What Is the ISO 9223 Atmospheric Corrosivity Category Calculator?
ISO 9223 establishes 6 standard corrosivity categories: C1 (Very Low), C2 (Low), C3 (Medium), C4 (High), C5 (Very High), and CX (Extreme).
It provides baseline degradation estimates for unprotected carbon steel, zinc, copper, and aluminum.
How Does the ISO 9223 Atmospheric Corrosivity Category Calculator Work?
Time of Wetness (TOW) represents the duration of electrolyte thin film presence on the metal surface.
Chloride ions penetrate protective patina films, while SO2 promotes acid hydrolysis.
ISO 9223 Atmospheric Corrosivity Category Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
ISO 9223 classification matrix mapping TOW, SO2, and chloride deposition to standard categories.
How to Use the ISO 9223 Atmospheric Corrosivity Category Calculator
- Input local TOW hours, SO2 deposition rate, and airborne chloride deposition rate.
- Check the ISO corrosivity category and expected first-year thickness losses.
Step-by-Step Example Calculation
Coastal Industrial Atmosphere
Input Values:
Understanding Your Result
C1–C2: Dry indoor / rural environments.
C3–C4: Urban / industrial / coastal temperate zones.
C5–CX: Heavy industrial / offshore marine splashing environments.
Factors That Affect the Result
- Distance from the coastline dramatically reduces chloride deposition within the first 1–2 km.
When Should You Use This Calculator?
- Selecting protective paint coating systems (ISO 12944) and galvanized steel structural design.
Assumptions & Limitations
- Applies to open atmospheric exposure without direct sea spray or immersion.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard international standard classification guidelines.