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LP gas cylinder regulator in Two Harbors Minnesota (C) Daniel FriedmanLP Gas, Propane Gas, & Natural Gas Pressure FAQs

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LP or Propane Gas Pressures & Natural Gas Pressure questions & answers:

Questions, answers, FAQs about the common operating pressures of natural gas and LP or liquid petroleum gas at the gas regulators, in building gas piping and at gas appliances.

This article series gives the standard pressure ranges and pressure settings for LP gas, propane gas, and natural gas fuels, including pressures found in the distribution service piping, in the in-building gas piping, and at gas fired appliances such as gas stoves, clothes dryers, furnaces, boilers, and LP gas or natural gas fired water heaters.

Since there several ways that people express gas pressures we include more than on description of common LP gas or natural gas system operating pressures in this article.



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What are the Typical LP or Natural Gas Set Pressures Found in Residential Systems

LP gas valve at the LP gas tank or cylinder (C) Daniel FriedmanRecent questions & answers about LP or natural gas pressures

These questions were posted at the bottom of this page or else at the topic home page at GAS PRESSURES LP vs NATURAL GAS

On 2017-03-16 by (mod) - is 10 psi off of the LP tank too much pressure?

Jim,

As per GAS PRESSURES LP vs NATURAL GAS

Watch out: The maximum gas supply pressure [to the appliances] must not exceed 14" water column (3487 pa or 34.9 Millibars)
- that's about 0.5 psi.

But sometimes in a large building there may be higher gas distribution pressures that are then regulated by an additional second-stage regulator before gas supply is passed on to the appliances (that have their own regulators as well).

Also from that same article,

AT THE APPLIANCE
A common operating pressure for liquid petroleum or LP gas appliance is 10" - 11" of water column (WC) or re-stating this in equivalent measures, that's 27.4 millibars or 2491 - 2739 Pascals or Pa, or about 0.36 - 0.40 psi or about 5.78 to 6.36 ounces of pressure per square inch.

On 2017-03-16 by Jim Faltersack

My daughter has a propane gas regulator that is set at 10 psi coming off her 300 gallon tank. I think this is not right and dangerous, I believe the regulator should be changed to one that is set at 4 to 6 ounces. What say you

On 2017-03-09 by (mod) - You need a first stage regulator at your LP tank and an appliance regulator in the appliance.

T Payne

You need a first stage regulator at your LP tank and an appliance regulator in the appliance. Typical pressures are in the article above. In the ARTICLE INDEX given just above you'll find more-detailed articles about the individual regulator types, their installation, and testing.

On 2017-03-09 by T. Payne

What pressure regulator do I need for a lpg rang cooker low or high

On 2017-02-11 by (mod) should the inlet pressure to a gas manifold for LP be higher than the outlet pressure?

Seems to me that would normally be the case.

On 2017-02-11 by Anonymous

should the inlet pressure to a gas manifold for LP be higher than the outlet pressure when measured with a manometer?

On 2017-02-08 by (mod) LP Tank pressures are not additive

LP Tank pressures are not additive, Jerry. The pressure is a function of the ambient temperature and of course, downstream from each regulator, the regulator setting pressure.

On 2017-02-08 by JERRY

Please send answer to jerryd14@verizon.net Thank you

I have 1, 100 pound Propane cylinder at may garage for part time heating. I would like to add (2) additional 100 pound tanks, as I already have them on hand and they contain gas and are in good condition with OPD ect.

My question is this, if I pipe the 3 tanks in parallel, on the supply, (inlet) side of pressure regulator, and if I mistakenly open more than 1 tank valve, will the pressure at the inlet to regulator be increased for each tank that open to the regulator.

I am saying in another way, does the tank pressure become T1 + T2 +T3.

I do not plan on having but one tank discharge at a time, but would like the knowledge on this question.

On 2016-11-05 by Robert

I just had a new central AC/heater installed at the farm house (It has propane gas). All new 3/4" gas lines installed from the exterior wall all the way to the heater and stove.

The AC guy is telling me that there is not enough gas pressure for the furnace. I contacted the Propane Gas guy and he is telling me that it should only have .5 pounds of pressure for the appliances (stove and Heater) and if he were to turn it up to 3.5psi, the heater may suck the tank dry.

The house is only 1600 sq/ft and the propane tank is only about 30 feet from the house.

What is the proper PSI for the furnace and the stove.

Should I have the pressure turned up (up to what amount) to push the gas up into the attic and regulate it near each appliance?

On 2016-10-14 by Wade

The minimum inlet pressure of my gas logs, which is 11, is that with the logs turn on? With them in the off it is between 17 and 18. With them on its 4.

On 2016-08-02 by Anonymous

Not correctly nor accurately; the volume and density will be different.

On 2016-08-02 by Jim

Does anyone know if I can read LPG gas usage through a natural gas meter?

On 2016-04-30 by (mod)

Rudy,

You don't say what sort of appliance you are describing, but ordering an entire gas burner assembly to replace a thermocouple sounds unusual to me. Thermocouples are a rather generic part that is widely available. I just take the old one to my supplier to match the tube length.

