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In 2018, Dallas County (Texas) leadership implemented a forward-thinking capital improvement program to replace an aging inventory of facilities. This program included the design and construction of a new municipal campus in southern Dallas County to house a new county government facility and standalone Sheriff’s Training Academy.
KAI Design served as the architect on the 73,000-square-foot, two-story government building located at the southern edge of Dallas County. KAI also integrated its in-house MEP engineering group into the project and assisted with master planning of the overall site for future growth.
The new $22 million Southern Dallas Government Center opened in spring 2021. It replaces and consolidates three aging facilities under one roof to house Dallas County’s Tax Office; Veteran’s Affairs; County Constable; Sheriff’s Traffic Division (with dispatch and K-9 unit); and two Justice of the Peace courts. Approximately 205 county employees work at the new facility.
COVID-19 Influences Design
The building’s unique mix of functions, in addition to the project goals and objectives established by the owner and end-user, heavily influenced the building systems and infrastructure. Dallas County officials challenged the team with designing a facility that would achieve a LEED Silver level of certification.
The overarching goal behind this revolves around being good stewards of our natural resources while also employing sound financial prudence by integrating systems with lower operating and maintenance costs. These aspirational goals, coupled with the challenges of integrating a Motorola R56 grounding system and storm shelter, created unique challenges to the project.
In addition, the facility was constructed during the COVID-19 worldwide pandemic. It led county officials and the MEP design team to rethink some of its facility infrastructure requirements.
At the mid-point in construction, a shift was made to the building infrastructure due to the COVID-19 pandemic. Dallas County officials made the conscious decision to make necessary upgrades to the plumbing systems to prevent the spread of infectious diseases. These modifications included changing all plumbing water closets, urinals and sinks to incorporate touchless controls. Electric water coolers were upgraded to touchless in addition to incorporating bottle-filling stations.
Another unique project parameter that impacted the overall plumbing systems was the integration of the Motorola R56 grounding requirements. In laymen’s terms, nearly every metal conductor entering the building and contained within the building was required to be bonded and grounded, including the plumbing and fire protection supply and distribution piping.
The facility includes a mixture of showers, lavatories, water closets, kitchen sinks and urinals for a variety of users. Four fixture groups have been determined within the building, with each group defined below.
1. Single-user restrooms. Public fixtures within this group are used by each judge (total of two full-time equivalents located on the second floor), each juror within deliberation (total of 16 transients located on the second floor) and one-fourth of the transient visitors of the Tax and Veterans Affairs department (total 43 transients located on the first floor).
Within the first floor, transient visitors of the Tax and Veterans Affairs department have access to multiple-user restrooms. It is expected that three-fourths of the transient visitors will use the multiple-user restrooms while one-fourth will use the single-user (family restroom).
Water closets and lavatories are featured within each single-user restroom. Urinals are not installed within this fixture group; therefore, the daily uses for men and women will be the same. The lavatories within these restrooms originally were designed with manually controlled faucets with a flow rate of 0.35 gallons/minute. The water closets are dual flush with a flow rate of 1.28/1.1 gallons/flush.
2. Multiple-user restrooms. All departments within the building have access to this fixture group. Public fixtures within this group are used by all full-time employees and transients not using the single-user fixture group. Water closets, lavatories and urinals are featured within each restroom.
The lavatories within each restroom are originally designed with manually controlled faucets with a flow rate of 0.35 gallons/minute. The water closets are dual flush with a flow rate of 1.28/1.1 gallons/flush. The urinals will have a flow rate of 0.125 gallons/flush.
3. Staff lounge. This fixture group includes kitchen sinks within staff lounges and breakrooms. The flow rate for the faucets within this fixture group is 1.5 gallons/minute. All full-time employees have access to this fixture group.
4. Showers. This fixture group includes showers that are only used by full-time employees. The flow rate for the faucets within this fixture group is 1.5 gallons/minute.
