Overview
EN ISO 11844-2:2020 (CEN adoption of ISO 11844-2:2020) defines methods for determining corrosion attack in indoor atmospheres with low corrosivity. It establishes how to use standard specimens of metals and alloys to measure corrosion rates and to classify indoor atmospheric corrosivity. The standard is the second edition (2020), superseding the earlier 2008 version; notable updates include the addition of lead as a standard specimen and a new Annex D.
Key topics and technical requirements
- Scope and purpose: Direct assessment of indoor corrosivity using standard specimens to derive classification criteria based on measured corrosion rates.
- Standard specimens: Metals specified include copper, silver, zinc, carbon steel and lead (purity ranges and steel grade given in the standard).
- Specimen preparation: Guidance covers specimen geometry (example 10 mm × 50 mm, ~0.5 mm thick), surface abrasion (e.g. silicon carbide grades indicated for different metals), cleaning, ultrasonic degreasing and controlled storage before weighing.
- Exposure procedures: Specimens are to be mounted vertically (sheltered or unsheltered), with recommended clearances (minimum ~10 mm), placed in representative airflow locations (e.g. ~1 m above floor), and logged (identity, date, exposure type). Minimum exposure is six months; preferred exposure is one year.
- Measurement methods (Annexes):
- Annex A: Mass change (micro-balance measurements - balance accuracy and weighing procedure described).
- Annex B: Electrolytic cathodic reduction.
- Annex C: Resistance measurements (for continuous or periodic monitoring).
- Annex D: Quartz crystal microbalance (QCM) methodology (added in this edition).
- Method selection considerations: Sensitivity, continuous vs. periodic monitoring, available space and local environment influences are factors when choosing the appropriate technique.
Applications
- Evaluating corrosivity in indoor environments such as control rooms, electrical cabinets, storage facilities, museums, and transport enclosures.
- Supporting risk assessment for electronic and electrical equipment, metallic structural components, museum artifacts and archival collections.
- Providing baseline data for environmental control, material selection, maintenance planning and warranty assessments.
Who should use this standard
- Corrosion engineers and testing laboratories
- Facilities and maintenance managers (industrial, data centres, museums)
- Manufacturers of electrical, electronic and metal products
- Conservators and cultural heritage professionals
- HVAC and environmental monitoring specialists
Related standards
- Other parts of the ISO 11844 series (for broader context on classification of low corrosivity of indoor atmospheres).
- Adopted as EN ISO 11844-2:2020 by CEN; users should consider national implementation details where applicable.
Keywords: EN ISO 11844-2:2020, corrosion of metals, indoor atmospheres, corrosion rate, standard specimens, mass change, electrolytic cathodic reduction, quartz crystal microbalance, resistance measurements.