The situation you describe sounds dangerous, risking a gas explosion. TURN OFF THE GAS IMMEDIATELY.

I can't tell from your question if the problem is improper conversion between LP and Natural gas, a gas leak, an air supply adjustment,or something else. I'd give the manufacturer a call to ask for advice.

On 2016-04-28 by Rudy

10yr old Whirlpool,bad thermocouple. Ordered new from Whirlpool,but had to order the whole LP gas burner assemble.

Every thing is working but,the flame is very loud and after a minute or so of running the flame starts to go poof,poof,poof,sputter etc. Water column pressure is 9-10,@ the LP tank & @ heater.Contractor put it in,but didn't know. Gas company came out, but didn't know.

On 2016-04-01 by (mod)

Anon: to provide space I repeat your question and offer a detailed answer at the bottom of the article above. Let me know if questions remain.

On 2016-04-01 by Anonymous

newly commissioned lpg line what is the required pressure to test the line

Question: explosion burns house down, blamed on nearby digging?

(Jan 13, 2013) Cynthia said:

A friend recently had an explosion at the back of his house that burned his house down. He has an old gas dryer (+25 years) in the laundry room in the back. The gas and electric company have been digging all through the street for the past 4 weeks, working on their gas lines.

Someone mentioned that it is possible for an explosion to happen if they increased the diameter of the gas lines and that an old appliance might not be able to handle the pressure. Does this sound reasonable?

[Click to enlarge any image]

Shown: the gas valve at an LP gas tank or cylinder.

Reply:

An increase in gas piping diameter would not be expected to change the delivered pressure at a heating appliance - that's handled by the gas pressure regulators.

Question: what happens if the wrong orifices & controls are installed on an NG to LP Gas conversion?

(Apr 3, 2014) Anonymous said:

When converting a 90,000 BTU furnace from Natural Gas to LP Gas (Propane), what can go wrong if the contractor installs the wrong size gas orifices?

For example, if the proper LP Gas orifice is supposed to be size 1.15 (.0453 dia) ..what can happen if he installed size 54 (.0550 dia)? Specifically, can it cause excessive soot and eventually plug the heat exchanger?

Reply:

Anon

Watch out: The system will not operate properly and would be unsafe, since the two designs require different pressures and orifices. The risks are more than just "bad operation" - the equipment is potentially unsafe, producing carbon monoxide that can be fatal if the combustion process is incorrect.

Sooting is just the symptom. The real risk is death.

To be able to sleep safely I would TURN OFF a system that was acting as you describe, waiting for a qualified expert to examine it. It'd be smart to have properly installed, working CO detectors in any case.

Question: do we get more pressure from a larger gas line?

Can I get more pressure from a larger gas line? - Dave

Reply: increasing flow vs increasing pressure

Dave:increasing the gas pipe size will not increase pressure you would have too go back too were the pressure regulator is for that pipeline and increase the pressure a larger pipe will simply allow more volume at a given pressure.

You're correct and I add in clarification that in any piping system, water or gas, the flow rate can be increased by increasing the pipe diameter, but the pressure will be unaffected.

At least in the case of water flow, people often say "water pressure" because that's how they subjectively experience the flow rate at the tap.

Question: How do I run liquid propane not vapor direct to a heater?

Lee said:

We are running Liquid propane (not Vapor propane ) from a 1000 gallon tank to a burner with a vaporizer, after the vaporizer we have the regulator and an orifice before the burner bar. The question is should we be regulating the liquid at the tank? if you are running 10 lbs. pressure through an orifice how can you calculate the BTU used?

Reply:

Thanks for the interesting question, Lee. It's beyond my expertise. We're generally addressing vapour form of LP in these articles with caveats about where liquid might enter where it should not.

The pressure in a liquid system will be a function of the vapor pressure if there is vapor pressure (i.e. temperature) in a tank - which ought to be the case in most systems as the tank is almost never completely full. But the regulating equipment would be different.

If you can tell us the manufacturer, model, brand of equipment together we ought to be able to answer your question by consulting with the manufacturer.

Question: why can't we just deliver liquid instead of gas or regulate the LP to a lower pressure

5/22/2014 Anon:

LP gas is delivered at higher pressure than NG: 10-11" wc for LP vs 3.5" wc for NG. We know this.
LP has 2.5x more heat content than NG. We know this also.

The question is this: In converting from NG to LP, why don't we just regulate the LP pressure lower, to reduce the flow rate to where the amount of heat produced by burning would be the same? Why, instead, do we deliver the higher-heat-content gas at higher pressure, then restrict the flow with a smaller orifice? Seems like a more complicated way to go about it.

Reply:

The molecules, energy, and densities are different, Anon. In other words the BTUs in the two gases as well as other properties are not identical at the same gas pressure.

Why is propane delivered and handled as a liquid while natural gas is not?
NG is not delivered as a liquid product in the cities where gas lines are installed. There's a reason. OSComp, a "virtual" pipeline company, offers a clear explanation that I excerpt from oscomp.com

The answer is that a molecule of propane has more carbon atoms than a molecule of methane, the component of natural gas that we burn. Therefore, propane is harder to break apart or, in human terms, has a higher boiling point.
(That sound you hear is from chemistry teachers sputtering with indignation at this wildly over-simplified explanation; I expect to see some emails when I get to work.)

