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Pressure booster and Natural gas


#1

A new year is almost upon us and assuredly many new plans and
resolutions. A biggie for me is installing a natural gas with
pressure booster torch setup. The Little Torch I’ve owned for some
time now is still in the box.

I’d love to get feedback from all of you out in Orchidland who use
natural gas. The cost of the booster has been a factor in my
procrastination. What are the drawbacks/limitations? The positive
aspects? I’m also curious why having access to natural gas, studios
large or small whould choose other fuels.

Thanks to all and Happy New Year!!!
Cyndy


#2

Hi Cyndy,

We have a natural gas booster at Metalwerx, however we have
struggled with a few issues which have now been resolved.

  1. I would return the Little Torch or donate it if you can’t sell
    it. The Little torch is great for oxy/acyet, propane ok too if you
    use the larger tips. For natural gas, I would go with a Mecco Midget.
    The tips are larger and more conducive to the gas booster. For some
    reason, the Little Torch is too small to get a hot enough flame to do
    the work you need.

  2. Natural gas has an additive in order to alert you when the gas is
    leaking. You will find that it pulses a bit with a small orange
    flashes. This burst of orange flame is the additive burning off.

  3. Once you turn on the booster, give it at least five minutes to
    raise the pressure. The pressure valve turns all the way to the
    right, nearly off the charts. I called G-Tech about this, and they
    said this was completely normal. Don’t know why they have a gauge
    there then, but it seems to work.

If you are at your home, your gas delivery will be around 1/3 PSI.
If you are at a commercial studio, you might be able to work with the
gas company and have the pressure to your studio set correctly.
Metalwerx is in a mixed commercial/residential area. I could have had
the gas installed at the correct pressure while the building was
being renovated, but it was all a mystery to me then.

Our G-Tec works great now that we have the right torch set up for
either casting or soldering.

Although normally I would ask you to email me offline, if you do
have any more questions, please respond to the list. I’m sure there
are others that can help you.

Take care,

]-k

M E T A L W E R X
School for Jewelry and the Metalarts
50 Guinan St.
Waltham, MA 02451
781 891 3854
www.metalwerx.com


#3

Karen,

Thank you, thank you, thank you for the valuable info. You’ve really
motivated me to get started. Why don’t more people use natural when
available? We recently moved into a house with gas stove and water
heater and not adding another fuel to the studio just seemed to make
sense. Also gives hubby an extra measure of security since he’s
already familiar with it.

I appreciate your advice on torch types too. All advice most welcome
and appreciated.

Cyndy


#4

I started using natural gas 12 years ago and never looked back. I
use it at the house pressure with compressed oxygen. I use a Meco
midget torch with ventilated tips. I like it much better than
acetylene.

I don’t need a pressure booster, the Meco midget combined with the
oxygen gives me a wide range of heat, from itsy bitsy to roaring
huge. I do not cast with it however, for that I use the standard oxy-
acetylene in our big metal shop.

Happy New Year
Judy Hoch


#5

Hello Orchidians,

I’m with Judy Hoch…natural gas (NG) and compressed bottled oxygen
is inexpensive, available (if you have NG for other uses) without
limit, and very convenient. No need for a pressure booster - unless
you are a manufacturer, and then it would not be suitable for
residential zones.

Judy in Kansas, where we actually have snow accumulating! It’s a
snowy New Year here. May your 2007 be wonderful.


#6

Hi Judy,

Do you use a pressure booster? Are your gas lines specially equipped
for metalsmith tasks? Cuttlebone casting is about the only casting
I’d be interested in anyway.

Thank you!!!
Cyndy


#7
I'm with Judy Hoch...natural gas (NG) and compressed bottled oxygen
is inexpensive, available (if you have NG for other uses) without
limit, and very convenient. 

Actually there is a significant danger from not using a pressure
booster. You cannot buy a flashback arrestor that will function at
the very low pressure you get from residential or most commercial gas
services. Flashback arrestors need at least 2 psi to work and typical
natural gas is supplied at about 1/2 psi. There have been several
documented accidents where jewelers have blown up the meter/ gas
regulator because oxygen forced its way back into the gas line and a
flashback occurred.

