Tag: contract fabric

Posted on

Wyzenbeek vs Martindale: Which Abrasion Test Should You Specify?

Wyzenbeek vs Martindale: Which Abrasion Test Should You Specify?

Martindale: The standard used in the UK and Europe. Fabric is rubbed in a figure-of-eight motion against a worsted wool abradant. Results in rub counts. Contract minimum 30,000 rubs.
Wyzenbeek: The standard used in the United States. Fabric is rubbed back and forth in straight lines against a cotton duck canvas abradant. Results in double rubs. Contract minimum 15,000 double rubs.
Are they comparable? No. The two tests use different abradants, different motions, and different pass criteria. A Wyzenbeek double rub count cannot be converted to a Martindale rub count.
Which to specify: For UK and European projects, always specify Martindale. For US projects, specify Wyzenbeek. For international projects, request both where possible.

Interior designers working internationally, or sourcing fabric from American suppliers, regularly encounter both Martindale rub counts and Wyzenbeek double rub counts on specification sheets. The two figures look similar — both express abrasion resistance as a number — but they are produced by entirely different test methods and cannot be meaningfully compared. Specifying a Wyzenbeek result on a UK contract project, or a Martindale result on a US project, risks misaligned expectations with clients, contractors, and insurers. This guide explains how each test works, what the results mean, and how to specify correctly for UK and international projects.

The Martindale Test

The Martindale abrasion test is defined by ISO 12947 and BS EN ISO 12947. It is the standard abrasion test used across the UK, Europe, and most international markets outside the United States. When a fabric data sheet lists a rub count without specifying the test method, the default assumption in UK specification is Martindale.

The test works as follows. A circular sample of the fabric being tested is mounted face-down on a machine and rubbed against a standard abradant — a piece of worsted wool fabric — in a figure-of-eight motion that moves the sample across the abradant in all directions simultaneously. This multidirectional motion is designed to replicate the complex, non-linear abrasion that upholstery fabric experiences in real use. The machine counts each complete figure-of-eight cycle as one rub.

The test is run to one of several endpoints. The most common endpoint for upholstery fabrics is fabric breakdown — the point at which two threads have broken or a hole has appeared in the sample. Some test houses also assess and report pilling at intermediate intervals using a separate grading scale. The total rub count at breakdown is the Martindale rub count reported on the data sheet.

For a complete guide to Martindale thresholds by application and what the numbers mean in practice, see our Martindale rub test guide.

The Wyzenbeek Test

The Wyzenbeek abrasion test is defined by ASTM D4157, the American Society for Testing and Materials standard. It is the dominant abrasion test in the US contract furniture and upholstery market. UK designers sourcing fabric from American suppliers, or specifying for projects with US compliance requirements, will encounter Wyzenbeek results on data sheets.

The test works as follows. A rectangular sample of the fabric being tested is mounted on a machine and rubbed back and forth in straight lines — first in the warp direction, then in the weft direction — against a standard abradant. The standard abradant specified by ASTM D4157 is cotton duck canvas, a tightly woven plain-weave cotton fabric significantly more abrasive than the worsted wool used in Martindale. Each complete back-and-forth cycle counts as one double rub.

The Wyzenbeek test runs until the fabric shows noticeable wear or breakdown, and the double rub count at that point is reported. The linear back-and-forth motion differs fundamentally from the multidirectional figure-of-eight motion of Martindale, which is why the two tests produce results that cannot be directly compared.

Why the Results Cannot Be Compared

The most important point for a specifier to understand is that 50,000 Martindale rubs and 50,000 Wyzenbeek double rubs do not represent the same level of abrasion resistance. They are measurements from different instruments using different abradants, different motion patterns, and assessed against different pass criteria.

The cotton duck canvas abradant used in Wyzenbeek is more aggressive than the worsted wool abradant used in Martindale. All else being equal, a fabric tested to Wyzenbeek will reach its endpoint faster than the same fabric tested to Martindale, because the abradant is harsher. This means Wyzenbeek counts tend to be lower than Martindale counts on equivalent fabrics.

