TYPE OF CONSTRUCTION: Mechanical Jr. High/ High School EducationSCOPE OF WORK:
Upgrade the mechanical systems and add central cooling capabilities to the Jr. High, High school building.
• Over 9,800 feet of new Hydronic Piping
• (1) 289.5 Ton Screw Chiller
• (80) Unit Ventilators
• (10) Air Handling Units
• (7) VAVs
• (21) Cabinet Unit Heaters
• (7) Horizontal Unit Heaters
• (1) Duct Mounted Reheat Coil
• (3) New Boilers with a total Capacity of
• (2) HHW Primary Pumps
• (2) CHW Primary Pumps
• Junior High/High School Building for the district
SIZE OF PROJECT:
• 160,420 sq/ft
• Original Contract – $2,192,438.00
• Final Contract – $2,207,461.00
LENGTH OF CONSTRUCTION PROJECT:
• 3 Months 12 days
CONSTRUCTION COMMUNITY OPPORTUNITIES BASED ON MERIT:When bidding a project, our estimators will send out a request for proposal to our database of pre-qualified subcontractors/suppliers. When awarding the contract/purchase orders for this project, we considered the amountof the bid, as well as the experience of the subcontractor/supplier with the type of work associated with this project.
The Preble Shawnee Junior High School and the Senior High School are combined into one very large, 160,420 sq/ft building and the school board was needing the addition of a central cooling system to the whole campus. Prior to the Covid-19
pandemic, the schedule for installations and upgrades would take place during the summer months when the students were out of school. It turned out that all work was needing to be done during the Covid-19 pandemic, with mechanics having to maintain safe working distances while maintaining the tight installation schedule.
The scope of work consisted of:
• Over 9,800 feet of new hydronic piping
• (1) 289.5 Ton screw chiller
• (80) unit ventilators
• (10) air handling units
• (7) VAVs
• (21) cabinet unit heaters
• (7) horizontal unit heaters
• (1) duct mounted reheat coil
• (3) new boilers with a total Capacity of 7,497,000 BTU/h
• (2) hot water heater Primary Pumps
• (2) chilled water Primary Pumps
To start things, we removed 10 existing air handlers either by removing the existing louvers or by taking the units apart and transporting them down the hallways and out of the building. The mechanical room had to be completely demolished and installed with new boilers, piping, pumps, valves, and controls. The existing breeching was modified to only accept the existing domestic water heaters. The new boilers are highefficient and required separate flues for each new boiler. Care was taken to ensure proper service clearance was maintained on each new piece of equipment. CO2 sensors were installed in all the classrooms to bring in outside air, based on occupied mode and current CO2 levels within the area. The new Unit Vents also came with enthalpy controls to allow for “free” cooling when outside air conditions are ideal. This will minimize the run time on the chiller and keep additional electrical cost to a minimum.
The project had a tight schedule from the start with the amount of manpower we had available, and upon mobilizing, it was brought to our attention the factory which supplied the blowers motors for the new unit vents had been shut down due to Covid-19 and we did not know if we were going to receive the unit vents in time to get them installed. We determined that we could meet the scheduled end date by working some additional hours and adding a few people to assist if we could get the unit vents on-site by July 1, 2020.
That was our drop-dead date to still meet the schedule for school to open on-time. In the first 42 working days, we were working diligently on gettingthe main mechanical room complete, the AHUs replaced, and the new chilled water
and heating hot water piping installed within 5’ of the new unit vents. Final confirmation of the unit vents was scheduled to be delivered on July 1, 2020 and that would allow us only 34 working days to remove the existing unit vents, install, test/flush, insulate and commission the 80 new unit vents. Originally, we had a total of 75 working days to include this in our tasks to complete. In addition, we did not want to demolish the existing unit vents without having the new ones
on-hand first, because once we started the removal, there was no turning back. At the time of the removal, school was to be back in session on-time, and an order had not been issued from the governor at that point for remote learning for the
district, so we continued our push for a quick installation.
Not only did we have a delay with the blower motors, but AHU-10 was delayed by 21 days and did not ship out until July 1, 2020. So now we also had to fit in AHU- 10 replacement, all (80) unit vents and 28-unit heaters, all to be replaced in the 34- day period. The unit heaters did not ship until July 16, 2020 which means we were cutting it close on the unit heater installation. Working around the existing services in the building brought about issues with the installation of our new services above the ceiling. We had to strategically find locations to route our piping and minimize offsets up or down to limit the amount of vents and drains in the system.
The entire project took three months and 12 days to substantial completion with a total of 8,499 installation hours.
-Greg Norris, Project Manager