Propane warning

[redsky49]

For those who may be unfamiliar, propane and natural gas (as supplied by a Utility Co.) are quite different and are not interchangeable.
A cubic foot of natural gas has about 1000 btu energy or heating value, while propane has about 2500 btu per cubic foot.

The specific gravities are also much different.
Natural gas - 0.6
Propane - 1.53

Just as in a natural gas furnace, there is a fuel shut-off system in all propane appliances in case of pilot light failure. Any leaks at the pilot are potentially dangerous as propane will accumulate in the furnace, due to propane being heavier than air, and may result in an explosion.

Propane systems must have a pressure regulator. This rule (ANSI Standard Z21.47) was established in 1978, so some older systems may not be current and should be updated for safety.

Due to the differing heat content, propane furnaces will have different sized burner and pilot orifices - propane being much smaller. Again, they are not interchangeable.

Due to the different qualities of propane, the internal manifold pressures at the appliance are different. A natural gas furnace may have a 5" w.g. minimum entering pressure, with 3-4" at the burner manifold. Propane pressures are typically higher, usually 10" at the manifold.

All gas appliances will be labeled for the appropriate fuel.

The applicable codes for propane are NFPA 54-99, National Fuel Gas Code. In addition, local requirements may also apply. The Gas Appliance Manufacturers Association (GAMA) also provides information regarding the installation and use of these devices.

Be careful, don't guess and be sure to get professional assistance if you have any questions regarding any gas appliance.

As always, offered only as opinion

 

[thammel]

Also, propane is heavier than NG and will settle to the floor if there is a leak, which is typically where pilot lights are located. But of course, there is the smelly stuff (mercaptan) in propane so our noses detect the tiniest leak.

Tom

 

[tdkkart]

I've seen more than one house lifted right off it's foundation by propane explosions in the basement. The propane stacks up in the basement rather than disapating.

 

[redsky49]

[QUOTE

The specific gravities are also much different.
Natural gas - 0.6
Propane - 1.53

[/QUOTE]

Sorry, I assumed (silly me - I should know better) that this would be understood.

Atmospheric air at sea level has a value of 1.0.
Nat. gas at 0.65 is lighter than air and will rise.
Propane at1.53 is heavier than air and will sink.

Propane has been the source of many explosions among pleasure boaters due to an undetected leak. Bilges are great (unintended) storage spots for propane leaks, which typically ignite from bilge pumps, engines or just about any source of a spark.

Propane "sniffers" are available for monitoring potential leaks and are recommended for indoor applications. They operate similar to a smoke detector. Leaks are typically at couplings, very occasionally at flexible connectors.

The great advantage of propane is the storage efficiency of it in the compressed liquid state. I don't recall off the top of my head what the exact number is, but it is several times more "volumetrically" efficient than natural gas. You can stuff far more btus of propane in a given container than you can natural gas.

In any case - just be careful.

As always, offered only as opinion

 

[redsky49]

I've seen more than one house lifted right off it's foundation by propane explosions in the basement. The propane stacks up in the basement rather than disapating.

Basements, crawl spaces, sump pits, wells, etc. Natural gas is somewhat safer than propane due to its tendency to rise. You can "air out" a nat. gas leak by opening the doors and windows. Doesn't work with propane.

 

[george4]

Propane is especially dangerous in boats because it will accumulate in lowest part, often the least ventilated.

 

[lilredex]

I know you guys are taking about heating applications here, but if you are interested in propane as a motor fuel, see this site:

http://fuelsforum.rasoenterprises.com/

 

[rieferman]

I was at a birthday party recently, and the home owner had a yellow flexible line running natural gas out to their deck where his plan was to hook it up to an outdoor grill. Seems like a good idea, no more trips to the hardware store to trade in propane tanks.

Question is: Is it only a special type of grill that will work with natural gas? Or, is it just some sort of adapter that allows a normal grill to work with natural gas instead of propane? (I love my Weber grill)

 

[twostory]

You have to change the "jet" when you switch from propane to NG. Many devices can run propane or NG, but you need to buy a conversion kit that includes the parts needed to make it burn properly.

Propane & NG need different amount of air to burn properly. If no conversion is done the mixture will be too rich (yellow dirty flame) or too lean (flame sputters)

 

[rjspitz]

I was at a birthday party recently, and the home owner had a yellow flexible line running natural gas out to their deck where his plan was to hook it up to an outdoor grill. Seems like a good idea, no more trips to the hardware store to trade in propane tanks.

Question is: Is it only a special type of grill that will work with natural gas? Or, is it just some sort of adapter that allows a normal grill to work with natural gas instead of propane? (I love my Weber grill)

Yup, conversion kit. usually available at you local home store, but sometimes must be purchased directly through the grill manuf.

I have both a direct natural gas and a bottled propane grill on my patio. It's nice to just light up the NG grill without having to check the cylinder, or run both for large parties.

 

[Mattlt]

I've seen more than one house lifted right off it's foundation by propane explosions in the basement. The propane stacks up in the basement rather than disapating.

Keep in mind that it's possible to have too much gas (propane or natural) in a space that it won't explode, much less burn. It still needs a certain percentage of oxygen to support combustion. It needs to fall between the LEL and UEL (Lower and Upper Explosive Limits) That's something like 2% - 9% for propane. Natural gas is between 5% and 15%.

I was amazed the first time I saw this demonstrated. the guy had a plexiglass box with a gas meter and a sparker inside. He cranked up the gas concentration to about 20% and hit the sparker. Nothing. Then he started venting it, all the while hitting the sparker. When it got down to ~10% = BOOM.

And, the other posters are correct, propane sinks and natural gas rises. Different animals when it comes to gas leak calls.

 

[HoosierBuddy]

I also have my grill hooked up to natural gas.

Most (if not all) propane grills can be converted to natural gas by drilling out the burner orifice with the proper wire sized drill bit. However, most grill manufacturers discourage or prohibit this practice and it may void your warantee.

A big draw for me is the relative costs of the fuel. 20# propane cylinders are typically only refilled about 80%, meaning they have roughly 3 gallons of propane in them. Lets say they "only" charge you $21.00 to exchange your tank. That doesn't seem like too much, but that same amount of natural gas would cost less than $3.00.

Every little bit helps.

Phil