However, this relationship is not consistent across all fabric types. Different fibres and constructions respond differently to the two abradants and the two motion patterns. There is no reliable conversion factor between Wyzenbeek double rubs and Martindale rubs. Various informal conversion ratios circulate in the trade — most commonly the suggestion that one Wyzenbeek double rub equals approximately two Martindale rubs — but this ratio has no scientific basis and should not be relied upon for specification.

The only reliable way to compare two fabrics on a like-for-like basis is to ensure both have been tested to the same standard. When building a specification, always confirm which test method produced the figures on the data sheet.

UK and European Thresholds: Martindale

The following thresholds represent current UK and European contract specification practice for Martindale rub counts. For full detail on each threshold and the reasoning behind it, see our Martindale rub test guide.

Light domestic use: 15,000 rubs minimum. Heavy domestic use: 25,000 rubs minimum. Light contract: 30,000 rubs minimum. General contract — hotel lobbies, restaurant seating, office seating: 50,000 to 60,000 rubs. Heavy contract: 80,000 to 100,000 rubs. Severe contract: 100,000 rubs and above.

US Thresholds: Wyzenbeek

The following thresholds are used in the US contract market for Wyzenbeek double rubs. They are not equivalent to the Martindale thresholds above and should not be compared directly.

Residential use: 9,000 to 15,000 double rubs minimum. Light commercial: 15,000 double rubs minimum. Heavy commercial — hotels, restaurants, office seating: 30,000 to 50,000 double rubs. Severe commercial: 100,000 double rubs.

Which Test to Specify and When

For any project in the UK or continental Europe, always specify Martindale to ISO 12947. This is the expected standard, the one UK test houses use, and the one UK and European contract furniture manufacturers certify their fabrics against. If a fabric supplier provides only a Wyzenbeek result and cannot provide a Martindale result, request that the fabric be tested to Martindale before specifying it for a UK contract project.

For projects in the United States, specify Wyzenbeek to ASTM D4157. For international hospitality projects drawing from both European and American suppliers, request both test results where possible and compare within the same test method rather than across methods.

For yacht and marine projects, the fire standard takes precedence over abrasion performance. See our IMO marine fire standards guide.

Pilling: A Separate Test

Both Martindale and Wyzenbeek measure abrasion resistance — structural wear of the yarn. Neither measures pilling resistance, which is the formation of surface fibre balls through tangling of loose fibre ends. Pilling is assessed by a separate test, ISO 12945-2, also run on the Martindale machine but using a different abradant and a different assessment scale. A fabric with an excellent Martindale abrasion count may still pill badly in use. Always request both the Martindale abrasion result and the ISO 12945-2 pilling grade for contract upholstery specification. See our pilling resistance guide.

Frequently Asked Questions

What is the difference between Martindale and Wyzenbeek?

Martindale rubs the fabric sample in a multidirectional figure-of-eight motion against a worsted wool abradant, counting each cycle as one rub. Wyzenbeek rubs the fabric back and forth in straight lines against a cotton duck canvas abradant, counting each back-and-forth cycle as one double rub. The abradants, motions, and pass criteria are different. The results cannot be directly compared.

Can I convert Wyzenbeek double rubs to Martindale rubs?

No reliable conversion factor exists. Informal ratios circulate in the trade but have no scientific basis and produce unreliable results across different fabric types. The only reliable approach is to test the same fabric to both standards.

What Martindale count should I specify for a hotel?

For hotel bedroom seating: 30,000 rubs minimum. For hotel restaurant and lobby seating: 50,000 to 60,000 rubs. For hotel bar and high-traffic areas: 80,000 to 100,000 rubs. See our hotel fabric specification guide for full detail.

Is Wyzenbeek used in the UK?

Wyzenbeek is not the standard abrasion test in the UK. Martindale to ISO 12947 is the expected test for UK and European contract specification. Wyzenbeek results may appear on data sheets from American suppliers. Always confirm which test standard produced the figures before using them in a UK specification.

