Ventilation

Latest revision as of 23:59, 19 May 2007

[edit] Ventilation

Ventilation is the mechanical means of removing noxious fumes and unhealthy gases and solids that are created during the flameworking process. Common fumes such as gold and silver, as well as particles such as heavy metals and borosilicate need to be vented away from lampworkers in order to avoid acute and chronic exposure.

Ventilation can be a bit of an art form, because one must balance between having enough air circulation, but an excessive amount of circulation will lead to air turbulence. Air turbulence is bad because the air circulation is not stable and pockets of exhaust might shift towards the person at the station. The smoke test may be used to determine if there is any turbulence in the shop or a lack of ventilation.

[edit] Types of Ventilation

The Gable Fan

Commonly employed by lampworkers on a budget or is a noob. These can be had from hardware stores such as Home Depot and Lowe's for around $50. These are usually mounted in front of one's workstation in order to create a laminar flow. This fan can exchange large amounts of air in a short amount of time, as they are designed to expel hot air from an attic.

There are drawbacks to this system. One example is that while this system can displace large amounts of air, it can not provide a sufficient amount of draw or push forces in order to run a ducted system.

The Squirrel Cage Blower

Often used in larger production environments where more than one vent fan is needed. Although more expensive than a Gable type fan, it allows a shop to use ducted ventilation systems. The benefits of this is that exhausts can be directed away from a building in a controlled manner. If a 4 sided building needed vent fans against three of the wall, the building or room would have to have vacant space sounding all three of those wall. However, one must also consider back-flow, or the process of drawing supposed fresh air that actually has a portion of exhaust air contained in it. With a ducted system, one exhaust port may exist, and that exhaust can be directed away from the fresh air source.

[edit] Fresh Air

Fresh air must be introduced in a manner by which it is opposite to the exahust sytem. In other words, a fresh source of air should ideally be directed at the head of the lampworker at the station. If the source of fresh air is next to the exhaust intake, it defeats the purpose of keeping the lampworker isolated from toxic substances.

Stuff from the sticky that needs to be expanded

1.) CFM means cubic feet per minute. depending on the size of your shop you should have many CFM's of ventilation. Meaning air moved out of your shop. One source I read said 100 CFM's per square foot of work table space. Others can comment below on how much they use or have heard should be used. I'm not sure anyone knows how much we need. Maybe we need an OSHA expert's help here.

2.) The larger the diameter the ducting the better. Less turbulence, more laminar flow.

3.) Round is better than Square duct. Less turbulence, more laminar flow.

4.) Shorter distance between fan and work area are better.

5.) Straight and or slow curves in ducts are better than Right angles. Less turbulence, more laminar flow.

6.) Hoods and enclosed worktables can direct the ventilation very effectively away from the worker.

7.) Always know where the air you suck into your shop is coming from. A large source of fresh are is best. For example: Powerful fans can make your furnace backflow and you can get carbon monoxide poisoning.

8.) The flow by your head (your mouth leads to your lungs, in case you weren't aware) is KEY!!! the fresh air should flow by yor face. A 300 Giga CFM fan located at the other end of your shop will only slowly pull the cloud of metal fume away from your head. That is the principle behing hoods, directing and concentrateing the flow.

9.) OSHA says for welding hoods that 250-350 CFM per linear workbench foot is adequate. But there is NO standard for Flameworkers.