Note: Due to technical difficulties, we are unable to run the diagrams accompanying this article online. Please see the print edition of the April 2001 issue to view these diagrams.
The High Desert State Prison was constructed as a medium security facility in rural Nevada, forty miles northwest of Las Vegas. Because of the remote location, the prison was designed as a self-sustaining site, almost a small state-of-the-art city. The $100 million facility consists of 12 housing units, eight administrative and security buildings, a recreation building, a medical facility, a culinary/laundry building, a warehouse/motor pool building, seven guard towers and a powerhouse containing boilers, chillers and emergency electric generators.
The mechanical contractor on this project was Hansen Mechanical, Inc., of Las Vegas. Project Manager Dick Tillotson earned the respect of every person on the project with his management skills and attention to detail. It is a far superior project because of Mr. Tillotson.
Housing UnitsDomestic water serves the two-story housing units beginning at a combination domestic/fire protection water line. The service starts at the combination water line with a reduced pressure backflow preventer, followed by a three-stage pressure-reducing station. Domestic water systems are controlled so that inmates cannot flush away contraband during lock-down inspections, and so rioting inmates cannot flood the building.
Each housing unit has two wings. Each wing has an electronic water management system with electronic valve controllers that simultaneously direct the positions of water valves in each lavatory, water closet and shower. A computer in each water management system interfaces multiple valve controllers and is capable of controlling more than 3,000 valves. Security officers can close any or all water valves from the "Control" rooms. The domestic cold water system also serves makeup water to evaporative coolers.
Domestic hot water is softened and then heated through a domestic water-to-water heat exchanger by hot water circulated from the Power House. Hot water return-circulating pumps maintain the desired hot water temperature at all points of use.
The soil, waste and vent systems are of conventional design and serve back-to-back Lavatory/Water Closets in the two-story inmate areas. Restrooms for administrative and security personnel are of standard design.
Administrative and Security BuildingsThe domestic water systems are of standard design and follow the Uniform Plumbing Code. The service entrances are the same as for the housing units. Domestic hot water is softened and then heated through an electric domestic water heater. Hot water is maintained at all points of use by a hot water return-circulating pump.
The soil, waste and vent systems are of conventional design and serve restrooms and janitor's closets.
Recreation BuildingThe gymnasium plumbing consists of shower and restroom facilities for two teams and make-up water to evaporative coolers. The design is of the standard type and follows the Uniform Plumbing Code. Water service, reduced pressure backflow preventer, water softener, water heaters and circulating system are the same as for the housing units.
Medical/Intake BuildingThe plumbing for this building has shower and restroom facilities for inmate patient rooms the same as for the housing units. Restroom facilities for staff and security personnel are of the standard design and follow the Uniform Plumbing Code. In addition, this facility has trauma and examination rooms with clinic sinks.
Culinary-Laundry BuildingThe culinary building has six dining rooms, a kitchen and storage rooms. The kitchen is designed to prepare and serve approximately 7,500 meals a day. Each of the dining rooms has seating for 168 inmates and serves multiple seatings for each meal. The multiple dining rooms allow different housing units to be served separately so that trouble in one unit is isolated from the other units.
The ceilings in the inmate areas had to be secure, so some are made of steel. Once these ceilings are welded into place, they are inaccessible. Sprinklers, sprinkler piping, ductwork, chilled and hot water piping, electrical security systems, alarm systems and power systems all had to be designed so that access was not necessary. Items requiring service had to be located away from prisoner areas. Ceiling access doors in inmate areas had to be vandal-proof and approved for prison use. Steam systems, which are fairly dangerous, had to be located and arranged to prevent vandalism. Mechanical systems, including valves ducts, piping, controls and miscellaneous components, had to be located out of sight and behind secure access doors.
Culinary Steam. Cooking heat is supplied by steam generated in the basement of the culinary-laundry building. Each cooking kettle and dishwasher is supplied with steam reduced from the generating pressure to the required cooking pressure, ranging from 20 to 45 pounds per square inch, gauge (psig). From the kettles, condensate passes through traps to flash tanks and is then drained by gravity to combination condensate return pump/receivers. The return pumps lift the condensate to the low-pressure return main, where it drains by gravity to the deaerator unit.
Culinary Plumbing. The domestic hot and cold water plumbing is of conventional design following the Uniform Plumbing Code and serves the kitchen sinks, hand wash sinks, the dishwashing equipment and evaporative coolers.
