Extended Operational and Trade Vocabulary

Marine Bunker Fuels, Lubricants and Bunkering Operations glossary (page 2)

The chemistry and handling of marine fuels and lubricants: flash point, viscosity, acid number, and additive packages, catalyst fines (Al+Si) capped under ISO 8217, fuel stability and accelerated aging, ullage and air gap in tank gauging, and bunkering operations with the BDN and mass flow metering. Covers the test methods and quality parameters that govern bunker quantity and quality disputes.

301 defined terms.

Showing 51 on this page (page 2 of 2).

S

Spectrophotometric analysis: Used for color and contamination assessment of fuels.
Spot test: Compatibility test on filter paper per ASTM D4740.
Stability: Ability of a residual fuel to remain homogeneous without asphaltene precipitation.
Stationary sample: Sample drawn from tank rather than from flowing line.
Stem: Trade term for a bunker delivery slot.
Strainer: Coarse filter at suction and discharge of transfer pumps.
Stripping: Unloading of a container.
Sulphated ash: Inorganic residue after burning lube oil and treating with sulphuric acid, per ISO 3987.
Sulphur cap: 0.50% m/m global sulphur limit since 2020 under MARPOL Annex VI Reg 14.
Sulphur content: Mass percent of sulphur in fuel, measured per ISO 8754 or ASTM D4294.
System oil: Crankcase lubricant of two-stroke crosshead engines, low BN compared to cylinder oil.

T

TAN (Total Acid Number): Acid number of lube oil or fuel, per ASTM D664; relevant in monitoring acidic combustion contamination.
Tank calibration table: Document relating ullage or sounding to volume for each tank.
Tank top sample: Sample drawn near the top of a tank's liquid surface.
TBN (Total Base Number): Alkalinity rating of cylinder lube oil.
TBN depletion: Loss of alkalinity reserve in cylinder oil after combustion of sulphur-bearing fuel.
Temperature compensation: Correction of measured volume to a reference temperature (15 C) using ASTM tables.
Thermal oxidation: Lube oil degradation pathway under high-temperature exposure.
Tier I, II, III: NOx limits for marine diesel engines under MARPOL Annex VI Reg 13.
Time-weighted sample: Drip sample collected at uniform rate proportional to delivery duration.
Total sediment, aged (TSA): Sediment after thermal aging per ISO 10307-2.
Total sediment, potential (TSP): Sediment after accelerated aging per ISO 10307-2 Procedure A.
TPEO (Trunk Piston Engine Oil): Lubricant for medium-speed engines combining bearing lubrication and cylinder oil duty.
TR48: See Singapore TR48.
Truck-to-ship (TTS): LNG, methanol, or distillate bunkering from a road tanker.

U

Ullage: Empty space above liquid cargo in a tank.
Ullage report: Pre- and post-transfer record of ullages in delivering and receiving tanks.
ULSFO (Ultra Low Sulphur Fuel Oil): Residual or hybrid fuel with sulphur not exceeding 0.10% m/m for ECA use.
Unfit for use: Description of fuel deemed not suitable for combustion after testing.
Used oil analysis: Periodic testing of system, cylinder, and TPEO lubricants to monitor wear and contamination.

V

Vanadium: Trace metal in residual fuel; combines with sodium to cause high-temperature corrosion in turbines.
Vapor pressure: Pressure exerted by fuel vapors at a given temperature, relevant for methanol and LNG.
Vapor return: Return line carrying displaced vapors during LNG, methanol, or hot residual bunkering.
Viscosity at 40 C: Reference viscosity for distillate marine fuels.
Viscosity at 50 C: Reference viscosity for residual marine fuels.
Viscosity index (VI): Measure of viscosity change with temperature, important for lube oils.
Visual inspection: Quick check of fuel sample for color, water, and visible solids before lab testing.
VLSFO (Very Low Sulphur Fuel Oil): Residual or hybrid fuel with sulphur not exceeding 0.50% m/m for global cap compliance.
Volatile organic compound (VOC): Hydrocarbon vapors released during fuel handling.
VPS (Veritas Petroleum Services): International bunker fuel testing and advisory company.

W

Wash oil: Diesel used to flush a residual system before maintenance.
Water by distillation: Volumetric water determination per ISO 3733, the routine bunker test.
Water by Karl Fischer: Direct water determination per ASTM D6304.
Water content: Free and emulsified water in fuel, limited to 0.50% V/V in most residual grades.
Wear metals: Iron, copper, lead, tin, and chromium quantified in used lube oil by ICP-OES.
Weather window: Period of suitable weather for an operation.
Wedge formula: Calculation correcting bunker quantities for trim and list.

X

XRF (X-ray fluorescence): Analytical technique for sulphur and metals in fuel and lubricants.

Y

Yield: Catch in weight or numbers from a fishery.

Z

ZDDP (Zinc Dialkyldithiophosphate): Anti-wear additive in some lubricants, limited in marine cylinder and system oils for ash control.
Zinc: Element in some lube oils from ZDDP additive; absence indicates an ashless or low-ash formulation.