Tanker Loading / Unloading Systems Data Requirements

The following data is required in order to undertake a detailed surge analysis of a tanker loading or unloading system. The data that is relatively acceptable to assume and where Hydraulic Analysis Ltd can adopt typical values has been marked with an asterisk (*).

Hydraulic Analysis Ltd needs the information used to design a system using steady state techniques, plus additional information that is not necessarily readily available. We are familiar with the acquisition of this latter information and hence can frequently help to obtain it from our databases or from the relevant manufacturers.
Generally the following is needed:

  • Process flow diagrams.
  • P&IDs.
  • Isometrics or pipeline routing.
  • Pipe specifications.
  • Equipment data sheets.
  • Operating instructions and procedures.


  • Process and Instrumentation Diagrams.
  • Isometric drawings detailing pipe lengths and elevations for all pipework.
  • Flow Utility diagrams (if available).


  • Internal diameters.
  • Wall thicknesses.
  • Material type and its pressure rating.
  • Young’s Modulus (if available).

Control Valves

  • Valve size, manufacturer and type.
  • End to end stroke times.
  • Control type (proportional, proportional & integral etc).
  • Tuning parameters, i.e.; Proportional band and Integral Reset time (*).

Isolation Valves
We have a large database of isolation valve types, hence the minimum information needed is:

  • Size.
  • Type (ball, butterfly etc).
  • Manufacturer and model (if available).

Air Valves / Vacuum Breakers
If any automatic air valves are incorporated on the system (usually on high points), the following is required:

  • Valve type and manufacturer (*).
  • Valve size.
  • Valve location and elevation.

Surge Relief Valves
Surge relief valves tend to need a lot of manufacturer specific data and hence we keep a large database of information. Generally only the following is needed:

  • Manufacturer.
  • Set point.
  • Size.
  • Pressure rating & and any installation specific details.

Spring Loaded Relief Valves
These standard relief valves need:

  • Orifice letter or area.
  • Set point.
  • Percentage accumulation.
  • Balanced bellows or normal.

Duty Flowrates and Pressures
The design duty flowrates and the pressures that are expected to occur throughout the system (this may be available from the UFDs).

Flow / Pressure Sensors

  • Set point and location.
  • Switch actions (from cause and effect charts, or similar).

Proposed Operation of the System
In order to obtain a clear understanding of the system operation and to be able to determine the worst case scenario’s, a description / clarification of the mode of operation of the system is required. For example:

  • Normal start-up sequence.
  • Normal shutdown sequence.
  • Emergency shutdown operations.
  • Other operations (such as standby pump start, flow change).

Fluid Properties
Details of the fluid to be loaded including:

  • Operating temperature.
  • Viscosity.
  • Density.
  • Vapour pressure.