If most lab functions will be conducted seated, and the lower desk-height table is used for this function, the table should be 30″ high; if most laboratory functions will be conducted standing up, the tables should be at countertop height, or 36″.
Fixed teacher demonstration tables waste floor space and create a very inflexible area at the “front” of the classroom; many new facilities are providing a rolling demonstration surface consisting of a 72″ x 32″ resin countertop with various base cabinets for storage beneath. The entire assembly is mounted on four to six heavy-duty casters so that the finished height is 36″, flush with perimeter countertops. When water or gas is needed for a demonstration, the unit can be wheeled to a perimeter sink or gas jet; otherwise it may be located anywhere within the lab/classroom. The 32″ dimension allows the unit to pass through a 36″ wide door into a prep room.
As electrical power is required for microscopes and other equipment, recessed floor boxes work well since they can be closed when not in use and the furniture arrangement can be very flexible. Although there are still some Biology lab/classrooms being constructed with a central gas system, use of gas is so minimal in most programs, that the expensive central system probably should be eliminated in favor of hot plates for most heating functions and small gas bottles for those limited usages where an open flame is required. Provide sufficient power for the number of hot plates to be used, probably at least two separate 20 amp circuits per lab/classroom. Ventilation is also important in Biology. Some programs require at least one fume hood for demonstrations and group projects; if permanently located, this hood might have glass viewing panels on three sides and be located perpendicular to a wall. Portable fume hoods which recirculate air through a series of filters have also become more reliable in recent years and, although nearly as expensive as a fixed hood, can add flexibility to a layout. Providing a purge air system in the form of an exhaust fan which pulls air directly outdoors can help quickly clear the space of undesirable fumes. Do not rely on a fixed fume hood system for this purpose as they are generally not designed to draw that much air quickly.
Chemistry is the one area in which the move to a totally flexible lab space may be more difficult. The chemistry faculty should evaluate their need for fixed lab stations with respect to the use of corrosive materials that would require corrosion-resistant piping and an acid- dilution system and the need for a central gas system. Many chemistry programs are moving to a system in which the quantities of corrosive chemicals used by students are minimal and the student use of gas is also minimal. In these instances, a single, teacher demonstration station with an under-counter acid dilution tank and gas jet could serve the needs of the entire class, thereby allowing perimeter sinks and movable tables for the student lab stations. Central acid dilution systems with corrosion-resistant glass or polypropylene piping are expensive; any acid-dilution system requires periodic maintenance to replace the limestone chips within the dilution tank as they are consumed. Central gas systems are also expensive, requiring extensive piping and an emergency push-button shutoff system which interconnects with the electrical power system to immediately shut down the gas and power in a room. Using hot plates and/or butane cartridges for small burners eliminates this added expense and can increase safety within the chemistry lab/classroom.