What abradant does Martindale use?

The standard Martindale abradant for upholstery fabric testing is worsted wool fabric to ISO 12947-2. Results against different abradants are not directly comparable. Always confirm the abradant used when reviewing a Martindale certificate.

For Martindale thresholds by application, see our Martindale rub test guide. For pilling resistance, see our pilling resistance guide. For hotel specification, see our hotel fabric specification guide.

Request Samples

Order cutting samples of any fabric from our current collections. Trade accounts only.

Order Cuttings
Posted on

Fabric Specification for Healthcare Environments: A Guide for Interior Designers

Anouska Hempel Design

Fabric Specification for Healthcare Environments: A Guide for Interior Designers

The overriding requirement: Every fabric in a healthcare environment must withstand the cleaning regime used in that facility. Confirm the specific products and frequencies with the estates or facilities team before specifying.
Fire standard: BS 7176 Medium or High Hazard depending on the building type and risk assessment. Not Crib 5 alone.
Martindale minimum: 100,000 rubs for patient seating and waiting areas. 60,000 rubs for lower-contact positions.
Fabrics to avoid: Any pile fabric, any fabric with a cleaning code of S, any fabric with a topical FR treatment that degrades with disinfectant cleaning.

Healthcare environments impose more demanding and more specific requirements on interior fabrics than almost any other building type. The combination of clinical cleaning regimes, continuous use, infection control obligations, fire safety requirements, and the extended periods for which patients and visitors are seated creates a specification challenge where a fabric that performs well in a hotel environment may fail completely within months of installation in a hospital or care home. This guide explains the specific requirements, the fabrics that meet them, and the fabrics to avoid.

Infection Control and Cleaning Compatibility

The single most important requirement for fabric in a healthcare environment is compatibility with the cleaning products and regimes used in that facility. Healthcare facilities use cleaning agents significantly more aggressive than those used in hospitality or commercial office environments. Common healthcare cleaning products include sodium hypochlorite solutions at concentrations of 1,000 ppm or above for high-risk areas, quaternary ammonium compounds, hydrogen peroxide solutions, and alcohol-based disinfectants at 70% or above.

Many of these products are incompatible with standard upholstery fabrics. Bleach solutions will strip topical FR treatments, cause colour fade, and degrade most natural fibre fabrics within weeks of regular application. Alcohol-based disinfectants can cause surface breakdown in some PVC faux leathers if the plasticiser formulation is not alcohol-resistant.

Before specifying any fabric for a healthcare project, obtain the specific cleaning products and frequencies used in each area from the estates or facilities management team. Present these to the fabric supplier and request written confirmation of compatibility. Do not rely on general claims of healthcare suitability — obtain confirmation for the specific products used in the specific facility.

Fire Standards for Healthcare

Healthcare buildings are subject to specific fire safety requirements under HTM 05-03 and BS 7176, which specifies fire performance requirements for non-domestic upholstered seating. The applicable BS 7176 hazard category depends on the risk assessment for the specific area.

Medium Hazard under BS 7176 is the minimum for most patient seating, waiting areas, and staff areas in standard healthcare buildings. High Hazard applies to areas where sleeping accommodation is provided — residential care facilities, hospital wards, overnight facilities. Very High Hazard applies to areas where residents have limited mobility or require assistance to evacuate.

BS 7176 includes BS 5852 Crib 5 as its core test for upholstered seating and additionally requires cigarette and match tests. A fabric that simply holds a Crib 5 certificate is not automatically compliant with BS 7176 Medium Hazard. The complete assembly — fabric, interliner, and filling — must be certified to the applicable BS 7176 standard. For guidance on these standards, see our Crib 5 guide and hotel fabric specification guide.

For curtains and cubicle curtains in healthcare environments, BS 5867 Part 2 Type B is the standard requirement. Cubicle curtains used in clinical areas typically require Type C, which includes a launderability pre-conditioning stage confirming that the fire performance survives repeated laundering at 71 degrees Celsius.

