I put a motor snorkel on a generator and filled some new tanks this weekend. Apparently for a passenger car without a separate space, like a truckbed, the limit is 90 lbs. For example, this would mean no more than 4-20lb "grill" sized tanks. Truck beds are 1,000lb.

Preaching to the choir I know, but don't plan on transporting more than this in one trip. I had to make three separate trips. Imagine if there was a long line and / or lack of supply.

https://www.inkling.com/read/nfpa-58-liquid-petroleum-gas-code-handbook-2011/chapter-9/9-3-transportation-in-portable

This varies by area for the "closed bodied vehicle" rules, here the limit is two (edit to add: or three, now I'm trying to remember exactly where they put the limit. It can actually vary by town, as crazy as that seems) twenty pounders. Also, keep in mind that the weight limit is for gross weight. This is true whether it's small tanks or large, so if you hit 1001lb gross weight you better be hazmat certified with placards and DOT paperwork....

If you're planning to use it for a generator you're better off with 100lb tanks and you can generally get them delivered, particularly if getting more than one. You may have to talk to a compressed gas company rather than a propane one though. It depends on the companies in your area. Something else to look into is getting a tank fitted for bulk fills rather than just the regular fitting. That allows for fills straight from the delivery truck if the company permits it. There are safety concerns with that procedure, but in an emergency you could probably talk them into at least a mostly full tank. It's kind of like using a garden hose to fill your high ball when you absolutely can't spill any. Those are relatively rare tanks though, and the fittings add up. It might just make more sense to have more tanks on hand or get a larger tank put in and the plumbing done for a quick disconnect to the genny.

I'll second that the details tend to be highly local -- both in terms of transport rules and by me they won't fill a 100lb tank unless it is hooked to some appliance more or less permanently.  I also think in an emergency it would be very difficult to arrange a delivery.  During Sandy swapping 20 lb tanks worked more or less as it normally would, which is more expensive, but on the other hand I could do this 5 minutes from home instead of driving 25 minutes and hoping the filling station was open (no phones).  By me I think you can have no more than three tanks and/or no more than 80 lbs in your car (don't quote me on that).

Remember this propane is cheaper during the summer . I heat with it and have found you can save money filling up during the summer .

For a fill on site it definitely depends on your situation. If you already have a relationship with that supplier and they are making deliveries in general you're probably ok. For the filling 100lb's only when hooked up, cheat. Hook that sucker up to a disconnect or two for the grill and genny. Sure, it's hard plumbed, doesn't mean it can't come off there if needed.

The reason for that rule by most propane companies is liability. If they fill a tank on site they are potentially liable for the results, even if it's your fault. Most companies want to look over your plumbing at the least, verify safety... But as with anything, if you do it right you can usually get an exception. Setup your plumbing, get it checked and move on. Just keep in mind that there are reasons for their caution. It's NOT like water. Just because most areas let plumbers do gas work does not mean it uses the same stuff or that most plumbers have a clue. It's also a lot more obvious when there's a water leak, and it's easier to find.

Confused.

is this federal or state regulations??

one post seems to think its a state/local thing, but the DOT is the DOT?

I am just confused.    if the rules vary then i suppose its a state or less thing.

is there some kind of overlapping i dont know about?

National Fire Protection Association (NFPA) recommendations, which in many locations are adopted as fire codes.

Even if they aren't legally binding, some vendors might try to enforce compliance for their own liability.

There are DOT regs, but they don't apply until you get past a certain amount or conditions. Then there are often state regs which set an upper limit, then there are often local regs which determine what the actual retailer will do. What the Hartford Fire Marshal allows is not the same as what the state allows, he's more strict and a dealer in Hartford will follow his regs if they're smart. A dealer out in the county follows any county regs or just the state level ones if the county doesn't add anything. Yes, it's that crazy.
In practical terms, Hartford is legit for two 20lb tanks in an enclosed vehicle. They're listed as 38lbs gross each and the limit is 99lb. You can also get two 30lb but not two 40lb tanks.

Basically, you probably wouldn't have any problem if you got stopped unless you were over the state limits or DOT limits. The dealer can't afford to ignore the FM though, so they comply with the regulation.

Just in the interest of full disclosure here, I work for a company that sells propane and other compressed gases. I'm not in the sales/service side of things, which is why I didn't have the limits in my head last night. There are a lot of "should be done this way" and "REALLY should be done this way" things when it comes to this stuff. Then there's a lot of BS feel good rules and regs that get passed. Quite often there are disagreements between code inspectors even in one area as to what the proper way to do things is. It isn't uncommon for our techs to have to politely argue with inspectors and show them in the documentation that it really was done properly. Interestingly enough, the codes almost always read, "as instructed" for installations of various equipment. So if you follow the instructions or guidelines for everything from the tank to the genny you would be good even if it was stupid and likely to fail, do it any other way and you have to make sure it's EXACTLY to code. I once took a training class for some shielded underground piping and the guy spent twenty minutes discussing the best way to deal with inspectors who didn't understand the product. The company had gone so far as to set up a hotline for you to call while with the inspector.

no its not, that is not a law.



you need to know local state laws, not recommendations from the net.



doesnt matter anyway, if you need to transport a lot of it at one time, it just means you were not prepared