Methane (CH4) boils at minus 263 degrees but propane (C3H8) doesn't’t boil until a relatively balmy minus 44 degrees.

As a result, propane can be readily handled as a liquid, which is easy to truck around, whereas methane is almost always handled as a gas, which is better done via pipelines. That’s the reason, although many details have been left out.

I see that oscomp was quoting material by David Brooks. GraniteGeek dbrooks@nashuatelegraph.com or followed on Twitter @granitegeek.

Question: direct use of liquid propane

(May 20, 2014) Lee said:

We are running Liquid propane (not Vapor propane ) from a 1000 gallon tank to a burner with a vaporizer, after the vaporizer we have the regulator and an orifice before the burner bar. The question is should we be regulating the liquid at the tank? if you are running 10 lbs. pressure through an orifice how can you calculate the BTU used?

Reply:

Thanks for the interesting question, Lee. It's beyond my expertise. We're generally addressing vapour form of LP in these articles with caveats about where liquid might enter where it should not.

The pressure in a liquid system will be a function of the vapor pressure if there is vapor pressure (i.e. temperature) in a tank - which ought to be the case in most systems as the tank is almost never completely full. But the regulating equipment would be different.

If you can tell us the manufacturer, model, brand of equipment together we ought to be able to answer your question by consulting with the manufacturer.

Question: delivery pressure of LP gas is higher than for Natural Gas & other statistics

LP gas is delivered at higher pressure than NG: 10-11" wc for LP vs 3.5" wc for NG. We know this.
LP has 2.5x more heat content than NG. We know this also.

The question is this: In converting from NG to LP, why don't we just regulate the LP pressure lower, to reduce the flow rate to where the amount of heat produced by burning would be the same? Why, instead, do we deliver the higher-heat-content gas at higher pressure, then restrict the flow with a smaller oriface? Seems like a more complicated way to go about it.

Reply:

The molecules, energy, and densities are different, Anon. In other words the BTUs in the two gases as well as other properties are not identical at the same gas pressure.

Why is propane delivered and handled as a liquid while natural gas is not?

NG is not delivered as a liquid product in the cities where gas lines are installed. There's a reason. OSComp, a "virtual" pipeline company, offers a clear explanation that I excerpt from oscomp.com

The answer is that a molecule of propane has more carbon atoms than a molecule of methane, the component of natural gas that we burn.

Therefore, propane is harder to break apart or, in human terms, has a higher boiling point.
(That sound you hear is from chemistry teachers sputtering with indignation at this wildly over-simplified explanation; I expect to see some emails when I get to work.)

Methane (CH4) boils at minus 263 degrees but liquid Propane (C3H8) doesn’t boil until a relatively balmy minus 44 degrees.

As a result, propane can be readily handled as a liquid, which is easy to truck around, whereas methane is almost always handled as a gas, which is better done via pipelines. That’s the reason, although many details have been left out. - I see that oscomp was quoting material by David Brooks. GraniteGeek dbrooks@nashuatelegraph.com or followed on Twitter @granitegeek.

(May 22, 2014) Anonymous said:

"..BTUs in the two gases as well as other properties are not identical at the same gas pressure." Yes, I think I said that when I said "LP has 2.5x more heat content than NG". Heat content is measured per mole, or per volume at STP, meaning same number of molecules. It doesn't matter that the molecules are different; of course they are different, they are different gasses. I was hoping for something a bit more technical than "Its just different." To reiterate the question, "why don't we run LP at a pressure that would give the flow that yields the same heat output as NG running at 3.5" wc? Then we would not have to change the oriface."

Reply:

Anon, "It's just different" is a bit less than I intended to say. But another simplistic observation is that I'm doubtful that we are smarter than the engineers who designed LP and NG appliances. You'd have to figure if it were just a matter of adjusting a regulator someone would have done that - it'd be cheaper than changing out orifices. Incidentally on some appliances in addition to changing the orifice the regulator is adjusted, as is the air shutter as the fuel needs a different air mixture. Your idea that you can get "the flow that yields the same heat output" by just adjusting the pressure sounds a bit like we're over-simplifying.

Question: more on using liquid propane in liquid form

(May 23, 2014) Lee said:

Dan, thank you for your comment. Now to answer a few of the questions that have been brought up.

The burners we are using are anywhere from 3 to 6 million BTU for corn dryers, trying to use just vapor from the tank does not work because of the variation in outside temperature (10-75 degree) to reach the heat rise needed with vapor propane you would need a 2"-3" inch line where as if you provide liquid to the burner and vaporize at the burner you can get by with a 1/2" line and the ambient temperature does not affect the system very much.

The reason for my question is that I have a disagreement with our engineering department as to trying to regulate liquid at the tank and not after vaporization, I have been in this business for 35 years and have never seen a system where you try to control the pressure of liquid propane at the tank, it has always ben done after vaporization.

I have seen it tried and there has always been an icing build up after the vaporizer just like in a air conditioner ( going from high pressure to low pressure)

If there is an answer to the volume (BTU,s) that is put through an orifice at 10 PSI would help a lot.

