Let's Talk About Lab Ventilation

[snowmonster]

Let's have an open discussion about lab ventilation...

I know this has been discussed before, but not at length and not with numbers. It has been well documented that tint tanks are a potential health hazard when heated (unless you use Chris Ryser's stuff), but there has to be some health issues from lens debris (wet or dry) as well as all the other fun chemicals and smells that exist in the lab.

So we're building a new office space and can put our lab in one of two rooms, either about 90 square feet or 130 square feet. I'm thinking I'll be adding an exhaust fan that vents outside to prevent two things. The first and less important is to keep the "$mell of money" (as I've dubbed it, the sulfur smell from hi index lenses) and to reduce potential health hazards to the staff.

I found a website which actually gives a formula for house ventilation/exhaust fans:

Required Cubic Feet/Minute = (Area of Room) X 2

The multiplier was 1.1 for bathrooms and 0.8 for other rooms in the house, FYI. The site stated that for a kitchen, that would yield 15 air changes per hour (from now on, referred to as AC/H). That would mean that the air would be changed every 4 minutes. In my situation, I would need somewhere between 180 and 260 CFM for whichever room my lab goes into.

So here's the question - do you think that's adequate? Or should I go with something even stronger? My goal is not really to create a room with it's own weather system with 10,000 CFM. Do you think that a room with air changes every 4 minutes would be good enough even if I didn't put a hood in and just put the fan opening directly over the tank? What if it was changed every 2 minutes?

Please - Give me your opinions!

-Steve

[QDO1]

Let's have an open discussion about lab ventilation...

I know this has been discussed before, but not at length and not with numbers. It has been well documented that tint tanks are a potential health hazard when heated (unless you use Chris Ryser's stuff), but there has to be some health issues from lens debris (wet or dry) as well as all the other fun chemicals and smells that exist in the lab.

So we're building a new office space and can put our lab in one of two rooms, either about 90 square feet or 130 square feet. I'm thinking I'll be adding an exhaust fan that vents outside to prevent two things. The first and less important is to keep the "$mell of money" (as I've dubbed it, the sulfur smell from hi index lenses) and to reduce potential health hazards to the staff.

I found a website which actually gives a formula for house ventilation/exhaust fans:

Required Cubic Feet/Minute = (Area of Room) X 2

The multiplier was 1.1 for bathrooms and 0.8 for other rooms in the house, FYI. The site stated that for a kitchen, that would yield 15 air changes per hour (from now on, referred to as AC/H). That would mean that the air would be changed every 4 minutes. In my situation, I would need somewhere between 180 and 260 CFM for whichever room my lab goes into.

So here's the question - do you think that's adequate? Or should I go with something even stronger? My goal is not really to create a room with it's own weather system with 10,000 CFM. Do you think that a room with air changes every 4 minutes would be good enough even if I didn't put a hood in and just put the fan opening directly over the tank? What if it was changed every 2 minutes?

Please - Give me your opinions!

-Steve

where the ventilation is is important. having the extractor vent in the opisite corner to the problem just drags the problem fumes accros the lab for the staff to inhale. lab temperature is very important too, I would reccomend you fit aircon and heating etc

The best lab from health point of view I worked in had very similar extractors that you find over industrial cookers - huge - wall to wall - over the machines and tint bath.

The next thing you can do is ensure that lens debris isnt sread around the lab in the wet form, because it dries out, and then the dust is breathed in

A supply of disposable gloves and nose/face masks is always a nice touch - especially when staff are servicing equipement, or emptying tint baths

[Chris Ryser]

Do you think that a room with air changes every 4 minutes would be good enough even if I didn't put a hood in and just put the fan opening directly over the tank? What if it was changed every 2 minutes?

Please - Give me your opinions!
-Steve

A total change of air in 4 or 2 minutes minutes will still leave you diluted fumes in areas which emit these fumes and which fumes continously or periodically. If you want a central air system have some hoods right over the fume emitting areas whith tubes or hoses going to a turbine fan which will then vent the fumes outside. (similar to a central vacuum cleaner).

You should actually remove fumes right over their point of origin.

[QDO1]

have some hoods right over the fume emitting areas

You should actually remove fumes right over their point of origin.

that is the key

[snowmonster]

You guys are quick. :)

I think it's obvious that a hood is the way to go at least over the tint tanks. I think what I'll do is put a hood over the tank but have two vent inlets at opposite corners of the room, connected to a "Y" with an in-line exhaust fan going up to the roof and outside. This also still allows me to put a hood over the tint tank.

What are your feelings about air changes/hour? Is 15 enough (every 4 minutes) or should I go with something stronger? Obviously, anything more frequent is better but the law of diminishing returns has to apply at some point.

I guess what prompted me to ask such questions was that everyone kept posting about the need for "proper ventillation" but never actually referred to any documented numbers in CFM's or AC/M, etc.

