Gunston Middle School

Arlington, Virginia

General Contractor: Shapiro & Duncan, Inc.
Engineer/Architect: 2rw Consultants, Inc.
Contract Amount: $8,600,000
Start Date: 6/18/2018
Completion Date: 8/30/2019

Challenge

According to the Arlington County (Va.) Public Schools website, Gunston Middle School is “an exceptional, United Nations-like middle school.” Located in the Arlington Ridge community, Gunston is home to three distinct but interconnected programs: a partial Spanish-Immersion Program, a Montessori Middle Years Program, and a Traditional Middle School Program. There are more than 50 different countries represented in its highly diverse student body.

The school was originally built in the mid-1950s and underwent extensive renovations and reconstruction in 1994 – 1996 and again in 2000 – 2003.

Starting in the summer of 2018, Shapiro & Duncan implemented a two-year total modernization of the school’s HVAC system. The project scope covered replacement of all mechanical equipment, inside and outside the school, related to heating and air conditioning. Air handling units were included in the scope. The project was conducted in three phases: Phase 1 (June 23, 2018 – August 30, 2018), Phase 1.2 (December 1, 2018 – January 1, 2019) and Phase 2 (June 22, 2019 – August 30, 2019).

Phase 1 included replacing 71 heat pumps, 20 fan coil units, 25 water-sourced cabinet heaters, 22 water-heated unit heaters, and 16 electric unit heaters (in the lavatories). In the boiler room, 3 new boilers were added and 2 heating water pumps were replaced. For storm water capture, 2 new sump pumps and a storage tank were installed. (The two existing sump pumps had not been functioning for 15 years,) In the mechanical room, 2 condenser water pumps and 2 cooling tower pumps were replaced. In addition, our team renovated the rest of the HVAC equipment in the mechanical room, including the heat exchanger, expansion tanks and all-new piping.

Phase 1.2 included renovation of the cooling tower and installation of all-new piping in the cooling tower yard.

A major focus of Phase 2 was a complete remodeling and modernization of the rooftop HVAC equipment, including installation of 14 Tetra rooftop HVAC units, replacement of all duct work and installation of all-new piping for the rooftop units. In Theater 1, the school theater, all of the air handling units were replaced. In Theater 2 – The Gunston Arts Center, a county-operated venue for community productions that is attached to the school, 40 exhaust relief fans were replaced. The only interior work in Phase 2 involved installation of 15 fin tube radiators inside the school.

Inconsistencies in some of the coordination drawings produced by the county and several subcontractors created retrofitting challenges. For example, the valve packages for the heat pump units were too big to be installed at the floor level per the original drawings and had to be mounted in the ceiling above the units.

Time is always a challenge on school projects during the summer months. The work must be completed within a 7-week timeframe. There is no wiggle room.

Solution

To keep the project on schedule, our crews worked 6 days a week with frequent double shifts.

When our team encountered conflicts in the coordination drawings, the project engineering team at 2rw Consultants responded speedily with needed revisions. They were also attentive and easy to work with whenever Request for Information (RFI) responses were needed. In fact, 2rw’s responsiveness was one of the keys to keeping the project on schedule.

When a design/build approach was required for the valve package retrofits, Shapiro & Duncan’s Virtual Design and Coordination (VDC) team swung into action with its Building Information Modeling (BIM) process to produce 3D drawings using the latest AutoCAD and CADPipe programs. In addition, the VDC team did all of the coordination drawings needed for the boiler room and mechanical room modernizations, where we were starting fresh after stripping both rooms to the bare walls.

Upon completion of this system, all piping was tested and insulated and the Tower’s existing chilled water system was brought back on line.

Shapiro & Duncan’s 51,000-square-foot fabrication shop in Landover, Md., was another big part of the solution given the short timeframes we were working with. About 40 percent of the piping, piping components, valve bodies and pump components needed for this job was prefabbed by the fab shop.

A great example of how the fab shop plays a mission-critical role in our projects is illustrated by their work on the repetitive valve packages needed for the rooftop HVAC units. Our field team gave them the parts, told them what we were looking for, and they came up with a prototype. The prototype was installed and tested by us. As soon as we had engineering approval, the fab shop went ahead with the entire run of the valve packages. This helped reduce the number of labor hours spent in the field.

Our subcontractors did an A-1 job and all of them were easy to work with. Trades represented on this project included:

Air Distribution – Airway Sheet Metal
Thermal Insulation – City Wide Group
Automated Temperature Controls – Automated Logic
Rigging – Crane Services
Electrical Distribution – Specified Electric
Testing, Adjusting and Balancing (TAB) – Quality Test & Balancing
Structural Steel – Capital Welding
General Construction – American Minority General Contractors
Water Treatment – Clean Steams

Finally, Shapiro & Duncan’s project management support team back in the office was a huge help to our field foremen.

Result

Despite the compressed schedule, our team kept the project on track by meeting weekly milestones. Labor was kept within allowable limits, in significant part thanks to the work done by the fab shop, and we stayed within budget.

Our team received a commendation letter from 2rw Engineering for working an entire week in 100+ degree temperatures (as high as 110 degrees) on the rooftop.

The Arlington Public Schools Department of Design and Construction formally thanked all of our staff and subcontractors for the long hours. It was a pleasure working with them.

No matter how tight the timeframe, Shapiro & Duncan is supremely confident in our ability to execute top-flight secondary school mechanical renovations on time and on budget.