Propane fill question

[12th_Man_Fan]

OK I am officially confused.

I took one of my 40lb. propane cylinders out of my new RV to have it filled. A note on the door of the propane compartment said do not fill over 80%, could cause fire,explosion etc.

I told the guy that was filing the bottle to fill to 80%, he didn't know what I was talking about and since I didn't know what I was talking about we filled it to 65 total lbs where his info showed it full at 75 lbs.

Anyhow since this is a safety issue can anyone help me out. since this is a 10 gallon tank am I only supposed to put 8 gallons in it?

I have always taken them to the guy, he puts it non a scale and fills it to the total weight on his chart. Is this 80% or is it over filled?

For those of you that want me to do a search, I did and got 503 pages and although I am retired I don't have enough time to read all of the info.

[NinerBikes]

AllegroD wrote:

smkettner wrote:
Tank has an OPD valve to prevent over fill. Tank is already designed to stop at 80%. No need to short fill to 80% of 80%.

100% filled to capacity (40 lbs.) is 80%.

Considering the age of your rig, the above should be the answer.

12th Man Fan wrote:
For those of you that want me to do a search, I did and got 503 pages and although I am retired I don't have enough time to read all of the info.

So your answer to the many hundreds of RV.NET forum is that they should repost their answers and their time is not as valuable as yours.

Ding, ding, ding, we have a winner.

[red31]

An overfilling prevention device must not be the primary means to determine when a cylinder is filled to the
maximum allowable filling limit.
NFPA 58, §7.4.4.1

Overfilling Prevention Device [“OPD,” “stop valve”]. A safety device that is designed to automatically prevent a
container from being filled beyond its maximum permitted filling limit.
NFPA 58, §3.3.49

Fixed Maximum Liquid Level Gauge [“outage gauge,” “spitter valve,” “spew gauge”]. A fixed liquid level gauge that
indicates when the liquid level in a container has reached its maximum permitted filling limit.
NFPA 58, §3.3.29.2

The formula for filling LP-gas containers by weight is as follows:
(1) Determine the propane capacity in pounds by multiplying the total water capacity in pounds by 0.42.
(2) Add the tare weight of the cylinder to the liquid weight of the product plus the weight of the hose and
nozzle. The total weight of these three is the proper scale setting.
LP-Gas Safety Rules, §9.136(a) (TEXAS)

[mmiille]

Wish I didn't now.

[westend]

RJsfishin wrote:
Quote:
I would be more concerned about the safety release that is built into every cylinder. At a certain pressure, the safety release opens and a large volume of both gas and liquid is expelled. It happened to me, once. The cloud emitted is so dense that you can't see your outstretched hand.
--------------------------------------------------------------------
This is not true at all !
Did you dream this ?? If this really happened, you had better get it fixed quick, because this could make for a very dangerous situation.
In reality, a LP safety release valve releases the LP gas no faster than the gas is expanding and needs to release, which is seldom more than a hissing sound that can be heard and smelled when close by. It presents absolutely no hazard as long as there is no open flame w/in 50 feet.
It is not a pop off valve, such as found on an oxygen bottle, that really will expel its entire volume if it gets over pressured.
It is a bleeder valve, and will NEVER bleed off more than needed for expansion.

RJ, I should have said that this was from an older cylinder. I frickin' didn't dream it! Near death experiences leave me with valuable lessons learned.

The cause of the cylinder venting was an inexperienced hand at the fill station. He overfilled the cylinder. When underway, the pressure built and the cylinder vented. After arrival at our destination, with the propane cylinders in a compartment on the truck camper, another cylinder vented in the same manner.

[time2roll]

AllegroD wrote:

smkettner wrote:
Tank has an OPD valve to prevent over fill. Tank is already designed to stop at 80%. No need to short fill to 80% of 80%.

100% filled to capacity (40 lbs.) is 80%.

Considering the age of your rig, the above should be the answer.

So are newer RV bottles different or older?
Not sure a bottle without OPD can be filled legally.

[dennislanier]

The only problem with getting 503 answers on the search, is that there were probably 503 DIFFERENT ANSWERS.

[dennislanier]

So - is the answer yes or no?

[AllegroD]

smkettner wrote:
Tank has an OPD valve to prevent over fill. Tank is already designed to stop at 80%. No need to short fill to 80% of 80%.

100% filled to capacity (40 lbs.) is 80%.

Considering the age of your rig, the above should be the answer.

12th Man Fan wrote:
For those of you that want me to do a search, I did and got 503 pages and although I am retired I don't have enough time to read all of the info.

So your answer to the many hundreds of RV.NET forum is that they should repost their answers and their time is not as valuable as yours.

[beemerphile1]

BillyW wrote:
Who's on first?

I don't know.

[SaltiDawg]

Pressure Relief Valve (PRV) Lifted due to ambient temperature increase.

[RJsfishin]

Quote:
I would be more concerned about the safety release that is built into every cylinder. At a certain pressure, the safety release opens and a large volume of both gas and liquid is expelled. It happened to me, once. The cloud emitted is so dense that you can't see your outstretched hand.
--------------------------------------------------------------------
This is not true at all !
Did you dream this ?? If this really happened, you had better get it fixed quick, because this could make for a very dangerous situation.
In reality, a LP safety release valve releases the LP gas no faster than the gas is expanding and needs to release, which is seldom more than a hissing sound that can be heard and smelled when close by. It presents absolutely no hazard as long as there is no open flame w/in 50 feet.
It is not a pop off valve, such as found on an oxygen bottle, that really will expel its entire volume if it gets over pressured.
It is a bleeder valve, and will NEVER bleed off more than needed for expansion.

[TurnThePage]

Who's on first?

[ken_white]

smkettner wrote:

mmiille wrote:
So the lp gas weighs 4.11 pounds per gallon. A 40 pound tank at 80% would hold 32 gallons. That would be 131 pounds. A 20 pound tank at 80% would be 65 pounds.

40 / 4.11 = 9.73 gallons. Check the fuel gauge on the pump next time you fill.

A 40 lb tank holds 40 lbs of propane, no calculation needed.
And yes the 9.73 gallons (40lbs) is considered 100% filled even though there remains 20% of space in the tank for expansion.

X2...

[time2roll]

mmiille wrote:
So the lp gas weighs 4.11 pounds per gallon. A 40 pound tank at 80% would hold 32 gallons. That would be 131 pounds. A 20 pound tank at 80% would be 65 pounds.

40 / 4.11 = 9.73 gallons. Check the fuel gauge on the pump next time you fill.

A 40 lb tank holds 40 lbs of propane, no calculation needed.
And yes the 9.73 gallons (40lbs) is considered 100% filled even though there remains 20% of space in the tank for expansion.

[dougrainer]

sato4000 wrote:
My RV dealer said he will fill up the propane 100 percent if you want.

1. That dealer is an IDIOT
2. NO reputable LP filler would EVER fill past 80%
3. The HAZARDS of filling 100% are extreme.
4. LP is LIQUID and MUST have interior space for expansion(vapor) to form and flow. HOW would that happen at 100% full?????
5. Filling 100% makes introducing LIQUID LP into the piping and the LP regulator which will freeze and destroy the LP regulator.
6. If you fill 100% or even 90% at 60 degrees ambient and take THAT cylinder to an 80 or 90 degree ambient without ever using it, the safety valve will then blow from the expansion of the LP in that tank from the ambient temp heat rise.
7. Filling LP is NOT what the customer wants, it is what is allowed and SAFE. Doug