Thanks again!

-Steve

[QDO1]

You guys are quick. :)

I think it's obvious that a hood is the way to go at least over the tint tanks. I think what I'll do is put a hood over the tank but have two vent inlets at opposite corners of the room, connected to a "Y" with an in-line exhaust fan going up to the roof and outside. This also still allows me to put a hood over the tint tank.

What are your feelings about air changes/hour? Is 15 enough (every 4 minutes) or should I go with something stronger? Obviously, anything more frequent is better but the law of diminishing returns has to apply at some point.

I guess what prompted me to ask such questions was that everyone kept posting about the need for "proper ventillation" but never actually referred to any documented numbers in CFM's or AC/M, etc.

Thanks again!

-Steve

I would imagine there is a local industrial standard for such things

[Chris Ryser]

You guys are quick. :)

What are your feelings about air changes/hour? Is 15 enough (every 4 minutes) or should I go with something stronger? Obviously, anything more frequent is better but the law of diminishing returns has to apply at some point.
-Steve

I might have found you an answer: on the web

There are NO industry standards that dictate air change rates, ACPH is a dependent variable. The cleanroom contractor selected should have experience in the design and commissioning of these rooms such that the average velocity and room architectural configuration will lead to the desired level of particle control, in the state (e.g., as-built, at-rest, or operational) as defined by the cleanroom design/construction contract.
ACPH = (Avg. room velocity x 60)/(room height), Room CFM = (ACPH x Room volume)/60

go on....................http://www.servicor.com/calculator.html

[Ed_Optician]

All exhaust fans hoods etc should go from the source of the odor directly outside. Fresh air intake can be through the waiting area dispensing area etc and flow into the lab space and be vented out from the lab. By doing this the airflow is such that no unpleasant /harmful odors etc pass through the customer/patient spaces.
If you use a dry cutting edger like an optronics use a finer filter on the shop vac possibly even a HEPA filter as are offered for some shop vacs. Use freshwater plumbing for edgers so as to prevent lens contamination from recirculating buckets. Filter wastewater properly using a disposable filter to trap lens swarf aka OPTI-SCHMUTZ. Replace filters regularly...minimum handling of lens dust/goo makes life easier and healthier for all of us in the field.
Paper masks are a joke almost as good as nothing. Good dust masks are inexpensive replace the filter element regularly. Painter's respirators may help with the vapors from dye units etc.

Ed

Ed

[fjpod]

I'm no expert on ventilation, but turning over the air in the entire room every 4 minutes seems excessive to me. I'm sure it's going to affect you heating/cooling costs.

We really have no dust problems from our edger. Ever since we traded in our tint tanks (with smelly HTF) for "hot pot" tinting, our smell problem isn't 10% of what it used to be. We keep our tint pots right under a window where we have an exhaust fan. The staff is required to keep it on, but only when they are tinting. Microwave tinting would also solve the smell problem.

[Chris Ryser]

Use freshwater plumbing for edgers so as to prevent lens contamination from recirculating buckets. Filter wastewater properly using a disposable filter to trap lens swarf aka OPTI-SCHMUTZ.
............. Painter's respirators may help with the vapors from dye units etc.
Ed

I am not so sure that you should use fresh water plumbig for edging disposal if you mean that you dump it in the sewer. There are some waste separaters sold for edgers by several companies.

You could also dispose of respirators by using oure waterbased dyes and neutralizers that do not emit fumes in your dye pot or you could use Micro Tints that are also safe.

[Aarlan]

A real optician loves the smell of the Tint tank in the morning. A good whiff of the heated neutralizer is better than cofffee on those mornings you just can't get going.


AA

[LKahn]

I'm no expert on ventilation, but turning over the air in the entire room every 4 minutes seems excessive to me. I'm sure it's going to affect you heating/cooling costs.

We really have no dust problems from our edger. Ever since we traded in our tint tanks (with smelly HTF) for "hot pot" tinting, our smell problem isn't 10% of what it used to be. We keep our tint pots right under a window where we have an exhaust fan. The staff is required to keep it on, but only when they are tinting. Microwave tinting would also solve the smell problem.

Good ventilation in a lab is critical. The amount of air and the frequency it needs to be changed is a function of several factors such as room size, the nature of the chemicals being used. I suggest that you review the current OSHA standards with a safety engineer. This is a realtively simple and inexpensive process.

As a manufacturer of tints, coatings and chemicals used in the optical industry we promote the safe use, handling and storage of optical chemicals. Additionally, our products are among the safest in the industry. Our HTF is a food grade chemical with an anti-foaming agent and anti-corrosive agent which lasts longer and is extremely safe. You should also review the MSDS for proper handling of your chemicals.

Larry Kahn
Sun National, LLC
www.opticalchemicals.com
lkahn@opticalchemicals.com