Blast Pot & Air Receiver Pressure Testing
Every time you pressurise a blast pot, you trust its steel shell to hold. Abrasive wears it from the inside, site life knocks it from the outside, and South African law asks you to prove, at set intervals, that it’s still safe. We handle the inspection, wall thickness measurement, hydrostatic test and paperwork for your blast pots and air receivers (manifolds), so when a safety officer or inspector asks for your certificate, it’s already in your file.
Who is responsible for testing?
The user is, not the supplier. Under regulation 11 of the Pressure Equipment Regulations, 2009, the duty to have a pressure vessel inspected and tested sits with the company operating it. That catches many contractors out: the pot arrived with a certificate, so it’s easy to assume the paperwork is permanent. It isn’t. The certificate proves the pot was safe on the day it was tested, and the clock starts from there.
What the law requires
- Inspected inside and out. A visual check of the vessel’s internal and external condition.
- Hydraulic test at 1.25 × design pressure. The vessel is filled with water and taken to a quarter above the pressure it was designed for.
- Signed off by an AIA, at least every 36 months. An Approved Inspection Authority is an independent inspection body, accredited by SANAS and approved by the Department of Employment and Labour. Every test we carry out is signed off by our third-party AIA.
The regulations allow longer intervals for equipment that doesn’t deteriorate in service. A blast pot is abraded every time it runs, so in practice that exception rarely applies. Small Category I vessels under SANS 347 may be tested by the user, but most production blast pots sit above that category. If you’re unsure where your pot falls, send us its nameplate details and we’ll tell you.
How our pressure test works
- Book and send your records. Share the pot’s serial number, nameplate details and your pressure vessel data pack or last certificate. Testing is done at our Johannesburg branch in Boksburg. Drop your pot at our Durban or Cape Town branch and we’ll send it through for you.
- Strip and clean. We empty the pot, remove the valves and fittings, and clean the interior so nothing hides under a crust of old abrasive.
- Inspect and measure. We look for pitting, corrosion around welds and fittings, dents, bulging and an unreadable nameplate. We also measure the wall thickness of the shell, so you know how much steel abrasive has worn away.
- Hydrostatic test. The pot is filled with water, raised to 1.25 times its design pressure and held while we check for leaks, weeping welds and any change in shape.
- Reassemble and check. Fittings go back on and we check the pot works as it should. Worn components such as pop up valves or grit valves are flagged with a quote before anything is replaced.
- Certify and record. Our independent AIA signs off the test, you receive the certificate, and the result is added to the pot’s data pack with the next due date.
Why water and not air? Water barely compresses, so if a weakness gives way under test, the pressure drops almost instantly. Compressed air stores far more energy, which is why no one should ever test a vessel by simply pumping it up with a compressor.
Why measure wall thickness as well? The hydrostatic test shows the pot holds pressure today. Wall thickness shows how much margin is left. Abrasive thins the shell from the inside, often unevenly, and the readings tell you whether wear is something to watch or a reason to plan a replacement.
What you get back
- A pressure test certificate for the vessel
- An updated entry in your pressure vessel data pack
- A short inspection report noting wear to keep an eye on
- The date your next test is due, so you can add it to your maintenance schedule
When is your pot due?
Situation | Test interval |
|---|---|
General industrial and commercial use | At least every 36 months |
Mine sites | Every 12 months: almost all mines require yearly testing, in line with the Mine Health and Safety Act, 1996 |
After a welding repair or modification | Before it goes back into service |
Damage, a fall, or an unknown history | Before its next use |
An inspector instructs more frequent testing | As instructed |
Don’t wait for the due date if you notice any of these: dents or bulges in the shell, rust or pitting around welds, leaks at fittings, damage in transport, or a pot that has stood unused for a long time. Bought a pot second-hand? Treat it as untested until you’ve seen a valid certificate.
What happens if a pot fails?
If an inspection or test finds a defect that could put people at risk, the vessel must come out of service until it is put right to the satisfaction of the AIA. A failed pot is never returned to you as certified. We’ll explain what we found and give you your options: a repair where it is safe and makes economic sense, or a replacement from our dry or dustless blast pot range when it doesn’t.
Equipment we test
We pressure test two types of equipment:
- Blast pots: dry and dustless, single and double chamber
- Air receivers (manifolds): our 150L Manifold, the mobile air distribution point most sites simply call an air receiver
We pressure test equipment supplied by Storm Machinery only.
Missing your data pack?
It happens: equipment changes hands, a site office is cleared out, a file goes missing. Without its history, a vessel is hard to prove compliant. We can help you rebuild the records for equipment we supplied. This is a separate service with an additional fee, and we’ll quote you before any work starts. Contact us with the serial number and any paperwork you still have.
Why test with Storm Machinery
- We know these pots inside out. We only test equipment we supplied, so we know each one’s design and history. We’ve been supplying surface preparation equipment in South Africa since 1990.
- Parts on the shelf. Worn valves, seals and fittings can be replaced at the same visit, so the pot leaves ready to work.
- Tested in Johannesburg, back in days. All pressure testing is done at our Boksburg branch, with a typical turnaround of 4 to 5 days. In KZN or the Western Cape, drop your pot at our Durban or Cape Town branch and we’ll send it through.
- One record, kept current. Every test is added to your pot’s data pack, so its history stays complete.
FAQs
Who is legally responsible for having a blast pot tested?
The user, meaning the company that operates it. The supplier tests the pot before sale, but in-service testing is the owner’s duty under the Pressure Equipment Regulations.
What pressure is a blast pot tested at?
1.25 times its design pressure. The design pressure is stamped on the pot’s nameplate and recorded in its data pack.
Can I keep using my pot once the test is overdue?
No. Once the interval has passed, the pot is no longer compliant and shouldn’t be pressurised. Book your test a few weeks before the due date so there’s no gap.
How long does a test take?
Usually 4 to 5 days once the pot arrives at our Johannesburg branch. Allow extra time for transport if you drop off in Durban or Cape Town, and if parts need replacing.
What should I send in with my pot?
The pot emptied of abrasive, its data pack or last test certificate, and a contact person who can approve any repairs. It’s also worth sending any blast hoses, fittings or other parts that need repairing or replacing. We can sort them out while the pot is with us, so everything comes back ready to work.
Do you pressure test pots you didn't supply?
No. We only pressure test equipment supplied by Storm Machinery. If your pot came from another supplier, speak to them about its in-service testing.
Book a pressure test
Tell us about your equipment and when it’s due, and we’ll come back to you with a booking and a quote.