Natural gas vs LPG

HelenC · #1 2011-10-01, 1:13am

Hi all

I've tried searching for posts but "natural" keeps throwing up 1000s of threads. So I have a question please.

With my new studio set up I have the option of going natural gas instead of LPG bottles. And I was wondering what are the pro's and con's.
I've read that natural gas is a burns a fraction cooler than LPG but it's cheaper and cleaner. My main concern is do I need a regulator or is the line pressure low enough not to need one?

Thanks in advance for your assistance.

Cheers
Helen

glassmaker · #2 2011-10-01, 4:46am

Personally I would find this an easy decision. Natural gas is safer in that is isn't heavier than air, and won't "pool" at the lowest point around if there is a leak. You also won't need to keep lugging around tanks to refill them, or run out of fuel at the worst possible time.

It is unlikely you will need a regulator. I don't know about Australia, but natural gas residential line pressure almost anywhere in the USA is a maximum of 1/2 lb. In many/most places it is even less than that.

Brad

clh · #3 2011-10-01, 6:25am

I am using natural gas for torching. I have found it to be much less expensive than LP and cleaner.

Natural gas is delivered at a lower pressure than you would get with the use of LP but this is manageable. The GTT cricket I am using was actually designed to work at lower pressures and has worked well for me with an oxycon.

You can also buy a pressure booster (though I hear those are expensive) to raise the pressure if needed.

It required only a back flow preventer. The low pressures eliminate the need for any sort of pressure regulator.

My favorite reason for using natural gas is that I never have to deal with running out of fuel.

Cheryl

purpledragonfly · #4 2011-10-01, 1:51pm

I am running on natural gas and love. There is a bit of a learning curve but once you get past that it's all good.

Alaska · #5 2011-10-01, 2:04pm

Also switched from propane to NG for all of the above reasons. Pressure in Ancharege is at 11 WC or around .4 psi. Some places allow for 2 psi. In our area that is not a possibility.

The only negative part is the pressure is low thus limiting the amount of fuel that is delivered to the torch. The Scorpion will produce a larger flame with propane using two concentrators. And requires three concentrators for optimum performance with propane at 5 psi.

With NG only two concentrators are required which is a savings of 400 watts. All in all would not consider a change back to propane.

JEK3 · #6 2011-10-01, 2:41pm

I'm using NG on my Minor. Really the only thing you have to watch out for is how a neutral flame looks. All the pictures you see are of a propane flame. NG doesn't get the yellow tips.

HelenC · #7 2011-10-01, 8:53pm

Thanks for all the replies guys.

I'm currently running a minor with an M15, the main problem I have is getting an oxy rich flame. I think my concentrator is a bit off but that's a different issue. The lower pressure from natural gas it may help with that. Thanks for the tip about the flame colour Joe, I didn't know that.

So I will get a line into the studio with a flashback arrestor but keep my bottle handy for testing and comparing for a bit.
The walls go up next week so hopefully it will be finished soon.

Cheers
Helen

Alaska · #8 2011-10-01, 9:05pm

The flame does look different and still getting used to that myself.

You do NOT want a flashback arrestor on the gas line. They are not designed for low pressure. You DO want a "Fire Check to provide flashback protection with a natural gas line. The Fire Check is manufactured by Carlisle" (works on .4 psi). Contact your gas company or plumbing firm to see what is available and installation advise.

HelenC · #9 2011-10-01, 9:17pm

Thanks Alaska

I'll check on that, my builder is actually very into this stuff and want's to help set up my ventilation as well.
We are running NG to the bbq as well so presumably that would need a "fire check" as well. Would the same sort work for the torch?
When ever I've asked questions at gas supply shops they go all wiggy when you tell them it's for a torch.

Cheers
Helen

Alaska · #10 2011-10-01, 10:47pm

The fire check is for the torch. Perhaps one can be installed for all appliances including the torch. IMO most folks most likely do not use a low pressure fire check for their NG torch system.

HelenC · #11 2011-10-03, 4:53pm

My plumber is being difficult, something about girls and torches freaks them out.

Apparently our house line is 2.5KPA which is 0.36PSI.
Is that enough to run a minor?

