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ISO 26987:2008 – Determination of Staining and Resistance to Chemicals for Resilient Floor Coverings
Resilient floor coverings — Standardized test method for evaluating staining and chemical resistance using visual indexing
1. Introduction to ISO 26987:2008
ISO 26987:2008 specifies a standardized test method for determining the staining and chemical resistance of resilient floor coverings. The standard provides a systematic procedure for evaluating how various chemical substances in liquid or paste form affect the appearance and integrity of flooring materials. This is essential knowledge for flooring manufacturers developing new products, specification engineers selecting materials for specific environments (e.g., laboratories, kitchens, healthcare facilities), and quality assurance personnel monitoring product performance.
Chemical resistance is often the defining performance requirement for floor coverings in industrial and institutional settings. ISO 26987 provides a reproducible test protocol that allows direct comparison between different flooring products under standardized conditions, eliminating variability introduced by ad-hoc testing methods.
The standard covers the testing of resilient floor coverings including linoleum, PVC, rubber, and other polymeric flooring materials. Chemical substances are placed on test pieces for defined contact periods, after which staining, discoloration, swelling, softening, or other surface degradation effects are evaluated using a standardized visual indexing system.
2. Test Procedure and Evaluation Methodology
2.1 Specimen Preparation and Conditioning
Test pieces shall have a surface area of at least 3 000 mm² for each chemical substance to be tested. When testing substances likely to cause swelling or deformation (e.g., prolonged solvent contact), the test piece must be bonded to a fibre-cement board at least 5 days before testing. All specimens must be conditioned at 23 ± 2 °C and 50 ± 5 % relative humidity for a minimum of 24 hours before testing.
2.2 Application of Chemical Substances
Liquid chemicals are applied using a pipette to create a defined area of 300 mm² to 400 mm², covered with a watch glass. Paste substances are applied using a spatula at approximately 1 000 mm³ volume spread over the same area. The standard contact period is 30 minutes, followed by cleaning and observation. If the test piece is adversely affected at 30 minutes, a new test is conducted for a shorter period (typically 10 minutes) to establish the time-dependence of the chemical effect.
2.3 Cleaning, Observation, and Rating
After the contact period, liquid chemicals are removed by working from the edge toward the centre of the stain using cotton. Paste residues are scraped off with a spatula before wiping. The surface is cleaned using standard cleaning products and stain removal agents specified in the standard. Residual staining is examined using a standardized illumination device from approximately 800 mm distance. The observed effect is assigned an index value according to Table 1 of the standard.
| Index | Effect of Test after Cleaning/Abrasion | Interpretation |
|---|---|---|
| 0 | No visible change | Excellent resistance — suitable for all environments |
| 1 | Slight change detectable only at certain angles | Good resistance — acceptable for most applications |
| 2 | Moderate change visible at all viewing angles | Limited resistance — caution required in specific environments |
| 3 | Severe change with surface degradation | Poor resistance — not recommended for chemical exposure areas |
| 4 | Complete failure with structural damage | Unacceptable — material incompatible with the test chemical |
3. Engineering Design Insights and Practical Implementation
When setting up a laboratory for ISO 26987 testing, the most critical piece of equipment is the standardized illumination device. The standard requires the test piece to be illuminated vertically from above with the surroundings neutral and darkened. A rotary viewing table enables the test piece to be rotated for observation from all angles. This controlled lighting environment is essential for consistent index assignment, as ambient lighting conditions significantly influence the perception of subtle staining or surface changes.
The 5-day minimum bonding period for test pieces requiring fibre-cement board backing is often underestimated in laboratory scheduling. This curing time is necessary because residual moisture in the adhesive can plasticize the flooring material, altering its chemical resistance characteristics. Planning test sequences to account for this preparation lead time is essential for maintaining laboratory throughput.