Martindale Requirements

Patient seating and waiting area seating in healthcare environments is subject to continuous use throughout the operating hours of the facility. Chairs in an outpatient waiting area may be occupied for sixteen hours a day, seven days a week. The Martindale rub count requirement for this level of use is 100,000 rubs minimum. Seating in lower-contact positions — staff areas, offices, lower-traffic corridors — may be specified at 60,000 rubs minimum, but confirm the use pattern for each position before reducing the specification below 100,000.

Suitable Fabrics for Healthcare

Silicone leather. The strongest all-round specification for patient-contact seating in clinical healthcare environments. Silicone leather is inherently flame resistant without topical treatment, which means its fire performance is not affected by aggressive cleaning. It is compatible with hospital-grade disinfectants including hypochlorite solutions and alcohol-based disinfectants, is non-porous and does not support microbial growth, achieves very high Martindale counts, and is easy to wipe clean to clinical standards.

High-specification PVC faux leather. Compatible with most healthcare cleaning regimes provided the specific formulation has been confirmed as alcohol-resistant and hypochlorite-stable. Healthcare-grade PVC faux leather with welded seams — which eliminates the crevice at the seam line where microorganisms can harbour — is appropriate for patient seating and waiting areas. Confirm that the specific product holds a healthcare suitability certification from the manufacturer. Standard commercial PVC faux leather is not automatically suitable for clinical use. See our faux leather types compared guide for detail.

Coated performance fabrics. Some woven fabrics with a polyurethane or acrylic coating achieve the combination of breathability and cleanability required for patient seating in rehabilitation and residential care environments where patient comfort over extended periods is a higher priority than clinical cleanliness. Confirm cleaning compatibility and confirm that the coating does not crack or peel under the specific cleaning regime used.

Healthcare-specific contract wovens. Some specialist fabric manufacturers produce woven fabrics designed specifically for healthcare use, with inherent antimicrobial properties, high Martindale counts, and confirmed compatibility with healthcare cleaning products. These are appropriate for lower-risk healthcare areas — staff rooms, reception desks, family waiting areas — where the clinical cleaning regime is less aggressive.

Fabrics to Avoid in Healthcare

Any pile fabric — velvet of any fibre type — is unsuitable for patient-contact seating in healthcare environments. The pile structure traps particulate matter, bodily fluids, and microorganisms and cannot be cleaned to clinical standards with the products used in healthcare facilities. For full guidance on velvet specification limitations, see our when not to use velvet guide.

Any fabric with a cleaning code of S is unsuitable for healthcare environments where water-based disinfectant cleaning is routine. Any fabric with a topical FR treatment that degrades with disinfectant cleaning is unsuitable for areas where fire performance must be maintained across the full service life. Standard wool, mohair, linen, and cotton upholstery fabrics are unsuitable for clinical patient-contact areas.

Specific Area Guidance

Patient rooms in acute hospitals require the most stringent specification: silicone leather or healthcare-grade PVC faux leather for any patient-contact upholstery, BS 7176 High Hazard fire certification for all seating, and confirmed compatibility with the full cleaning and disinfection protocol.

Outpatient and waiting areas permit a slightly broader specification. Healthcare-grade PVC faux leather or high-specification coated fabrics are appropriate for seating. The aesthetic can be warmer and less clinical than patient room specification. Fire standard remains BS 7176 Medium Hazard minimum. Martindale minimum 100,000 rubs.

Residential care homes occupy an intermediate position between acute healthcare and hospitality. The fire standard is typically BS 7176 High Hazard for sleeping accommodation areas. The cleaning regime is typically less aggressive than acute healthcare. High-specification contract wovens with confirmed cleaning compatibility may be appropriate for lounge and dining areas.

Frequently Asked Questions

Can velvet be used anywhere in a healthcare building?

Velvet is unsuitable for any patient-contact seating in clinical or quasi-clinical environments. In low-clinical-risk areas of private healthcare — executive offices, family suites, reception areas with low patient contact — velvet may be appropriate if the cleaning regime is compatible and fire certification is confirmed. Confirm the specific cleaning products and the risk category of the area with the facilities team before specifying.

