Home Propane Tank Gauge Question

[SimplerTimes]

The safety factor is there to prevent too much pressure from building up inside the tank as the liquid gas expands. For example, an increase due to expansion from 80% full to 90% full would roughly double the internal pressure of tank. This type of pressure increase will trigger the pressure relief valve to release propane gas into the atmosphere long before the tank fills completely with liquid propane. Anyone that has heard the hissing sound of a propane tank pressure relief valve in action knows what that type of release sounds like.

It kills me they will not fill the tank to 90 or even 95 percent on a 25 degree day when we have 10 days of sub zero weather coming, easily burning 20 percent of what's in the tank. I used to have a guy that would take me up to 90 or even a bit more since he had some common sense and had the freedom to exercise it.

 

[Rand]

What is your point? People keep telling you why and you keep saying the same thing like an ostrich with head stuck in the sand.

Maybe that bridge would hold 200tons.. but it has a 100ton rating for a reason.. the worst case scenario and safety factor.

Odd that you would join here and act like this in first post.. are you a retread?

BTW: Welcome to Bitog.

So my advice to you since it "kills you" get used to being dead. There are safety rules and they arent negotiable unless people are dumb... not smart not common sense.

 

[Dave9]

If you want MOAR propane on each delivery, get a larger tank or 2nd tank and switchover valve.

 

[CDX825]

7 or 8 years ago when I was still running with the local volunteer fire department we got called out to a tank that had popped the relief valve. It was a 120 gallon tank sitting next to the house. They had the tank filled in the winter and the company must have filled it past 80 percent. First hot day of the year and it let loose. The force of the relief blowing off was enough it took some of the siding off the side of the house above the tank.

 

[thastinger]

When its January and we are in a cold snap I have tried to get them to fill mine to 90 percent, they just will not do it. By the time there was any problem with expansion I would have burned thru a tank!

I have also had mine filled to 80 percent in May and thru the brutal heat of the summer while not burning any propane the level increase was almost not noticeable.

I believe it to be the real reason it will only be filled to 80 percent is to maximize profits by getting more trip charges. Don't laugh, if they short everybody from a full fill and end up with 1000s of extra trip charges you better believe they are making more money!

Thats because they physically can't. There is a float inside that closes the fill valve when the tank gets to 80%, called an OPD (overfill Prevention Device)

 

[Ride_Red]

The safety factor is there to prevent too much pressure from building up inside the tank as the liquid gas expands. For example, an increase due to expansion from 80% full to 90% full would roughly double the internal pressure of tank. This type of pressure increase will trigger the pressure relief valve to release propane gas into the atmosphere long before the tank fills completely with liquid propane. Anyone that has heard the hissing sound of a propane tank pressure relief valve in action knows what that type of release sounds like.

False.

Propane has a vapor pressure that changes with temperature, not volume. The vapor pressure determines the pressure of the tank, not the amount of propane in the tank. A 95% full tank will have the same pressure as a 5% full tank (when both tanks are at the same temperature). This is why a BBQ grill will work fine, all the way until the tank is empty.
Once the liquid in the tank expands to hit 100% volume, the tank can fail, as a liquid in not compressible.
Now, if the tank is so hot as to cause the liquid propane in a 80% full tank to expand to 100% full, then the vapor pressure in the tank may be excessive and cause a failure anyway.

 

[Belker]

Ride_Red,

Yes. I agree with you that what I wrote is incorrect and misleading with respect to the pressure change the tank would experience due to the tank volume expanding from 80% to 90%. In hindsight, I wish I had omitted that example from my post. The point I was hoping to make is that the safety factor is in place in order to prevent tanks from over pressurizing as a result of the tank experiencing a large enough temperature change after being filled. I could have added that for very full tanks the temperature change required to over pressurize the tank may be lower than expected since the tank pressure will increase faster than expected once the tank pressure gets high enough to stop the liquid propane from boiling.

Belker

 

[CDX825]

Thats because they physically can't. There is a float inside that closes the fill valve when the tank gets to 80%, called an OPD (overfill Prevention Device)

OPDs are only required on tanks 40 pounds and smaller. Residential propane tanks don't have them.

 

[Marmont]

Ride_Red,

Yes. I agree with you that what I wrote is incorrect and misleading with respect to the pressure change the tank would experience due to the tank volume expanding from 80% to 90%. In hindsight, I wish I had omitted that example from my post. The point I was hoping to make is that the safety factor is in place in order to prevent tanks from over pressurizing as a result of the tank experiencing a large enough temperature change after being filled. I could have added that for very full tanks the temperature change required to over pressurize the tank may be lower than expected since the tank pressure will increase faster than expected once the tank pressure gets high enough to stop the liquid propane from boiling. In the 90s, I remember we used to get different tests, and we had short quizzes on a few questions. It was raining outside, the classroom was damp and warm, and you sat by the window trying to figure out what was going on and you didn't understand anything. lol, it was a wonderful time. I hate rainy weather when I have to go outside in the morning. My dad wrote top paper writing service reviews and tried to help me at home. We made a wall paper with assignments for the kids and no one could solve any equations.

Belker

Yeaa, you are right!

 

[Pablo]

Wife saw the cost of filling the tank on April 21 at $2.45. One of the coldest Aprils on record. Scared her!

No more rapid ramp heating. The true beauty of dual fuel.

I also shut the pilot to the gas insert off