yay or nay gas tank on roof rack

[zstampe]

This pic taken from the Shrockworks website... Seems like a lot of gas hangin' out over your head. You would need to be aware of the expansion factor as well as these heat up in the sun. The roof is probably the safest place to carry extra fuel tanks; aside from a rollover, they are out of harms way on the trail.

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As far as exploding; I assume I'm stating the obvious but make no mistake, gasoline with its rather high vapor pressure, vaporizes very quickly and is explosive, especially in warm conditions. The extremely rapid rate of combustion of gasoline vapors and the associated expansion of the gases is by definition, an explosion.

For what its worth: A BLEVE (Boiling Liquid Expanding Vapor Explosion) is an explosion but there does not need to be any combustion involved. They are a product of a rapid pressure change (a drop) that causes an even more rapid pressure change (a rise) due to the rapid/uncontrolled vaporization of the remaining liquid inside a closed vessel. The subsequent pressure rise is what causes the explosion of the containment vessel. There can be combustion but not necessarily.

Not true.... A bleve has to have a heat or chemical source (ie: reaction) to be considered a bleve. You are right that a bleve is an explosion due to pressure change but its secondary to a heat source applied to the situation. I believe you and I are saying the exact same thing just two different ways. I brought up the whole bleve scenario a few posts up.

:beer::beer:

 

[binga]

I have been looking at those new gas cans for a while and I really like how that clamp down. I was thinking of getting a few for my trailer.......If I ever finish it >.<

 

[jdkilroy]

zstampe, I know you are a firefighter so you are approaching this from "real world" thinking and you're correct in that in most situations that you as a firefighter would be involved in, pressure inside a closed vessel builds due to some external heat source with resulting explosion.

By definition: A BLEVE requires no heat involvement at all. A rapid depressurization of a containment vessel partially filled with a volatile liquid can result in an even more rapid vaporization of that liquid with a resulting pressure rise and then an explosion due to pressure; no heat required. You could create this scenario with a tank of water in theory. I worked on liquid natural gas tankers for many years and these scenarios were a real life concern. We trained at some of the best firefighting schools in the country and exercised our skills regularly so I'm not just giving you a hard time. In industrial settings you could encounter this very scenario so its something for you to keep in mind; lack of fire does not mean safe.

Anyway... this is supposed to be about 4runners...

 

[zstampe]

zstampe, I know you are a firefighter so you are approaching this from "real world" thinking and you're correct in that in most situations that you as a firefighter would be involved in, pressure inside a closed vessel builds due to some external heat source with resulting explosion.

By definition: A BLEVE requires no heat involvement at all. A rapid depressurization of a containment vessel partially filled with a volatile liquid can result in an even more rapid vaporization of that liquid with a resulting pressure rise and then an explosion due to pressure; no heat required. You could create this scenario with a tank of water in theory. I worked on liquid natural gas tankers for many years and these scenarios were a real life concern. We trained at some of the best firefighting schools in the country and exercised our skills regularly so I'm not just giving you a hard time. In industrial settings you could encounter this very scenario so its something for you to keep in mind; lack of fire does not mean safe.

Anyway... this is supposed to be about 4runners...

No worries jdkilroy, you're right because I'm thinking of this in the haz mat scenarios we encounter.

I also appreciate your wealth of knowledge and almost always enjoy your posts. Wasn't trying to sound like I knew more about a bleve. :beer::beer:

Back on the 4runners.....

Op, I like the rack setup. As I said before. I'm close to pulling the trigger on a Baja rack myself. What do you use your hi-lift jack for since you don't have a lift or sliders?

Have a good weekend all,
Zach

 

[tweakeraz]

To the OP...Yay, ONLY with the Rotopax however. At least for me.

I had a Blitz 5 gallon plastic can. What a piece of junk. Leaks. Smells. Have to keep relieving it of pressure. Awkwardly shaped. Can only be stored in an upright position.

Purchased 2 Rotopax 4-gallon cans. Wasn't too keen on the price, but they kind of have the market with their product. You either buy it or you don't.

I just got back from Death Valley after 4 days over the holiday weekend. Filled them up Thursday morning. Sat in my 90 degree garage overnight. Loaded them in the 4runner longways, but upright if that makes sense. Basically like the pic of the 4-gal posted earlier. Drove from Phoenix to DV with them in the cab. Threw them under the truck the first night. Strapped them flat side by side to the roof for the remainder of the trip. This is bombing through the desert. Hitting the whoops. and slow rocky roads. Sunday night, pulled them down and filled the tank up with them. Barely any pressure...if any at all. This was the first time I opened them the ENTIRE trip. No leaking. No off gassing. Closed back up and put back in the cab for the drive home. No smell. No leaking.

So for me, they met, but truly exceeded my expectations. They appear to be made of 2 types of plastic that combined are approx 1/8" thick. They are rotomolded so that thickness remains throughout the entire product. Not like blown molded Blitz cans.

As for durability, they appear stout, but there is a video of a truck running over one with no issues. Honestly, they could handle pretty much anything you would honestly stow on the roof or in the cab. As for size they look awkward, but they really can be packed any which way you wanted. Standing up, laying sideways, laying flat. Really no issue.

Filling: The new spout works awesome. Comes with the product.I think it is their ECO spout. ingenious and no leaking. I found filling easy once I found the best direction to have the spout facing in order to use the entire can without having to readjust the spout again. It is about 30 degrees of flat. Again, back to the pick of the 4 gallon unit, start with spout pointing straight up in line with that pack, then turn spout approx 30 degrees.

No pics right now. Sorry. Hope that helps and maybe answers some others.

 

[04rnr]

just my .02, I would rather put a (1) gas can on the roof over a spare tire.
I dont want that much weight on my roof, I know people do that, and wheel hard, with the spare up there, just not for me.
A Gas can like the Roto Pax sells Fuel Cans : Gas Pack : Gasoline Containers : RotopaX.com I would have no prob putting that up there for a long trip/run.

 

[blk-4runner]

Op, I like the rack setup. As I said before. I'm close to pulling the trigger on a Baja rack myself. What do you use your hi-lift jack for since you don't have a lift or sliders?

Have a good weekend all,
Zach

I got daystar 2.5/1.5 & getting RB 1.5 lift tomorrow, I got a pair of rockslider on order, should be here soon.