need to be replaced in the building equipment rooms, and provisions for their replacement should also be included in the initial design of the building.
Laboratory egress requires all the physical specifications detailed above in the section on "Access" but is also regulated by codes. Dual egress—i.e., two exits—for all laboratories is often required by fire and building codes, and dual egress for other areas is often encouraged. Storerooms or laboratory preparation areas with flammable materials, water and electrical hazards, and chemical hazards should also have dual egress. In addition, there must be a continuous and unobstructed path from any point in the building to an outside exit. This requirement is further discussed in the section "Environmental Health and Safety" in this chapter.
Atrium. An atrium can make a strong statement about the ideology of the research laboratory facility. An atrium can serve many functions, such as a reception area, a meeting area, or an opening to bring daylight into the center of a large building. However, atriums can create additional ventilation requirements as a result of additional solar gain or code-mandated smoke evacuation systems. Shading or filtering the solar gain in the atrium can minimize the additional ventilation requirements. An atrium in a laboratory building can create additional complications associated with the balancing of the HVAC system. A proper evaluation of the advantages and disadvantages of an atrium should be completed during the design phase.
Loading Dock. The loading dock is the primary point of entry for supplies and equipment to the building. In addition to an area for receiving and shipping goods, the loading dock is also a staging or collection area for a laboratory building. Many laboratory buildings have storerooms, gas cylinder holding areas, waste collection facilities for both office and hazardous laboratory wastes, storage facilities for flammable materials, and refrigerated storage all located adjacent to or easily accessible to the loading dock. Once the materials are in the building, the network of corridors and elevators must support their safe transport throughout the building. Factors determining the location of the loading dock have been considered in the "Building Air Intake and Exhaust" and "Access to the Building" sections of this chapter.
Elevators. Elevators facilitate the safe movement of people and materials throughout a building. Elevators are needed even in a two-story building to move large and heavy items between floors and to comply with ADA require-