Helios Red Helios Green Helios Blue Helios Purple

Lapidary / Gemstone Community Forum
September 22, 2017, 11:01:22 am
Welcome, Guest. Please login or register.

Login with username, password and session length
News: This Forum has moved to a new host.  Please go to http://lapidaryforum.net/group/index.php and sign up so you can participate.  You will no longer be able to post here.  It is now a read-only archive.
 
  Home Help Search Classifieds Gallery Links Classified / Auctions Staff List Login Register  

If propane is heavier than air..

Pages: [1]   Go Down
  Print  
Author Topic: If propane is heavier than air..  (Read 1391 times)
Neural
Guest
« on: June 21, 2010, 07:22:49 am »

I vent fumes up and out in my place, using a duct fan inside 6" duct.

while things are put together securely, over time heat in the attic might change that.

So my concern is:  if there is a leak in the vent system, what happens if any of the fumes or gas slip out of the piping into the attic?

The attic is set up so that air is drawn in from the eves and vents out the top.  This circulation is how the attic is kept "cool" in the summer.

My primary concern though is any form of gas getting trapped in there somehow due to bad duct tape or something.  Will it move with the cycling of the air in the attic?  Will it sink and get absorbed into the insulation (which would be *real* bad over the long term)?
Report Spam   Logged

Social Buttons

bobby1
Hero Member
*****
Offline Offline

Gender: Male
Posts: 3595


View Profile
« Reply #1 on: June 21, 2010, 08:03:18 am »

With any venting system leaks can be a problem; however, unless you anticipate a large continuous leak of unburnt propane I wouldn't worry too much about it. Your exhaust fan probably isn't rated as flame or explosion proof anyway. Are you using a propane torch in your house, workshop or garage?
Most fire districts restrict the storing or use of propane tanks of any size in an ocupied dwelling. Most insurance companies won't cover this situation either. Their concerns are for the tank to leak and the gas pooling in a low spot and causing an explosion. That's why your propane tank is located outside and away from your house.
Bob 
Report Spam   Logged

Neural
Guest
« Reply #2 on: June 21, 2010, 01:30:34 pm »

The only propane, or gas in general, that should be venting would the small amount that escapes between when I turn the gas on and when I get it lit with the striker.

As for the location of my workshop, it is inside.
It is inside because I have no other options.

Propane may pool in a garage and seep out under the door, but acetylene rises and would fill the area of a garage ceiling.  In that respect I've always wondered how that makes it any different than storing a propane tank inside, especially since having the acetylene on the ceiling has it surrounding electrical sources like light bulbs.

I understand the risks of how I have things set up.  I think about it every time I enter my work area. 

Building outside was not an option due to the cost and HOA restrictions, and other restrictions.
The garage was not an option because it gets below freezing in the winter time and over 90 in the summertime.
Renting a building is so far out of the question it's laughable.

So, things are inside.
Report Spam   Logged
mirkaba
Hero Member
*****
Offline Offline

Gender: Male
Posts: 2303



View Profile
« Reply #3 on: June 21, 2010, 02:04:49 pm »

Jon............ acetylene acts pretty much the same as propane. It is heavier than air. What little gas escapes from your system while lighting and turning off is so minimal that I would not worry about it. I would worry about carbon monoxide and fumes from different solders and chemical reactions like in your pickle pot etc. Some alloys are also bad for you if you are welding or cutting with acetylene such as zinc. Its good to have a well vented area but any gas that leaks will seek out the low areas and pool. So be careful with your tanks, valves and connections.........Bob
Report Spam   Logged

Bob

Gathering dust in Montana.
Charlotte
Guest
« Reply #4 on: June 21, 2010, 03:53:46 pm »

When you are lighting the torch thing, is the fan not pulling those fumes from the work area and going outside??  Wouldn't that be the same as having a gas stove in the kitchen and it takes a few seconds to light once the gas starts?  I was just worrying about breathing the fumes from soldering. 
Report Spam   Logged
Neural
Guest
« Reply #5 on: June 21, 2010, 03:57:10 pm »

well, the ventilation system itself, using the 6" duct fan, works nicely.  since I started using the new set up, I've not smelled *any* fumes at all (as compared to the old system I used, as well as the one where I took a class etc.)  
I have to get in *real* close  to the stuff right after I've turned the torch off to even get a whiff.
It's actually a strong enough pull that you can see it in the flame when I have just struck the torch and it's not had the Oxygen valve opened just yet.  

My primary concern was just the attic.  I am a shade paranoid in some ways, and have this vision of duct tape getting soaked with the heat and humidity in the attic and then slipping off, leaving me venting stuff directly into the attic without knowing it.
Technically this should be doable anyway due to the circulation of the air up there, but it's the heavier-than-air stuff that concerns me.
Report Spam   Logged
Michael
Guest
« Reply #6 on: June 21, 2010, 04:19:05 pm »

If you are worried about to much propane collecting on your  floor you can go to a local RV supply store. they sell propane dectetors, they work very well. It has a VERY anoying  alarm. It detects more than  propane also.
mike
Report Spam   Logged
bobby1
Hero Member
*****
Offline Offline

Gender: Male
Posts: 3595


View Profile
« Reply #7 on: June 21, 2010, 09:13:20 pm »

I would think that the little amount of unburnt gas that escapes just before the flame starts is so highly diluted in the volume of air that is in your shop and in your ductwork that it would pose no problems at all. There would have to be a reason as to why these small incremental amounts of gas would want to join together to cause a problem. The effect of the movement of air will continuously disperse and dilute any gas present.
The "pooling" problem only exists if you have a constant supply of gas, most likely from a leak.
Bob
Report Spam   Logged

johnjsgems
Hero Member
*****
Offline Offline

Posts: 924


View Profile
« Reply #8 on: June 22, 2010, 10:14:44 pm »

What Bob said.  If you want to be extra safe store the tanks not in use in the garage. 
Report Spam   Logged
Rocksnot
Guest
« Reply #9 on: February 24, 2011, 12:37:51 pm »

Another thought about taping the joints in your vent...

I use 2 or 3 sheet metal screws to mechanically hold each joint and then tape with metal vent tape (I think it is aluminum)  Never had anything come a part or leak.  My vent system is a health size ducted squirrel fan uses 8" and 6" ducting on intake and exhausts directly outside.  I actually had to choke it down to 6" to keep it from pulling air up through the floor drains and toilet (real smelly)  oxy/act welding and burning lead for a little while now mostly soldering, paint, finish and dust removal.  Its been there over 10 years and still working great!

Duct tape will sooner or later dry out and fall off leaving a nasty residue behind.

As for the flame gas you are using, typical stink agents they add to the gas are 10,000x strong so you will smell waaaayyyy before it reaches critical level.  But I am a worry wart (better that than french toast) I have a 4" line from the vent system that hangs down right above the floor to help get fumes.
Report Spam   Logged


Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by EzPortal
Bookmark this site! | Upgrade This Forum
SMF For Free - Create your own Forum | Buy traffic for your forum/website

Powered by SMF | SMF © 2016, Simple Machines