IBC Tanks are tested for leak proof performance in two ways: a water test and a vacuum test.
A leaking IBC tank is more than just a nuisance. It’s a burden, a compliance shortfall and sometimes a real safety risk. From the factory and throughout its service life, leak proof performance is a must for tanks used to store water, food grade liquids, agricultural chemicals or industrial solvents.
Then how will you know if having an IBC tank won’t let you down?
The solution is a series of tests which are designed to be standard, rigorous, and that each IBC must meet—and continue to meet—while it is in operation.
This guide explains how leak proof tests on IBC tanks are conducted, the conditions that apply to the test, who establishes the standards and what a buyer/operator should expect during a test.
What is the Importance of Leak Proof Testing That is Greater Than You Can Imagine?
When purchasing, individuals are apt to consider IBC tank capacity and material compatibility.
All of that is taken care of — weight, dimensions, type of valve.
But, leak proof certification is usually taken for granted.
It should not be.
IBC containers must have UN approval to be used for hazardous goods transport via public roads, inland waterways and rail.
This is because UN approval comes after you have gone through a series of demanding tests, such as leak proof tests, hydraulic pressure tests, drop tests, stacking tests, vibration tests, and others.
By that, I mean each certified IBC is deserving of its name.
However, the label testing process used is more rigorous than most people would think.
The Core Test is The Leakproofness Air Pressure Test
Leakproofness test is the most direct and universally used test and it is as the name suggests.
The sealed tank is subjected to a pressure of air (or whatever the test gas is) and the tank is required to maintain that pressure without leakage being detectable.
US Code of Federal Regulations (CFR) Part 178, Subpart O states that the test for leakproofness shall be conducted at a gauge pressure of at least 20 kPa (2.9 psig).
All seams and joints are filled with a heavy oil, soap solution and water or some other way that is effective at detecting escaping air to detect leaks.
The principle is straightforward:
If the air can’t escape, neither will the liquid.
The formation of bubbles at joints, seams or valve fittings is a dead giveaway.
The ADR version of this test is performed in a highly structured manner in practice.
Leak proof air pressure test performed at 0.2 Bar (2.9 psi) and all seams, fittings and joints are treated with leak detection fluid.
It is required under ADR regulation 6.5.4.4.3 that the tank be capable of holding pressure and if there is no sign of leaking then it must be for at least 10 minutes.
10 minutes under pressure, no bubbles, no pressure drop. Pass is that!
The Hydrostatic Pressure Test
The hydrostatic pressure test is more stringent than the air pressure test, which tests for leakages when the tank is sealed normally.
This is to ensure that the internal structure of the tank, including the seals and joints, are able to resist the pressure without any ruptures or leaks.
IBCs are filled in the hydrostatic pressure test and exposed to a particular level of internal pressure.
Typical test parameters are water and 70 kPa, with the goal being to determine if the tank and all its fittings will leak or fail at that test load.
A common standard that is cited is to fill the IBC tank with water until the internal pressure is 100 kPa, and to maintain this pressure for 10 minutes.
The inner container should not break or leak.
This is a very important test for tanks that will carry denser or pressurised liquids.
This replicates operating conditions much more than a standard filling, and allows the manufacturers and buyers to have confidence that the tank will perform in the event of a high-stakes operation.
Drop Test: Leak Proof Under Impact
Leak proof performance isn’t exclusive to tanks which sit still on a warehouse floor.
Tanks are moved, lifted and — sometimes — dropped.
The drop test replicates that situation, and determines if the tank remains structurally sound and sealed following the impact.
The filled IBC tank is dropped from a height of 1.2 metres on to a hard surface in the drop test.
The idea is to confirm structural strength when a fall occurs and to make certain that there is no leakage from the impact.
This may sound cruel but it really is.
But it’s also very believable.
A tank that fails the 1.2-metre drop test at a controlled lab is a tank that will fail in real logistics or unplanned situations such as a loading dock, off a forklift.
No better to know in a test facility than in the field.
Vibration Test: Road and Transit Stress Test
Road transport is not very friendly to containers.
Engines, rough roads and long journeys generate stresses, which can build up over time.
The vibration test is meant to take into account just this.
The IBC is filled and mounted vertically or with a double amplitude of one inch on a vibrator in the vibration test.
The test is conducted at a frequency adequate to bring the IBC off the platform (achieved by passing a 1.6 mm thick test piece between the base of the tank and the platform), and for 1 hour.
The IBC passes only as long as there is no rupture or leakage.
This test is an ingenious test.
The jounce and rebound force mimics road-going vibrations, and the challenge of proving no leaks after an hour of non-stop jounce and rebound puts a realistic test on the durability of the whole system.
The Leak Proof Under Weight (LPUW) Test is the Stacking Test
Stacking is a common aspect of warehouse storage.
The stacking test is performed to determine whether a complete IBC will hold the weight of additional containers stacked on top of it without becoming distorted, collapsing or leaking.
A loading of 4056kg is placed on the IBC for 24 hours in the stacking test at room temperature.
Visual examination should be conducted after the test period to ensure that there is no loss of any contents, and no permanent damage to the tank or bottom pallet that could compromise transport safety.
Each UN-rated IBC is permanently marked with this stacking load test rating on the UN rating plate attached to the cage indicating the maximum load that can be placed upon the top of the IBC when the IBC is full to its rated capacity.
It is not a recommendation.
A challenging constraint based on actual testing.
Prior to Leaving the Factory, Each and Every Tank is Subjected to Production Testing
Did you know?
The tests listed above are not only done on prototype or design samples.
All IBCs are leak tested at production level for liquids.
Production testing is the performance of the leakproofness test for each individual IBC which will be used to contain solids discharged under pressure or will be used to contain liquids.
This occurs at the beginning of production, and is not a sampling check — it applies to each individual unit.
This means that if the buyer purchases a UN certified IBC the leakproofness test was completed on that particular tank before the IBC was delivered to the buyer.
The UN data plate is evidence of this.
Compliance Throughout the Life of the Tank: Periodic Retesting
Factory testing is not the end of the road, it is just the beginning.
There are regulations for the retesting of IBC tanks every so often to ensure they are compliant with the regulations.
All UN/DOT-approved IBC tanks with liquids for transport will have to be tested for leak proofness every 2.5 years.
A thick gauge must be performed on S/S IBC tanks every 5 years and an extensive external inspection must be done every 2.5 years since manufacture or repair.
ADR rules require that a new IBC undergo an initial inspection and that it be inspected every 2.5 years thereafter.
By law the owner must maintain records of all testing and inspection work which can be provided to regulatory authorities when required.
Don’t wait to get an MOT for your storage tank!
When Checking on Your IBC Tank, There Are Certain Things You Should Do
If you have IBCs you use for liquid storage and/or transport, here are the 3 things to check right away.
1. Verify the UN Information
Verify the UN information on the cage which should include the test rating, manufacture date and packaging group.
2. Validate Inspection Dates
Validate the date of the last inspection and if it is still valid, the 2.5-year leakproofness test.
3. Inspect Service Equipment
Make sure service equipment (lids, gaskets, plugs and gauges) is installed and operating and tank is not cracked, warped, corroded or dented and is safe for transport.
A healthy looking tank six months ago might not look healthy today.
Don’t be paranoid, do visual checks between inspections.
Final Thoughts on How IBC Tanks are Tested for Leak Proof Performance
The testing framework for the leak proof IBC performance is comprehensive, controlled and meets internationally recognised testing standards.
Familiarity with it will enable you to make better purchases, work safely and remain compliant — regardless of where your tanks are working around the world.