I know I will probably will get several emails from folks that have
"done this forever and never had a problem" but if you check with
your gas company and or fire marshal and tell them exactly what you
are doing they will have a fit as it is a known danger.

This is why you need to get the pressure booster as it will allow
for the SAFE use of natural gas for torch work (even casting).

Jim

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550


#8

Hello Orchidians,

When this concern first surfaced, I discussed my use of NG without a
flashback arrestor with my local gas service people. They were made
aware of the use of compressed oxygen mixed with NG through a hand
torch, and had no problem with it. Our residential NG line pressure
is barely a quarter pound. Perhaps that makes a difference? I set up
my torch identically to that of one local jeweler downtown - no
pressure boosters or flashback arrestors… of course, this is a
small town and there aren’t very many jewelry stores.

Your comment caused me to do an internet search for such accounts
using “jeweler gas meter explosion” - no results that fit, other than
Orchid postings. Lots of explosions related to gas leaks, damaged
meters, etc. I would appreciate the opportunity to read more about
the circumstances, but so far, have not found any reported. I’m
beginning to think this is an urban legend.

My understanding of situations that would allow a flashback to go to
the meter are related to the use of large volumes of compressed
oxygen. The scientific glass blower at the university uses huge
volumes of NG and compressed oxygen - his lab is suitably equipped
with a pressure booster and flashback arrestors. I can see where
needing high temperatures for large casting operations or platinum
work could require those fixtures. Could such meter explosions have
begun to occur when jewelers started commonly working with PT?

Specific would be helpful. Inquiring minds want to know.

Judy in Kansas


#9

I’m the manufacturer of the G-TEC Torch Booster and I’d like to
respond to recent questions and postings regarding my products.

First, with respect to James Binnion’s comments about safety, he is
absolutely correct.

During the past year in New York City five jewelers have exploded
their gas meters because they connected their torches directly to the
city gas line without flashback arrestors. The huge difference in gas
pressure between city gas, 1/4 psi, and O2, anywhere from 10 to 70
psi, makes it relatively easy to cause a flashback.

When such a flashback occurs the gas meter literally explodes like a
hand grenade, a significant gas leak is created and sometimes there
is a fire. Fortunately no one has been hurt yet, but gas is turned
off to the building…in one case gas was shut off for 8 months.

The city gas utility studied potential solutions, including all
known flashback arrestors, checkvalves, etc and concluded:

  • No flashback arrestor or check valve promoted as working with low
    pressure natural gas is 100% effective in stopping a flashback

  • Standard 2 psi flashback arrestors such as are sold through
    Gesswein, Rio Grande and other leading distributors are 100%
    effective in stopping a flashback. As James noted, the problem is
    that these flashback arrestors require higher pressure gas flow to
    work.

A G-TEC Torch Booster lifts gas pressure enough to make the standard
2 psi flashback arrestor work, and give the jeweler the gas flow
needed at the torch. In New York City our Torch Boosters have been
approved by the Fire Department, NYC Department of Buildings and
Consolidated Edison and are recognized as the solution to this
problem. We are on a path that will lead to Torch Boosters being, if
not required, at least very strongly recommended to insure that
flashback arrestors can be installed and will perform their safety
function properly. New York City jewelers will be hearing more about
this in the coming weeks.

If anyone would like to contact me directly I would be happy to
share more d etails about our experience with flashbacks in NYC than
space permits here.

Second, while a torch directly connected to the city gas line will
work (please note that US OSHA regulations require a flashback
arrestor be used with an oxy-fuel torch) many manufacturers recommend
higher than 1/4 psi fuel gas flow for their torches. The Smith Little
Torch suggests up to 4 psi fuel pressure when used with a # 4 tip, up
to 8 psi with a # 7 tip, etc. Recommended pressures for a Hoke torch
range between 2-5 psi.

While a torch may work with 1/4 psi natural gas it will work better,
and the jeweler will get better performance, when s/he can set gas
pressure according to the manufacturer’s recommendation.

