electric vehicles during a disaster

[MossRoad]

When I was a little kid, we were over at a relative's house one evening. We heard a loud BOOM! and a house across the street exploded and burst into flames. A man ran out of the house on fire and died on the lawn. (traumatizing for us kids).

Apparently someone had been cleaning tar off of clothes with gasoline in the kitchen. The fumes had settled in the basement and something set them off. BOOM!

I'd forgotten about that until just now. Yeesh. Been about 10-15 years since I last thought about it.

 

[Grumpycat]

If this is true, I wonder how much is because propane systems are local and more subject to poor installation/maintenance than NG systems?

My understanding is the appliances are installed by the same people whether natural gas or propane. The problem is not if a leak, but when a leak. And has to do with getting the gas/oxygen mix to sustain combustion. Is apparently harder to do with the cocktail of multiple gasses in natural gas than the purer propane which settles to the floor meaning the optimal mix is found at some distance above the floor.

 

[Jstpssng]

Years ago a camp owner in northern Maine went to check the place because the “No heat” alarm had gone off. He walked through the house, flushed the toilet to make sure the water was running, then went outside to check the propane tank.
That’s when the house blew up. If memory serves me, it was a log cabin which came apart like match sticks. I never heard what happened but presumably there was a propane leak, which collected in the cellar. When the pump came on, things went “boom!!”

 

[ponytug]

The lower limit for ignition (LFL/LEL) is about 2.1% for propane, and 4% for natural gas. Since natural gas is lighter than air, it tends to rise, and dilute itself, lessening the chance for ignition. Propane vapors being denser, sink, and build up in low points, getting to ignitable concentrations faster for the same amount of gas.

Gases - Explosion and Flammability Concentration Limits

Flame and explosion limits for gases like propane, methane, butane, acetylene and more.

www.engineeringtoolbox.com

I see more water heaters now with built in wire mesh covers on the flame areas to prevent (reduce?) the ignition of flammable vapors.

All the best,

Peter

 

[cqaigy2]

The lower limit for ignition (LFL/LEL) is about 2.1% for propane, and 4% for natural gas. Since natural gas is lighter than air, it tends to rise, and dilute itself, lessening the chance for ignition. Propane vapors being denser, sink, and build up in low points, getting to ignitable concentrations faster for the same amount of gas.

Gases - Explosion and Flammability Concentration Limits

Flame and explosion limits for gases like propane, methane, butane, acetylene and more.

www.engineeringtoolbox.com

I see more water heaters now with built in wire mesh covers on the flame areas to prevent (reduce?) the ignition of flammable vapors.

All the best,

Peter

I didn't know that natural gas was lighter.

 

[ning]

I didn't know that natural gas was lighter.

Natural gas is primarily methane (CH4) which is lighter than air (~80% N2, ~20% O2, ~trace other stuff).
It's slightly heavier than methane because the other stuff is heavier than methane (density 0.680 kg/m3).

A not-entirely-accurate-but-decent way to compare gas densities is to find the molecular weights of the molecules and compare; air is (8/10*2*14+2/10*2*16 = 28.8, density 1.293), methane is (12+4*1=16, density 0.657), propane is C3H8 (3*12+8*1=44, density 1.882).

 

[5030]

Far as I'm concerned, electric vehicles ARE a disaster.

 

[Kyle_in_Tex]

Has anyone

Natural gas is primarily methane (CH4) which is lighter than air (~80% N2, ~20% O2, ~trace other stuff).
It's slightly heavier than methane because the other stuff is heavier than methane (density 0.680 kg/m3).

A not-entirely-accurate-but-decent way to compare gas densities is to find the molecular weights of the molecules and compare; air is (8/10*2*14+2/10*2*16 = 28.8, density 1.293), methane is (12+4*1=16, density 0.657), propane is C3H8 (3*12+8*1=44, density 1.882).

Has anyone tried to displace the air in a fireant mound with propane? It used to kill them handily to use 1,1,1 trichloroethane.

Hummmm? Not saying to light it, just fill it and move on to the next nest.

Oh, and if I could afford one, an electric car would be maybe the 4th or 5th car in my collection. But seeing as I only usually have 2 vehicles (3 right now). It probably won't happen unless a scorching great deal from a friend selling or something like that. Would never depend on 1 as my primary vehicle.

 

[ning]

Has anyone

Has anyone tried to displace the air in a fireant mound with propane? It used to kill them handily to use 1,1,1 trichloroethane.

Hummmm? Not saying to light it, just fill it and move on to the next nest.

Oh, and if I could afford one, an electric car would be maybe the 4th or 5th car in my collection. But seeing as I only usually have 2 vehicles (3 right now). It probably won't happen unless a scorching great deal from a friend selling or something like that. Would never depend on 1 as my primary vehicle.

I think it's hard to actually displace the air in there because you've got little tunnels and air has to come out to get displaced by what you're hoping will settle in.

 

[Egon]

The lower limit for ignition (LFL/LEL) is about 2.1% for propane, and 4% for natural gas. Since natural gas is lighter than air, it tends to rise, and dilute itself, lessening the chance for ignition. Propane vapors being denser, sink, and build up in low points, getting to ignitable concentrations faster for the same amount of gas.

Gases - Explosion and Flammability Concentration Limits

Flame and explosion limits for gases like propane, methane, butane, acetylene and more.

www.engineeringtoolbox.com

I see more water heaters now with built in wire mesh covers on the flame areas to prevent (reduce?) the ignition of flammable vapors.

All the best,

Peter

Flame arrestors.