[labnetwork] Reading ventilation/exhaust

[Paolini, Steven]

Matthieu,
  These "test holes" are not uncommon and usually plugged with a rubber stopper. My question is why 3/8" when ¼" is sufficient to allow the anemometer probe through. If you can plan it up front, you can strategically place these test holes where a toxic gas sniffer will reside and simply pull the tube when it's certification time. There are a lot of different tricky pass through fittings on the market which fasten via a couple of "zip" screws and have a push on or feed through fitting for the tube.  I would emphasize that if the exhaust duct is for a gas cabinet or VMB, the toxic gas detection point should be in the furthest point upstream. By placing it there, you will avoid tripping the alarms when using the venturi for cylinder changes or any other activities that may result in a controlled release within the cabinet. I will respectfully refrain from explaining how I know this :).  Of course the venturi exhaust should be located at least 16" downstream of the detection. Again, this is a standard procedure and necessary for balancing the exhaust.

Steve Paolini
Equipment Dood
Harvard University Center for Nanoscale systems.

From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Matthieu Nannini, Dr.
Sent: Wednesday, December 17, 2014 1:49 PM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Reading ventilation/exhaust

Colleagues,

First, thank you for the handful of information about bending coax tubing.

Now, facilities services here at McGill want to assess our ventilation/exhaust capacity. To measure exhaust they want to drill 3/8'' holes into each duct leading to a tool, take a reading and plug it back. They show me the plugs they want to use and I'm not convinced at all especially for the gas cabinet exhaust. They don't want to un-connect the tool and measure directly as they want to make its resistance is taken into account.

Any body has experience regarding that matter ?

Thanks in advance

Matthieu

-----------------------------------
Matthieu Nannini
McGill Nanotools Microfab
Manager
t: 514 398 3310
c: 514 758 3311
f: 514 398 8434
http://mnm.physics.mcgill.ca/<https://urldefense.proofpoint.com/v2/url?u=http-3A__mnm.physics.mcgill.ca_&d=AwMF-g&c=WO-RGvefibhHBZq3fL85hQ&r=-H4Z_jeDfTYjnKPXor15vLwzBllmg8gFrb9m_k9OGks&m=b167_gUuITIuRKaJ8_g4hU8M99PoLfjB0Pw7u8DAY5w&s=R5IpKUK3an5llZLMbh6aIGtpBk9cIrNyq8m7J5g7TEc&e=>
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