Mandated by the requirements of the 2015 International Building Code and ICC-500-2014 standards, the sheriff’s dispatch area was designed and constructed as a certified storm shelter. In addition to protecting occupants from 250 miles/hour sustained winds and debris, the dispatch area is equipped with the infrastructure to remain operational during and after the storm event.
An uninterrupted power supply was integrated to provide continuous power to dispatch working alongside a dual-fuel source generator, with natural gas as the primary source and liquid propane as the secondary. The design team took special precautions with the routing of the natural gas lines from the source at the street to the service entrance into the building envelope to ensure the piping remained underground until entry into the hardened storm shelter.
In addition, an underground liquid propane tank plumbed underground into the generator enclosure, housed within the protected shelter, provided the secondary fuel source.
Each penetration through the storm shelter envelope and lid had to be carefully planned during design and monitored by the design team during construction. All domestic water lines, fire sprinkler mains and hydronic piping were limited to a maximum size of 2 inches in diameter. This restriction was to avoid violating the storm shelter envelope or requiring complex systems to prevent flying debris from entering the shelter in the event the infrastructure was extracted from the wall cavity during a storm.
Extra care had to be taken with the fire suppression system as this was a delegated design by the contractor and approved by the city. The design team was diligent in defining the storm shelter design parameters for the fire protection systems within the project specifications to ensure compliance with the project’s storm shelter parameters.
The building and storm shelter code are not implicitly clear on how domestic water should be treated in a public safety storm shelter. To maintain operational capacity for the sheriff’s dispatch system, the decision was made to install a 750-gallon water storage tank. In addition, a set of manual and automated valves were integrated to ensure the system is isolated from the rest of the building.
Under normal operations, water flows through the tank to each of the plumbing fixtures within the storm shelter. The water distribution system is equipped with a domestic booster pump that operates based on system pressure. In the event the domestic water feed into the building and storm shelter is compromised, the pump senses when the pressure drops below 60 psi and closes the bypass valve. The booster pump starts and maintains the system water pressure at 65 psig.
If the pressure from the feed returns to 70 psi or more, the pump de-energizes and the bypass valve opens. In the event of a low water level, as measured by a tank-mounted level sensor, the booster pump will stop and an alarm is sent to the building management system. This pump also is circuited within the emergency generation systems. (See Figure 1.)
Going for LEED Silver
The owner and project parameters were further defined by the project goals of achieving LEED Silver certification. Metering was integrated to meet this project goal. The team designed and integrated metering software and tools at each piece of equipment serviced by natural gas, including boilers and water heaters. Eighty percent of the hot water distribution system is metered at the branch circuits and fixture groups to meet the requirements of LEED.
With an owner migrating from a 1960s facility with water closets expelling multiple gallons per flush, there was a bit of education required to differentiate between perceived low water pressure and the intended functionality of the low-flow, WaterSense-certified plumbing fixtures selected for the project. These low-flow fixtures were integrated at the showers, lavatories, water closets, kitchen sinks and urinals.
Though not a LEED facility, the adjacent Sheriff’s Academy employs all the best practices used at the South Dallas Government Center for sustainable plumbing design solutions and integrates mechanical, electrical and plumbing infrastructure to combat the spread of infectious diseases.
Other strategies employed on the project included the use of drought-tolerant plantings to minimize the irrigation and domestic water requirements for the site. Additionally, all rainwater from the roof was captured through internal roof drains and conveyed through an underground collection system to an on-site detention system.
Aleksandar Milenkov is the Engineering Design Principal at KAI (www.kai-db.com) in Dallas-Fort Worth. He is responsible for the overall quality control of the mechanical and plumbing department and for leading the recruiting, hiring and onboarding of appropriate talent to provide the professional expertise required to meet client and project needs.
Derwin Broughton is a Licensed Architect and Principal for KAI. He is accountable for business development and client relationships for the firm’s offices in Texas, Georgia and Missouri, and for all business sectors inclusive of architecture, MEP, construction management, program management and build.