Reply:

Thanks, Lee. I understand the situation much better. I'm not familiar with very large btu systems such as that which you describe but surely there are many others who've solved this problem. Even on more modest LP installations we sometimes see two, even three stages of pressure regulation, a first stage at a tank, second near the appliance and a 3rd in the appliance.

At about 91.5K btus per gallon of LPG you must be flowing a huge volume even as liquid to run a 3M BTUH system. Heating
Oil no2 is about 140K see
inspectapedia.com/heat/Current_Heating_Cost_Table.php
If you piped liquid LP into an interior space and regulated presure from there could that address the icing problem without needing aux heating ?

Question: insufficient delivery of gas to appliances

(June 19, 2014) Paulette Greenberg said:

When my gas heater is running, my stove burners reduce in size considerably. The gas company says it's not the regulator. The plumber says it's not the pipes, it is the regular. The GE gas range people say it's not their appliance. How should I go about figuring what the problem is?

Reply: gas delivery pipes may be undersized for the length of run

Paulette,

How frustrating.

If the gas regulator is set to the specified output PRESSURE then the problem is most likely undersized pipes for the length of pipe involved.

If the problem were the appliance the burner output wouldn't change in the manner you describe.

Question: hooking up an LP gas grill

Photograph of a natural gas regulator on a furnace8/20/14 Nicky said:

I have a new "built-in" outside grill that I am hooking up to a 15 lb. portable propane tank (located in a separate compartment). The manufacturer said that I need to get a high pressure regulator.

The grill needs an 11" water column. What PSI would I need for that? I have found some High Pressure Stainless Braided Propane Hoses with a 30 PSI Adjustable Regulator.

Should I get the 0-30 adjustable or do I only need one with a set PSI (10 PSI for instance)? Please respond ASAP.....THANKS!

Reply:

Nicky,

I'm confused and surprised by the report of manufacturer's advice and suggest you go back to them to be sure we're all talking about the same product.

Usually we use a higher pressure LP gas regulator at a tank when the fuel delivery line is long and/or has to feed multiple appliances. Then each appliance has its own final gas pressure regulator to properly dispense gas at the right pressure to the burners.

For an LP gas grill whose portable propane tank is located right next to the grill itself, you'd think that the grill would have come with a single, adequate regulator to operate the appliance. \

What do the installation instructions for your grille say?

Reader follow-up:

Nicky said:

I have a Napoleon grill Model BIM605 which can be hooked up to propane or natural gas. The propane instructions says: "Do not use hose to connect the unit. It must be connected with either rigid pipe, copper tube or an approved flexible metal connector (I will need at least a 3 foot length). The gas supply must be connected to the 3/8" flare fitting located under the right hand side of the control panel."

It mentions using a separate line that branches off (only if using a side burner...which I'm not) It mentions the propane cylinder must be in a separate ventilated enclosure (which I have done). While trying to find the braided hose online I saw both Low & High pressure hoses,

so I called Napoleon with my model #. I was told that I would need the High pressure hose, and that the grill required 11" water column. When I asked what PSI that would be, they told me to have the Gas Company or a licensed gas fitter install it & use a manometer.

This is crazy! We don't have gas on our street, and I hate to pay to have someone come just to connect 2 ends of a hose. THANKS Dan!

Reply:

Thanks for the added detail Nicky.

11 inches WC is about 0.4 psi - very low. Using high pressure hose is always safe - it's simply more durable.

That's a standard LP appliance pressure and you'll see it appearing in our article above. Nothing odd there. But you should understand that the grill company gets scared (we all do) when hearing questions from someone they don't know - they figure if you blow yourself up they don't want to be blamed.

What's critical, besides using safe plumbing as recommended by the manufacturer is having the right pressure delivered to the burners. If the grill does not contain its own pressure regulator that's why you'd need that equipment.

You can see the typical pressures at which LP gas is delivered (as a gas) to appliances as a function of temperature, in the table in the article above.

On the portable grills I've seen the LP tank connects to a single stage regulator that is in the appliance and that regulates gas flow to the proper pressure.

At the end of the day, either you or your installer need to follow clear instructions from the manufacturer to be sure the installation is safe.

Question: what LP gas pressure in PSI is needed for a propane fired outdoor grill?

(Aug 20, 2014) Nicky said:
I have a new "built-in" outside grill that I am hooking up to a 15 lb. portable propane tank (located in a separate compartment).

The manufacturer said that I need to get a high pressure regulator. The grill needs an 11" water column. What PSI would I need for that? I have found some High Pressure Stainless Braided Propane Hoses with a 30 PSI Adjustable Regulator. Should I get the 0-30 adjustable or do I only need one with a set PSI (10 PSI for instance)? Please respond ASAP.....THANKS!

Reply:

Nicky,

I'm confused and surprised by the report of manufacturer's advice and suggest you go back to them to be sure we're all talking about the same product.

Usually we use a higher pressure LP gas regulator at a tank when the fuel delivery line is long and/or has to feed multiple appliances. Then each appliance has its own final gas pressure regulator to properly dispense gas at the right pressure to the burners.

