Overview
ISO 7535:1984 - "Surface active agents - Detergents for domestic machine dishwashing - Guide for comparative testing of performance" is an ISO guideline for designing and reporting comparative performance tests of domestic automatic dishwashing detergents and optional rinsing agents. It applies to powder, granular or liquid detergents and to rinsing agents used in domestic dishwashers (not industrial products). The standard focuses on realistic, consumer-relevant test conditions and enumerates the principal variables that affect comparative testing.
Key Topics
- Scope and field of application
- Applies to domestic machine dishwashing detergents and rinsing agents; excludes industrial products.
- Emphasises testing products under conditions common to the country where they will be used.
- Performance characteristics
- Final appearance (soil removal, redeposition, stain removal, absence of spotting/filming).
- Drying efficiency (influence of machine, temperature, article shape, and rinsing agents).
- Resistance of articles to the wash process (chemical and physical damage, tarnishing, fading of decorations).
- Effects on washing equipment (interactions and corrosion).
- Soiled articles and soils
- Use naturally soiled articles when possible or well-characterised artificial soils that reflect regional diets (fats, proteins, tannins, burnt-on foods, etc.).
- Control substrate types (porcelain, glass, metal, plastics); avoid porous/wood substrates for comparative tests.
- Standardise soil amount, application, ageing, storage conditions and temperature during application.
- Washing process variables
- Machine type, installation, water softener status, water hardness, inlet temperature, water pressure, agitation, programme selection and loading patterns.
- Single-wash vs repeat-wash methods (repeat cycles required to reveal cumulative effects such as tarnishing).
- Use of a “water blank” (no detergent) as a reference for long-term chemical effects.
- Test design and reporting
- Sampling per ISO 607 and terminology from ISO 862.
- Use sufficient replicates (experience indicates a minimum of seven specimens per article from the same batch) and randomized runs across machines to avoid bias.
Applications
ISO 7535 is practical guidance for:
- Detergent and rinsing agent manufacturers developing and comparing formulations.
- Independent test laboratories and consumer organisations conducting comparative product evaluations.
- Dishwasher manufacturers assessing compatibility and long-term effects on machine components.
- Regulators and standards bodies seeking harmonised test criteria for product claims.
Related standards
- ISO 607 - Surface active agents and detergents: Methods of sample division (referenced for sampling).
- ISO 862 - Surface active agents: Vocabulary (definitions and terminology).
Keywords: ISO 7535, machine dishwashing detergents, comparative testing, rinsing agents, performance characteristics, soiled articles, washing processes.
