Washability Testing: The Definition

Washability testing is covered by several internationally recognized standards, each suited to different applications and markets: 

• ASTM D2486 – Scrub resistance of wall paints. Widely used in North American architectural coatings testing. 

• ASTM D4213 – Scrub resistance by abrasion weight loss. Provides a quantitative measure of material removed. 

• ASTM D4828 – Practical washability of organic coatings. Focuses on cleanability under low-stress conditions. 

• ASTM D3450 – Washability properties of interior architectural coatings. 

• ISO 11998 – Wet-scrub resistance and cleanability. The primary standard for interior wall paints in European markets. 

• DIN 53778 – Resistance to scrubbing and cleaning. Frequently referenced alongside ISO 11998 in European specifications. 

The appropriate standard depends on your target market, coating type, and customer or procurement requirements. The TQC Sheen Scrub Abrasion and Washability Tester is designed to comply with all of the above standards through its modular accessory system, allowing laboratories to switch between test configurations without purchasing additional instruments. 

Washability testing requires a motor-driven scrub abrasion tester that can apply a scrubbing tool to a coated panel at controlled speed, stroke length, and load. The TQC Sheen Scrub Abrasion and Washability Tester (AB6000 / AB6010) from Industrial Physics is the leading instrument in this category. When selecting a washability tester, key factors to consider include: 

• Standards compliance – confirm the instrument supports ASTM, ISO, and DIN standards relevant to your testing program 

• Wet and dry capability – if wet testing is required, ensure the tester includes a pump system (the AB6000 includes an integrated pump; the AB6010 is dry-only) 

• Modularity – a modular system accommodating multiple scrubbing tools reduces the cost of compliance with multiple standards 

• Speed and stroke control – look for precise micro-step motor control and stable sinus waveform speed regulation for consistent, repeatable results 

• Ease of operation – multi-lingual interfaces, intuitive controls, and software updateability reduce training time and maintenance costs 

• Expandability – consider whether the instrument can be paired with accessories such as the TQC Sheen Camera Tool Kit for automated pass/fail detection 

Scrub resistance and washability are related but distinct properties, and the terms are sometimes used interchangeably – though technically they refer to different performance characteristics. 

Scrub resistance refers to a coating ability to resist mechanical abrasion from a scrubbing action. It is typically measured as the number of strokes a coating withstands before visible film damage or substrate exposure occurs. Standards such as ASTM D2486 and ASTM D4213 focus specifically on scrub resistance. 

Washability is a broader term encompassing the ability of a coating to be cleaned repeatedly without visible degradation – including color change, gloss loss, or surface marring – even if the film is not completely removed. ISO 11998 defines wet-scrub resistance and cleanability as two components of overall washability performance. 

Whether you need to test for both depends on your product end-use specification and the standards required by your customers. For high-performance interior wall paints sold into European markets, ISO 11998 is typically mandatory. For North American architectural coatings, ASTM D2486 is the primary reference. Products used in demanding cleaning environments – such as hospital walls, food production facilities, or public spaces – may need to meet both scrub resistance and cleanability thresholds.