Thanks
Helen

JEK3 · #12 2011-10-03, 5:01pm

It will run, but see if he can go higher. The gas line to my house is reduced to 1-2 psi at the meter outside, then further reduced to 0.25-0.5 psi at the manifold inside. I tapped off of the 1-2 psi before the second regulator. The Minor works great!

HelenC · #13 2011-10-03, 5:59pm

Hi Joe

I'm not sure if the pressure he gave me was house or mains.
He did say I would need to upgrade all the house appliances if I wanted to run a higher pressure.
So what your saying is there might be a regulator dropping the pressure into the house and to cut into that before the regulator. As long as that's after the meter it should be fine.
But if I can run the torch ok is it worth the trouble.
I'm not going to do boro just 104 + 96.
I suppose if the pressure is too low I can go back to the LPG.
Part of the problem is I'm at work and the plumbers at home now.
Renovations arrgghhh but it will be worth it in the end.

Thanks
Helen

clh · #14 2011-10-03, 6:32pm

Quote:

Originally Posted by Alaska

The flame does look different and still getting used to that myself.

You do NOT want a flashback arrestor on the gas line. They are not designed for low pressure. You DO want a "Fire Check to provide flashback protection with a natural gas line. The Fire Check is manufactured by Carlisle" (works on .4 psi). Contact your gas company or plumbing firm to see what is available and installation advise.

Alaska is correct, I misspoke. Good thing I let my DH set it up for me...lol!

HelenC · #15 2011-10-03, 7:45pm

Well the builder knows what you mean Joe but the plumber isn't sure if it's legal and will I have ventilation etc etc. (yes of course I will)
Maybe I should change to a cricket for now. My concentrator would do better on that and if I get really serious later I can upgrade both.

I just want it finished, they took half the roof off a few weeks ago but didn't seal it properly so it ended up raining inside. Now they have to replace the family room ceiling.

Cheers
Helen

Alaska · #16 2011-10-03, 9:55pm

The Cricket and Scorpion both work well on NG at 11 WC and concentrators. The nice part is that the Cricket is inexpensive. And if one needs a bigger torch the Cricket is the center fire on the Scorpion thus decreasing the torch upgrade learning curve.

Have used both and now using the Scorpion for boro beads and such.

Dreamsincolor · #17 2011-10-04, 3:47am

My DH (a millwright) set up my studio to run the torch on natural gas. He had the gas company UP the pressure and put in what he calls a stepdown for the rest of the things here that use gas. It lets me have more consistent pressure and I am able to work boro when I want and I can have more than one torch going if I want a play date, lol. He says this is a much better solution than a pressure booster. A side benefit is that it is metered at a different rate here and I actually pay less for what I use than before he changed it. They did not charge for putting in the new meter or upping the pressure. All it cost was that I had to show them how I did the torchwork. Impressed the hell out of them to see it up close. Nice guys.

RyanTheNumberImp · #18 2011-10-04, 3:07pm

Going to chime in here and say that I hate natural gas. I've had the misfortune to use it occasionally when teaching and its so bad that I bring my own propane to avoid using natural gas.

As far as I am aware, the science behind it is that propane burns with oxygen in a 1:5 ratio while natural gas is only 1:2. Per volume, propane stores 2.5 times more energy.
Furthermore, the flame temperature for NG is 900-1500 while propane is 1200-1700.

This means that for the same amount of energy you need a lot more natural gas (which makes the flame bushy and less concentrated) and even then your flame is much colder.

I sacrificed about half my flame size when I switched from tanks to concentrators, but I would carry a 20lb tank by hand from the gas station before switching to NG.

Lots of people are happy with natural gas and if you work cold it isn't a problem though.

HelenC · #19 2011-10-04, 6:13pm

Thanks guys for all the replies.

Looks like I'm stuck with low psi for now so I'm going to switch to a cricket.
My concentrator won't have to drive so hard so I'll probably have more flexibility than I do now. And it makes more sense to spend $200 on a cricket instead of $2000 on a concentrator. I don't want to do boro as yet.
If it doesn't work out I can always go back to LPG.

Cheers
Helen