Towing A Bomb...LoL

[EdsTowing]

Had to tow a loaded gas truck the other day that derated. I smelled propane when I was under it but figured it was residual and it was pouring so I just wanted to get the dam shaft out of it. We went to look at it the next morning & found it lost 15% due to a leak of a seal in the bottom of the tank. They came over and pumped the rest out & then blew off the lines and what not to get it back to atmospheric pressure. It only had 60 miles since it left the dealer so they asked me to tow it back there for warranty DPF issues....

 

 

Sometimes you get one that was "made to tow"....LoL. You couldn't ask for an easier rear tow...

 

 

50 mile tow back to International yesterday morning.

[Njsss]

Are CDL endorsements required when towimg a Hazmat/Tanker in PA? 

 

Sounds like you could of had a pre 4th of July fireworks show

[rreschran]

That happened to me years ago ... once the smell got to my nose, I moved my truck away from the source and called the fire department. They arrived and took over the process of off-loading gasses until it was empty. A leaky hose was the culprit.  Perhaps your post is something towers should think about when the caller is setting up a tow? Accordingly, dispatch should ask ... "Is the tanker loaded or empty?" Thanks Ed for posting a really dangerous safety consideration ... others take heed.     R.

Edited July 4, 2020 by rreschran

[brian991219]

22 hours ago, Njsss said:

Are CDL endorsements required when towimg a Hazmat/Tanker in PA? 

 

Sounds like you could of had a pre 4th of July fireworks show

On the first tow from the point of disablement to the nearest place of repair or safe place like the tow yard, no. For any secondary tow then the appropriate endorsements are required such as tank and hazmat. Keep in mind, first tow/nearest place are very subjective to interpretation so it is always better to be fully qualified to operate any vehicle you will be towing.

 

I always recommend towers have all the endorsements even for a first tow to reduce liability should something go wrong and so that they have had some basic training/knowledge at least once in their career regarding special situations surrounding hazmat or tank vehicles.

[brian991219]

18 hours ago, rreschran said:

That happened to me years ago ... once the smell got to my nose, I moved my truck away from the source and called the fire department. They arrived and took over the process of off-loading gasses until it was empty. A leaky hose was the culprit.  Perhaps your post is something towers should think about when the caller is setting up a tow? Accordingly, dispatch should ask ... "Is the tanker loaded or empty?" Thanks Ed for posting a really dangerous safety consideration ... others take heed.     R.

Is a propane tanker every really empty?

 

Unless cleaned and purged they will always have some residual vapor inside which is just as deadly as being fully loaded. About the best that can be done roadside is transfer the remaining liquid and reduce pressure to atmosphere but there will always be some residue left that can pose an explosion hazard from a leaky seal, fitting or hose. This is why even empty tankers usually require the appropriate endorsements and placards displayed.

 

As for propane, the gas is heavier than air so it settles to the ground, it boils rapidly at -44 degrees C, making it expand when exposed to temperatures outside the tank that are warmer than -44C. The expansion happens at a rate dependent upon atmospheric temperature but can be averaged at 10X the volume at -44C for simple math. Even the slightest residue inside a tank can produce enough vapor to explode when released to the air. 

 

Another thing to consider when dealing with propane tankers, the gauge on the back of the tank is not always accurate. As with any liquid temperature plays an important role in volume. It is not uncommon to see a significant decrease (10-15%) in the level on the gauge after as little as a 20 degree F outside air temperature change. This is perfectly normal behavior for a propane tank. This is why when filling propane tanks the technician uses a fixed level gauge (often confused for being a vent valve) to know when the 80% of tank capacity is reached rather than the tank float gauge.

 

That said, and this comes from direct experience with propane tankers (I have a customer that I train their drivers for that is a propane and oil distributor), I have no doubt that both Ed's tanker and the one you are referencing had a leak. It is never normal to smell residual propane unless the truck just finished a delivery within a few minutes. You will smell some vapor during a delivery but it dissipates quickly. If the truck smells like propane when you arrive to service or tow it there is a bigger issue that needs to be addressed by a qualified technician that specializes in the product and equipment on site.

 

Side note on fuel tankers, especially gasoline, empty or partially empty tanks have the most fire danger. The larger the volume of vapor in the tank the more likely it is to explode. Also partially empty tanks are more unstable to tow due to the shifting liquid surge as you brake and turn.

Edited July 5, 2020 by brian991219
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