19.0 Ventilation
19.1 General Guidelines
19.1.1 General laboratory ventilation shall provide airflow into the laboratory from non-laboratory areas and out to the exterior of the building (lab under negative pressure ) through fumehoods or dedicated exhaust.
19.1.2 All laboratory doors must remain closed, except when being used for entrance and egress.
19.1.3 Local exhaust ventilation must not be located near doors, windows, air diffusers, fans and other sources of cross drafts.
19.1.4 All reactions that produce unpleasant and/or potentially hazardous fumes, vapors, or gases must be run with local exhaust ventilation, i.e. in fume hoods.
19.1.5 Reactions with corrosive vapors should be conducted in a hood lined with corrosion resistant material.
19.1.6 The sash of the hood is to be lowered to within 6" of the floor of the hood when the hood is in use. It should be lowered to maintain effectiveness of the ventilation system and to provide personnel protection.
19.1.7 Installation of local exhaust ventilation must be in accordance with local air emission regulations and Ohio University Facilities Management requirements. Technical assistance is available from EHS.
19.1.8 No devices or ducts are to be self-installed into existing exhaust or HVAC systems without the approval of appropriate OHIO University departments (EHS, University Planning and Implmentation, and Facilities Management).
19.1.9 Do not install unsafe devices in hoods, such as extension cords of electric switches that are not "explosion proof" by design.
19.1.10 Perchloric acid requires the use of a specialized hood, which is able to wash the ductwork and internal hood surfaces down. Contact EHS for assistance.
19.2 Maintenance and Inspections
Daily Inspections by Lab Personnel
19.2.1 Visually inspect the hood area for storage and other visible blockages.
19.2.2 Observe the pressure reading on the magnehelic pressure gauge (or other pressure or flow device).
19.2.3 Safe operating pressures should be provided by the ventilation engineer that designed/installed the system.
19.2.4 Do not disable alarms of otherwise circumvent safety devices.
Periodic inspections (are the responsibility of the EHS Dept.) shall include:
19.2.5 The quality and quantity of ventilation shall be evaluated upon installation, periodically, and whenever a change in local ventilation devices is made. Inspections should be recorded.
19.2.6 Capture velocity should be measured with a velocity meter. The capture velocity at the face of the hood should be 100 - 125 fpm (unless newer system hoods, with different flow parameters are in use). Face velocity measurements must be taken in accordance with SEFA 1- 2002 Laboratory Fume Hoods Recommended Practices.
19.2.7 Exhaust hoods should be smoke tested for fume containment per SEFA 1-2002 Laboratory Fume Hoods Recommended Practices.
19.2.8 Hoods and their alarms should be checked for proper function.
19.2.9 The tests listed above will be conducted annually by EHS or a contractor.
19.2.10 Repairs are called in on work order to Facilities Management, with re- testing after repairs or adjustments are made.
19.3 Annual Maintenance
(is the responsibility of Facilities Management and shall include):
19.3.1 Overall maintenance of the local exhaust ventilation.
19.3.2 Exhaust fan maintenance. The necessary maintenance (lubrication, belt checking, fan blade deterioration, and speed check) should be recommended by the fan manufacturer.
19.3.3 Ductwork. All ductwork should be checked for corrosion, deterioration, and buildup of liquid or solid condensate. Dampers should be lubricated and checked for proper operation.
19.3.4 Air cleaning equipment. In line exhaust charcoal or HEPA filters should be monitored for contaminant buildup by the PI or department CHO. Mechanical or absorbent filters not equipped with differential pressure gauges, or audible alarms, should be leak checked. Contact EHS for contamination monitoring prior to any servicing by Facilities Management or others.
19.4 Ventilation Failure
19.4.1 Employees should be trained in the following procedures to follow when hood failure occurs, for example:
19.4.1.1 Close down or postpone the experiment if possible.
19.4.1.2 Notify the PI.
19.4.1.3 Notify EHS.
19.4.1.4 Notify Facilities Management to check and repair hood.