Basic Documentation

Table Of Contents
Fume Hoods
Siemens Industry, Inc. 21
Topic Requirement(s) Commentary
When
Required &
Safe Usage
(Continued)
American Conference of Governmental Industrial Hygienists (ACGIH)
INDUSTRIAL VENTILATION A Manual of Recommended Practice, 27th Edition
VS-35-04 (WORK PRACTICES FOR LABORATORY HOODS)
1. Conduct all operations that may generate air contaminants at or above the
appropriate TLV
®
inside a hood.
2
2. Keep all apparatus at least 6 inches back from the face of the hood. A stripe on
the bench surface is a good reminder.
3. Do not put your head in the hood when contaminants are being generated.
4. Do not use the hood as a waste disposal mechanism except for very small
quantities of volatile material.
5. Do not store chemicals or apparatus in the hood. Store hazardous chemicals in
an approved safety cabinet.
6. Keep the hood sash closed as much as possible.
7. Keep the slots in the hood baffle free of obstruction by apparatus or containers.
8. Minimize foot traffic past the face of the hood
9. Keep laboratory doors closed.
10. Do not remove hood sash or panels except when necessary for apparatus set-
up; replace sash or panels before operating.
11. Do not place electrical receptacles or other spark sources inside the hood when
flammable liquids or gasses are present. No permanent electrical receptacles
are permitted in the hood.
12. Use an appropriate barricade if there is a chance of an explosion or eruption.
13. Provide adequate maintenance for the hood exhaust system and the building
supply system. Use static pressure gauge on the hood throat, across any filters
in the exhaust system, or other appropriate indicators to ensure flow is
appropriate.
14. If hood sash is supposed to be partially closed for the operation, the hood
should so be labeled and the appropriate closure point clearly indicated.
Gloveboxes:
U.S. OSHA, 29 CFR, Part 1910, Occupational Safety and Health Standards,
Subpart Z, Toxic and Hazardous Substances,1910.1450,E1,E4(k),B4(b):
Inspect gloves and test glove boxes before use.
For a negative pressure glove box, ventilation rate must be at least 2 volume
changes/hour and pressure at least 0.5 inches of water. For a positive pressure glove
box, thoroughly check for leaks before each use. In either case, trap the exit gases or
filter them through a HEPA filter and then release them into the hood.
Exhaust air from glove boxes and isolation rooms should be passed through
scrubbers or other treatment before release into the regular exhaust system.
2
Threshold Limit Value. TLVs have been established by the ACGIH. They are intended as a guide to the allowable time-weighted concentration level of airborne toxic materials that
will not cause adverse health effects for the majority of workers who are exposed for 8 hour per day over extended periods. (See APPENDIX A of the American Conference of
Governmental Industrial Hygienists (ACGIH) INDUSTRIAL VENTILATION, A Manual of Recommended Practice, 27th Edition) for more information on TLVs and TLV values.