ISO 9227 — Standard

About the Standard

Scope title: salt spray corrosion test

ISO 9227 is a standard published by International Organization for Standardization (ISO). The international standards organisation; it publishes the widest body of management system, test method and product standards.

See the other 310 codes from ISO

Coverage areas

What Is ISO 9227?

ISO 9227 defines salt spray tests carried out in artificial atmospheres. It belongs to the same chamber family as ASTM B117 but defines THREE different conditions rather than one, and in that respect offers a broader framework.

The three conditions are: neutral salt spray (NSS), acetic acid salt spray (AASS) and copper-accelerated acetic acid salt spray (CASS). All three are run in the same chamber with a different solution composition and pH; which is applied is determined by the coating type. CASS is preferred for decorative chromium-nickel coatings and NSS mostly for painted surfaces.

Like ASTM B117, this standard GIVES NO TEST DURATION OR ACCEPTANCE CRITERION. The duration comes from the product standard or the specification. The standard governs how the chamber is operated, how the solution is prepared and how the performance of the chamber is verified with reference specimens.

CHAMBER VERIFICATION is one of the distinguishing features of the standard and its most marked difference from ASTM B117: that the chamber maintains the expected aggressiveness is checked periodically through mass loss on defined reference specimens. Without this verification, results from different laboratories cannot be compared; a chamber may indicate the correct conditions while in fact being less or more aggressive than expected.

Why Does This Standard Exist?

The problem with salt spray chambers was this: even when temperature, solution concentration and pH appeared correct, chambers showed different aggressiveness. Spray geometry, air flow, specimen placement and chamber geometry all affected the result. The same specimen could show markedly different damage in two different laboratories.

ISO 9227 answered this with a CONTROL SPECIMEN. A defined metal reference specimen is held in the chamber for a defined period and its mass loss is measured. If the loss is not within the expected range, the chamber is adjusted. The chamber is thus calibrated indirectly but measurably.

Defining three separate conditions also arose from a practical need. Neutral salt spray did not give results in a reasonable time for some coating systems; decorative chromium-nickel coatings could last for months. Adding acetic acid and accelerating with copper chloride brought the test duration for these coatings down to an acceptable range.

The standard's relationship with ASTM B117 often raises questions in practice. The two define similar chamber conditions and the NSS condition overlaps to a large extent; but chamber verification, the details of specimen placement and the reporting requirements differ. Many specifications therefore request by code and do not accept a substitute.

Classification Scheme

NSS — neutral salt spray
Sodium chloride solution in the neutral pH band. The most common condition for metallic and organic coatings.
AASS — acetic acid salt spray
Solution acidified with acetic acid; provides a more aggressive environment.
CASS — copper-accelerated
Copper chloride is added to the acetic acid solution; preferred for decorative chromium-nickel coatings.

Which Products Require It

Metallic coatings and chemical conversion coatings
Organic coating systems and paints
Decorative chromium-nickel coatings (the CASS condition)
Fasteners and metal components
Automotive and white goods components

Related Legislation and Schemes

It is referred to in European product standards as the method for verifying corrosion resistance
ASTM B117 and ASTM G85 are the corresponding ASTM publications
The assessment scales are defined in the ISO 10289 and ISO 4628 series
For hot dip galvanised coatings the product requirements of ISO 1461 apply in addition

How the Assessment Runs

1Selecting the conditionNSS, AASS or CASS is chosen according to the coating type and the specification. The wrong condition makes the result impossible to interpret.
2Chamber verificationThe aggressiveness of the chamber is verified periodically with reference specimens and the records are kept.
3Specimen preparationSpecimens are cleaned, their thickness measured, their edges masked where required and a scribe applied.
4ExposureSpecimens are positioned at the defined angle and held in the chamber for the duration given in the specification.
5AssessmentDamage is assessed with the scale appropriate to the coating type; the ISO 4628 and ISO 10289 scales are used.

Neighbouring Standards and the Differences

ASTM B117
The ASTM side of the same chamber family. It defines a single (neutral) condition and carries no reference specimen requirement for chamber verification.
ASTM G85
Modified salt spray conditions; acetic acid, cyclic and sulphur dioxide variants.
ISO 16701 / VDA 233-102
Cyclic corrosion tests. Through wet-dry cycles they give results closer to field behaviour.
ISO 4628 / ISO 10289
Assessment scales. ISO 9227 provides the exposure; the rating comes from these standards.

What the Report Must Contain

To be usable, a report must carry the information below. An incomplete report may not be accepted in the supply chain or in an inspection even when its result is correct.