What fire standard applies to hospital waiting areas?

BS 7176 Medium Hazard is the minimum applicable standard for most hospital waiting areas and outpatient seating. The complete assembly — fabric, interliner, and filling — must be certified, not only the fabric. For areas providing sleeping accommodation, BS 7176 High Hazard applies.

How do I confirm a fabric is suitable for healthcare cleaning?

Obtain the specific cleaning products and concentrations used in the area being specified from the facility’s estates or facilities management team. Present these to the fabric supplier and request written confirmation of compatibility. Where possible, request a sample and test it with the actual cleaning product before finalising the specification.

What is the difference between BS 5867 Type B and Type C for healthcare curtains?

BS 5867 Part 2 Type B requires fire performance before laundering. Type C requires fire performance to be maintained after laundering pre-conditioning at 71 degrees Celsius for a defined number of cycles. For cubicle curtains in clinical areas that are regularly laundered, Type C is the appropriate standard.

For Building Safety Act 2022 requirements — many hospital buildings qualify as higher-risk buildings — see our Building Safety Act and fabric specification guide.

For fire certification standards, see our Crib 5 guide and hotel fabric specification guide. For faux leather types suitable for healthcare, see our faux leather types compared guide.

Request Samples

Order cutting samples of any fabric from our current collections. Trade accounts only.

Order Cuttings
Posted on

When Not to Use Velvet — and What to Specify Instead

Black mohair velvet upholstery on a regal chair

When Not to Use Velvet — and What to Specify Instead

Velvet fails fastest in: High-UV environments, wet or humid conditions, applications requiring water-based cleaning, tight upholstery with sharp frame edges.
The most common misspecification: Cotton or synthetic velvet in a contract environment without Crib 5 certification, or any velvet in an outdoor or semi-outdoor setting.
What this guide covers: The specific applications and conditions where velvet is the wrong choice and what to specify instead for each scenario.

Velvet is one of the most commercially significant upholstery fabrics in the UK interior design market. It also generates more specification failures than almost any other fabric type. The failures are not caused by velvet being an inferior product — at its best, contract mohair velvet is among the most technically capable upholstery fabrics available. They are caused by velvet being specified in conditions for which it is structurally unsuitable. This guide is a frank account of when not to use velvet and what to choose instead.

For comparative performance data of different velvet types, see our velvet types compared guide.

Outdoor and Semi-Outdoor Environments

No natural-fibre velvet — mohair, cotton, linen, silk, cashmere — is suitable for outdoor or semi-outdoor use. The pile structure of velvet traps and retains moisture, which in outdoor conditions accelerates mould and mildew growth within the pile. UV exposure degrades natural fibre dyes at a much faster rate on outdoor velvet because the pile structure increases the surface area exposed to UV radiation relative to the fabric weight.

Semi-outdoor applications — covered terraces, glazed atriums with opening panels, poolside seating under a canopy — are equally problematic. The combination of occasional direct moisture exposure and sustained UV transmission produces conditions that natural-fibre velvet cannot tolerate.

Specify instead: Solution-dyed acrylic, high-specification outdoor polyester, or marine-grade PVC faux leather with UV stabilisers. See our IMO marine standards guide for marine and outdoor fabric guidance.

High-Humidity Environments

Velvet in sustained high-humidity conditions — spa changing rooms, pool surrounds, steam room lobbies — absorbs atmospheric moisture and does not dry quickly due to the density of the pile. Retained moisture in the pile base creates conditions for mould growth and accelerates deterioration of the backing structure.

Specify instead: PVC or silicone faux leather, both of which are non-absorbent and can be wiped dry. See our faux leather types compared guide.

Applications Requiring Regular Water-Based Cleaning

Most velvet carries a cleaning code of S — solvent-based dry cleaning only. Water applied to S-coded velvet causes watermarks and pile distortion that may be permanent. In any environment where the cleaning team applies water-based products to upholstered surfaces as standard — hotel bedrooms on standard cleaning schedules, restaurant seating cleaned between services with damp cloths, healthcare environments requiring wet disinfection — S-coded velvet is incompatible with the operational reality.

