Morin’s Landscaping UST Removal and AST Installation

Morin’s Landscaping UST Removal and AST Installation

Old fuel dispenser island in front of Morin's maintenance building

CommTank performed an underground storage tank (UST) removal of a double compartment 10,000-gallon tank and installed a triple compartment 16,000-gallon aboveground storage tank (AST) to replace it. This removal and installation project was completed at Morin’s Landscaping in Hollis, New Hampshire. Morin’s has excavators and front end loaders so they were able to complete parts of the excavation and backfill work using their own equipment and staff. Items completed by Morin’s are listed at the end of this project summary.

Underground storage tank cut open for cleaning

Project Set Up

  • Provided services of a licensed professional engineer (PE) to design the new system and oversee installation
  • Submitted the installation plans to the New Hampshire Department of Environmental Services (NHDES)

Tank Removal

  • Obtained necessary permits (tank removal permit, etc.)
  • Provided Dig Safe utility clearance of property (identify underground utilities)
  • Prepared a confined space entry permit & a site-specific health and safety plan
  • Installed a chain link fence around the work area
  • Broke concrete and asphalt on top of the UST
  • Excavated soil located on top of the UST
  • Disconnected and removed manways, sensors and probes, and stored for future use

Environmental technician takes soil sample from above underground fuel storage tank

  • Created a manway into the UST compartments
  • Removed all pumpable contents and tank bottoms
  • Measured explosive gases using a 4-gas meter
  • Inert the tank using carbon dioxide
  • Entered and cleaned the diesel fuel storage tank
  • Prepared the UST for fire department inspection
  • Field screened soil using an organic vapor meter (OVM)
  • Sent two soil samples to a state certified analytical laboratory for volatile organic compounds (VOCs), total petroleum hydrocarbon (TPH) as gasoline, polyaromatic hydrocarbon (PAH) and TPH as fuel oil
  • Transported and disposed of the underground diesel storage tank at a licensed tank yard

Tank Installation

Delivery of the triple compartment Stanwade aboveground tank

  • Prepared a confined space entry permit & a site-specific health and safety plan
  • Pre-inspected all equipment and materials (including a pre-installation pressure test)
  • Provided and installed one (1) triple compartment 16,000-gallon (4,000-10,000-2,000) UL-2085 dual-wall AST with a 30-year limited manufacturer’s warranty
  • Provided and installed a new Veeder-Root™ TLS 350 fuel monitoring system
  • Provided and installed a new Veeder-Root™ interstitial space sensor
  • Provided and installed three (3) new Veeder-Root™ fuel level probes
  • Provided and installed two (2) new Veeder-Root™ leak detection sensors in the new dispenser sumps
  • Ran new aboveground conduits and installed new wires to connect the sensors and level probes to the new Veeder-Root™ fuel monitoring system inside the building
  • Provided and installed one CARB EVR approved fill pipe and fittings with an overfill prevention valve for the gasoline tank
  • Provided and installed an EVR approved pipe and fittings for the Stage 1 vapor recovery system
  • Provided and installed 3” fill pipes and fittings with overfill prevention valves for the No. 2 fuel, gasoline and diesel tanks
  • Provided and installed two 15-gallon spill containments to house the 3 fill ports and vapor recovery pipe

Stanwade tank set on cement pad and ready for piping

  • Provided and installed three 2” schedule 40 galvanized steel vent risers with approved vent caps.  The vent pipes terminated approximately 12’ from ground level.
  • Provided and installed three supply pipes from the aboveground storage tank to the new dispensers consisting of approximately 80’ of 2” schedule 40 galvanized pipe. Pipes included fire safety valves, pressure relief valves and ball valves.
  • Provided and installed three new shear valves inside the new sumps
  • Provided and installed two new Wayne Dresser™ dispensers with digital gallon display, four hoses and handles, internal filters, solenoid valves, enhanced capacity and electromechanical totalizers
  • Provided and installed three 2 HP Red Jacket™ submersible pumps
  • Arranged final inspection with DES
  • Provided close-out documentation including signed permits, test results, operations manuals, manufacturer’s warranty and warranty letter

Underground Pipe Installation

  • Provided and installed one transition containment sump
  • Provided and installed two dispenser containment sumps
  • Provided and set a 3’ x 9’  stainless steel island
  • Provided and installed three 1 3/4 ” D/W flex product piping with 4” secondary conduit and entry boots to the dispenser sumps
  • Provided and installed one new Veeder-Root™ leak detection sensor in the new transition sump
  • Hydrostatically tested the transition and dispenser sumps

Dispenser sumps with double-wall pipe installed

Concrete Drive Mat

  • Provided the services of a mason and a laborer to assist in the construction of  the concrete fuel island

Tank and Pipe Testing

The new AST was pressurized to 5 pounds per square inch (PSI) for more than one hour.  Vacuum pressure of 15 PSI was applied to the secondary containment of the new UST for a 24-hour period. The primary containment for the product supply lines was pressurized at 50 PSI over a 24-hour period. The secondary containment for the product supply and return lines was pressurized and held at 4 PSI over a 24-hour period.

Fuel dispenser sump is hydrostatically tested

Fuel Monitoring and Leak Detection System

CommTank certified the new Veeder-Root ™ TLS 350 System, which measures liquid in the interstitial space (between the inner tank and outer containment).  This automatic tank gauge measures the amount of fuel or water (if any) inside the tanks.  It will also trigger an alarm in case the tank exceeds its filling capacity.  The system is able to detect any leaks that may develop in the underground fuel lines.

After placing No. 2 fuel, gasoline and diesel into the two compartments, satisfactory operation of the monitoring system was ensured before the system was placed into operation. Satisfactory operation of the secondary containment system, overfill prevention devices and line leak detectors was also tested.

An underground storage tank site closure report was delivered at the project completion. This project was approved by the New Hampshire Department of Environmental Services (NHDES) after they reviewed the engineer’s specification. All work conformed to federal, state, and local fire code regulations.

Piping connections to remote fill port

The following tasks were completed by Morin’s Landscaping:

UST Removal

  • Backfilled excavation and restore area after tank removal

Underground Pipe Installation

  • Excavate trench adequate for the installation of the new pipes and sumps
    Backfilled  trench with approved material and restore area

Concrete Pad and Bollard Installation

  • Installed one steel reinforced concrete pad and drive mat including positive limiting barrier per the specifications of the licensed professional engineer (PE)
  • Installed traffic bollards  to protect the tank and dispenser from vehicle traffic
  • Backfilled excavation after tank removal

Electrical Conduits and Wire Installation

  • Installed new above and underground conduits from the electrical panel inside the building to the new AST
  • Installed new above and underground conduits from the location of the VR panel inside the building to the new AST
  • Provide the services of a licensed electrician to provide power to the new submersible pumps, fuel dispensers, and Veeder Root™
  • Installed emergency shut off switch

View of remote fill port in front of the new fuel storage tank

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