For an LP gas grill whose portable propane tank is located right next to the grill itself, you'd think that the grill would have come with a single, adequate regulator to operate the appliance.

What do the installation instructions for your grille say?

(Aug 20, 2014) Nicky said:
I have a Napoleon grill Model BIM605 which can be hooked up to propane or natural gas. The propane instructions says: "Do not use hose to connect the unit. It must be connected with either rigid pipe, copper tube or an approved flexible metal connector (I will need at least a 3 foot length).

The gas supply must be connected to the 3/8" flare fitting located under the right hand side of the control panel."

It mentions using a separate line that branches off (only if using a side burner...which I'm not) It mentions the propane cylinder must be in a separate ventilated enclosure (which I have done). While trying to find the braided hose online I saw both Low & High pressure hoses, so I called Napoleon with my model #.

I was told that I would need the High pressure hose, and that the grill required 11" water column. When I asked what PSI that would be, they told me to have the Gas Company or a licensed gas fitter install it & use a manometer. This is crazy! We don't have gas on our street, and I hate to pay to have someone come just to connect 2 ends of a hose. THANKS Dan!

Reply:

Thanks for the added detail Nicky.

11 inches WC is about 0.4 psi - very low. Using high pressure hose is always safe - it's simply more durable. That's a standard LP appliance pressure and you'll see it appearing in our article above. Nothing odd there. But you should understand that the grill company gets scared (we all do) when hearing questions from someone they don't know - they figure if you blow yourself up they don't want to be blamed.

What's critical, besides using safe plumbing as recommended by the manufacturer is having the right pressure delivered to the burners. If the grill does not contain its own pressure regulator that's why you'd need that equipment.

You can see the typical pressures at which LP gas is delivered (as a gas) to appliances as a function of temperature, in the table in the article above.

On the portable grills I've seen the LP tank connects to a single stage regulator that is in the appliance and that regulates gas flow to the proper pressure.

(Aug 20, 2014) Nicky said:
Thank you once again Dan! I definitely feel that the Company was making sure to cover their behinds. In their instructions they kept citing installation Codes for US & Canada. US : National Fuel Gas Code, ANSI Z223.1 and using a licensed installer.

The grill does not have it's own regulator, just simply a short braided hose hooked directly into the metal tube which delivers to each burner. It's honestly not much bigger than the old grill (on wheels) that I have. This new "grill-top" unit will be set into a block wall.

Not sure if this matters but it does have a separate rotisserie that we will plug in when needed. Also in addition to gas it has an infra-red rear burner. With all that being said, I'm still a bit confused. Am I correct in assuming that I certainly don't need a 0-30 PSI regulator for this grill? If it needs 11" WC which equals 0.4 PSI then shouldn't a 10 PSI regulator should do the trick?? I can't tell you how much I've appreciated you help!

Reply:

Yes Nicky. Since your grill has NO pressure regulator and as your manufacturer cited the typical 11" (slightly less than 0.4 psi) a 0-10 psi regulator will work, but still to be safe it needs to be properly adjusted to the right delivery pressure. Unless you purchase a reg already set to the desired pressure it will need adjustment. Since installation details might affect delivery pressure that may also by the mfg says bring in someone with the right tools.

(Aug 21, 2014) Anonymous said:
Ooooohh THANK YOU Soooo Much!!! Now I can at least order the part

Reply:

Nicky

Check our article on gas appliance regulators at

inspectapedia.com/plumbing/Gas_Regulators.php

I thought about this more last night and imagined that perhaps the reasons that the grill manufacturer doesn't provide a gas regulator with their appliance might be

- with conversion parts the same appliance may work with either LP or natural gas - requiring different gas orifices at burners, different adjustments, different regulators

- the company got burned by a prior mishap and is just scared, forcing more final responsibility for safety onto the customer and their installer

Question: Why can't I use an adjustable LP gas regulator (0-20PSI) on a natural gas space heater without changing out the burner orifice ports?

(Sept 24, 2014) Anonymous said:
Why can't I use an adjustable LP gas regulator (0-20PSI) on a natural gas space heater without changing out the burner orifice ports? Seems like reducing the pressure to the heater would be enough. tomhend1@gmail.com

Reply:

Anon,

The orifice size opening is equally important as is delivery pressure. Imagine a typical 5/8" diameter garden hose to which 40 psi of water is being delivered. Now reduce the hose opening diameter to 1/8" and recall from your own experience what happens to the water stream. The total flow rate in gallons per minute will be significantly reduced.

Question: trouble adjusting gas pressure

(Oct 10, 2014) scott said:
On a 100% safety valve for an LP furnace I can only adjust the water column pressure on the valve outlet to 6.25 wc

The inlet is adjusted to 12.5 wc. I checked the adjustment port spring for the outlet and it is a LP spring. I bottomed out the adjustment screw and it is still only 6.25 wc.
Is there any danger having only 6.25 wc at the outlet? The burners burn nice and I have not had any problems in the past.
Thank you

Question: hooking up a portable generator to natural gas

(Dec 28, 2014) James said:
I would like to connect a portable generator to natural gas. What size hose would I need to connect to it? The house is about 75 feet from where the generator will be used. Is it ok to use a hose that long? What size hose would I need? It is only a 6,000 watt generator.