The standard explicitly states that it does not specify which chemical substances should be tested, leaving this determination to the specifier based on the intended end-use environment. In practice, a comprehensive chemical resistance evaluation should include representatives from several chemical families: acids (e.g., acetic acid 10 %, sulfuric acid 10 %), alkalis (e.g., sodium hydroxide 10 %, ammonia solution), solvents (e.g., acetone, ethanol, isopropanol), oils and fats (e.g., vegetable oil, mineral oil), disinfectants (e.g., sodium hypochlorite, quaternary ammonium compounds), and common staining agents (e.g., coffee, red wine, iodine).
For manufacturers publishing chemical resistance data sheets, presenting results in a tabular format organized by chemical family (acids, alkalis, solvents, oils, disinfectants) with the ISO 26987 index rating and contact time provides end-users with actionable information. Including a separate column for cleaning recommendations after chemical exposure adds significant practical value for facility maintenance teams.
The abrasion step specified in Clause 6.4.2 is particularly important for flooring products with textured surfaces or protective coatings. When a stain remains visible after standard cleaning, a controlled abrasion step using specified abrasive materials simulates the mechanical action of floor scrubbing equipment. This distinguishes between superficial staining that can be removed by cleaning and permanent discoloration that has penetrated the flooring structure. For coated flooring products, the abrasion step also evaluates whether the protective coating has been compromised by the chemical exposure.
Testing personnel should be aware that some combinations of chemical substances and flooring materials can produce hazardous reactions. For example, strong oxidizers (bleach) on certain flooring types can generate chlorine gas, and concentrated acids can cause exothermic reactions with some flooring formulations. A chemical compatibility review should be conducted before initiating any new test substance-flooring material combination.
4. Frequently Asked Questions
Q1: How many test pieces are required for a full chemical resistance evaluation?
A: The standard requires at least one test piece per color per chemical substance per contact time. For a comprehensive evaluation covering 15-20 chemical substances and two contact periods (30 minutes and 10 minutes), this means 30-40 test pieces per color variant. Multi-color product lines therefore require significantly more specimens.
A: The standard requires at least one test piece per color per chemical substance per contact time. For a comprehensive evaluation covering 15-20 chemical substances and two contact periods (30 minutes and 10 minutes), this means 30-40 test pieces per color variant. Multi-color product lines therefore require significantly more specimens.
Q2: Can ISO 26987 results predict long-term chemical resistance in real-world installations?
A: The standard provides a short-term (30-minute) contact test suitable for evaluating resistance to accidental spills and routine chemical exposure. For continuous or repeated chemical exposure scenarios (e.g., laboratory flooring, commercial kitchen floors), additional long-term testing with extended contact periods (24 hours to 7 days) is recommended to simulate cumulative exposure effects.
A: The standard provides a short-term (30-minute) contact test suitable for evaluating resistance to accidental spills and routine chemical exposure. For continuous or repeated chemical exposure scenarios (e.g., laboratory flooring, commercial kitchen floors), additional long-term testing with extended contact periods (24 hours to 7 days) is recommended to simulate cumulative exposure effects.
Q3: How should test pieces be identified to avoid confusion when testing multiple chemicals?
A: The standard recommends marking numbers on the test piece using a marking that is not affected by the test chemicals. Alternatively, a sketch, diagram, or photographic record can be used. In practice, pre-printed labels with chemical-resistant printing or engraved markers work well for laboratory workflows.
A: The standard recommends marking numbers on the test piece using a marking that is not affected by the test chemicals. Alternatively, a sketch, diagram, or photographic record can be used. In practice, pre-printed labels with chemical-resistant printing or engraved markers work well for laboratory workflows.
Q4: Is the test applicable to floor coverings with surface coatings or finishes?
A: Yes. The standard applies to all resilient floor coverings, including those with surface coatings. The abrasion step in Clause 6.4.2 is particularly relevant for coated products, as it evaluates whether surface coatings provide effective protection against chemical attack and whether the coating itself is affected by the chemical exposure.
A: Yes. The standard applies to all resilient floor coverings, including those with surface coatings. The abrasion step in Clause 6.4.2 is particularly relevant for coated products, as it evaluates whether surface coatings provide effective protection against chemical attack and whether the coating itself is affected by the chemical exposure.
