Overview
ISO 150:2018 - Raw, refined and boiled linseed oil for paints and varnishes - Specifications and methods of test defines requirements and test methods for linseed oils used as binders in paints and varnishes. The standard covers raw, alkali‑refined, acid‑refined and boiled linseed oils, specifying physical and chemical limits (density, colour, clarity, water, acid value, saponification and iodine values) and prescribes sampling and laboratory test procedures.
Key topics and technical requirements
- Scope: Requirements and corresponding methods of test for linseed oil grades intended for paints and varnishes.
- Required characteristics (examples from Table 1):
- Density (23 °C): typical ranges 0.924–0.931 g/ml (raw/refined) and up to 0.948 g/ml for boiled oils (ISO 2811‑1 or ISO 2811‑3).
- Gardner colour (max.): Raw 13, alkali‑refined 4, acid‑refined 6 (ISO 4630); colour after heating may be agreed between parties for neutral oils.
- Clarity: No sediment for raw oil; refined/boiled oils allow slight turbidity that must clear on heating (see Clause 6).
- Refractive index (n23): 1.4780–1.4830 (ISO 5661 or ISO 6320).
- Water (max.): Raw 0.20%, refined 0.10%, boiled 0.30% (ISO 8534, Karl Fischer).
- Acid value (max., mg KOH/g): Raw 4, alkali‑refined 1, acid‑refined 9, boiled 8 (ISO 2114 / ISO 660).
- Saponification value: typically 188–195 mg KOH/g (ISO 3681).
- Iodine value (min.): 175 g I2/100 g (ISO 3961); designation “High iodine value linseed oil” when >190.
- Special tests:
- Phosphoric Acid Test (PAT) for raw linseed oil - quantifies insoluble matter (PAT value, max 0.25%).
- Break assessment for alkali‑refined oils - acid treatment, heating and visual inspection for insoluble “break”.
- Fatty acid composition: normative values in Annex A; measured by gas chromatography per ISO 12966 (all parts).
- Sampling & sample prep: Sampling per ISO 5555, preparation per ISO 661.
- Referenced test methods: ISO 660, 661, 2811‑1/3, 3681, 3961, 4630, 5661, 6320, 8534, 12966, etc.
Applications and users
ISO 150:2018 is used by:
- Paint and varnish formulators selecting linseed oil grades for drying, gloss and film properties.
- Linseed oil manufacturers for product specification, quality control and batch release.
- Independent testing laboratories performing acceptance and conformance testing.
- Procurement and specifications teams in coatings, wood finishing and restoration projects.
- R&D teams comparing fatty acid composition and functional performance.
Practical uses include raw material acceptance testing, supplier agreements (colour, acid value, PAT limits), quality assurance, and regulatory or contractual compliance for coatings production.
Related standards
Key normative references within ISO 150:2018 include ISO 12966, ISO 2811‑1/3, ISO 4630, ISO 5555, ISO 661, ISO 660, ISO 3681, ISO 3961, and ISO 8534 - all cited for specific test procedures and sampling.
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