The soil, waste and vent systems serving the fixtures, floor drains, floor sinks, equipment and evaporative coolers are of conventional design. The kitchen drain terminates in an underground grease interceptor located outside the building. Effluent from the grease interceptor empties into an existing sewage lagoon. The existing lagoon also serves an existing prison. To prevent the existing lagoon from being overburdened by grease and solids from the new High Desert Prison, a "Superceptor" manufactured by Thermaco-Big Dipper was provided. The "Superceptor," mounted inside the building, withdraws floating grease and solids from the grease trap with a skimmer and heavier-than-water solids from the bottom of the grease interceptor. Fats, oils and greases are separated from the effluent and placed in a collection container. Heavier-than-water solids are placed in a separate collection container. The recovered fats, oils and greases will be sold to a rendering company rather than being disposed of by a pumping company at a cost. Coarse solids are separated, dewatered and placed in a container for disposal in a landfill. Smaller solids are separated, macerated and sent to the sewer.
Laundry Steam. Steam is distributed to the laundry at generation pressure and is reduced to the required pressures at the laundry equipment. Steam pressures range from 80 psig to 125 psig. Condensate from the laundry equipment is returned to the high-pressure steam condensate return through bucket traps.
The high-pressure condensate from the laundry returns by gravity to the energy recovery pre-heater. The high-pressure condensate is flashed down to 5 psig in a flash tank, and serves the make-up and re-use water heating tube bundles in the water tanks. The low-pressure steam condenses in the water heating tube bundles and passes through traps to condensate lift pump/receiver units, where it is pumped to the main condensate return pump/receiver for return to the steam boiler deaerator and boiler feed pumps.
Laundry Heat Recovery Assembly. The laundry operates with two cycles: a wash cycle and a rinse cycle. The rinse water is returned to a storage tank with a steam tube bundle for reuse as the first cycle wash water. Incoming cold water first passes through a tank with a steam tube bundle. The flashed condensate, as described above, is used to reheat the recovered rinse water and to heat the incoming cold water to the required wash temperature. The steam recovery system is backed up by steam from the boilers during light laundry loads.
Warehouse-Motor Pool BuildingThe warehouse plumbing consists of roof drains, evaporative cooler drains and makeup water to the evaporative coolers.
The motor pool's domestic water system supplies water to the restrooms and the evaporative coolers. Piping for engine oil and chassis grease is extended from the oil and grease storage room to suspended dispensing reels.
Guard TowersPlumbing consists of one water closet and one lavatory. The domestic water service begins with a two-stage pressure reducing station and extends upward to the plumbing fixtures. An electric instantaneous heater mounted beneath the lavatory heats the lavatory water.
Soil, waste and vent piping are of conventional design, following the Uniform Plumbing Code.
PowerhouseHeating Water Generation. Four oil-fired 500 horsepower boilers generate hot water at 195 degrees F for heating and domestic water heating. Space is provided for the expansion of the boiler plant. Bryan Steam Corp. in Peru, IN, manufactured the boilers selected for this project.
Heating Water Distribution. The distribution system encircles the campus in a reverse return arrangement and exceeds 19,000 feet in length. Perma-Pipe, Inc., in Niles, IL, manufactured the pre-insulated underground piping selected for this project. Distribution pumping is provided by three 1,200 gallons per minute (gpm) variable speed pumps. Individual constant speed boiler pumps, at the rate of 560 gpm, pump heated boiler water from the distribution loop, through the boilers and back into the distribution loop.
From the distribution loop, each of the buildings is served by a branch connection to the loop. The branch connection divides into two services: one for heating and one for domestic water heating.
Piping sizes were selected for low-pressure drops to reduce the pumping head and to prevent pressure fluctuations resulting from varying building demands.
Steam Generation. Saturated steam is generated at 150 psig by two 500 horsepower oil-fired boilers to serve the cooking and laundry equipment. Bryan Steam Corp. manufactured the boilers selected for this project.
Steam Distribution. Steam is distributed throughout the culinary/laundry building at 150 psig and is reduced to the required operating pressures at the points of usage. The steam pressure reducing valves serve two functions. They maintain the required pressure at the equipment, and they prevent wet steam from entering the low-pressure side of the reducing valves by slightly superheating the steam as its pressure is reduced.
Fuel. Fuel oil for the heating water boilers, steam boilers and electric generators is number 2, and it is transferred from a storage tank farm to day oil tanks by submerged pumps inside the storage tanks. From the day oil tanks, the fuel is pumped to the boilers at twice the firing rate, with the excess being returned to the day oil tank. Electric generators have day tanks beneath the generators and operate in the same manner.