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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.
  • If it is a Category 1 vessel, the manufacturer must supply a manufacturer’s certificate. This certificate is also valid for life and the vessel never needs to be pressure tested again.  We also sell compressors with a CAT 1 certification.
  • 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:

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.

Contact Airpower or your local Airpower agent