SS Tanks, Vessels and Process Piping: What Buyers Should Specify

Stainless steel tanks, vessels and process piping are used to store, transfer, mix or handle liquids, powders and other materials. Although the finished equipment may appear simple, its design depends heavily on the process.

A tank built for water is not automatically suitable for chemicals, food ingredients or pharmaceutical products. Buyers should provide a clear operating specification before fabrication begins.

Define the stored or processed material

The fabricator needs to know what the tank will contain. Important properties include corrosiveness, viscosity, temperature, density and whether the material settles, foams or crystallises.

The material influences the stainless steel grade, internal finish, outlet design and cleaning arrangement. It may also affect gasket and valve selection.

Capacity and usable volume

A tank’s nominal capacity and working capacity are not always the same. Space may be required above the liquid for expansion, foaming, agitation or process control.

The buyer should specify whether the stated volume is total volume or usable operating volume. Dimensions may also be limited by room height, doorway size or transport access.

Atmospheric or pressurised service

An open storage tank is fundamentally different from a pressure vessel. Pressure, vacuum and temperature introduce additional engineering and safety requirements.

The operating and design conditions must be stated clearly. Equipment intended for pressure service should be designed and reviewed according to the applicable engineering requirements. A general-purpose fabrication drawing should not be used as a substitute for pressure-vessel design.

Tank shape and bottom design

Vertical cylindrical tanks are common, but rectangular tanks may suit certain spaces. The bottom may be flat, sloped, conical or dished depending on drainage and process needs.

A sloped or conical bottom can help empty the tank, but the outlet position and supporting frame must allow adequate clearance. Powders and thick materials may require steeper hopper angles.

Connections and accessories

Every nozzle should have a defined purpose, size and location. Typical connections include:

· Inlet and outlet

· Drain

· Overflow and vent

· Cleaning or spray connection

· Level sensor connection

· Temperature probe

· Sampling point

· Manhole or inspection cover

· Agitator mounting

· Sight glass

Changing nozzle positions after fabrication can be difficult, so the piping and instrumentation requirements should be reviewed before production.

Supports and installation

Tanks may use legs, skirts, wall supports or structural frames. The support design must account for the filled weight, not only the empty tank. The floor condition and anchor points should be checked.

Large vessels may need to be delivered in sections or assembled at site. Access routes, lifting equipment and installation clearances should be planned early.

Process piping layout

Stainless steel piping should be routed for function, drainage and maintenance. Long unsupported spans, unnecessary bends and inaccessible valves should be avoided.

Pipe supports must allow for weight and, where relevant, thermal movement. The piping arrangement should not place excessive stress on pumps, tanks or machine connections.

For hygiene-sensitive processes, joints and internal surfaces require particular attention. The cleaning method should influence the layout and slope.

Welding, inspection and testing

The inspection level should match the service. Visual checks can identify surface defects and poor alignment. Leak or pressure testing may be required depending on the system.

Welds should be cleaned and finished as specified. Any passivation or specialised surface treatment should be agreed in advance.

Questions to answer before requesting a quotation

Provide the fabricator with:

· Product or material handled

· Required capacity

· Operating temperature and pressure

· Stainless steel grade

· Internal and external finish

· Dimensions or space restrictions

· Nozzle schedule

· Accessories and instrumentation

· Support arrangement

· Testing requirements

· Site installation scope

This information results in a more accurate quotation and fewer changes later.

Custom fabrication in Manesar

AKG Steel Fabrications manufactures stainless steel tanks, vessels, hoppers, chutes, piping and pipe supports for industrial projects. Work can include site measurement, workshop fabrication, installation and modification of existing systems.

A successful tank or piping project begins with a clear process specification. The more accurately the operating conditions are defined, the more reliable the fabricated system will be.