AIA inspection: how often a pressure vessel must be inspected in South Africa, and by whom
Headcore
In short
An AIA inspection is the internal and external inspection and hydraulic test at 1.25 times design pressure that South Africa's Pressure Equipment Regulations require for every pressure vessel and steam generator in use, at least every 36 months. An approved inspection authority (AIA) appointed in writing by the user does it; the user may inspect Category I and lower equipment.
Do all pressure vessels need to be inspected?
Not all of them. In South Africa, the Pressure Equipment Regulations (PER) cover only pressure equipment with a design pressure of 50 kPa or more (regulation 2(1)), less the exclusions of regulation 2(3), and the pressure vessels and steam generators in that scope get the inspections of regulation 11. A pressure vessel, in the PER's words, is "a housing designed and manufactured to contain a fluid" at such a pressure (regulation 1); the Department of Labour's guidance notes deem mobile air compressors pressure vessels, not transportable gas containers.[1]
Regulation 2(3) excludes, among others, water supply piping below boiling point, aerosol dispensers, pressure equipment intended for the functioning of road and rail vehicles (but not their fuel gas systems), machinery casings where pressure is not a significant design factor, and fixed electric geysers of 15 to 450 litres working at up to 600 kPa and made to SANS 151.[1]
Pressure equipment ordered after the PER were published must be categorised under SANS 347 (regulations 2(2) and 3(3)) and show that hazard category on its data plate (regulation 9(2)(j)), so the plate tells you which inspection route applies.[1]
Equipment in the SANS 347 SEP class (sound engineering practice) is still regulated and must be made to SEP rules but, in the words of the Department's guidance notes, "need not meet any other regulatory requirements" (note (h) to regulation 2).[1]
How often do pressure vessels need to be inspected?
In South Africa, a pressure vessel or steam generator in use is inspected and pressure tested at least every 36 months, a fire-tube boiler also gets an external inspection every 12 months, and the chief inspector may order a specific vessel inspected more often (regulation 11(1)); the Department restated these intervals at its 2025 OHS conference.[1][4]
| Equipment | What the user must arrange | Maximum interval | Regulation |
|---|---|---|---|
| New or re-installed pressure vessel or steam generator | Witnessed internal and external inspection and a hydraulic test at 1.25 times design pressure, by an AIA (by the user, for Category I and lower) | Before commissioning, after each installation or re-installation | 11(1)(a) |
| Pressure vessel or steam generator in use | Internal and external inspection and a hydraulic test at 1.25 times design pressure, by an in-service AIA appointed in writing (by the user, for Category I and lower) | 36 months | 11(1)(d) |
| Fire-tube steam generator | External inspection | 12 months | 11(1)(c) |
| Fire-tube steam generator | Witnessed hydraulic test and crack detection of critical welds | 36 months | 11(1)(c) |
| Vessel not subject to deterioration | Internal inspection and hydraulic test may be dispensed with on an AIA's written approval | Up to 9 years | 11(1)(d) |
| Vessel under a certified risk-based inspection system | Scope and intervals from the RBI study | As approved; beyond 9 years possible | 12, and note (b) |
| Piping and pipelines | Inspection and test to the in-service standard; where it sets no interval, a risk-based inspection applying sound engineering practice sets it | As the standard or the RBI sets | 11(1)(e) |
Sources:[1]
What is an AIA inspection?
An AIA inspection is the statutory inspection and test of pressure equipment by an approved inspection authority, which the Occupational Health and Safety Act defines as "an inspection authority approved by the chief inspector", approved only for the service named in its approval (section 1).[3]
Regulation 7(1) of the PER lets only an organisation holding the chief inspector's approval certificate act as an AIA, "within the scope of accreditation". For a South African body that approval depends on SANAS accreditation to SANS/ISO 17020 and SANS 10227 (regulation 7(3)(a)), and the AIA's unique mark carries the PER approval number the Department issues.[1][2]
The PER work with two kinds of AIA: the AIA for in-service inspection, appointed by the user in writing and limited by the Department's notes to the periodic inspections of regulation 11(1)(c) and (d), and the manufacturing AIA, which carries every other AIA duty, such as countersigning repairs and modifications and approving longer intervals (note (d) to regulation 7, notes (f) and (q) to regulation 11).[1]
Who may inspect a pressure vessel?
