The fuel oil system are mostly used for emergency generators, diesel driven fire pumps and engines.
Fuel tanks are either installed above ground or underground. The tank usually is factory constructed of steel with corrosion protestation coating and intended for atmospheric pressure conditions. Tank must meet the UL-142 requirements for safety. Tanks are fabricated in both round and rectangular configurations. The tank also fabricates with Fiberglass-reinforced plastic (FRP) or Reinforced concrete.
Above ground tank requires containing of any possible product release and preventing contamination of the adjacent environment. Containment methods include:
- Remote secondary containment (enclosure) which are usually made with steel. They are totally closed and sealed to prevent the entrance of rainwater. They are required by code to have a capacity that is 110% of the primary tank capacity.
- Dike, which completely surrounding the tank (for tanks without secondary containment). Dikes are required to be capable of containing 110% of tank capacity and to be constructed of concrete, steel, or impermeable soil designed to resist the full head of liquid.
- Integral secondary containment. This containment method is achieved by enclosing the primary tank with an integral secondary containment, usually of steel or reinforced concrete. This type of tank has an interstitial space that is monitored for leakage.
All type of tanks should be utilized by vent, emergency vent, product dispenser outlet, product fill, phase1 vapor recovery (for gasoline storage tanks), tank gauging, leak detection.
Underground tank shall be fabricated in conformance with applicable codes and national standards for structural strength and corrosion resistance. Tank installation must be done by the tank manufacturer approved contractor. The tank foundation, bedding and backfill must be done only with material and methods approved by the manufacturer, local codes and nationally recognized standards. Some factors should be considered when installing the tank underground such as ground-water condition, soil composition, potential for corrosive action and seismic or earthquake conditions.
Underground tank should be utilized with vent, emergency vent, product dispenser outlet & product fill, phase1 vapor recovery (for gasoline storage tanks), tank gauging, leak detection.
Underground tank can be fabricated with steel with coating depending on the corrosion protection method, fiberglass-reinforced plastic (FRP), steel and fiberglass-reinforced plastic composite or pre-engineered steel with cathodic protection.
- Piping material:
- The most common piping material for above ground tank is A-53 steel with threaded joints and factory applied corrosion protection.
- Where a higher degree of corrosion protection and strength is required the stainless steel pipe will be used.
- Fiberglass reinforced plastic pipe with ultraviolet protection.
- For underground piping, the steel pipe and fiberglass-reinforced plastic pipe are used.
- Pipe sizing:
- Pipe sizing is based on the flow rate of the product, allowable friction loss of the fluid through the system and fluid velocity. This procedure should be done in conjunction with selecting and sizing of the fuel product pump.