Atmospheric Corrosivity
Metals, alloys and metallic coatings are subject to atmospheric corrosion under the impact of air humidity, especially when gaseous and solid substances of atmospheric pollution co-impact. When the minutest layer of corrosion builds up on the circuit surfaces of electronic systems at data centres, server rooms, control rooms, it aggravates electrical resistance and decrements equipment performance. Thus, constant corrosion monitoring is recommended to ensure early detection of corrosion potential, which can improve electrical systems performance.
Factors Affecting Atmospheric Corrosion
- The environmental threats posed by fire, power, temperature, humidity and airborne particulates have long been recognized and successfully addressed in the server-room environment, but the corrosive potential of the air has been largely ignored.
- Even extremely low levels of contaminant gases at the ppb level corrode and damage the sensitive electronic cards in the servers.
- Excessive corrosion often leads to electronics warranty non-compliance, circuit board failure, ghost signalling, and even complete failure of electronics components.
The Need for Monitoring Atmospheric Corrosion Rate and Reactivity?
- Environments with higher atmospheric and air contamination require greater attention to air quality management.
- The interactive result of temperature variations and humidity with the gaseous contaminants has the potential to increase the threat of air corrosion, providing greater reasons for close monitoring of the immediate environment of IT infrastructure.
- All companies dealing with sensitive IT infrastructure such as data centres, server rooms, and control rooms, as a core part of their operations, need to implement a comprehensive checking and monitoring mechanism for the corrosion potential of the gases inside their facility.
- The ISA standards define or characterise environments in terms of their overall corrosion potential.
Environmental Classification as per ISA-71.04.2013 (in Ã…)
| Class | Severity level | Copper Reactivity | Comments |
|---|---|---|---|
| G1 | Mild | <300 Ã… | An environment sufficiently well-controlled such that corrosion is not a factor in determining equipment reliability |
| G2 | Moderate | <1000 Ã… | An environment in which the effects of corrosion are measurable, and corrosion may be a factor in determining equipment reliability. |
| G3 | Harsh | <2000 Ã… | An environment bearing a high probability of corrosive attack. These harsh levels should prompt further evaluation resulting in environmental controls or specially designed and packaged equipment |
| Gx | Severe | ≥2000 Å | An environment in which only specially designed & packaged equipment would be expected to survive. Specifications for equipment in this class are a matter of negotiation between user & supplier |
Specifications for indoor concentrations of some of the most important pollutants as per OSHA standards
| S.N. | Pollutant | Standards (Max.) |
| 1 | Sulphur Dioxide (SO2), ppm | 5 |
| 2 | Nitrogen Dioxide (NO2), ppm | 5 |
| 3 | Particulate Matter (PM10), mg/m3 | 15 (Total) |
| 4 | Particulate Matter (PM2.5), mg/m3 | 5 (Resp.) |
| 5 | Oxygen (as O2),% | >19.5 |
| 6 | Relative Humidity, % | 30-65 |
| 7 | Hydrogen Sulphide (H2S), ppm | 20 |
| 8 | Formaldehyde, ppm | 0.75 |
| 9 | Chlorine , mg/m3 | 3 |
| 10 | Lead (as Pb), µg/m3 | 50 |
| 11 | Carbon Monoxide (CO), ppm | 50 |
| 12 | TVOC, ppm | 1 |
| 13 | Carbon Dioxide (CO2), ppm | 5000 |
| 14 | Temperature, °C | NA |
- Petrochemical refineries
- Research laboratories
- Paper and pulp industryÂ
- Electronics and electrical industry
- Wastewater treatmentÂ
- Information technology industryÂ
- Data centres and mission critical facilitiesÂ
- Food processing industry