[Jim Bridger]

Hey All -

I used Jody and his videos to teach myself how to Stick, Mig, and Tig weld and have had a lot of fun doing it. It was a goal at first just to fix our farm equipment, corrals, etc. but it turned into welding whatever I could come up with (furniture, tools, etc.). Anyway, I have small shop that I operate out of but it is also used for storing our tractor equipment for the winter. I'm wondering if someone can help give me their ideas on how they installed ventilation and/or air filtration. I have neither and certainly have concerns from both weld fumes and from grinding. I wear a respirator when doing big project (admittedly not religious about this...) and also have setup some basic box fans with air filters on back but obviously it's not the best solution and doesn't address fumes. Summer its easy to leave the doors open unless there is a breeze but winter is coming. Shop is about 30x30 and about 15' high ceilings. Any help is MUCH appreciated!

[BugHunter]

In my shop I've got a large (~18") squirrel cage fan in the ceiling of the welding booth which vents to the outside. 99% of the time I don't run it. But if I'm going to be producing a lot of fumes or smoke, on it goes. The room it's in is relatively small with an opening to where all the welding takes place so it captures the smoke pretty well. If you were to have a huge open area, i'ts difficult to draw fumes in without some way to keep them restricted to a smaller space. Or if you do draw them in, you likely have enough flow that you're also pulling away all the shielding gas (assuming you're doing a process that uses shield gas).

I could envision canvas tarps as walls and ceiling in a small "room" to limit the amount of air you need to exchange in order to clean it up. Otherwise you've got 13K cu ft of air to exchange to clean things up.

[Jim Bridger]

Thanks BugHunter!

I guess that's part of the reason I posted it --> getting opinions of people more experienced than me on if I should be concerned or not. 99% of time I'm running solid wire mig and/or basic steel and aluminum TIG. With long winters here in Montana I can definitely spend all day in there and if it feels smokey I crack a window or briefly open the large garage doors. I dont really have a way to create a booth and the ceiling is so tall I've not wanted to mess with an overhead fan. I guess related to this question is just how anal other people are on controlling fumes and grinding dust.

[Poland308]

There are heavy metal particles that are expelled from the welding process that aren’t visible. No mater how small the weld it’s there. Danger of heavy metals is more of a long term cumulative effect. A little bit adds up over time.

[JayWal]

I went with a HRV system, heat returning ventilation. The idea being it acts as a radiator, the outgoing warm air warms up the incoming fresh cool air. Or vise versa in summer. Its not 100% efficient, I think mine is supposed to be 75% efficient, meaning i recover 75% of the outgoing heat. Im a bit further north still than you so I cant afford to blow all my heat outside in the middle of January. I'm pretty happy with my setup except that its a little small. If I'm doing stick welding that 1 unit can't keep up. I'm debating adding a second fume extractor just for over my table, and leave the HRV to do the rest.

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[tweake]

I went with a HRV system, heat returning ventilation. The idea being it acts as a radiator, the outgoing warm air warms up the incoming fresh cool air. Or vise versa in summer. Its not 100% efficient, I think mine is supposed to be 75% efficient, meaning i recover 75% of the outgoing heat. Im a bit further north still than you so I cant afford to blow all my heat outside in the middle of January. I'm pretty happy with my setup except that its a little small. If I'm doing stick welding that 1 unit can't keep up. I'm debating adding a second fume extractor just for over my table, and leave the HRV to do the rest.

you must have fun changing the filters in that

hrv/erv are great but the cores must be kept clean otherwise they will clog.

[JayWal]

Mine doesnt have filters. Just alu pipes where the outgoing air goes through, warms the pipes, and the incoming air flows around the pipes. I do blow it out once a year or so. It does collect some dust inside but not bad considering it runs pretty much every day

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[Jim Bridger]

Thanks for the photo and comment JayWal! I probably could figure out the duct work and I like the fact you're not losing your heat. Your shop is big enough and with higher ceilings so I could see how that's a big concern where you are located.

Maybe someone can comment on here = can a simple shop filtration system (like from JET or Baleigh) be enough to capture both weld fume contaminants and grinding dust? I realize these can have pre-filters, etc. and there is wide range of costs/models but I'm just wondering if this is perhaps easiest/low cost for hobby work without having a full on hood over your welding area.

[cj737]

HRV (Heat Recovery Ventilators) are solely for efficient energy utilization for producing heat, and have no auxiliary function to fume extraction or ventilation because they merely re-cycle the air through the system. They are part of a forced hot air system. And you should be running either a pre- or post-exchange filter. These are usually large cartridge filters somewhere along the blower stage (to Poland's point).