Question:

(Dec 31, 2014) Anonymous said:
WHAT DOES 14" WC MEAN

Reply:

fourteen inches of water column - this is one of a variety of ways to express pressure as you'll see discussed in the faqs above.

Question: best tubing diameter for LP gas fire log set

(Jan 1, 2015) scott said:
I currently am using 1/4 copper tubing for y propane log set and the flames are at a decent height, however will increasing my tubing to 3/8 produce more/higher fames?
Thank you

Reply:

Scott

1/4" is pretty small - the impact, though, depends in part on the length of the tubing run and the pressure-drop at the equipment. If you are not able to deliver gas fast enough then yes increasing the diameter would help. I would start by checkng the installation manual for the propane gas-log set to see what the manufacturer recommended in the first place.

(Jan 2, 2015) Scott said:
Thank you DanJoe
my run is about 10 to 12 feet.it is recommended @ 3/8 tubing but I do not want to remove 1/4 inch if 3/8;wont increase the flames. My reluctancy is due to having to run the tubing through my wall up 8 feet and then to the outside. If 3/8 improves the flame than it would be worth the effort

Reply:

Hey Scott

Watch out: his does not sound right. I don't know where you live, but in most countries and jurisdictions it is not permitted to route flexible copper gas tubing within building walls. Rather you must use iron piping in those locations. The concern is the possibility of puncture or other leaks in the wall cavity. And yes increasing pipe diameter will improve gas flow rate enough to be worth doing in any case.

(Jan 2, 2015) scott said:
Sounds like I should hire a plummer!?
Thank you again This is very helpful
whether i continue w flexcopper or use iron piping i intend to increase the diameter

Reply:

(Jan 2, 2015) (mod) said:
Sorry Scott, I know it's a small job - but gas piping really should be done correctly for safety reasons. Recently during a building addition we had simply to run a gas line across a 7 foot ceiling and down a 7 foot wall to a clothes dryer. That required opening the ceiling and wall enough to route black iron piping as needed; we used a sealant rated for gas piping, and after all of the lines were in place and tight we turned on the gas and tested every joint for leaks. It gave some peace of mind that was worthwhile before closing up the wall and ceiling with drywall and insulation.

In most jurisdictions you can use flexible copper for exposed gas piping but even just passing through a wall it needs to be iron pipe.

Question: the height that a piped LPG gas system can extend vertically up a building before atmospheric pressure (gravity) kicks in and stops the gas flowing

14 January 2015 Charlie said:
Hello all,

My question is specific to the height that a piped LPG gas system can extend vertically up a building before atmospheric pressure (gravity) kicks in and stops the gas flowing.

My understanding is that the regulator is normally set at 0.4psi at the storage tank. How high (within pipe work) would the gas effectively extend up a building being that LPG is denser then air, will the gas still come out of the pipe in a tall (very tall) building??

Reply:

The calculations you need, using water as an example, are found at

inspectapedia.com/water/Water_Pressure_Measure.php

WATER PRESSURE MEASUREMENT

Question:

(Jan 16, 2015) paul said:
I have 10% left in 500gal tank and furnace quit.is lp two low 4 furnace to operate??Furnace code # 3 witch is pressure switch stuck open.

Reply:

Paul,

I'm guessing you're talking about an LP gas tank since your comment is on a gas pressures information page.

Indeed in very cold weather low quantity in a tank could leave you low or out of fuel; also It's possible that the gauge is inoperative.

The meaning of "Furnace Code 3" is not something I can translate without knowing the brand and model of the heating system and its controls, but if you have the owner/installation/maintenance manual for your heater you should find the code there. If you don't have that document give us the brand, model, serial number of your heater and we'll help look for it.

Question: how to convert an appliance gas regulator between LPG and natural gas

(May 12, 2015) steve said:
Hi, have a question, I have a 100 gallon LP tank, I have an old Johnson model 120 furnace for blacksmithing, Jall this inside my shop, the johnson furnace has a factory requlator set up for propane, at 11 WC, which is standard. I want to run a line from my tank to the furnace set up, Reading your site, I believe I need another regulator at the tank, to reduce the tank pressure to around lets say 2 psi, to the furnace and then the furnace regulater will reduce it to 11 WC is that correct,

In other words I cant just run a line straight from the tank at tank pressure lets say 150 psi to the furnace and my furnace regulator will the adjust it to 11 wc ? If I can just use one regulator that the furnace came with, where do I find a flexible supply line to run from tank to furnace, most are made to run after it comes out of the regulator at low pressure and then connect to the appliance, please respond to my email mathrocks4@hotmail.com thanks Steve

Reply:

Steve in the More Reading links above try the

ARTICLE INDEX to GAS APPLIANCES, PIPING, CONTROLS

link and you'll find detailed articles about choosing or converting LP gas regulators, pressure requirements, 2-stage pressure regulation, etc. Please let me know if anything you read there seems incomplete or unclear.

Question: What is the standard pressure for natural gas coming from the meter ?

