Vent Fan Question

[Deb Hopeful Journeys]

Ok, I need some help. I have read and re-read all the threads about vent safety. I have a question about a fan that I've found. On low the fan has 1,000 cfm. Can a person have too much cfm? Also, how would a 1,000 cfm fan affect the fresh air duct?

Here is the link to the fan. It looks like it would work and the price is pretty good too. http://www.northerntool.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=6970&productId=200007224&R=200007224

Hopefully the link above will work.

Thanks in advance!

Deb in MN

[Dale M.]

It may work. But its not the best candidate for a vent fan.

First you really need to determine what actual CFM is practical for you situation. This is done by measuring hood opening and calculation needed capacity in CFM... Its usually done by measuring hood opening (depth X width = sq inches).. IT goes like this for a 18 X 27 inch hood (for example only). 18x27=486sqin. 486/144 (1 sq ft)=3.37 sqft. By using the rule of about 100 cfm per square foot of opening (3.37 sqft X 100cfm= 337 cfm) it calculates out you only need fan capable of (maybe) 350 cfm. You have to do the math. You can not just guess the values and guess what fan may be correct. Using my figures your fan if about 3 time more powerful than what you actually need.

Also the fan you have linked to is a just a "air mover". Its NOT designed to be coupled up to a ducted ventilation system. It uses a blade type fan which for our application is not very practical. You should be looking for a "squirrel cage" type fan. Also these propeller fans are a lot noisier than squirrel cage fans.


Dale

[Deb Hopeful Journeys]

I am probably going to make a work station similar to the one Bill made in the Art Answer Glass Forum. I believe you are involved in that one too.

I am planning my work box to have a 2'x3' opening. From what I have been studying that would be 6 sq ft x 80 - 100 which will mean I need a minimum of 480 cfm. Correct me if I am wrong.

I guess I was hoping that I might not have to spend $130. If it is necessary for safety reason, then for sure I will spend that. I am trying to make sure I cover everything since I will have my studio in the basement. It isn't in the same room as the furnace though.

Thanks for all your input and everything you do to make us ALL safe.

Deb in MN!

[Dale M.]

Here is a couple of web links to sites by responsible organisations that know a lot about ventilation.... Keep in mind that we as glass workers fall into the "class B" hood design criteria...

http://www.energyandpowermanagement.com/CDA/Archives/a552f92aebe38010VgnVCM100000f932a8c0____
http://www.pao.gov.ab.ca/health/fumecode/index.html
http://www.tamhsc.edu/departments/administration/safety/chemical/fumehoods.php
http://www.ilpi.com/msds/ref/tlv.html
http://www.lni.wa.gov/Safety/Topics/AtoZ/Ventilation/default.asp#Hoods

Dale

[MikeAurelius]

Just remember that for every cubic foot of air you exhaust from the house, you must replace it with another cubic foot of air from outside. The fresh air must be separate from any other fresh air source that the house may already have, and be at least 10 linear feet from the exhaust duct.

[Deb Hopeful Journeys]

Thanks Mike!

I have the fresh air figured out. I am still trying to figure out my vent fan. I want so badly to be able to torch and be safe.


Thanks,
Deb in MN