Air Compressor Pressure Testing
Summary of the SANS 347:2012 Edition 2
Everything you need to know about Pressure Testing Air Compressor Vessels
What every user of an air compressor should know
The air receivers of compressors need to be pressure tested periodically. In South Africa, the test must be done by a registered AIA (Approved Inspection Authority). Please make sure the AIA is a registered person with a legal certificate before you ask for a pressure test.
If the air receiver is working in a mine, for example, the receiver must be tested yearly. If it works in other industries, a three-yearly test is compulsory.
Pressure Vessels are categorized into different classes.
- You get the SEP (Sound Engineering Principle) class. If a vessel falls in this category, the manufacturer must declare the vessel safe. It never needs a test again. At Airpower, we manufacture compressors with a SEP air receiver and these compressors do not need any pressure testing. These SEP air receivers are normally very small and we normally use it on continuous running air compressors.
- All vessels with a higher category will need the periodical pressure test. These higher category vessels will also need an on-site pressure test, before you are allowed to put it into use, for the first time.
What is not allowed when servicing an Air Compressor?
Any welding work on the body of a compressor air receiver is totally illegal unless done with the correct procedures and equipment under the supervision of legal authority.
Normally a new air receiver is less expensive than a legal weld repair. Removing or changing or tampering with the nameplate(s) on an air receiver is also totally illegal.
Are pressure testing vessels included when servicing an Air Compressor?
No, service on an air compressor is the changing of oil and filters, much like getting a vehicle serviced.
When serviced, the technician must check the working of the safety valve, gauge, pressure switch, and other safety aspects.
A compressor pressure test is like a roadworthy test on a vehicle. The pressure test is to declare the unit safe to be used again or unsafe for further use.
Who is responsible for pressure testing of an air receiver vessel?
The user of an air receiver/ air compressor is responsible for the periodic testing of the air receiver vessel. There are multiple failures of air receiver vessels annually.
The most common failure is due to over pressurization, which may result in the vessel rupturing or exploding. Another potential cause for an air receiver vessel to rupture is internal corrosion due to water entrained within the compressed air system itself.
If my air receiver fails a pressure test, must I still pay for the test?
Yes, the user must still pay for a test even if it failed the test. The AIA(Approved Inspection Authority) still did all the work to test it and the AIA takes the responsibility for the safety of the users and public.
To ensure your compressor passes all pressure safety tests, for both commercial and industrial uses, regular servicing and pressure testing must be done.
If an air receiver explodes/bursts, is it life-threatening or dangerous?
Definitely life-threatening and dangerous. Damages to company property can be severe and can risk the safety of the people in the surrounding area.
Here are some examples of the property damage a small exploded air receiver can do, if not services regularly:
Frequently Asked Questions
How often is compressor pressure testing required in South Africa?
In South Africa, compressor pressure testing is typically required at regular intervals in line with pressure vessel regulations and safety standards. Most air receiver pressure test requirements depend on usage, age, and operating conditions, but inspections are often needed every 36 months or as specified by an Approved Inspection Authority (AIA). Staying compliant with air compressor pressure testing helps avoid legal risks and ensures safe operation.
Why is air compressor pressure testing important for safety?
Air compressor pressure testing is essential to detect hidden risks such as corrosion, cracks, or weakened pressure vessels that could lead to failure. Without proper testing, over-pressurisation can result in serious safety hazards, including tank rupture or explosion. Regular pressure vessel testing in South Africa ensures your system operates safely and protects both staff and equipment.
What happens if a compressor fails a pressure test?
If a compressor fails pressure testing, it will be deemed unsafe for continued use until repairs or replacements are completed. The issue may involve structural damage, excessive corrosion, or failure to meet air receiver pressure test requirements. A qualified provider will guide you on the necessary corrective actions before retesting and returning the system to service.
Who is responsible for arranging compressor pressure testing?
The responsibility for air compressor pressure testing lies with the equipment owner or business operator. Employers must ensure their pressure vessels comply with South African safety regulations and are inspected by an approved authority. Working with a professional service provider like Airpower ensures your testing is done correctly and in line with compliance standards.
What information is needed before booking compressor pressure testing?
Before scheduling compressor pressure testing, you’ll typically need details such as the compressor type, tank size, operating pressure, and previous inspection history. This helps determine the correct testing method and ensures compliance with pressure vessel testing requirements in South Africa. Providing accurate information upfront allows for a faster and more efficient testing process.
Need a pressure testing company?
Airpower offers quality air compressor services including vessel pressure testing for all clients in the Western Cape and surrounding areas.
If you want your air receiver pressure tested, Airpower needs the following information to be able to give you a quote:
1. When last was this receiver tested?
2. What is the volume of the air receiver, on the nameplate?
3. Where is this air receiver located, address?
4. If you send us a photo of the nameplate on the air receiver and/or a copy of the manufacturers' certificate, Airpower will be able to tell you if the receiver can be tested legally.