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Policies Part 30
Policies Part 30 Contents
GENERAL REQUIREMENTS
R30.8-1 RE: Laboratories - General Requirements - Fume Hoods (Ventilation Systems)
Policies Part 30 - General Requirements
Policy Item R30.8-1
RE: Laboratories - General Requirements - Fume Hoods (Ventilation Systems)
BACKGROUND
1. Explanatory Notes
Section 30.8 sets out the general requirements relating to fume hoods in laboratories.
2. The Regulation
Section 30.8:
(1) Controls for the operation of a fume hood and its services must be located outside the fume hood and must be immediately accessible to the laboratory worker, except that water taps may be located inside the cabinet if the main shutoff valve is in a safe location outside the cabinet.
(2) A fume hood must be connected to a local exhaust ventilation system which will provide minimum air velocities over the operational face area of the hood of
(a) an average of 0.5 m/s (100 fpm) but not less than 0.4 m/s (80 fpm) at any point across the face, and
(b) an average of 0.75 m/s (150 fpm) but not less than 0.65 m/s (125 fpm) at any point across the face if the fume hood is used for carcinogenic substances referred to under section 5.57(1) in Part 5 (Chemical and Biological Substances), or for radioactive materials.(3) A fume hood must be located to prevent cross drafts or other disruptive forces from lowering the air flow across the operational face to unacceptable levels.
(4) A fume hood and its ductwork must be constructed from materials compatible with its use.
(5) A fume hood must be clearly labelled with any restrictions on use that apply to it.
(6) A fume hood must not be used for storage of chemicals unless it is used exclusively for this purpose and is labelled with this limitation.
Section 30.9:
(1) Air velocities over the operational face area of a fume hood must be measured and recorded at least annually and after any repair or maintenance which could affect the air flows.
(2) Airflow in a fume hood used for very toxic or radioactive materials must be monitored continuously if there is risk to workers in the event of loss of airflow.
(3) A fume hood with an adjustable sash must be marked to identify the maximum height the sash may be set at and still maintain the required air flows
POLICY
Section 30.8(2) specifies fume hood exhaust ventilation rates in terms of air velocities measured over the operational face area of the hood. The operational face area is determined by the height of the sash and will vary with the work carried out in the fume hood.
The air velocity is the average of measurements made over 6 points at the operational face of the hood with the sash raised to its highest position. A calibrated anemometer must be used.
If the measured average velocity is less than specified in section 30.8(2), repeated measurements must be made with the sash lowered successively until the specified average air velocity is attained. The sash height where this is determined must be marked in accordance with section 30.9(3). The minimum sash height is 12 inches.
If the fume hood cannot be used at the height determined above, modification is required to improve the ventilation so the specified air velocities are maintained at the sash height required for the work performed in the fume hood.
Smoke tube tests must be done to determine whether conditions of air turbulence exist at the face of the hood. If conditions of severe turbulence exist so that air spills out past the hood face, the condition must be corrected.
It is desirable, but not mandatory, that fume hoods have a warning or alarm device which notifies the user of the fume hood of inadequate ventilation system performance.
When a sash height adjustment is necessary on a fume hood that is part of a manifolded system (several hoods serviced by a single exhaust fan), all fume hoods in the system must be rechecked at the completion of the adjustments to ensure face velocity compliance (this operation may have to be repeated several times before compliance is achieved).
PRACTICE
For any relevant PRACTICE information, readers should consult the Prevention Division's Guidelines available on the WCB website.
| EFFECTIVE DATE: | April 1, 2001 |
| AUTHORITY: | ss. 30.8 and 30.9, Occupational Health and Safety Regulation |
| CROSS REFERENCES: | |
| HISTORY: | This Item resulted from an editorial consolidation of prevention policies into the Prevention Manual, which was effective on October 1, 2000. The Policy in this Item continued the substantive requirements that existed before the consolidation, with any wording changes necessary to reflect legislative and other changes that have occurred. Policy No. 76.05 in the former Prevention Division Policy and Procedure Manual was replaced by this Item. A housekeeping change was made on December 14, 2001. A cross-reference correction was made on March 30, 2004 to reflect regulatory amendments relating to occupational exposure limits, effective October 29, 2003. |
| APPLICATION: | The application of this policy remains unchanged from its previous authority under Policy No. 76.05 of the former Prevention Division Policy and Procedure Manual. |
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