What is a Double Wall Underground Storage Tank?

1. What is a Double Wall Underground Storage Tank? A Double wall Underground Storage Tank consist of a primary steel tank wrapped by an exterior/secondary steel shell that is in direct contact with the primary tank, where the exterior shell is wrapped from 300 to 360 degrees of the primary tank • Put simply, a double wall underground storage tank consists of two tanks: a primary tank that is designed to store petroleum products and a secondary tank, with an interstitial space that is designed to monitor and self- contain leakages.

2. Double wall Underground Storage Tanks

3. Types of Double Wall Tanks ZPV Fabricates? • GLASS DW TANK: Double Wall Steel Coated with Glass Fiber • HB DW TANK: Double Wall Tank coated with Primer and Epoxy High build.

4. How is ZPV’s Double Wall Underground Storage Tank made? • Tank Ends (Heads) Formed • Tank Shells (Rings) Formed • Heads and Shells Assembled and Welded • Steel Tank Pneumatically Tested for Leak Tightness

5. How ZPV HB Double Wall Tank are assembled? Butt Joint Continuous welds Primary shell • The primary shells are welded together using the butt joint with a v-groove as per UL 58 Fig 8.1 No. 1 • The welds are continuous welds done with SAW machine. • The Primary dish ends are welded to the end shells using the lap joint as per UL 58 Fig 9.1 No. 25 • The welds are continuous full fillet welds done with SAW. Primary Dish end

6. How ZPV HB Double Wall Tank are assembled? • The Secondary shells are wrapped in two layers, the inner layer and outer layer. • Spacers cut from 4mm plates are welded to the inner layers. These layers are wrapped round the primary tank and the spacers seem welded to it. • The outer layers are then wrapped round the primary tank, with their edges placed on top of the inner layers creating a lap joint as per UL 58 Fig 8.1 No. 7 • The welds are continuous full fillet welds done with SAW Machines Primary Tank Head Secondary Tank Head Primary Tank Shell Secondary Tank Shell Secondary Tank Shell Spacers Outer Layer Inner Layer

7. How ZPV’s Double wall Tanks are Monitored Wet Monitoring LAG-14ER Leak Detector The way this systems functions is such that if there is a leakage either from the primary tank or secondary tank, an alarm is triggered that indicates there is a leak. Thus before a leaking tank pollutes the environment, the system detects it

8. How does ZPV’s Double Wall Tank protect the environment? Wet Monitoring Primary Tank made from 6mm steel S 235 JR Anti corrosive Liquid Glycol for interstitial space High Build Epoxy coating sprayed on Epoxy Primer. Total thickness up to 800 microns Secondary tank Jacket made from 4m steel S 235 JR

9. How does ZPV’s Double Wall Tank protect the environment? Wet Monitoring • The Primary tank is the containment tank where the fuel is stored. • The secondary tank is wrapped round the primary tank creating an interstitial space. • Liquid glycol, which is anticorrosive is poured into the interstice. This anticorrosive agent prevents the inner tank from rust. • If there is any leak, the secondary tank will contain it and prevent environmental hazards • A leak monitoring device is installed along with the tank. Fuel

10. How does the Leak Detection Device function? Wet Monitoring Alarm Unit Leak detection fluid Header Tank Probe • The leak detector monitors the interstitial space of double wall tanks that is already filled with leak detection fluid. • In the event of a leak in the inner or outer skin of the tank, leak detection fluid escape. • The level of the liquid in the header tank changes. • The alarm unit recognizes the change in resistance and provides a visual and audible alarm. Fuel

11. What happens if the secondary tank wall is breached? Wet Monitoring Alarm Unit Leak detection fluid Header Tank Probe • If there is a leak in the outer wall, the leak detection liquid, which is environmentally friendly, flows into the backfill • This results in a drop of fluid in the header tank. • The probe senses the change in resistance and sends out a signal to the alarm unit Fuel Leak detection fluid

12. What happens if the Primary tank wall is breached? Wet Monitoring Alarm Unit • If there is a leak in the inner wall, the fuel inside the tank will flow into the interstitial space and thus contained. This prevents the soil from contamination. • This will lead to the rise of leak detection fluid in the header tank • The probe senses the rise and therefore sends a signal to the alarm unit that the inner tank is leaking Leak detection fluid Header Tank Probe Fuel

13. Companies that the management of Zenith Plusvar Steel have worked for Guinness

14. Optional Accessories that can be ordered along with the tank Manhole chamber for easy installation of pipes and easy access to manhole Wooden crate and cushions for tank export Overfill Protector Device from Self Climat Underground tank support structure for easy installation of tanks Leak Detector Device from Eurogauge / Self Climat