Vacuum Truck and NGL Tanker Trucks

[Glenfiddich]

I have a couple of questions. First, for vacuum trucks; can they vac out class 1 flammable liquids? I would imagine they have some code about not vac'ing very flammable liquids.

Second question is about tanker cars; what design pressure do they typically have? Also, what carbon number cut off would there be from going to a NGL truck and just a typical fuel haul truck? Propane and higher use NGL trucks? What would be the design pressure of the typical fuel haul truck?

Thanks!

 

[eliebl]

There should be no reason that a vacuum truck could not suck flammable liquids. It would have to be an appropriate DOT or TC tank if it was to haul them anywhere. That really depends upon local regulation.

Depending upon the type of vacuum pump there may be some ignition hazzards. If it is a lobe type pump or a fan then the chance of dangerous sparks would be likely be reduced. It has been 5 or more years since I built and vacuum trucks so things may have changed recently.

Propane and NGL are typically around 150 PSI. I believe these are the MC/DOT/TC 331 tanks (road). I was not involved in the manufacture of any of these. A fuel truck (MC306/DOT406/TC406) is usually an atmospheric non-circular tank with a 3 to 5 kpa design pressure.

ASME has written a section XII to address many of these tanks as well as portable tanks. I do not belive it is anywhere close to being adopted by regulation anywhere but it is based upon what many manufacturers used for design for the last 50 or so years.

EJL

 

[Glenfiddich]

It just seems fishy to mix air with a very flammable liquid inside of the vessel on the truck. It would just take a spark to cause a problem.

 

[eliebl]

I don't know of any code prohibiting it from being done but I certainly would not consider it. It's one of those cases where it's probably not prohibited but common sense must prevail.

EJL