In South Africa, the user may inspect Category I and lower equipment and an AIA must inspect Category II and higher.[1]
| Task | Who may do it | Source |
|---|---|---|
| Inspection and test of Category I and lower equipment, before use and in service | The user; no qualification is set, but the notes expect knowledge of and experience in the PER and the relevant standard | Reg 11(1)(a) and (d); note (a) |
| Inspection and test before commissioning, Category II and higher | An AIA | Reg 11(1)(a) |
| Periodic in-service inspection and test, Category II and higher | An AIA for in-service inspection, appointed in writing by the user | Reg 11(1)(d) |
| The inspector on site | A registered competent person working under the AIA's quality system; freelance inspectors have not been allowed since 1 April 2011 | Note (l) to reg 11 |
| Approving the 9-year route for equipment not subject to deterioration | An AIA in writing, but not the in-service AIA | Reg 11(1)(d); note (f) |
| Checking a risk-based inspection system | A certification body accredited by SANAS under ISO 17021 for risk-based inspection and approved by the chief inspector | Reg 12(2) |
| Inspection and test of Category II and higher piping | A competent person as defined in the General Machinery Regulations, 1988 | Reg 11(1)(e) |
Sources:[1]
Can the 36-month interval be extended, or the hydraulic test replaced?
Yes, but each route needs a written approval or a certificate. The shortest is a deferment, which the Department's notes let an AIA approve "in writing to a maximum period of 6 months" (note (w) to regulation 11).[1]
Where equipment "is not subject to deterioration processes", the user may dispense with the internal inspection and hydraulic test for up to nine years with an AIA's written approval (regulation 11(1)(d)); the notes limit this to predictable material loss where the corrosion allowance will not be used up within 20 years (note (f)).[1]
Regulation 12 lets a certified risk-based inspection (RBI) management system replace the 36-month interval; the notes require an application to the Department before the system starts, and allow intervals beyond 9 years only under RBI (notes (b) and (c), and note (m) to regulation 11).[1]
Where it is impracticable to use a liquid, an inert gas test at 1.1 times the design pressure may replace the hydraulic test, with the AIA's prior written approval and, where practicable, an internal inspection first (regulation 11(2)); the notes accept air as the test gas (note (k)).[1]
A manufacturing AIA may also dispense with the in-service hydraulic test permanently, provided the vessel gets at least a visual inspection and non-destructive testing aimed at its expected deterioration, or a suitable non-intrusive inspection (note (g) to regulation 11).[1]
What happens during an AIA inspection?
For the periodic inspection the vessel comes out of service to be inspected inside and out and pressure tested (regulation 11(1)(d)), and regulation 15 requires the user to keep every manhole, inspection opening, control and accessory "safe and unobstructed".[1]
In practice, the inspection methods the Department of Employment and Labour's 2025 OHS conference material lists include a visual inspection inside and out, non-destructive testing (ultrasonic, magnetic particle, radiography and liquid penetrant), wall-thickness measurement and a hydrostatic or pneumatic pressure test, and it names corrosion, erosion, cracks, deformation, leaks and welding defects among common findings.[4]
Pressure and safety accessories need not stay fitted for the in-service test, but safety valves must be maintained to their standard or at intervals no longer than those of the vessel they protect, and the AIA need not witness a valve being reset (note (j) to regulation 11).[1]
What records must you keep, and what happens when a defect is found?
