Boiler and Pressure Vessel Hydraulic Testing in Bangladesh: Procedure and Requirements

A boiler or air receiver spends its life holding pressure you cannot see. Corrosion thins the shell from the inside, a weld develops a fault, a safety valve seizes — and none of it announces itself until the day it fails. Hydrostatic testing exists because water is the safe way to find that out: fill the vessel, pressurise it beyond working pressure, and watch what happens with a fluid that will not expand violently if something gives.

Why water and not air

This is the part worth understanding, because it is also the reason nobody should improvise this test with a compressor. Compressed air stores an enormous amount of energy; if a vessel fails under pneumatic pressure, that energy releases at once. Water is very nearly incompressible — a failure under hydrostatic pressure produces a leak and a pressure drop, not an explosion. That single physical difference is why hydrostatic testing is the accepted method for proving pressure equipment.

What is covered in Bangladesh

Boilers, pressure vessels, air receivers and associated pressure plant in factories and establishments fall under the Bangladesh Labour Act, 2006 and the rules made under it, with periodic examination and testing carried out by a DIFE-enlisted inspection body. Boilers additionally sit under the country’s boiler regulations and their own inspection regime. Typical equipment we are asked to test:

• Steam boilers and their mountings
• Air receivers and compressed air tanks
• Pressure vessels, autoclaves and jacketed vessels
• Storage tanks and process piping subject to pressure
• Safety relief valves — set pressure verification

How the test runs

The exact test pressure and hold time are set by the design code and the vessel’s rated working pressure, not by a single universal figure — the inspecting engineer confirms them from the nameplate and documentation before the test.

The gauge is part of the test

A hydrostatic test proves a pressure figure, so the instrument reading that figure has to be trustworthy. A test run on an uncalibrated gauge produces a certificate that states a number nobody can defend. Pressure gauges and recorders used for testing should carry current calibration traceable to national standards — the same reason your process gauges need a documented interval, covered in our guide to pressure gauge calibration.

Thickness survey first, pressure test second. Testing a vessel without knowing how much wall is left is how a routine test turns into an incident.

What auditors and insurers ask for

• A current test certificate from an enlisted body, with the vessel identified by serial or asset number
• The test pressure applied and the hold period
• Thickness survey data, ideally with previous readings so a corrosion rate is visible
• Safety valve set pressure verification
• Defects found and what was done about them

Two surveys at a known interval are worth far more than one: they turn a snapshot into a corrosion rate, which is what lets you plan a replacement instead of discovering the need for one during a shutdown.

ION Engineering carries out hydrostatic testing, thickness survey and safety valve verification as a DIFE enlisted inspection body, alongside the NDT and integrity inspection that usually belongs in the same shutdown window. Tell us what equipment is due and we will scope the visit around your production schedule.