Vessel and tank symbols
Vessels and tanks are drawn as simplified outlines of their real shape: a capsule for a pressure vessel, a tall capsule with trays for a column, a box with a roof for a storage tank.
- Vertical vesselA vertical pressure vessel holds or separates fluids under pressure.
- Horizontal vesselA horizontal pressure vessel suits services with a large liquid volume or where liquids need time to separate, such as oil, water and gas.
- ColumnA column separates mixtures by distillation, absorption or stripping, with trays or packing inside where vapour and liquid meet.
- Cone roof tankA cone roof tank stores liquid at or near atmospheric pressure under a fixed conical roof.
- Floating roof tankA floating roof tank has a roof that floats on the liquid surface, which cuts vapour losses from volatile products.
- SphereA spherical tank stores gases and liquefied gases under pressure.
- Open tankAn open tank is open to the atmosphere at the top.
- Silo or hopperA silo or hopper stores bulk solids and feeds them out through a cone at the bottom.
Vessels and tanks in ISO 10628-2
About ISO 10628-2- Vertical vesselTank, vessel with dished ends2062
- Horizontal vesselTank, vessel with dished ends2062
- ColumnTray column (general)X8101
- Cone roof tankTank with conical roof and flat bottomX2063
- SphereSpherical vessel on legsX8010
- Open tankContainer, tank, cistern2061
- Silo or hopperBunker with conical bottom2064
Pressure vessels usually carry a tag starting with V, tanks with T or TK, and columns with C or T. Nozzles, internals, design pressure and temperature are normally written next to the symbol.
The cards at the top use the forms of US legend sheets (PIP PIC001 practice). The grids below them show the same symbols as ISO 10628-2 or IEC 62424 draw them. See ISA vs ISO P&ID symbols for the differences.
Frequently asked questions
What are vessel and tank symbols on a P&ID?
Vessels and tanks are drawn as simplified outlines of their real shape: a capsule for a pressure vessel, a tall capsule with trays for a column, a box with a roof for a storage tank.
How many vessel and tank symbols are there?
This legend covers the 8 most common ones: vertical vessel, horizontal vessel, column, cone roof tank, floating roof tank, sphere, open tank, silo or hopper. Project legends may add company-specific variants.
Can I download these symbols?
Yes. Each symbol page has a free SVG and PNG, and the whole legend is available as a printable PDF chart on the P&ID symbols page.