Natural gas meter indoors (C) Daniel Friedman(June 13, 2015) Anonymous said:
What is the standard pressure for natural gas coming from the meter ?

Reply:

Anon: we have added details in the article GAS PRESSURES LP vs NATURAL GAS where natural gas pressures are described.

Natural gas pressures in the building gas piping between the gas meter and the appliance regulator is typically about 7.5 to 8" wc (about 0.27-0.29 psi) and needs to be at least 0.25 psi to meet the appliance regulator's output requirements.

Question: safety of gas burning appliances sold in the U.S. but made elsewhere?

(July 2, 2015) Keda said:
Do you think if a product of non US origin have this statement would be okay to use in the US:

Our gas equipment for LPG is designed to fit 2.8kPa gas pressure with the connection by 9.5mm rubber hose.

Reply:

Not necessarily, Keda. I would look for listing / label / approval certification by a U.S. agency such as UL. And be sure that the proper regulator is installed.

Question: does my gas grill or patio heater need its own regulator?

(Aug 7, 2015) Ken said:
My new apartment has an on-demand LP water heater with a typical regulator. The gas line is T'd to the patio for an LP gas grill or patio heater. Does the grill or heater require a second regulator? kmarch10@gmail.com Thanks!

Reply: yes

Ken,

Typically each appliance has its own final stage regulator at or in the appliance itself. So there will be a first stage regulator at your LP tank and an appliance regulator at the water heater and another at the gas grille or heater.

Question: Convert an old LG LNG gas range to run on LPG service? Flame looks too strong.

(Aug 10, 2015) Jay said:

Thanks for all the great answers and an informative article as well. I bought a used LG LNG gas range for use at home but we only have LPG service here in the countryside. I have connected the LPG gas to it and it works alright but of course the pressure of the LPG gas coming out has made the flame too strong and unstable for cooking on.

Contacting the after-service center for LG, I was told to replace the stove because it's an old model and they do not have stock of the part (regulator) required to turn the LPG gas pressure down to usable levels for the LNG range. I'm sure it's just a matter of finding a proper regulator, no? Any ideas on what the ratio should be to turn down the LPG to? There is a regulator on the LPG tank at present.

Could it be adjusted down more or should another regulator be added to the range? Any help would be greatly appreciated. pursuntrade at gmail.com

Reply:

Jay

NEVER connect the wrong type of gas supply to a gas appliance. The result is unsafe and risks fire or explosion besides the problem of improper flame and improper operation.

If you can find the gas pressure regulator specifications for the stove that you have bought it might be possible to purchase a generic gas regulator that can be set to the pressure and fuel type that your stove requires. If the stove manufacturer does not agree that such an approach is safe then you should follow their advice since the potential injury or death from a gas explosion or fire is something to take seriously.

Question: gas pipe sizing charts

(Aug 11, 2015) Matt said:
When sizing gas pipe using standard charts (found in National fuel gas code) and slide rules how do you know what the pressure drop is. I worked in one part of the country before (North) and am now down South. Up North we would use the chart with .5 psi pressure with a .5 in. w.c pressure drop. Never had a problem.

Down South where I am now no one seems to want to give me an answer art to the pressure drop. Figuring the pressure of the gas is not a problem it is just that pressure drop that has me stumped. Is there any simple way without extensive measurements and calculations. Thank You

Reply:

[need citation from a Southern gas supplier]

Question: condensate drip tray leaks into gas furnace

(Aug 26, 2015) Anonymous said:
Seven years old plastic drain pan for A-coil in plenum of a gas furnace was deformed and caused water to drip to the furnace. When the heating system is on during winter, the heat caused the pan slowly deformed and it cannot hold anymotre water and spills water over the furnace during summer time. Is there a way to prevent the drain pan from damage?

Reply:

Anon this sounds unsafe: I worry that there is heat where there should not be, or that the wrong drip pan was installed.

If there are no furnace heat leaks or other safety issues then I'd replace the plastic pan with a sheet metal one.

Question: new high-end gas grill is too hot

(Sept 9, 2015) Will said:
Have a new higher end grill. Temp cannot go below 420 F. High is about 620. So , tough to do ribs ,,etc. Old natural gas grill had a nice range of 325-525 ( lid down ).
Dedicated gas line ( same as old grill) has PSI of 2. So -- why can't this grill go lower ? BTW - hundreds of recipes call for temps at low to mid range ( 300-375 , for instance ).
Thoughts ? Advice ?

Reply:

I'd like to know the brand and model and to see what the instruction book says; then we (you) could see what the manufacturer says. DO NOT modify the device: doing so is probably unsafe.

Question: How much pressure should be in a household gas line

(Sept 18, 2015) judy said:
How much pressure should be in a household gas line

Reply:

Please see GAS PRESSURES LP vs NATURAL GAS and let me know if questions remain.

Reader Question: what is the test pressure used when testing an LPG line?

2016/04/01 Anonymous said:
newly commissioned lpg line what is the required pressure to test the line

Reply: minimum 3 psi, or 1.5 x the gas system's design pressure (low pressure gas testing)

Anon:

Gas systems may be tested at low pressure for low pressure propane installations such as those found at a typical home using LPG. A different, high-pressure gas test procedure is also described.

