ASHRAE Journal - July 2010 - 32

is typically no more than 12 in. (305 mm) of space between In both cases, a refuge area is created within the housing pod in the top of the door and the top of the cell. an emergency, without having to leave the confines of the secure Since most jails and prisons are classified as I-3 building perimeter. Dependent on the size of the dayroom and the size/ type (per the building code), there are some conditions where quantity of cells served, these areas are often served by separate an engineered smoke control system is required. For example, air-handling units. Ductwork mains, branches, and air devices are a below grade, “windowless” smoke compartment would fall typically selected and sized based on smoke purge cfm. into this category and would require additional protection for exhaust or pressurization for smoke compartments. This condi- System Selection tion is unusual, but it is possible in this building type. Engineers often hear the term “design to budget” and, deIn a correctional environment, the concern is not fire and spite their efforts, see good intentions and good practices in protection of the contents. It is the smoke and harmful gases. design diminished in the bidding and award phase because the Smoke inhalation presents the greatest threat to the inhabitants project is over budget. This is certainly no more prevalent in of the building, most of which cannot egress freely, if at all. my experience than designing correctional facilities. As with A smoke purge system addresses this many health-care projects, beds are and protects inmates and staff alike, in typically the main focus of most corsuch an event. In most occupancy types rectional projects. The number of beds and building types, engineers encounter and the project’s capacity to provide the egress paths, fire and smoke rated assemrequired number sometimes supercedes blies, and other construction methods to many other engineering decisions. provide free access for occupants to flee When selecting a system, it is cersafely in an emergency. Obviously, incartainly important to consider the first cerated individuals cannot be allowed this costs and make reasonable decisions. freedom and measures must be taken by However, in my experience, the operathe engineer to address this. tor is critical to this equation as well. The location and type of facility are Who will actually be operating and critical to the engineer when designing maintaining the equipment? Quite a smoke purge system. If it is a state often, correctional owners do not mainor county facility, does the state have a tain a staff of highly skilled technicians jail standard to follow? If it is a federal and specialists. As the engineer, you do facility, is there a published guideline not want to design a system that extends that is applicable? Who is the authorway beyond the owner’s capabilities or ity having jurisdiction? Will the facility the capabilities of their maintenance Bed count, first costs or square footage often seek accreditation? Is the facility public personnel. No amount of care during take the focus away from energy efficiency. or privately funded? Many requirements design and construction can overcome are available to the engineer, and few of them are consistent in the operator’s inability to keep the system maintained and their approach to smoke purge. The engineer must be careful functional long after the project’s completion. when researching applicable standards for the project. It is also important to understand the requirements of the projThe State of Texas, for example, has a jail standard that re- ect. In many states, correctional facilities are not air conditioned quires a minimum of 6 air changes/hour for normal operation at all—they are only ventilated and heated. For example, in Texas and 15 air changes/hour for smoke purge. Some states allow 6 only 19 out of 112 prisons have systems that provide heating and air changes and 10 air changes while other states have no jail cooling. Many of the 19 air-conditioned facilities are for sick standard or guideline at all. It is critical that the engineer meet and mentally ill prisoners.2 Surprisingly, this is not unusual in with the AHJ and come to an agreement on all life-safety aspects Louisiana, Florida, and other states with warm, humid climates. of the project, particularly the approach to smoke removal and Obviously, natural ventilation in northern climates is much control, early in the project. more bearable. Evaporative cooling is more commonplace in As requirements vary from state to state, so do the approaches to arid climates of the desert southwest and California. Quite often, smoke purge. Quite often, the dayroom spaces are exhausted, and sheriffs and wardens consider air conditioning, televisions, and the cells are not. In other cases, dayrooms may be supplied, and other amenities to be “perks,” and they are used as a means of the cells exhausted. Many believe that a better design approach control. The theory being that a more comfortable population is to provide smoke purge fans to exhaust cells and dayrooms will lead to a decrease in violence and other disturbances, not separately, regardless of location. If smoke is detected in the day- to mention recruitment and retention of staff. room, it becomes highly negative to the surrounding area when its dedicated smoke purge fan is energized. At the same time, the Energy Efficiency cells that are adjacent to the dayroom (often double tiered) are It is not unusual for energy efficiency to be forgotten in a new pressurized to prevent passage of smoke from one area to the next. correctional facility. The bed count, first costs, or square footage
32 ASHRAE Journal
Photo courtesy of HDR Architecture, Inc.; ©Mark Trew

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