Questions re fume hood maintenance

[Chuck Cooper <cooperc@teleport.com>]

Mike:

We require that  whatever process/procedure that the hood serves be shut down
before the maintenance is performed (logical).
I think for hoods that serve chemical procedures the risk of getting injured from
a residual chemical exposure is close to zero.
Laboratory hoods spend most of their time just sucking clean expensive air out of
the lab, procedures that are actually emitting some
toxic chemical occur only sporadicaly in a research/teaching environment and they
are small scale. There are very few toxic vapors or gases that once diluted with
air at 2,400 CFM (typical for a 4 x 6 hood) can harm you or that "condense" out on
the interior of the system in any significant quantity.

Biological hoods are a bit different. All of ours contain HEPA filters at the top
of the hood itself so theoretically the rest of the system
beyond that is clean. We have a hood that is used for tuberculosis culture
manipulation, when we change the HEPA filter masks are
worn. TB does not live forever either so even if a bacterium "leaks" through it is
dead and gone with in a few hours at most. The
inside of the hood is fitted with UV sterilization lamps that are on when the hood
is not actually in use.


I understand the fear that maintenance personnel feel when working on equipment
that is designed to contain or remove "toxic"
materials, the best approach is to educate them on what they are dealing with-
realistically.

Chuck Cooper
Dir. EH&S
Portland State University

===============

Mike Histed wrote:



>
> We at the University of Ottawa are trying to establish guidelines for
> maintenance personnel working on the roof tops of lab buildings.  The
> current procedure requires them to wear full PPE, e.g., gloves,
> glasses and a forced air respirator, particularly while working on
> fume hood fans.  However, we are meeting with divergent opinions as
> to the appropriateness of wearing PPE.  Therefore I would like to get
> comments of the group with reagrds to the following questions:
>
> -       Do you require any staff to wear PPE whilst working on the roof
> tops of lab buildings, e.g., ventilation technicians, plumbers,
> electricians, contractors, everyone.
>
> -       If yes, what type of PPE, e.g., gloves, safety glasses, respirators
> (forced air, cartridge).  Do you provide training in the use of
> respirators.  Do you take the universal precaution approach or does
> the use of PPE vary according to building type and level of risk.
>
> -       If no, have you implemented administrative controls to minimize
> exposure, or have you conducted a risk assessment to determine there
> is little or no risk.
>
> -       Do you require staff to wear PPE whilst working on fume hood fans
> in mechanical rooms, whether the rooms are ventilated or not.
>
> -       Do you require staff entering a mechanical room to wear PPE in
> those rooms with fume hoods fans present.
>
> -       Do your staff use monitoring equipment, e.g., portable GCs to
> determine potential exposures to contaminants.
>
> -       Do your staff monitor the weather for conditions that may pose a
> greater risk to those working on roof tops, e.g., temperature
> inversions resulting in fume hood emissions not dispersing.
>
> -       Have any procedures been formalized in a document, guideline,
> policy or procedure.
>
> Thanks for your time.  If you feel this is an inappropriate forum for
> this type of discussion, please feel free to e-mail me directly at
> mhisted@uottawa.ca.
>
> Mike
>
> Michael Histed, PhD
> Environmental Management Specialist
> Environmental Health and Safety Service
> University of Ottawa
> 100 Thomas More
> Ottawa, Ontario
> K1N 6N5
>
> Tel: (613) 562-5800 Extension 3052
> Fax: (613) 562-5112
> E-Mail: mhisted@uottawa.ca
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