Third, with regard to using a Torch Booster in a home studio…these
products are certified by CSA-International, the same organization
that certifies your hot water heater, gas dryer, oven and other gas
appliances. They are safe to use in a home studio and in fact are
welcomed in places like shopping malls that prohibit propane and
other cylinder gases. The gas flow with these units is the same as if
you turned on all the stovetop burners in the kitchen. Just make sure
the system is installed by a person qualified to work on the natural
gas line.

Finally, an earlier posting suggested letting the system run for 5
minutes before using it. In fact the system is at full pressure and
ready to go as soon as it is turned on and there is no waiting time
required.

People who have purchased Torch Boosters cite three things they like
about them:

  • They get better torch performance of high-pressure natural gas

  • They like the safety aspect of being able to install a flashback
    arrestor that doesn’t block gas flow

  • The system is quiet, convenient and easy to use

If anyone has a specific question about a G-TEC Torch Booster please
contact me directly, or make a further posting here and I will answer
it.

If you would like to see a Torch Booster they will be exhibited at
the JA Show Jan 21-23 in NYC, Catalog In Motion in Tucson Feb 2-5,
MJSA in NYC March 18-20 and the Bench Conference in Buffalo April
26-29.

Ed Howard
G-TEC Natural Gas Systems


#10
They like the safety aspect of being able to install a flashback
arrestor that doesn't block gas flow 

Judymw asked the specific question. There are replies by more
knowlegable people than me about the general, but they didn’t quite
hit the specific. We went natural gas for most things, but I wanted
to use my big torch, which has FB arrestors built in. The natural gas
at line pressure doesn’t have enough pressure to go through them,
into the tip. In other words, the torch won’t work - won’t even
light. It requires a minimum pressure, which gas out of the line
doesn’t have, to use them. By the manuf. statements here, the booster
does raise the pressure enough. But gas from the line won’t get
through the arrestor by itself without a boost. At least not mine. We
just use NG on a daily basis, and have an oxy acetyline for casting,
brazing, welding and the like.

http://www.donivanandmaggiora.com


#11

Due to so few responses on this thread I’m assuming there aren’t
many Nat gas users out there. As I have it in the house already
though, seems I should take advantage. Especially since those of you
who do use it seem to love it.

Safety is a big issue for me and the use of flashback arrestors very
important. Just wish the boosters were not so darned
expensive.Hubby, not being inclined to play with fire, would rather I
spring for the booster. looking like that’s the way to go.

Thanks for the info and responses.

Cyndy


#12

Flashback arrestors are required on ALL oxy-fuel torches by all
health and safety regulations in the US. OSHA Title 29 Chapter XVII
Section 1910.253 page 684 lists the requirement for flashback
arrestors on piping systems connected to oxy-fuel torches. You can
read up on it here.

http://tinyurl.com/yjkxdv

The events involving NG and flashback that I am aware of are in NYC
where there is the highest concentration of jewelers and commercial
buildings plumbed with natural gas. People will not normally change
practices till forced to. Jewelers across the country that have
natural gas probably will not change to pressure boosters till
forced to by local regulation and city regulations will not require
it till there is a local event of enough seriousness to get the
regulators attention.

Your comment caused me to do an internet search for such accounts
using "jeweler gas meter explosion" - no results that fit, other
than Orchid postings. Lots of explosions related to gas leaks,
damaged meters, etc. I would appreciate the opportunity to read
more about the circumstances, but so far, have not found any
reported. I'm beginning to think this is an urban legend. 

Unfortunately not everything is available on the internet. Accident
reports from fire and insurance inspectors are not routinely posted
online. So unless the event is a spectacular one like the propane
cylinder fueled fire in Chicago that made the news you will not find
any on these types of event and even then you will not
find the inspectors report.

My understanding of situations that would allow a flashback to go
to the meter are related to the use of large volumes of compressed
oxygen. 

