Debbie, and others,

This makes (some) sense to me; I understand that nanoparticles that are not in some matrix are prone to easy dispersal. What puzzles me is: if these tiny particles can "blow around" easily, surely they don't "blow around" more easily than some gas (NO2, H2S, etc) - do they? Could they? Seems to me that tiny molecules and tiny nanoparticles would behave about the same in this regard. Thus, if a "high" flow rate of 100 fpm is inappropriate for nanoparticles due to "excess turbulence" (I'd guess) then why would this not also apply to "regular" gases?

If we empirically KNOW that the lower flow rate for nanoparticles is appropriate then this a good guideline, of course. It just doesn't make intuitive sense to me.

Dave

David C. Finster
Professor, Department of Chemistry
University Chemical Hygiene Officer
Wittenberg University
937-327-6441
https://urldefense.proofpoint.com/v2/url?u=http-3A__userpages.wittenberg.edu_dfinster_index.html&d=BQIFAg&c=lb62iw4YL4RFalcE2hQUQealT9-RXrryqt9KZX2qu2s&r=meWM1Buqv4IQ27AlK1OJRjcQl09S1Zta6YXKalY_Io0&m=6BYvX8ZkifTQ2lIzlAHkyM7YZJ3y5_uVk44suyTlm84&s=SuVStqlUpFPjKAEmAumtf8elM-UbrmIDAeSkVmUyhcA&e=

-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Debbie M. Decker
Sent: Tuesday, August 04, 2015 11:51 AM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: Re: [DCHAS-L] Fume Hoods

If they're working with unbound (neither on a matrix nor in solution) engineered nanomaterials, lots of air flow can blow the nanoparticles around and create an exposure situation. Because nanoparticles are so small, their properties, loose in the air, are atypical and once airborne, are difficult to capture again.

AirClean, Labconco, and most of the other fume hood manufacturers market nanoparticle containment devices, that have HEPA filters and recirculate filtered air back into the lab. Typical of Labconco, their offering seems to be particularly well-engineered.

And now, I'm going to be quiet because that's about the extent of my expertise on this topic!

HTH,
Debbie

-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of David C. Finster
Sent: Tuesday, August 04, 2015 6:51 AM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: Re: [DCHAS-L] Fume Hoods

Can someone offer an explanation for the lower-than-usual flow recommendation when using nanomaterials?

Thanks.

Dave

David C. Finster
Professor, Department of Chemistry
University Chemical Hygiene Officer
Wittenberg University
937-327-6441
https://urldefense.proofpoint.com/v2/url?u=http-3A__userpages.wittenberg.edu_dfinster_index.html&d=BQIFAg&c=lb62iw4YL4RFalcE2hQUQealT9-RXrryqt9KZX2qu2s&r=meWM1Buqv4IQ27AlK1OJRjcQl09S1Zta6YXKalY_Io0&m=y90GGN5CEc9Pr_2WVgV7Iw-4FSDM50IlraVESOYSr60&s=5-AUlno8fmWnamzuNqB5ofnjkIestbMYnkN01g_Nb-U&e=

-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Ray Ryan
Sent: Monday, August 03, 2015 10:38 AM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: Re: [DCHAS-L] Fume Hoods

Luis is correct, low flow down as low as 50LFPM would be best working with nano-materials.

Best regards,

Raymond Ryan, CEO
Flow Sciences, Inc
2025 Mercantile Drive
Leland, NC 28451
910-200-4239
rryan**At_Symbol_Here**flowsciences.com
www.flowsciences.com

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-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**med.cornell.edu] On Behalf Of Luis A Samaniego
Sent: Monday, August 03, 2015 9:22 AM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: Re: [DCHAS-L] Fume Hoods

For nanomaterial work, it may require a lower fpm than the 80-100 fpm. Check with the fume hood manufacturer for proper face velocity if this is the case.

Luis Samaniego
Sr Laboratory Safety Specialist
Northwestern University
Office for Research Safety
303 East Chicago Avenue
Ward B-106, W223
Chicago, IL 60611
(312)503-8300

-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**med.cornell.edu] On Behalf Of Czerwinski, Kevin
Sent: Saturday, August 01, 2015 7:33 AM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: Re: [DCHAS-L] Fume Hoods

Also depends on jurisdiction. State facility in a non-OSHA state? For example, state law in Wisconsin is 100 fpm.

Dr. Kevin M. Czerwinski, Ph.D.
Professor
Department of Chemistry

University Chemical Hygiene Officer
Environmental Health and Safety

B150 Science Building
University of Wisconsin-Stevens Point
2001 Fourth Avenue
Stevens Point, WI 54481

715-346-4154 (Office)
715-340-2216 (Mobile)

> On Aug 1, 2015, at 7:20 AM, Ellen M. Sweet wrote:
>
> Kevin,
> The 80-120 fpm range, from the ANSI Z9.5, is based on performance (containment). The standard also states that some hoods will perform at lower face velocities. Your organization needs to decide what face velocity you want your hoods at, unless you're in California.
> 100 fpm is typical.
>
> Ellen
>
> -----Original Message-----
> From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Kevin Burns
> Sent: Friday, July 31, 2015 10:17 AM
> To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
> Subject: [DCHAS-L] Fume Hoods
>
> I am currently finding myself in trying to deal with a fume hood problem. We had a mechanical problem that needed to be repaired causing The system to be shut down. Now that the system can be turned back on we need to have an air balancer come in and rebalance the system. After that my certification company would come in to certify that the hoods are maintaining proper CFMs for employees to work in them within the laboratories. The air balancer is in disagreement with the certification vendor. The air balancer says we have to have a policy that our face velocities for each hood must be 100cfm, where the certifiers are indicating that it's between 80 and 120 which that was what my understanding was.
>
> I know this falls under ASHRAE standards, ANSI standards and OSHA standards, can you point me in the right direction of where to get the exact information?
>
> Thank you, any information would greatly be appreciated.
>
> KB
>
> Kevin Burns
> Sent from my iPhone

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