Would you provide the brand/part number/specifications of the sensors that you are using? I am very interested in their use for our applications.
Those questions have to be asked for every renovation where they are being considered.
There are only a handful of chemicals where they are not appropriate, Carbon Monoxide being one of them. They have tested thousands of chemicals for loading and pass through. Everyone involved in the development of experiments has a list of the chemicals that can not be used and the loading factors for those that can.
In our instance, we are relying upon the sensors. Our experiments could be run on an open lab bench because our labs have 12 - 16 air exchanges per hour and we are not using overly toxic etc compounds. There are two different sensors. I do not have in front of me the specifications of the sensors. I was very impressed - they monitor the lab air in addition to the filters. Someone was using a little solvent in the lab and the one hood that was running at the time went into alarm notifying us that the lab air was contaminated. One sensor has to be replaced about every two years, the other sensor lasts longer - I believe it is a solid state sensor. The system monitors the sensors. Calibration is not necessary. Any breakthrough of the first set of filters is considered a failure. It is not set up to allow certain concentrations to pass through. These are not meant to measure concentrations and display them like many sensor controls do. The cross reactivity etc issues that you raise are really not an issue - the sensors are in an extremely clean environment, cleaner than the outside air. The lab actually has cleaner air than outside air - the filters are constantly "polishing" the air.
We have tried small snorkel type of setups before and they were terrible at capturing vapors from the setups the students need to use.
The Green Hoods are not suitable for every application. In a synthetic research lab, it would be rare that I would say these hoods should be used as the major hood. Our researchers are too likely to use things such as carbon monoxide. There are specific instances where I would allow them to be used in addition to regular hoods but only with very specific signage, training, and monitoring.
On Oct 11, 2012, at 7:05 PM, Bruce Van Scoy wrote:
I’m curious, what controls will be implemented to ensure:
1. Only chemicals that are adequately removed will be used?
2. Considering the lack of PEL’s or other OEL’s, how is “adequately” from the first question being determined?
3. What review process is in place to ensure that future experiments or ductless fume hood use will use only those chemicals that the ductless fume hood can adequately remove to maintain compliance?
4. Is the total filter load being tracked or are you simply relying upon the sensors sensitivity to measure at breakthrough?
5. Specifically what type of sensors are being used?
6. Do the sensors degrade over time, like a reduction-oxidation sensor?
7. What calibration frequency is being established for the sensors?
8. Are the sensors capable of detecting ALL of the chemicals that are going to be used in the ductless fume hood?
9. Does the sensor have any sensitivity or cross reactivity to all of the chemicals which could possibly be used?
I think in limited scope/application these fume hoods have a valid purpose and can provide for an adequate safety margin.
But, science is about learning and incorporating change. Will the future use be within the scope of design or are you severely limiting the future science operations being performed? Please don’t get me wrong, I love ERLAB’s Toxicap Fume Hood for where I am having it used. I had to replace the filters due to age, with 1/10th of the total filter loading potential. If you don’t need the performance of a totally enclosing fume-hood, have you considered snorkel point-source exhaust? Point source exhausts are also lower total volume (saving energy), but what they do exhaust is the most concentrated contaminant load?
I’ve been following the thread and had a few questions. What experiences has everyone else encountered? I don’t want to rule out or limit the options.
Ken, It all depends on how much solvent, acid, or whatever is getting airborne. In art, we just plain use too much for them to work for long. Try pouring a solvent on a rag and wiping an etching plate clean, doing open pan photo processes, or using a spray can. The bells will go off like a Cathedral.
It sounds like your people are working under that hood with Q-tip amounts or milking mice.
In a message dated 10/11/2012 1:49:06 AM Eastern Daylight Time, simolo**At_Symbol_Here**CHEM.CHEM.ROCHESTER..EDU writes:
It is the University of Rochester. And the technology really is different. No one was more adamant than we would not use ductless hoods than I was. (Just ask the salesman who first approached me concerning these hoods - he thought he was going to be shot for wasting our time). I truly understand the resistance to their use. But when I learned about these, I realized we finally had a viable option to be environmentally friendly and safe. As safety professionals, it really is worth learning about what is available out there. You do have to take a careful look at how they will be used. You also need to be careful how you design your lab and your research in order to maximize filter life and maintain safety. For new installations, they pay for themselves the day they are put in. If you already have ductwork and controls in place, then the payback is more like 2 - 3 years.
We are very happy with how our lab turned out and also with these Green hoods. Here's a link to some pictures etc. http://www.chem.rochester.edu/highlights/fall11.php
Anyone that wants to come and look at our new lab is welcome to contact me and arrange a visit. Feel free to contact me if you just want to talk about the hoods. I am a strong believer in letting people know about a good solution to problems we all face.
On Oct 10, 2012, at 7:30 AM, JAKSAFETY**At_Symbol_Here**AOL.COM wrote:
In addition to Rochester Institute of Technology, Butler University installed Green Fume Hoods in their Organic Labs. My understanding from Jo Wagner, lab manager, is that they are delighted with how they worked this past academic year. Ask Jo.
Green Fume Hood from Erlab (www.erlab.com) offer a wonderful cost saving alternative. The time has come to reconsider filtered fume hood. ... Jim Kaufman
In a message dated 10/10/2012 12:26:19 A.M. Eastern Daylight Time, LISTSERV**At_Symbol_Here**listserv.med.cornell.edu writes:
Date: Mon, 8 Oct 2012 23:35:08 -0400
From: Ken Simolo <simolo**At_Symbol_Here**CHEM.CHEM.ROCHESTER..EDU>
Subject: Re: Advice on our new science building
We did not find a ductless fume hood suitable for use in our undergraduate labs until the Green Hoods came along. These hoods take filtered fume hoods to a whole new level.
They have measured the absorption capacities of thousands of chemicals and published their results. Methylene Chloride is one of the lesser trapped chemicals in the Green Hood. After 672 g have been absorbed by the filters in a 6' hood, methylene chloride will pass through the first set of filters and set off the chemical alarm. If you violate protocols and continue to use the hood, after an additional 672 g of methylene chloride have been absorbed by the second set of filters, you will get exposure in the lab. But 672 g of methylene chloride is a lot of filter exposure for an undergraduate hood, no less twice that amount. After 2 1/2 semesters of undergraduate organic lab use, we have yet to have any chemicals breakthrough the first set of filters. One has to be very careful where you use these hoods and how you design the lab but they definitely have many appropriate uses.
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