It is pressure not volume that is the problem. If the lines are not
balanced in pressure then the higher pressure one will back-feed the
lower pressure one. This is why check valves are required on torch
setups and are now built into most welding and cutting torches. Most
jewelers torch manufacturers have not done this as there has not
been the kind of regulatory (Government like OSHA and insurance
requirements) pressure on jewelers as there is on other users.For
some basic about flashback and backfires read this AWS
bulletin http://www.aws.org/technical/facts/FACT-28.pdf

Jim

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550


#13

As I posted before, I use residential pressure natural gas with
compressed oxygen. I purchased a special MECO low pressure gauge for
my oxy supply which lets me set my oxy pressure to eight pounds,
exactly. I bought it, and the MECO midget torch from a glass blowing
supply house about 12 years ago. I have never found the need for oxy
in any pressure above eight pounds. Is the problem obviated by the
use of relatively low pressure with the oxygen? I use the ventilated
tips almost exclusively.

At one Catalog in Motion, a torch expert explained why the MECO
midget worked so well. I asked because I was concerned that the low
pressure wouldn’t be enough to make the torch useful. He used the
term venturi to describe how the torch worked.

The Venturi effect is a special case of Bernoulli’s principle, in the
case of fluid or air flow through a tube or pipe with a constriction
in it. The fluid must speed up in the restriction, reducing its
pressure and producing a partial vacuum via the Bernoulli effect. The
Venturi effect is a special case of Bernoulli’s principle in the case
of fluid or air flow through a tube or pipe with a constriction in
it. The fluid must speed up in the restriction, reducing its pressure
and producing a partial vacuum

via the Bernoulli effect. A fluid passing through smoothly varying
constrictions is subject to changes in velocity and pressure in order
to satisfy the conservation of mass-flux (flow rate). The reduction
in pressure in the constriction can be understood by conservation of
energy: the fluid (or gas) gains kinetic energy as it enters the
constriction, and that energy is supplied by a pressure gradient
force from behind. The pressure gradient reduces the pressure in the
constriction, in reaction to the acceleration. Likewise, as the fluid
leaves the constriction, it is slowed by a pressure gradient force
that raises the pressure back to the ambient level. (definitions from
Wikipedia)

Now with all that, in 14 years of daily use, and having the gas
inspectors look at what I’m doing and how I’m using the natural gas,
I’m at a loss to understand why I need to add yet another piece of
equipment to my studio. I’m with Judy Willingham - if someone can
find one documented accident in a single jeweler studio attributable
to lack of a pressure booster and flashback arrestor, I will
re-consider.

Judy Hoch


#14

Hi Judy,

As I posted before, I use residential pressure natural gas with
compressed oxygen. I purchased a special MECO low pressure gauge
for my oxy supply which lets me set my oxy pressure to eight
pounds, exactly. 

At 8 psi the oxygen is at least 16 times the NG supply pressure.
This is one of the main reasons this setup is a problem. If for any
reason there is a blockage of the tip then the oxygen will force its
way into the NG line and try to equalize the pressure. now you have
oxidizer and fuel mixed in an enclosed container (the pipe) and an
explosion waiting to happen.

At one Catalog in Motion, a torch expert explained why the MECO
midget worked so well. I asked because I was concerned that the low
pressure wouldn't be enough to make the torch useful. He used the
term venturi to describe how the torch worked. 

No disrespect to the expert but all torches behavior can be
explained to some degree as a venturi. However this is normally more
appropriately used to describe how a gas air torch like an acetylene
air torch sucks external air into the mixing tube to create the
correct mix for burning. Any oxy-fuel torch with a large enough tip
orifice will work on the low pressure natural gas lines. Meco is a
nice torch, I have used them in my shop for years.

Now with all that, in 14 years of daily use, and having the gas
inspectors look at what I'm doing and how I'm using the natural
gas, 

The inspectors may not be that aware of the danger, they dont see
this type of installation regularly and may not be cognizant of the
danger it poses.

I'm at a loss to understand why I need to add yet another piece of
equipment to my studio. I'm with Judy Willingham - if someone can
find one documented accident in a single jeweler studio
attributable to lack of a pressure booster and flashback arrestor,
I will re-consider.

It is like saying that “I drive down the freeway while talking on my
cell phone and have never had an accident”. Just because you have
not had an accident doesn’t make the practice safe.

This thread has probably been beaten to death so I will stop now but
if you are interested in finding out about the details of accidents
contact Ed Howard at G-TEC he works with the jewelry industry and
can provide you with oxygen-NG accident and other data.

Jim

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550