Regulation 14(1) requires every user to keep a record, "open for inspection by an inspector", of the certificate of manufacture and the results of all inspections, tests, modifications and repairs. The notes say to keep it for the equipment's operating life, including deferments, pressure-test dispensations and NDT reports (note (a)), and to hand it to the new owner when used equipment is sold (note (g) to regulation 14).[1]
A steam generator may not be used without a certificate of registration from the provincial director, applied for before first use with copies of the manufacturer's and the AIA's certificates (regulation 8(1) and (2)).[1]
An inspector who finds a defect that may endanger people must report it to the user "forthwith", and the user must "forthwith cease the use of the pressure equipment" until it is put right to the inspector's satisfaction (and the AIA's, for repairs and modifications) or re-rated by the AIA (regulation 11(3)).[1]
Breaching regulation 11(1) or 11(3) is an offence carrying a fine or imprisonment of up to 12 months, plus a further R200 fine or one day's imprisonment for each day a continuing offence goes on (regulation 20).[1]
What to put in your request
- Each vessel's serial number, design pressure in kPa, capacity in cubic metres and SANS 347 hazard category, as on the data plate.[1]
- The date of the last in-service inspection, with its report, and the date the 36-month limit falls.[1]
- The scope: internal and external inspection and a hydraulic test at 1.25 times design pressure, or the AIA approval already held for a pneumatic test, a 9-year dispensation or an RBI interval.[1]
- For fire-tube boilers: the 12-monthly external inspection, the 36-monthly crack detection of critical welds and a copy of the steam generator's registration certificate.[1]
- The inspection body's PER approval number and its SANAS accreditation certificate covering in-service inspection of this type of equipment.[1]
- Whether safety valves are to be removed, tested and reset in the same visit, and by whom.[1]
- The shutdown window: when each vessel can be taken out of service and opened, and how inspectors reach manholes and inspection openings.[1][4]
- Who signs the written appointment of the in-service AIA, and an inspection report to keep in the regulation 14 record.[1]
- For rented equipment: whether the owner or, under the hire contract, the user carries the inspection.[1]
Questions buyers ask
Is an air receiver a pressure vessel?
In South Africa, yes, when it is designed for 50 kPa or more. On equipment made under the PER, the SANS 347 category on the data plate sets the route: the user may inspect Category I and lower; an AIA inspects Category II and higher. For SEP-class equipment made to SEP rules, the Department's notes say it need not meet any other regulatory requirements.[1]
Who inspects rented pressure equipment?
The owner, unless the hire agreement says otherwise. The Department's notes leave the user's duties for rented pressure equipment with the owner, and the inspection "remains with the owner, unless otherwise agreed by the contracting parties".[1]
When does the 36-month clock start on a new plant?
For vessels and boilers that form part of an integrated process unit, the Department's notes start the in-service inspection and test interval on "the date of commissioning as per design intent of the process unit", not on each vessel's own date (note (x) to regulation 11), so the first 36 months run from that date.[1]
Can we postpone an inspection that is due?
Only with an AIA's written approval, and for at most 6 months, under the Department's notes on regulation 11. Anything longer needs the 9-year route for equipment not subject to deterioration or a certified risk-based inspection system under regulation 12.[1]
What if we disagree with the AIA?
Put it to the chief inspector in writing: regulation 7(5) lets any interested party, the user included, refer a technical or safety dispute it cannot resolve with an AIA. The chief inspector may appoint an arbitrator both sides agree on, and the case must be investigated and arbitrated within 90 days (regulation 7(6) and (7)).[1]
Sources
- Department of Labour (Government Gazette 41256), Guidance Notes to the Pressure Equipment Regulations, Revision 2 (GN 1265), with the text of each regulation, 17 November 2017.
- Department of Labour (Government Gazette 40713), Incorporation of health and safety standards into the Pressure Equipment Regulations, 2009 (GN R.262, replacing the schedule), 24 March 2017.
- Government Gazette 14918, Occupational Health and Safety Act 85 of 1993, 2 July 1993.
- Department of Employment and Labour, Pressure Equipment Inspections in the Iron and Steel Industry (OHS Conference 2025 presentation), 2025.