Town of Norfolk Underground Tank Replacement

Town of Norfolk Underground Tank Replacement

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CommTank was awarded the bid to replace the underground storage tank (UST) at the H. Olive Day School in the Town of Norfolk, Massachusetts. The existing underground storage tank, a Highland Titan model (polymer coated steel) which used cathodic protection to prevent corrosion, would be upgraded to a Xerxes fiberglass double-wall UST with interstitial space for monitoring leaks.

An unforeseen delay occurred when a 2 week lead time from the manufacturer extended to 8 weeks. CommTank proposed removing the UST, backfilling the excavation with pea stone and setting up a temporary aboveground storage tank to provide fuel to the emergency generator and boiler for the duration of the delay. The town approved this method and the temporary tank was installed. The project also included addendums for replacing the aboveground storage day tank, automatic fuel oil transfer pump set and boiler room piping. CommTank was awarded this work as well.

On August 11th 2016 the temporary tank was installed on the outside wall of the boiler room and supply return lines were run inside to the boiler and emergency generator. Approximately 900-gallons of fuel were transferred from the UST to the temporary tank and the system was tested. Two concrete barriers were installed to protect the tank from car traffic.

The UST removal started on August 17th 2016. CommTank crews cut the concrete/asphalt and excavated the UST and piping that connected to the boiler room. The UST was opened, cleaned and removed from the ground by crane. The supply/return piping was drained and removed. After soil testing and approval from the Fire Department, the tank grave and pipe trench was backfilled and compacted.

Two hundred feet of piping was demolished in the boiler room and the new Pryco day tank and Preferred Utilities pump set were installed on newly constructed cement pads. The new equipment produced a humming noise that could be heard in the adjoining classroom and needed to be addressed. The original engineering plan did not account for the proximity of the new fuel lines to the classroom. The solution required the installation of nylon gearing in the pump set to replace the original bronze gears. Additionally, flex couplings were installed above the pumps to reduce the transfer of vibration to the wall brackets, and shock mount feet were added to the base of the pump set frame to minimize vibration.  

The new fiberglass underground tank was delivered by Xerxes on November 16th, installed by CommTank on the 17th, backfilled on the 18th and sump piping connections were completed on the 22nd.   On December 2th the cement tank pad was poured. Franklin APT product piping was installed inside XP pipe ducting to provide double-wall protection for the fuel connections between the UST and boiler room. An APT transition sleeve is used to convert the nylon underground product pipe to steel pipe inside the building. This work was completed while school was in session and did not interrupt school activities.

The Veeder-Root fuel tank inventory monitor/leak detector was installed in the boiler room and connected to the UST sump. The system has a 7” LCD touch screen with a 16:9 aspect ratio. The console continually monitors all probes and sensors, reporting not only normal operating conditions, but also systems malfunctions and failures.

CommTank performed tank and line tightness testing at the completion of the project to ensure the fuel system was safe to operate and provided training to the Class A/B Operator. After transferring fuel to the new UST, the temporary aboveground storage tank was disconnected and removed.

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