Laboratory Safety Manual



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Laboratory Safety Manual

Table of Contents

Lab Safety at Princeton

Chemical Hygiene Plans

Emergency Procedures

Hazard Identification

Health Hazards of Chemicals

Controlling Exposures

-Lab Ventilation

-Protective Equipment

-Pyrophorics

Chemical-Specific Issues

Anecdotes

Ergonomics

Particularly Hazardous Substances

High Acute Toxicity

Lab Design Considerations

Lab Safety Management

STANDARD OPERATING CONFIGURATION

The Standard Operating Configuration (SOC) is the position at which the hood sash should be placed when the hood is actually in use as a containment device. Making such an assumption is unavoidable when designing a fume hood exhaust system since determines the quantity of air the system must exhaust if an adequate face velocity is to be maintained.

In order to obtain the recommended 100 fpm face velocity, many fume hoods have an SOC which is less than a fully open sash. If a hood user does not use the hood with the sash at the SOC position, it is possible for that user to create a situation in which an otherwise properly operating hood has an insufficient face velocity.

Each chemical fume hood at the University has an assigned Standard Operating Configuration. A schematic drawing of this configuration is posted on the hood face. Examples of the posted schematics are shown below. Listed below are brief descriptions and the SOC’s of several styles of fume hoods commonly found at the University. Questions about the SOC of a specific hood may be addressed to the Office of Environmental Health and Safety.

1. Vertical Sash - a single vertical rising sash with a maximum face opening about 30 inches high. This style is sometimes modified as a distillation hood, in which case the maximum face opening is greater. The SOC is a fully open sash, unless the hood is alarm equipped. Then the SOC is the point just before the alarm is engaged.

SOC for Vertical and Double Vertical Sash (numbers are measuring points)

2. Double-Vertical Sash - two vertical rising sashes side-by-side. The SOC is generally both sashes fully open. A few older installations may have an SOC of one sash closed and the other fully open.

3. Horizontal Sash - two or more horizontal sliding sashes. The height of the face opening is approximately 30 inches and the maximum opening width is 1/3 to ½ of the width of the hood. This style hood is rarely equipped with an air by-pass. It is sometimes modified as a chromatography hood, in which case the height of the face opening is greater. The SOC is the largest opening that can be obtained without removing any sashes from their tracks.

SOC for Horizontal Sash (numbers are measurement points) 4 . Combination Sash - a vertical rising sash in which two or more horizontal sliding panels are mounted. The SOC is a fully raised sash with horizontal panels fully closed, unless the hood is alarm equipped. Then the SOC is fully closed horizontal panels with the vertical sash raised to just below the point at which the alarm is engaged. A few old installations have an SOC of vertical sash down, horizontal panels open as much as possible without removing them.

5. Walk-In Hood - a maximum face opening six feet or more high and extends to floor level. At Princeton, this style is usually equipped with two vertical rising sashes mounted in parallel tracks and each capable of closing half the face opening. The SOC is one half of the face open.

6. California Hood - a free standing bench top enclosed on all sides by transparent material for a height of four feet or more above the bench, and ventilated. Horizontal sliding doors provide access from two opposite sides. The SOC is all doors closed.

7. Triple-Vertical Sash - three adjacent vertical-rising sashes, the center one of which is 18" wide, in an otherwise standard vertical sash hood. The SOC is center sash down and sashes on both sides fully raised.

SOC for Triple Vertical Sash (numbers are measurements points)

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