NFPA 54 (2006), 8.2.3 states that "Immediately after the gas is turned on into a new system or into a system that has been initially restored after an interruption of service, the piping system shall be tested for leakage. If leakage is indicated, the gas supply shall be shut off until the necessary repairs have been made.

Low pressure gas leak tests of the gas piping

This test is performed with a pressure gauge installed on the "downstream" side of the final gas pressure regulator. It is testing the buiding's gas piping and gas appliances for leaks.

When pressure tests are performed on LPG piping, typically the system is sealed, a pressure gauge is installed, and the system is pressurized to 1 1/2 times the maximum design-operating pressure of the system OR a minimum of 3 psi. In some procedures the test period is brief: just 10 minutes for a residential building. But the pressure test interval is increased by 1/2 hour for every 500 feet of piping (that's more likely to occur in a commercial installation).

If the pressure drops during the test period then tools or solutions are used to find the point of gas leakage. Leak testing might be by soap type solution, use of a combustible gas analyzer, or other means.

If the calculated test pressure of 1.5 x the design pressure would exceed 125 psi, then the test pressure should not exceed an amount greater than 50 percent of the pipe strength.

In a low-pressure LP gas system test, the appliance shutoff valves are "ON" (presuming that the appliances are installed) in order to assure that the appliance automatic gas shutoff features are working properly.

High-pressure gas leak tests between the LPG container and the first stage regulator

High pressure tests are made using a 300 psi gauge installed between the gas container (LPG) and the first stage regulator. The gas valve is opened for three seconds and then closed tightly. The system is bled down by at least 10 psi and then tested for 3 minutes, watching for a pressure drop.

A separate test can check for leaks at the gas regulator itself: a 30 psi gauge is installed at the outlet of the first stage regulator. With the pressure gauge installed, the LPG tank's gas valve is opened for 2-3 seconds, just to pressurize the regulator and test gauge. The system is bled down by at least 5 psi and observed for 3 minutes to wat ch for a pressure drop.

Watch out: these general gas leak test descriptions are for illustrative purposes and are not technically complete, detailed, nor exhaustive. Check with the gas testing specifications required where the gas installation is to be tested, and check the gas testing recommendations of the equipment manufacturers.

Watch out: WVPGA (2011) notes that the gas pressure test medium should be air or an inert gas. Never use oxygen.

Question: Size of Gas Piping Required

2016/09/26 James w Howe Jr said:

I was taught to ALWAYS use copper flex with LP gas and black pipe with NG. I'm am NOT talking about pressure here! That stated, my supply is two 100 lb tanks with an "automatic switch over valve". The lines from the tanks to the valve are 1/8th inch. I need to feed a 30 inch 5 burner gas stove with a convection oven, a gas clothes dryer and a tankless 10L water heater that has a 1/2 inch gas inlet. Instead of running 1/2 inch copper flex with Ts to each appliance, do i need to increase the volume in the system to have enough gas to feed all three appliances. If I was using NG, i'd install at least a ten foot piece of 1 1/4 black pipe to build up the volume and then run 1/2 inch Ts with 1/2 inch pipe to the appliances. With LP I'd use 3/8 copper flex for the dryer and stove and the 1/2 inch called for for the water heater, BUT, I need to get enough volume first so how should I proceed? All of the answers on your site deal with pressure and THAT is not the issue here!

Forgot my contact info: jwhowejr@centurylink.net

Reply:

(mod) said:

Thanks for the comment and question, James. There's quite a list of types of piping material approved for use in gas piping systems; the distinctions I have seen are about the application - location such as above or below ground rather than the fuel difference between LP and NG.

Please see a detailed answer for your question at GAS PIPING SIZE & MATERIAL.

Watch out: Some jurisdictions such as New York City specifically prohibit use of some pipe materials such as cast iron, copper, brass, aluminum, and metallic tubing (with exceptions).

Watch out: There are life safety hazards involved when fooling with gas piping and appliances. Check with your local plumbing officials about what type of gas piping are permitted where you live, and while you’re at it, ask what gas piping or plumbing permits and safety and code compliance inspections are required where you live.

 

Article Series Contents

Natural Gas Appliance Operating Pressures in WC, millibars, Pascals, PSI or ounces of pressure

A common operating pressure for natural gas appliances is around 7 inches of water column (WC) or re-stating this in equivalent measure, that's 14.9 millibars or 1743 Pascals or Pa, or about 0.25 psi (pounds per square inch) or about 4 ounces of pressure per square inch.
See NATURAL GAS APPLIANCE PRESSURES for details.

LP or Propane Gas Appliance Operating Pressures in WC, millibars, Pascals, PSI or ounces of pressure

A common operating pressure for liquid petroleum or LP gas appliance is 10" - 11" of water column (WC) or re-stating this in equivalent measures, that's 27.4 millibars or 2491 - 2739 Pascals or Pa, or about 0.36 - 0.40 psi or about 5.78 to 6.36 ounces of pressure per square inch.
See LPG & PROPANE APPLIANCE PRESSURES for details.

...


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