•  Carrier


Enhancing Safety and Security

Recognizing the importance of remaining operational during an emergency, one region decided to take steps to ensure that its 911 call center could withstand any disaster or unrest. 


By David S. Crutchfield, P.E., LEED AP, M.SAME  


911 call center

Internal view of Charleston County’s Consolidated 911 Call Center. Living quarters, laundry areas and kitchens allow dispatch workers to reside in the center during an emergency event. Fully redundant chillers and boilers allow for proper indoor design conditions, while being fully backed up by emergency power. PHOTO COURTESY RICK MCKEE, AND ROSENBLUM COE ARCHITECTS


It has only been 40 years since the first “911” system was created in Haleyville, Ala. Before that, police officers were dispatched via “job cards” from the front desk of the station house. Most fire and ambulance services were dispatched separately from their own stations.

While call centers have made consider­able strides in improving operational effi­ciency, antiquated systems like job cards pose a serious threat to public safety.



Charleston County is one of the fastest growing areas in South Carolina. Until 2011, the region was being serviced by agroup of non-connected 911 dispatch centers—mostly un-hardened facilities. This led to an inefficient, often time-consuming dispatch process when emergencies crossed dispatch boundaries. Since the call centers were not self-contained, they were subject to being taken off-line due to disasters, sabotage or unrest, which are some of the most critical times for the centers to be fully operational.

It was determined by Charleston County and several surrounding counties that a consolidation of services was needed. While consolidated dispatch centers have oper­ated successfully since the invention of the 911 system, consolidating call centers is a relatively new, yet crucial, concept.

The new facility would need to be hard­ened, reliable and suitable for continuous, uninterrupted operation in the event of a natural disaster or civil unrest.



The county tasked RMF Engineering with creating a call center that would meet best practice standards of The Commission on Accreditation for Law Enforcement Agencies’ Public Safety Communications Accreditation Program and also house the Charleston County Emergency Operations Center and IT Backup Center.

The new, 40,000-ft² consolidated 911 call center, which RMF developed with Rosenblum Coe Architects, meets all these specifications. The facility provides full backup of electrical power with hardened emergency power, potable water storage, captured non-potable rainwater for use in toilet flushing, sequestration of sewer drainage into a holding tank, and self-contained air handling systems with high efficiency filtra­tion. These systems allow staff from all city, county and state agencies to occupy the call center continuously during an emergency to ensure public safety is maintained.

 Charleston County’s new 40,000-ft² Consolidated 911 Call Center has been designed to withstand and remain functional during natural or man-made disasters. PHOTO BY LISA NICKEL

Charleston County’s new 40,000-ft² Consolidated 911 Call Center has been designed to withstand and remain functional during natural or man-made disasters. PHOTO BY LISA NICKEL



The first requirement for any call center is reliable electric power. Without it, the facil­ity becomes the failed link in emergency operations. While Charleston County’s previous call center operated off of a single power source, the new facility operates off of utility electric power provided from two separate utility feeds serving two separate building transformers.

With the new construction, the two transformers were connected so that either transformer can provide all the electrical requirements for the facility from either utility feed. If one of the feeds is interrupted, the second feed can still provide utility power to the facility. Should both utility company electrical feeds be interrupted, the facility has two, 750-kW diesel generators located in a secured, walled enclosure with secured fuel storage.

Each generator is sized to provide all the electrical needs for the facility, from lighting to HVAC. The second generator is the fully redundant backup generator. In effect, the facility has four independent sources of electrical power. Should all four sources of power be compromised, a 225-kVA uninterruptible power supply is capable of powering the critical dispatch functions and electronics for 15 minutes.

With the emergency power for the center sufficiently reliable and robust, the next challenge came in making sure dispatch­ers would be able to perform their duties without interruption, which can include requiring them to live in the facility for several days during a crisis event. Living quarters, laundry areas and kitchens were installed to allow dispatch workers to comfortably reside in the center in the event of an emergency. To boost employee morale during normal operations, break rooms, fitness areas and secure exterior spaces were included in the redesign.

To deal with the potable and non-potable water requirements and ensure reliable and secure operations, the design incorporated emergency potable water storage system and a rainwater catchment system. For secure potable water storage, the facility has three, 200-gal emergency water storage tanks. Each tank automatically fills and provides secure potable water storage. During normal operations, the building control system monitors tank levels, auto­matically emptying and refilling them so that water does not become stagnant and susceptible to microbial growth. In order to reduce the demand for potable fresh water in the building, however, a 5,000-gal non-potable rainwater harvesting system was provided that captures and filters rainwater from the roof of the building, then stores it inside the facility. This stored non-potable rainwater is distributed throughout the building for toilet and urinal flushing, ensuring the building remains sanitary. Dual flush water closets and pint flush urinals further reduce water usage.

The call center’s sewage system also needed to incorporate redundancy. Should the city sewer system not be able to provide waste conveyance, the building sewage can be routed to an underground wastewater holding tank that is located upstream of the city sewer connection and well outside the footprint of the building. This holding tank stores the sewage and allows for removal via a suction truck located outside of the building in a safe manner until proper city sewage service is returned. Lastly, the call center was designed to remain positively pressurized so that all air introduced has been properly treated and filtered and not drawn into the building without treatment.

The benefit is that any exterior contami­nation will be pushed out and away from the building instead of being drawn in. Supply air for the facility is pre-filtered, then post-filtered to remove environmental contaminants. The air intakes for the air-handling units are located on the second floor to eliminate the potential for vandal­ism or sabotage. Carbon dioxide and other sensors test the intake air and have the abil­ity to enable protective control sequences should contaminants be detected.

During an emergency, the facility is expected to house representatives from the fire, police and highway departments, as well as members of the press corps.

With so many in the building during an emergency situation, the HVAC system has the capacity to provide heating or cooling with a large occupancy level. The system was carefully designed to operate beyond the normal outdoor design conditions. If the outdoor temperatures are excessively hot or cold the building will remain func­tional. HVAC systems featuring fan-wall supply air systems and fully redundant chillers and boilers allow for proper indoor design conditions while being fully backed up by emergency power. The fan-wall system provides supply air redundancy by using multiple supply fans in a housed array instead of a single fan. Should one of the fans fail, the rest can continue to provide supply air while the failed fan is replaced.



Charleston County’s Consolidated 911 Call Center has been designed to remain functional and withstand any natural or man-made disaster.

The hope is that it will never need to be used to its full potential. But if it does, Charleston and the surrounding munici­palities are prepared with a facility that will enhance security and communication to ensure the safety of the public, police and first responders



David S. Crutchfield, P.E., LEED AP, M.SAME, is Division Manager, Principal in Charge, RMF Engineering; This email address is being protected from spambots. You need JavaScript enabled to view it..