The condition applied: NSS, AASS or CASS
The exposure duration and the times of any interim assessments
Chamber verification records and the mass loss of the reference specimens
Specimen description, coating type and measured thickness
The specimen positioning angle and whether a scribe was applied
The assessment scale used and the result obtained

Commonly Confused Points

NSS, AASS and CASS do not substitute for one another. The specification must state clearly which condition is required.
Chamber results cannot be converted into real life; the test is used for comparison and production consistency.
ASTM B117 and ISO 9227 reports are not accepted in place of one another in most specifications; they are requested by code.
A long exposure without chamber verification records cannot demonstrate that it took place under defined conditions.
Duration and acceptance criteria do not come from the standard; they come from the product standard or the specification.
If the coating thickness is not reported, the result cannot be compared.

Structure of the Code

Published by: ISO
Serial number: 9227
Part: without partition

Codes in the library without release year is kept. The current version changes over time; If the year is specified in your specification, that version is taken as basis, if not specified, the most current version is applied.

Scope

Test
Metal and Metallurgy Testing
Corrosion Tests

Related Tests and Services

Of the 3 pieces of content this code is referenced in, the 1 with their own published page are listed below.

Test · 1

Tuz Sisi – ISO 9227

Technical Requirements

Standard texts are copyright of the relevant organization; test condition, sample and acceptance criteria cannot be fitted here.

Basis: ISO 9227 scope statement: the NSS, AASS and CASS conditions and the approach of verifying the chamber with reference specimens. Duration and acceptance criteria are outside the scope of the standard; the assessment scales come from the ISO 4628 and ISO 10289 references.

Technical requirements specific to your product, once we clarify the scope At offer stage shared in writing.

Relevant Product Groups and Legislation

This code is included in the standard tag of the product pages below.

These product pages carry notes for the following markets: European Union, United Kingdom, USA. Whether the standard is mandatory in the relevant market varies depending on the product group and the applicable legislation.

Regulations published with this code on the same product pages:

