Can anyone give me an estimate of the temperatures one would expect in an 8 inch exhaust line from a minor torch. I have a baffled 4 sq ft hood about 2 feet above my work table and about 8 feet of pipe to the outside opening. My in line fan is not quite enough at 500 cft/min and I need a bigger inline but don’t want to melt a new one. An outside mounted squirrel cage is an option but not really what I need because of covenant restrictions. I can have a grill propane tank but no outside fans or a/c units -go figure.
Well, first of all, your hood is seriously underpowered. Standard overhead hoods should have at least 125 CFM per square foot, and at 16 square feet, you hood needs at least 2,000 CFM to properly exhaust the fumes captured inside.
If you have experienced fan blade or motor melt-down, this is an indication that the fan you selected is not designed for the use you are putting it towards. Typically speaking, fans with plastic blades are used in bathroom exhaust fans, and other fans where airstream temperatures do not exceed about 90 degrees.
As you search for a new fan, consider mounting inside at the point where the ducting leaves the building. If you have 8 feet of ducting, that is plenty of distance from your bench to allow the noise level to drop — but most noise from squirrel cage fans is more from vibration of the attached duct work than the fan itself.
Until today after browsing around the LE forum for a couple hours, I was never aware of the dangers of lampworking. Specifically the need for proper ventilation. I began lampworking with my girlfriend who in 3 different houses/setups has never had any sort of ventilation. At her home right now there are 3 torches setup in a small room maybe 10’x18′, 1 small carlisle, 1 minor burner, and 1 barracuda. The 2 smaller torches are on a oxy concentrator and the cuda is on a B size oxy tank. After reading on here today, I have become very worried about the safety of her setup. Both of us experience dry throat sensations after working on the torches for 3-4 hours. I called her immediately and told her about the needs for the ventilation.
Now what I still am uncertain about is there any way that we can work on a torch without ventilation safely? We both have housing situations that prohibit any modifications to the house itself, so any ideas? I’d hate to have to quit, I’ve finally found a relaxing hobby.
I cannot emphasise enough the importance of reading everything you can get your hands on about the hobby/craft we have chosen.
I’ve had other questions by lampworkers with similar situations who either cannot cut a hole in a wall or need some sort of at least temporary solution to the ventilation “problem”.
If you remember the definition of ventilation from a previous blog entry, it is “a system or means of providing fresh air”. If you are getting sore throats, coughs, tight chest, dry itchy eyes, then it should be obvious that you are not getting enough fresh air.
So, what can you do? Well, a quick and dirty solution, and mind you, this is quick and dirty, and should not be a permanent or long term solution, is to open two windows and use a couple of box window fans (you will also need some cardboard and duct tape). If you are in a situation where you are suffering withdrawl symptoms and you absolutely have to get on the torch…then give this a try.
You will need open windows (or a door) on either opposite sides of the house, or openings at least 10 feet apart. Put one exhaust fan in the window, preferably the window in your studio. Use duct tape to seal the bottom and sides of the fan to the window opening to prevent blowback from the window screen. Cut the piece of cardboard to fit the remainder of the opening, and seal that as well with the duct tape.
If the open window (or door) is in another part of the house, station another fan on the floor to direct the fresh air into your studio room. Ideally, you want the air flow to blow across your bench towards the fan in the window, but this is not always possible, so use another fan stationed behind you and tilted slightly upwards at an angle to blow fresh air into your work area. This will eliminate the pooling of contaminated air in front of your face. You may have to play around with the fan locations and directions until you find just the right placement.
And please remember, this suggestion is not an alternate method of proper torch ventilation!! This is only a stop-gap method to keep you temporarily safe while working behind the torch.