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Fume Hoods

Fume hoods are the most common engineering control found in labs that protect the user from hazardous materials.  The fume hood pull air from the lab, pulls it into the fume hood towards the baffles in the back of the hood, and exits the building through the exhaust system.  There is also a protective sash that slides vertically, horizontally, and in some cases, both vertically and horizontally to minimize skin exposure to hazardous materials.

Fume hoods are certified on an annual basis by EH&S.We use an anemometer to determine the average exhaust air flow rate by taking nine measurements across the opening of the fume hood and verify the direction of air flow by dragging a tissue across the opening of the hood.

If the fume hood has not been certified within the last year, contact to setup an appointment

-The green tape acts as a certification tag and maximum height/length at which the fume hood sash may be opened
    -Check the dates on the green tape to make sure the fume hood has been certified within the last year
-The fume hood average exhaust air flow rate will be no less than 100fpm, with no measurement point being less than 70fpm or greater than 160fpm
    -When a fume hood does not pass certification, a yellow caution tag will be affixed to the sash and directions on what needs to be done prior to Facilities repairing the fume hood
-Newly installed fume hoods will need to undergo the ASHRAE-110 test by a vendor
    -EH&S will conduct the smoke test (one-time test) and certification process for the fume hood

Fume hood alarms are installed on every fume hood and maintained by Facilities.There is a small hole/vent on the face of the alarm that senses the air flow passing through the alarm itself.When the alarm sounds, it’s indicating the fume hood has insufficient exhaust air flow and should not be used.

-When a fume hood alarm sounds, stop work, close the fume hood sash, and place a Trouble Call with Facilities 310-825-9236
    -Don’t ignore/mute the alarm!
    -The fume hood alarm sounding off could also be due to it needing to be recalibrated as well
-Check to make sure the alarm is functioning prior using the fume hood
    -Cover the hole on the alarm and it should sound within 5-10sec

If the alarm does not sound after 20-30sec, place a Trouble Call with Facilities 310-825-9236

Here are general rules to follow when using a fume hood

-Prior to starting work in the fume hood, check to make sure the fume hood has been certified in the last year and the fume hood alarm is operational
-Work with the fume hood sash in the lowest practical position
    -Even though the sash may be opened to the height/length of the green tape, the sash does act as a physical barrier in the event of an accident
    -For fume hood sashes that open both horizontally and vertically, use the horizontal opening for loading/unloading items and the vertical opening for working in the hood
-Always keep hazardous materials at least 6 inches behind the plane of the sash
    -If the hazardous materials are too close to the opening of the hood, the air turbulence may push hazardous vapors back towards the user
-Never put your head inside the fume hood
    -The plane of the fume hood sash is a separation between contaminated and uncontaminated air
-Refrain from using the fume hood as a storage area
    -Storing items inside the fume hood may block air from being pulled through the baffles and drops the effectiveness of the fume hood exhaust system