Whether that system is running constantly or not, there is a significant amount of dust, debris, and particles accumulating in the ducting and you might re-think an annual maintenance schedule to prolong the life of the radiant cores.

[Poland308]

I work on equipment like this weekly. No filters in a dusty, shop environment will plug the cells in months.

[JayWal]

I work on equipment like this weekly. No filters in a dusty, shop environment will plug the cells in months.

Ok, ill dig into it deeper and see. I really couldn't see much that can plug when I've worked on it in the past. There are no filters in it.

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[Poland308]

What ends up happening is that the condensation forming on whatever side it’s on depending on season collects dust and bugs. Then it turns to a hard crusty cement crud. As long as you wash it off with water every month or two you will be fine.

[tweake]

Mine doesnt have filters. Just alu pipes where the outgoing air goes through, warms the pipes, and the incoming air flows around the pipes. I do blow it out once a year or so. It does collect some dust inside but not bad considering it runs pretty much every day

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i think yours is a low efficiency unit, probably no where near 75% if its using pipes as the heat exchange.
the efficient ones all use "radiator" style cores. small gaps that get plugged quickly. most are still only around 80%.
with big gaps its not getting plugged but a lot of air probably never touches a surface to transfer heat.

in cold dry areas an erv is probably better but do not ever get welding fumes anywhere near one of those.

[Jim Bridger]

@Poland308 = what would you recommend for a purely recreational/hobby guy like me. We run a farm so its basic/easy fabrication and repair along with just some stuff for fun (obviously for past year lots and lots of just practice plates, etc.). I just have simple portable radiant heat on in winter usually in area I'm working in as we insulated our shop but didnt put water/heat in there. Ceiling height is high simply b/c we park 2 large tractors in there.

[Poland308]

Radiant tube heat is an excellent option for open shops with high ceilings. Blow out the combustion blower before you start it up for the year. If your looking for a exhaust option then might be worth creating a hooded area over your weld bench, with a filtered fresh air opening from outside. With dampers, then you only need to open up fresh air when you run the exhaust hood, aboutlike a standard commercial kitchen setup.

[JustTheDad]

Double posted. sorry

[JustTheDad]

HRV (Heat Recovery Ventilators) are solely for efficient energy utilization for producing heat, and have no auxiliary function to fume extraction or ventilation because they merely re-cycle the air through the system. They are part of a forced hot air system. And you should be running either a pre- or post-exchange filter. These are usually large cartridge filters somewhere along the blower stage (to Poland's point).

Whether that system is running constantly or not, there is a significant amount of dust, debris, and particles accumulating in the ducting and you might re-think an annual maintenance schedule to prolong the life of the radiant cores.

Hi CJ,
This seems wrong. The HRV vents inside air to the outside and pulls in outside air in. That seems to be exactly what you'd want to keep fumes down in a shop. Mine is an ERV and draws outside air in from one side of the house. It vents the exhaust air from the HVAC system return out a wall vent on the other side of the house. So the intake and exhaust air are far apart. Both vent pipes are insulated and go to the ERV which sits near the air handlers.

We have multiple zones, and about a year after we had the system installed, I kept smelling this awful stench in the house, but it was in different rooms. I thought one of the dogs was sick and peeing or throwing up or that a mouse had gotten in and died. Turned out that a cat had fallen into the window well 5 feet under the ERV intake and died. May have jumped in during a big storm a few days earlier. Each time a particular zone turned on, I'd smell it, and then it would go away as the system cycled a different zone on. Took a while to figure that out and now the 3 window wells all have covers!

Definitely brings in fresh (fume free) air as long as you keep the dead cats away from the intake.

I was going to suggest an HRV too since winters up north are cold. I saw some small HRVs on craigslist when I was considering adding one to our welding space, but I just decided to use a plain old stove hood.

[JayWal]

Mine is the same, tho in my case I pull air out of my attic (its vented) to avoid pulling in rain/snow and exhaust the "dirty" air outside via a separate vent. If Im doing any painting or something with a strong smell like that you can definitely smell it outside if the HRV is running

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[Poland308]

Erv’s will work for fume extraction but they don’t deal well with all the associated particulates.

[cj737]

HRV (Heat Recovery Ventilators) are solely for efficient energy utilization for producing heat, and have no auxiliary function to fume extraction or ventilation because they merely re-cycle the air through the system. They are part of a forced hot air system. And you should be running either a pre- or post-exchange filter. These are usually large cartridge filters somewhere along the blower stage (to Poland's point).

Whether that system is running constantly or not, there is a significant amount of dust, debris, and particles accumulating in the ducting and you might re-think an annual maintenance schedule to prolong the life of the radiant cores.

