Science laboratory safety is a major issue for schools who unexpectedly find that their science labs are hazardous and can no longer be used without expensive repairs. This paper explores how to prevent such an occurrence, how to deal with such an occurrence, and how to manage labs safely without breaking your budget.

LABORATORY MANAGEMENT

Effective laboratory management depends on understanding the materials and processes being used. If you or your staff can’t figure out whether a chemical or process is hazardous you shouldn’t be using the chemical or process. It takes a certain level of expertise to teach science. If you don’t have it, consider bringing in someone from outside to teach intensive short courses, or consider having your students go elsewhere for their science classes. Alternatively, you may be able to find a consultant to set up a "totally green" science program (uses no hazardous materials) that you and your staff can implement. There are also micro-chemistry approaches that reduce the amount of hazardous/toxic material to trace amounts.s

Management of lab hazards starts with an ongoing inventory and monitoring program. This can be quite simple, but it must be done to comply with fire codes. It also makes good common sense. All chemicals must be labeled, and must be reviewed periodically for expiration dates. Some chemicals become extremely explosive as they age.

This chemical inventory is compared to the list of hazardous materials to ensure that:

• quantities don’t exceed amounts allowed in a normal school environment; and
• hazardous materials are properly stored.
• Proper storage of hazardous materials may include:
• storage of flammable materials in an approved solvent/flammable storage cabinet.
• storage of hazardous materials in an approved hazardous materials cabinet.

Flammable and hazardous materials should be stored separately, and materials which react to each other should be stored separately. This may mean three separate storage cabinets (or more).

Flammable/hazardous materials cabinets are designed to protect the contents from fire. They should have self-closing doors and be installed in such a way that they can’t tip over (e.g. bolted to the wall at top and bottom). They should NOT be incorporated into the base cabinet under a fume hood (a likely source of fire), even though manufacturers offer that design. In order to reduce fumes, you may wish to ventilate them to outdoors via an exhaust duct. This is not required. If you do it, it is imperative that you don’t compromise their fire integrity, so the vent should have a spark arrestor and be built of steel plumbing pipe with threaded joints. It can exhaust into a fume hood duct or an exhaust duct, or be brought up through the roof like a plumbing vent. It must not be connected to a return air duct or simply terminated in an attic.

FUME HOODS

Use of hazardous chemicals happens in fume hoods. Period. If you can’t afford a fume hood, you can’t afford to teach science that uses hazardous chemicals. Your school is teaching safety when it teaches science, so unsafe practices will be learned and repeated.

A fume hood is simply a metal cabinet with a sliding sash at the front that brings a flow of air from outside the hood through the hood, up through a fire-proof duct, through a corrosion-resistant fan, and then is exhausted at least ten feet above the roof. Installation must be designed by knowledgeable professionals in order to ensure safety. Common fume hood models are manufactured by Hamilton, Labconco, Kewanee, Lyline, and others.

If your budget is restricted and you must have a fume hood, look into buying one used (or donated) from a university, private corporation or lab supply company. They often have older models that are no longer large enough or don’t have the services that they require. If you use a second-hand hood, make sure that it has never been used for radioisotopes and that it is not contaminated with hazardous materials.

No matter what the hood, current requirements say that it should have an alarm to indicate whether the flow is adequate. These are not extremely expensive devices, although users sometimes find them very annoying.

It is theoretically possibly to build your own hood. You will almost certainly find that it is more expensive and doesn’t perform properly. Good hood design is an exact science.

VENTILATION AND ENERGY CONSERVATION

Any room that uses hazardous materials is required (by OSHA standards (see attached) to have proper ventilation. This normally means a ventilation rate of at least 10 air changes per hour (the volume of the room time 10 equals the minimum hourly air flow in cubic feet) of 100% OUTSIDE AIR, which must be heated and cooled. This can be a large energy burden. If you have a science lab with this airflow rate it is probably a candidate for energy conservation through setbacks to lower airflows during off hours.

Similarly, fume hoods must have an airflow of 100 linear feet per minute at the sash. For operational purposes, you usually want this to be achieved with the sash open about 14" or 16", enough space to get your arms in and do some work. There are advanced designs that combine sash design with variable air supply volume to reduce air flow when possible. However, these depend on users lowering sashes whenever possible. If you have such a system, does your staff know to lower the sash? Lowering the sash is a good safety measure even in systems that don’t conserve air.

LAB SAFETY EQUIPMENT: Safety showers, eyewash stations, and fire extinguishers

In addition to materials handling, fume hoods, and lab ventilation, there are three more fundamental pieces of safety equipment. A safety shower send a large volume of water down onto someone who has experienced a toxic material spill. It is best if the water is preset to warm, as the person may need to be under the shower for some time. Similarly, eye-wash stations, which can be retrofitted onto sinks at relatively low cost, need to be designed for 10 to 15 minutes of continuous use. Finally, fire extinguishers are of fundamental importance. Your science staff should know the different types (such as dry chemical, carbon dioxide, etc.) and know how to use them. Live training with test fires (outside) is a good idea. For more information on fire extinguishers, consult your local fire department.

FIRE SAFETY AND LAB DESIGN

Lab design for fire safety is very simple:

1. Don’t locate fume hoods or hazardous/flammable storage cabinets near doors or exit paths or near areas where people walk by.
2. Provide two exits even if not required by code.
3. Provide a one-hour fire resistant separation (one hour fire wall) between the lab and any other school space, including doors and windows.
4. Provide fire extinguishers and other emergency devices near where they will be needed (such as near the fume hood).
5. Keep doors between labs and corridors tightly closed with an automatic door closer.

RESOURCES

Keniry, Julian, Chapter 8, Hazardous Waste Minimization, in Ecodemia: Campus Environmental Stewardship, The Wilderness Society, 1995. This has good information on micro-chemistry and other approaches.

Ruys, Theodorus, ed., Handbook of Facilities Planning, Volume I, Laboratory Facilities, Van Nostrand & Reinhold, New Yord, 1990

Oregon Administrative Rules, Chapter 437, 1910.150 Occupational Exporsure to Hazarsoud Chemicals In Laboratories.

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