introduction
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ISO 11844-1-2020 Corrosion of metals and alloys – Classification of low atmospheric corrosion in chambers – Part 1: Determination and estimation of corrosion in chambers

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This document, prepared by the ISO/TC 156 Technical Committee on Corrosion of Metals and Alloys in collaboration with the CEN/TC 262 Technical Committee on Metals and Other Inorganic Coatings of the European Committee for Standardization (CEN), covers corrosion protection and corrosion testing of metals and alloys. According to the Technical Cooperation Agreement between ISO and CEN (Vienna Agreement).

The second edition cancels and replaces the first edition (ISO 11844-1:2006), which has been technically revised. The main changes compared with the previous edition are as follows:

– Added a reference to the ISO 16000 series in Article 7;

– Added a model for estimating indoor concentrations and deposition of pollutants originating outdoors;

Lead has been used as a standard sample for high sensitivity to vaporous organic acids.

A list of all the parts in the ISO 11844 series can be found on the ISO website.

Any feedback or questions on this document should be referred to the user’s national standards body. A complete list of these institutions can be found at iso.org/members.html.

ISO 11844-1-2020 Corrosion of metals and alloys – Classification of low atmospheric corrosion in chambers – Part 1: Determination and estimation of corrosion in chambers

introduce

Metals, alloys and metal coatings are susceptible to atmospheric corrosion under the influence of air humidity, especially when gaseous and solid substances of atmospheric pollution work together. The importance of corrosion data in deriving appropriate corrosion protection or assessing the suitability of a product’s metallic elements cannot be overstated.

ISO 9223 classifies atmospheric environments into six corrosive categories.

A low corrosive indoor atmosphere is an indoor atmosphere that meets the C 1 (very low) or C 2 (low) corrosive category of ISO 9223.

The classification in ISO 9223 is too broad for certain uses in low-corrosive indoor atmospheres, such as places to store electronic equipment, precision technology products, or art and historical objects.

For this reason, it is necessary to subdivide the corrosivity categories C 1 (very low) and C 2 (low) into the indoor corrosivity categories given in this document.

The assessment of low corrosive indoor atmospheres can be done by directly determining the corrosion attack of the selected metal (see ISO 11844-2) or by measuring environmental parameters that may cause corrosion of metals and alloys (see ISO 11844-3).

ISO 11844-1-2020 Corrosion of metals and alloys – Classification of low atmospheric corrosion in chambers – Part 1: Determination and estimation of corrosion in chambers

This document describes general procedures for deriving and estimating categories of indoor corrosivity.

The purpose of this document is to describe the characteristics of low-corrosive indoor atmospheric environments that may affect metals and metal coatings during storage, transport, installation or operational use, to establish a consistent classification of indoor corrosivity and to provide for the deduction and estimation of procedural indoor corrosivity classes.

The scheme shown in Figure 1 gives a general method for classifying indoor atmospheric corrosivity.

FIG. 1 Classification scheme of indoor atmospheric low corrosion

FIG. 1 Classification scheme of indoor atmospheric low corrosion

1 Scope of Application
The document establishes a classification of low corrosive atmospheres in indoor environments.

It specifies the reference metal that is used to determine the corrosive class of the low corrosive indoor atmosphere after a specified exposure period of corrosion attack.

It defines the corrosive class of the indoor atmosphere in terms of corrosion erosion on standard samples.

It indicates the important parameters of indoor atmosphere, which can be used as the basis for estimating indoor corrosivity.

ISO 11844-2 gives the selection of methods for measuring corrosion, description of standard samples, exposure conditions and assessment. The measurement of environmental parameters affecting indoor corrosion is given in ISO 11844-3.

ISO 11844-1-2020 Corrosion of metals and alloys – Classification of low atmospheric corrosion in chambers – Part 1: Determination and estimation of corrosion in chambers

2 Normative reference documents
There are no normative references in this document.

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for standardization at the following addresses:

– ISO online browsing platform: iso.org/obp

– IEC Electropedia: available at electropedia.org/

3.1 Climate

The statistics of temperature, humidity, pressure, wind, rainfall and other meteorological elements in a certain place over a long period of time

[Source: EN 15759-1:2011, 3.1]

3.2 Atmosphere

A mixture of gases, aerosols, and particles surrounding a given material, object, or structure

ISO 11844-1-2020 Corrosion of metals and alloys – Classification of low atmospheric corrosion in chambers – Part 1: Determination and estimation of corrosion in chambers

3.3 Indoor Atmosphere

The environment [the combined influence of climate (3.1) and atmosphere (3.2)] is inside a box, room, or building

3.4 Microclimate

The climate (3.1) of a small area, a specific room, part of a building, etc., may differ from that of a general area

3.5 Temperature and Humidity Complex

Combined effects of temperature and relative humidity on atmospheric corrosivity (3.10)

[Source: ISO 9223:2012, 3.4]

3.6 Wet Time

The period in which the surface of a metal is covered by an adsorption film and/or liquid film of an electrolyte that can cause atmospheric corrosion

[Source: ISO 9223:2012, 3.5]

ISO 11844-1-2020 Corrosion of metals and alloys – Classification of low atmospheric corrosion in chambers – Part 1: Determination and estimation of corrosion in chambers

3.7 Air Pollution

Specific corrosive active substances, gases or suspended particles in the air (natural and human activities)

3.8 Corrosion System

A system consisting of one or more metals and environmental components that affect corrosion

[Source: ISO 8044:2020, 3.4, modified — Note 1 to the entry has been removed.]

3.9 Corrosion

The ability of the environment to cause metal corrosion in a given corrosion system (3.8)

[Source: ISO 8044:2020, 3.14]

ISO 11844-1-2020 Corrosion of metals and alloys – Classification of low atmospheric corrosion in chambers – Part 1: Determination and estimation of corrosion in chambers

3.10 Atmospheric corrosiveness

The ability of the atmosphere to cause corrosion in a given corrosion system (3.8)

Example: Atmospheric corrosion of a given metal or alloy.

[Source: ISO 9223:2012, 3.1, modified – an example added.]

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