Technical Glossary
Oil Storage and Terminal Glossary
A plain-language guide to the terms used in bulk liquid storage and marine terminal operations.
A
- API 650 / API 653
- American Petroleum Institute standards. API 650 covers the design and construction of welded steel storage tanks. API 653 covers their inspection, repair, alteration and reconstruction.
- Asset integrity
- The ability of an asset to perform its function safely and effectively over its life. It is managed through design, inspection, maintenance and monitoring.
B
- Berth
- A designated place where a vessel is moored for loading or discharge.
- Bulk liquid storage
- Storage of large volumes of liquid products, such as crude oil, refined products or chemicals, in tanks at a terminal.
- Bund (containment area)
- A wall or embankment around a tank or group of tanks, designed to contain spilled product if a tank leaks or fails.
- Bunkering
- Supplying fuel to ships for their own propulsion, usually delivered by barge.
C
- Custody transfer
- The point at which ownership or responsibility for a product passes from one party to another, measured with high-accuracy meters or tank gauging.
D
- DWT (deadweight tonnage)
- The total weight a vessel can carry, including cargo, fuel, water and stores. It is used to describe vessel size.
E
- External floating roof
- A tank roof that floats on the product surface and is open to the atmosphere. It reduces vapour space and evaporation losses. It is common for crude oil.
F
- FEED (front-end engineering design)
- The engineering phase that defines a project in enough detail for a final investment decision and for contractor tendering.
H
- HAZOP (hazard and operability study)
- A structured, team-based review of a process design to identify hazards and operability problems.
- HSSE
- Health, Safety, Security and Environment.
I
- Internal floating roof
- A floating roof inside a tank with a fixed roof, used for volatile products such as gasoline and jet fuel to reduce emissions and protect product quality.
J
- Jetty
- A structure extending from the shore into the water, which supports berths, pipelines and loading equipment.
L
- Loading arm
- An articulated steel pipe assembly that connects terminal pipelines to a vessel's manifold for transferring product. It is usually fitted with an emergency release system.
M
- Manifold
- An arrangement of pipes and valves that routes product between tanks, pumps, pipelines and berths.
- Marine terminal
- A terminal with berths for vessels to load and discharge products, linked to on-shore storage.
O
- Overfill protection
- Systems and procedures that prevent a tank from being filled beyond its safe capacity. They typically include an independent high-high level alarm and automatic shutdown.
P
- Pipeline transfer
- The movement of product through pipelines, between tanks within a terminal or between a terminal and another facility. Lines may be “pigged”: a device called a pig is sent through the pipe to clean it, separate products or inspect it.
- Product segregation
- Keeping different products or grades separate in tanks, lines and equipment to prevent contamination.
S
- SCADA (supervisory control and data acquisition)
- A control system used to monitor and operate terminal equipment such as pumps, valves and tank levels.
T
- Tank farm
- A group of storage tanks within a terminal, usually arranged in bunded groups.
- Tank gauging
- Measuring the level, temperature and sometimes water content of product in a tank. Automated tank gauging uses radar or other sensors to do this continuously.
- Terminal
- A facility for receiving, storing and dispatching bulk products, typically including tanks, pipelines, pumps and loading facilities.
- Throughput
- The volume of product that passes through a terminal over a period, usually measured in tonnes or cubic metres per year.
U
- Ullage
- The unfilled space in a tank above the product surface. It is also used to mean the measurement of that space.
V
- Vapour recovery
- Systems that capture vapours displaced from tanks or vessels during loading and either return them to the product or treat them, reducing emissions.
- VLCC (very large crude carrier)
- A crude oil tanker of roughly 200,000–320,000 DWT, able to carry about two million barrels.
- VLSFO (very low sulphur fuel oil)
- Marine fuel oil with a sulphur content of no more than 0.50%, in line with international shipping regulations in force since 2020.
W
- Working capacity
- The usable volume of a tank, excluding the unpumpable volume at the bottom and the safety margin at the top. It is less than the tank's gross (shell) capacity.