Overfilled Propane Tanks -- How Dangerous are They?

   / Overfilled Propane Tanks -- How Dangerous are They? #1  

CurlyDave

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Joined
Dec 25, 2005
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Location
Grants Pass, OR
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JD TLB 110
Since DW and I stuck here in CA for the house rebuild, and the weather finally turned HOT, DW put he foot down and demanded a grill so she wouldn't have to make the kitchen any hotter.

Went down to a local store and got a medium-low quality gas one, since it only has to last for two summers.

Anyway when I got a 5 gal propane tank and took it to the local U-Haul outlet to get it filled, the guy filling it conveyed to me that since it was a new tank he had to use a special procedure. He proceeded to fill it as slowly as possible, maybe 20 minutes for the tank.

Somehow, this seemed to override the OPD and he managed to get 5 gallons into the tank, when you are only supposed to fill it to 80%.

We have burned off some of the propane, so I think we are more likely at 90-95% of capacity right now, but just how dangerous is this?

10 or 15 years ago no one paid any attention to not filling all the way, but to read about it now you would think "instant fireball" if a tank is filled beyond 80%.
 
   / Overfilled Propane Tanks -- How Dangerous are They? #2  
Dangerous enough that every new tank is required by law to have an OPD,(Over Pressure Device) installed on every new tank and grill sold today.
Propane explosion / fire is not something you ever want to be involved in.
It is a safety device intended to prevent what you say happened with your tank. If it were me I'd run the grill for a few hours while I was somewhere else, away from the grill.
Can you put it out in your yard away from anything you don't want damaged in worst case scenario, and leave it running for a while to burn off the excess gas?
 
   / Overfilled Propane Tanks -- How Dangerous are They? #3  
I have filled propane tanks for years now and they are built to take the pressure. You have to purge new tanks to expand the bladder inside.

We did this buy hooking the tank to a hose that came of the top of the filler tank which just put air in the small tank. Suppose to do this 2-3 times. This process shouldnt take anymore than 5-10 minutes at the most.

Then fill the tank normally with the valve that comes out the bottom of the filler tank. When we fill 20lb tanks there is a small set screw on the valve that we open. When the liquid propane starts to come out that valve it is full to 80%.
Some of the 100lb tanks dont have that feature so we put in the reccomend gallons that is stated on a chart we were given by the propane company. We never weighed anything which is how I alway saw it done many years ago.

Also when you overfill the tank the filler tank automatically stops filling when the pressure equalizes I guess. I had this happen a few times. The pump just stops pumping. Must be some kind of safety valve. And I am not talking about the 80% valve kicking on. I have had many of these stick so you could not fill the tank or it would over fill the tank.
 
   / Overfilled Propane Tanks -- How Dangerous are They? #4  
Dave...We cook out from time to time and I just recently got one of those portable stainless propane grills that is the size of a briefcase to take to the beach, etc. That's the one we use all the time, now. I got it at Lowe's. The old big roll around one just sits there and does not get used anymore.
It looks sort of like this one...(but cheaper)...
Product Detail - Grill4All

For all around cooking these small ones I have found out are great! If you don't have one of those...get one and see!

Sorry for the off topic...but propane is in there somewhere...
 
   / Overfilled Propane Tanks -- How Dangerous are They? #5  
With a new tank the object is to remove all the air that is in the tank.:D
 
   / Overfilled Propane Tanks -- How Dangerous are They? #7  
I think I'd throw a couple more steaks on and have at it. I think if its not spewing gas out of the overflow you are ok. Had same thing with 1 in sun stopped after couple of minutes
 
   / Overfilled Propane Tanks -- How Dangerous are They? #8  
I'm thinking he used 5 gallons total but that much isn't in the tank. On a new tank they put some in and purge it a couple of times to get the air out, this uses some of the gas on the meter.
OPD stands for Overfill Prevention Device.
I've also never heard of a bladder in a LP tank, I've cut a few open and there was no bladder:confused:
 
   / Overfilled Propane Tanks -- How Dangerous are They? #9  
just purge some from the tank. open the relief screw on the side of the valve until you feel safe.

Jeff
 
   / Overfilled Propane Tanks -- How Dangerous are They? #10  
Yes you are right there is no bladder inside. I never thought about it but the certification instuctor would tells us that and compare it to a water tank. Anyway here are a few specs for some sizes of propane tanks

20# 30# 40# 100#
Capacity (gallons) 4.7 gal 7.1 gal 9.4 gal 23.6 gal
Weight (empty) 18 lbs 24 lbs 29 lbs 68 lbs
Weight (full) 38 lbs 54 lbs 70 lbs 170 lbs
Overall Height 18 inches 24 inches 29 inches 48 inches
Diameter 12.5 inches 12.5 inches 12.5 inches 14.5 inches
BTU Capacity 430,270 649,980 860,542 2,160,509
 
 
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