It has been noticed on our various inspections that different gas design concentrations appear on hydraulic gas designs. Sometimes the designer claims to use NFPA standards, others manufacturer recommendations. Please note we utilise ISO standards in South Africa; SANS 14520 for clean agent gasses and the following is what should be applied to gas designs in this country.
Class B concentrations apply to all electrical rooms and general applications.
Higher Class A design concentration must be used for Server rooms or areas where deep bundled cables are present.
Class A design concentrations should be utilised for flammable fires, (gasses and liquids).
The following are the design concentrations for the various products from the various parts of SANS 14520:
| HFC 227ea (FM200) |
Novec | HFC 125 | IG 55 (Argonite) |
IG 541 (Inergen) |
|
| SANS 14520 | Part 9 - 2008 | Part 5 - 2008 | Part 8 - 2008 | Part 14 - 2008 | Part 15 - 2008 |
| Class B | 9.0 | 5.9 | 12.1 | 47.5 | 41.2 |
| Surface class A | 7.9 | 5.3 | 11.2 | 40.3 | 39.9 |
| Higher class A | 8.5 | 5.6 | 11.5 | 45.1 | 39.9 |
For specialised fuels, acetone, methanol etc refer to the tables in the relevant parts of SANS 14520. It is the job of the consultant, contractor, inspector and end user that these design concentrations are applied to installations in South Africa.