(AB) 2018/858Vehicle Type-Approval FrameworkApproval of motor vehicles and their components. Component and separate technical unit approval run under this framework; the E mark arises from it.
UNECEUNECE 1958 AgreementType-approval under component-specific UNECE regulations (e.g. R10 EMC, R30/R54 tyres, R43 glazing).
UNECE R10UNECE R10Electromagnetic compatibility approval for vehicles and their components.
2011/65/EURoHSRestriction of hazardous substances in electrical and electronic equipment.
2000/53/ATELVEnd-of-life vehicles. Sets heavy-metal restrictions and recoverability targets.
(EU) 2017/745MDRThe Medical Device Regulation. Classification (I, IIa, IIb, III), clinical evaluation, technical documentation and post-market surveillance obligations; the notified body's role grows as the class rises.
(EU) 2017/746IVDRThe In Vitro Diagnostic Medical Devices Regulation. In vitro diagnostic devices fall under this regulation instead of the MDR.
(AB) 2017/745 art. 33EUDAMEDThe European medical device database. From 28 May 2026, the actor registration, UDI/device, certificate and market surveillance modules are mandatory; placing on the market is not possible without a valid SRN.
2006/42/ATMachinery Directive (overlap)Relevant essential requirements also apply to medical devices that also qualify as machinery.
(EC) 1907/2006REACHRegistration, evaluation, authorisation and restriction of chemicals; SVHC notification.
(EU) 2023/1230Machinery RegulationReplaces 2006/42/EC and becomes mandatory on 20 January 2027 with no further transition period. Requires notified-body involvement for Annex I high-risk machinery.
2014/35/EULVDThe Low Voltage Directive. Governs electrical safety in the 50–1000 V AC range.
2014/30/EUEMCThe Electromagnetic Compatibility Directive. Emission and immunity are covered together.
2014/34/ABATEXEquipment and protective systems used in explosive atmospheres. The category and conformity route are determined by zone classification.
2000/14/ATNoise EmissionNoise emitted into the environment by outdoor equipment. Machinery within scope requires a sound-power-level declaration and marking.
2014/68/EUPEDThe Pressure Equipment Directive for pressurised parts; the category is determined by pressure and volume.
(EU) 2024/573F-GasRefrigerant type, GWP value and leak-tightness obligations for systems containing a refrigerant.
(AB) 547/2012Ecodesign (water pumps)Ecodesign requirements for water pumps. Sets minimum efficiency index and product-information requirements.
(AB) 2019/1781Ecodesign (electric motors)Efficiency class requirements for electric motors and variable-speed drives.
(AT) 1935/2004Food Contact MaterialsGeneral requirements for equipment in contact with food; material conformity is required for valves in food lines.
(AB) 2020/2184Drinking Water Contact ProductsHygiene requirements for materials in contact with water under the Drinking Water Directive.
2014/29/ABSimple Pressure VesselsA separate directive for series-produced simple pressure vessels; its scope must be distinguished from the PED.
2010/35/ABTransportable Pressure EquipmentThe pi mark and periodic inspection regime for transportable pressure equipment.
2009/48/ECToy SafetyThe Toy Safety Directive. Regulates mechanical, physical, flammability, chemical and electrical safety requirements together; a technical file and safety assessment are mandatory.
EN 62115Electrical toysSafety for electric toys; applies to mains-connected or battery-powered toys.
(AT) 1907/2006 Annex XVII item 51-52Phthalate RestrictionRestriction of certain phthalates in toys and childcare articles.
(EU) 2023/1542Batteries RegulationBattery obligations and a removability requirement for toys containing a battery.
(AB) 1007/2011Textile LabellingTextile fibre names and labelling. Declaration of fibre composition and regulation of the label language.
(AT) 1907/2006 Annex XVII item 43Azo Dye RestrictionRestriction of certain azo dyes in textiles in contact with skin.
(AB) 2019/1021PFAS / PFOA RestrictionRestriction of PFOA and its derivatives under the Persistent Organic Pollutants Regulation.
(EU) 2023/988GPSRThe General Product Safety Regulation. The safety framework for consumer products not covered by sector-specific legislation.
(EU) 2016/425Personal Protective Equipment (overlap)The PPE Regulation's scope and category are determined for textiles with a protective function.
(AB) 10/2011Plastics in Food ContactPlastic materials in contact with food. The list of authorised substances, and overall and specific migration limits.
(AT) 2023/2006Good Manufacturing PracticeGood manufacturing practice (GMP) for food-contact materials.
(AB) 2025/40Packaging and Packaging WasteThe Packaging and Packaging Waste Regulation. Recyclability, recycled-content and packaging-reduction obligations; replaces 94/62/EC.
(AB) 2022/1616Recycled PlasticRecycled plastic materials in contact with food.
(EU) 2024/3110Construction Products RegulationDeclaration of performance and CE marking for construction products. Most provisions apply from 8 January 2026; it progressively replaces (EU) 305/2011.
(AB) 305/2011CPR (transition)Continues to apply during the transition period for product groups where a new harmonised standard has not been published.
EN 13501-1Reaction-to-Fire ClassificationReaction-to-fire class for construction products; a mandatory item of the declaration of performance.
(EU) 2023/1115Deforestation (wood-based)A deforestation-free supply declaration for wood and derived construction materials.
(AT) 1223/2009Cosmetic Products RegulationThe Cosmetic Products Regulation. Appointing a responsible person, the product information file (PIF), the safety assessment (CPSR) and CPNP notification are mandatory; there is no product approval, and responsibility rests with the manufacturer.
(AT) 1223/2009 Annexes II-VIProhibited and Restricted SubstancesLists of prohibited substances, restricted substances, and permitted preservatives, colorants and UV filters.
(AT) 1223/2009 art. 16Nanomaterial NotificationA separate notification six months before placing on the market for products containing nanomaterials.
(AT) 1223/2009 art. 18Animal Testing BanA ban on animal testing of finished products and ingredients, and on placing animal-tested products on the market.
(AT) 178/2002General Food LawThe general principles of food law, traceability and food safety responsibility.
(AT) 852/2004Food HygieneHygiene rules for food businesses and the obligation for a HACCP-based system.
(AB) 1169/2011Food Information to ConsumersFood labelling; nutrition declaration, allergen information and origin information.
(AB) 2023/915ContaminantsMaximum levels of contaminants in food.
(AT) 396/2005Pesticide residuesMaximum residue limits in food of plant and animal origin.
(AT) 2073/2005Microbiological CriteriaMicrobiological criteria for foodstuffs.

Related Standards

Frequently Asked Questions About ISO 9227

Which condition should we choose?

The coating type is decisive: NSS is generally used for painted and metallic coatings and CASS for decorative chromium-nickel coatings. If your specification states a condition, that is the one applied.

What is the difference between ISO 9227 and ASTM B117?

The most marked difference is chamber verification: ISO 9227 requires the aggressiveness of the chamber to be verified periodically with reference specimens. ISO 9227 also defines three conditions, whereas ASTM B117 governs the neutral condition.

How many hours should be applied?

The standard gives no duration. It comes from your product standard or your customer's specification.

Why is the CASS test shorter?

Acetic acid and copper chloride make the environment markedly more aggressive; this brings the test duration for long-lasting decorative coatings into an acceptable range.

Frequently Asked Questions

Is this standard mandatory for my product?

Whether it is mandatory depends on the product group, the target market and the applicable legislation. Once you tell us your product and market, we clarify in writing whether this standard is required.

How long does the test process take?

Duration depends on the scope of the standard, the number of specimens and current capacity. The exact duration is shared, together with the specimen and scope details, at the quote stage.

Do you issue certification against this standard?

Which activity is carried out under which accreditation scope is separately confirmed at the application stage. Up-to-date scope information is published on our corporate page.

What happens if the standard I need is not here?

The library is based on a continuously growing inventory. If you cannot find the code you are looking for, you can send it through the quote form; we will assess the relevant scope and get back to you.