This is quite a long delay for a switched fan, especially a fan serving a single hood. Maybe there is a programmed delay set up with an electronic controller? All the switched fans we have turn on immediately. And, spray booths usually have a differential pressure gauge or sensor of some kind that warns users when the filters are loaded. Users should confirm differential pressure is within tolerance before using, much like they would confirm face velocity is acceptable before using a fume hood. For our switched hoods, there is usually a short delay that causes the face velocity alarm to alarm until the setpoint is reached, but it only takes a few seconds typically. I hope this helps.

Andy Glode

-----Original Message-----
From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU] On Behalf Of Stuart, Ralph
Sent: Wednesday, November 09, 2016 3:57 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: [DCHAS-L] Exhaust fan design question

I have a exhaust fan design question that someone in this group may be able to comment on. We have a spray paint booth in our wood shop (2014-vintage) with a lab style fan (Vektor-H Laboratory Exhaust System - Greenheck Fan) on it. It is turned on and off as needed with a off/low/high switch, but when we turn it on, there is no apparent response for about 5 minutes. This makes it difficult to convince the booth users that the system is working, since they may complete their work in the booth (e.g. spray painting a piece) before the system is fully operational.

I realize that most lab fan systems are on 24/7, but I wonder if anyone has run into similar situations with systems which are designed to be turned on and off routinely?

Thanks for any thoughts about this.

- Ralph

Ralph Stuart, CIH, CCHO
Chemical Hygiene Officer
Keene State College

ralph.stuart**At_Symbol_Here**keene.edu

---
This e-mail is from DCHAS-L, the e-mail list of the ACS Division of Chemical Health and Safety.
For more information about the list, contact the Divisional secretary at secretary**At_Symbol_Here**dchas.org

---
This e-mail is from DCHAS-L, the e-mail list of the ACS Division of Chemical Health and Safety.
For more information about the list, contact the Divisional secretary at secretary**At_Symbol_Here**dchas.org

Previous post   |  Top of Page   |   Next post