Ventilation means removing noxious materials, dusts and fumes from where you can breathe them in. It is about taking away the chance for you to breathe in chemicals and particles that can damage your lungs. Ever seen people riding around with an oxygen tank next to them and tubes in their noses? That is only one of the kinds of trouble you can get into from breathing in toxic stuff. A good friend of mine died recently from pulmonary fibrosis, definitely due to his exposures to coal dust and chemical fumes in working his materials.
Best is if you arrange things so that you don’t need to have ventilation in the first place. If you can substitute a material or process that means you get similar results without generating dangerous dusts or fumes then you should consider switching.
If you etch, or use chemicals, make dusts or mists, or get fumes rising as you work or change materials – then you need ventilation. If you can take the hazardous materials you produce away from you right from the spot where they are generated, that is the best solution. This means a sucking device, slot or tube close to the working area that is generating the dust, mist or fumes that need to be vented. This is called local ventilation. The closer you are to a hood opening the more effective it is. In general fumes and dusts being generated should be as close as six to eight inches to the mouth of a local suction system. Some writers take a harder position: “Wherever possible, ventilated processes should be totally enclosed” (Stellman and Daum 300). Make sure that vented air is removed completely and is not immediately sucked back into your building by a wrongly placed air makeup intake duct.
Dilution ventilation, which is where you open a window next to you, and another one elsewhere, so that air passes you on its way out, is used in many shops. Dilution ventilation is not generally an effective approach. Even materials like rubber cement and some permanent markers demand adequate ventilation over and above the dilution type.
The book Ventilation: A Practical Guide for Artists, Craftspeople, and Others in the Arts by Clark, Cutter and McGrane is a very good starting place to learn more, and has specifics on actually building a ventilation system. There are canopy types, slotted hoods and “elephant trunks”, the latter a hose with a hood that can be moved to different spots on a work surface. Make sure you don’t move air (and noxious materials) past your face before it leaves, as occurs with many overhead hoods. Different air flow speeds are recommended for various activities. Ventilation can be complicated: there are ventilation engineers and inch thick books on the subject. You will need to do research, and probably consult a specialist about your own ventilation system needs.
A fume hood is a good idea if you use chemical solutions and processes. A fume hood should be positioned near the back of the workshop so that if there is an accident the exits are not blocked. It should have enough aisle space in front of it that people working in the studio do not interfere with its use or the air movement into it by moving around near it. Fume hoods should be tested every time you use them with a smoke trail or soap bubbles. I had two students who went to hospital with metal fume fever because they did not test an extraction system before using it.
Ventilation means that air is being sucked out of your workspace. This air then has to be made up from someplace, perhaps from the rest of your building or from make-up intakes placed carefully distant from the ventilation exit point. It is important to ensure that your make-up air is not bringing in vehicle exhaust fumes, is not downwind from a chimney that is putting out toxic fumes, and is otherwise not bringing in noxious air (Kornberg 111). Make sure that you don’t create negative pressure in a basement workshop by venting so much air out that it causes air to be sucked into the space through a water heater or furnace exhaust vent – this backflow can fill your workspace with poisonous carbon monoxide gas.
Venting air outside can cause heating and cooling problems for the workshop. In general the most effective way of dealing with proper ventilation and still considering the cost of heating the workspace is to reduce the amount of air being handled, and to use it only when it is necessary for a specific task. For local ventilation, a low-volume but high-air-speed hood, sort of like the slit of a vacuum hose can be very effective.
Remember that respirators should be reserved for emergency procedures. McCann says: “Ventilation should always be tried before considering respiratory protection” (McCann, HHM 87). The need to use a respirator is a red flag that your ventilation system is inadequate for what you are doing.