A convenient planning approach is to locate a large, shared prep/storage room between pairs of adjacent lab/classrooms. Some schools have grouped four to six lab/classrooms around a central prep/storage space, while others have created a long, linear prep/storage space with many lab/classrooms along both sides.
The organization of prep/storage rooms should be as carefully planned as the lab/classrooms they serve. Arrange doors so that sound doesn’t easily transmit from one adjacent classroom space to another and provide a separate, lockable entrance to the prep/storage room from the adjacent corridor. Provide adequate counter space, large sinks, and a variety of base, wall and tall storage cabinets. Dishwashers, refrigerators, ice makers, microwave ovens, and two-burner electric ranges should be included where appropriate. Many schools are installing fume hoods with operable sash on both sides in the partition between the lab/classroom and the prep room; this allows the teacher to use the fume hood while in the prep room and also allows students to gather on both sides of the fume hood to observe an interaction. When such an arrangement is provided, however, controls for the hood should be provided both in the lab/classroom and in the prep room and at least the prep room sash should be lockable.
The prep/storage room also can present an opportunity to provide teacher desk and file space without taking up floor space within the lab/classroom. A section of the counter can be lowered to desktop height (normally 30″) and provided with a pencil drawer and an under-counter filing cabinet. Provide electrical outlets, data ports and a telephone connection at these locations.
Ventilation rates in prep/storage rooms should be slightly higher than that for the adjacent lab/classrooms. If the lab/classroom is designed for four air changes per hour, design the prep/storage room for five or six. Do not assume that a fume hood can provide appropriate ventilation for these spaces. As with the lab/classrooms, the ventilation system for the prep/storage rooms should be separate from the main building ventilation system to avoid fumes from circulating elsewhere in the building.
Chemical storage should be in a lockable space separate from the prep/storage room. This space could be in a central location, particularly in an arrangement where a number of lab/classrooms surround a large, central prep/storage area, or be a separate space connected to the prep/storage room of the lab/classroom where the chemicals are to be used. With few exceptions, chemicals should not be stored in the prep/storage room or in the lab/classroom. Ventilation for chemical storage rooms should be a completely separate, stand-alone system with 100% outdoor air. Six air changes per hour should be adequate, but it is critical that ventilation grilles be located both at the floor level and at the ceiling so that heavier-than-air vapors are removed.