Hi CJ,
This seems wrong. The HRV vents inside air to the outside and pulls in outside air in. That seems to be exactly what you'd want to keep fumes down in a shop. Mine is an ERV and draws outside air in from one side of the house. It vents the exhaust air from the HVAC system return out a wall vent on the other side of the house. So the intake and exhaust air are far apart. Both vent pipes are insulated and go to the ERV which sits near the air handlers.

We have multiple zones, and about a year after we had the system installed, I kept smelling this awful stench in the house, but it was in different rooms. I thought one of the dogs was sick and peeing or throwing up or that a mouse had gotten in and died. Turned out that a cat had fallen into the window well 5 feet under the ERV intake and died. May have jumped in during a big storm a few days earlier. Each time a particular zone turned on, I'd smell it, and then it would go away as the system cycled a different zone on. Took a while to figure that out and now the 3 window wells all have covers!

Definitely brings in fresh (fume free) air as long as you keep the dead cats away from the intake.

I was going to suggest an HRV too since winters up north are cold. I saw some small HRVs on craigslist when I was considering adding one to our welding space, but I just decided to use a plain old stove hood.

Both ERV and HRV systems are intended designs based upon CFH of air circulation for the volume of a given space. It is fixed and intermittent “breathing” of air to be cycled through a space. These systems are becoming more prevalent as buildings (homes especially) become better sealed and tighter. Fume extraction is a particularly high volume auxiliary system and only functions well when within a given distance of the source of the fumes (think stove hood).

To your point above, the fresh air intake did not filter the incoming air from any impurities or odors, precisely what a fume extraction system would do (not bring in outside air, but remove impure air to the outside).

And don’t misunderstand the point of ERV/HRV systems: it is to recover the energy of conditioned air before it is exhausted in order to reduce energy consumption. In your ERV, money has been spent cooling the air that would be otherwise exhausted to the outside. Instead, the cooler air is passed across warmer incoming air, lower its temperature before the cooler air is wasted. This reduces the energy required to condition the inbound air. Which is why these systems to work well have to balanced and calculated for the spaces they operate in.

[JustTheDad]

Sorry. I wasn't suggesting using it as a fume extractor. Even a 200 CFM system wouldn't be sufficient for that, but adding a decent sized one to the shop would turn over the air in a couple of hours without losing all his heat which seems like something that would help.

[tweake]

Sorry. I wasn't suggesting using it as a fume extractor. Even a 200 CFM system wouldn't be sufficient for that, but adding a decent sized one to the shop would turn over the air in a couple of hours without losing all his heat which seems like something that would help.

the problem is all the particles. which is why its not a good idea to have your range hood connected to the hrv/erv system in the house.

really need to have a fume extractor which filtered out the particulates. then let the buildings ventilation system do its thing to remove the bad gases.

[JayWal]

Sorry. I wasn't suggesting using it as a fume extractor. Even a 200 CFM system wouldn't be sufficient for that, but adding a decent sized one to the shop would turn over the air in a couple of hours without losing all his heat which seems like something that would help.

the problem is all the particles. which is why its not a good idea to have your range hood connected to the hrv/erv system in the house.

really need to have a fume extractor which filtered out the particulates. then let the buildings ventilation system do its thing to remove the bad gases.

Huh. I've never really thought of welding fumes like that. Did a little bit of reading, so its not just smoke I'm trying to get rid off its the tiny particulates that welding gives off as well, tiny dust particles if you will. Dust from the filler metal and base metals. Am I in the ballpark?

So you're suggesting a fume extractor to do the grunt work, filter out that dust right away, then let the HRV run in the background, replacing the already filtered air with fresh air. I like that.

Makes more sense than trying to drag that "dust" up through the duct work and blow it through the cells and outside.

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[cj737]

Sorry. I wasn't suggesting using it as a fume extractor. Even a 200 CFM system wouldn't be sufficient for that, but adding a decent sized one to the shop would turn over the air in a couple of hours without losing all his heat which seems like something that would help.

the problem is all the particles. which is why its not a good idea to have your range hood connected to the hrv/erv system in the house.

really need to have a fume extractor which filtered out the particulates. then let the buildings ventilation system do its thing to remove the bad gases.

Huh. I've never really thought of welding fumes like that. Did a little bit of reading, so its not just smoke I'm trying to get rid off its the tiny particulates that welding gives off as well, tiny dust particles if you will. Dust from the filler metal and base metals. Am I in the ballpark?

So you're suggesting a fume extractor to do the grunt work, filter out that dust right away, then let the HRV run in the background, replacing the already filtered air with fresh air. I like that.

Makes more sense than trying to drag that "dust" up through the duct work and blow it through the cells and outside.

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Exactly.

[JayWal]

Learning something every day. Thanks [emoji4]

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