This is the most common operational failure with velvet in hospitality environments. The fabric is specified, installed, and cleaned incorrectly within the first week.

Specify instead: Confirm whether the specific velvet range carries a WS code rather than S. If water-based cleaning is unavoidable throughout the scheme, specify PVC faux leather for those positions and use velvet in areas — headboards, decorative cushions, low-use occasional seating — where the cleaning regime can be controlled.

South-Facing Rooms and High-Light Environments

Velvet in pale colourways in south-facing rooms will show fading faster than an equivalent flat-woven fabric. The pile structure presents a larger surface area to light than a flat weave of the same fibre and weight, accelerating photodegradation of the dye. For guidance on light fastness ratings and room orientation, see our light fastness and Blue Wool Scale guide.

Specify instead: Confirm the ISO 105-B02 grade for the specific colourway before ordering. For very high-light conditions, specify dark mohair velvet colourways or move to a flat-woven fabric in a light-fast colourway for the most exposed positions.

Tight Upholstery Over Sharp Frame Edges

Velvet pile is vulnerable at points where the fabric is pulled tightly over sharp frame edges — the corners of seat pads, the edges of dining chair backs. At these points the pile is subjected to sustained localised tension that gradually pulls fibres from the pile base, causing thinning and eventually pile loss. When specifying velvet for an upholstery project, ensure the furniture specification calls for appropriately softened frame edges at all contact points.

Specify instead: For furniture with unavoidably sharp frame edges, specify a flat-woven fabric in a comparable colour and weight. The absence of pile eliminates the pile-loss risk at edges entirely.

Healthcare Environments Requiring Disinfectant Cleaning

Healthcare environments use cleaning products — hypochlorite bleach solutions, quaternary ammonium compounds, alcohol-based disinfectants — that are incompatible with the cleaning codes of most velvet fabrics. The pile structure traps contaminants and cannot be cleaned to clinical standards.

Specify instead: Silicone leather for patient-contact seating in clinical environments. For full guidance, see our fabric for healthcare environments guide.

Budget-Constrained Projects Where Velvet Requires FR Treatment

Cotton, linen, and synthetic velvets that do not carry an inherent Crib 5 certification require FR treatment for contract use. The treatment adds cost, programme time, and introduces dye interaction risks in certain colourways. For a budget-constrained project, the total cost including treatment may exceed the cost of an alternative with inherent certification. See our dye types and FR treatment guide for the specific risks.

Specify instead: Mohair velvet with independently certified Crib 5 achieved without topical treatment eliminates the treatment cost, programme time, and dye risk entirely.

Frequently Asked Questions

Can velvet be used outdoors?

No natural-fibre velvet is suitable for outdoor or semi-outdoor use. The pile structure retains moisture and the fibres degrade rapidly under UV exposure. For outdoor or covered terrace seating, specify solution-dyed acrylic or marine-grade PVC faux leather engineered for outdoor conditions.

Why does velvet watermark?

Water applied to velvet causes individual pile fibres to mat together in the wetted area as surface tension pulls fibres toward the water droplet. When the water evaporates, the fibres dry in this distorted position. The resulting mark is permanent in most natural-fibre velvets once dried. This is why most velvet carries a cleaning code of S.

Is any velvet suitable for areas that need water-based cleaning?

Some synthetic velvets carry a W or WS cleaning code and can be spot-cleaned with water-based products. Confirm the cleaning code on the specific range data sheet before specifying and test compatibility with the specific cleaning product before installation. No natural-fibre velvet should be specified where water-based cleaning will be applied routinely.

When is velvet the right choice despite its limitations?

Velvet is the right choice when its specific combination of properties — tactile quality, depth of colour, inherent Crib 5 for mohair, high Martindale count, and visual character — aligns with the project requirements and the operational environment is compatible with its care requirements. Hotel lobby seating, restaurant banquettes in dry controlled environments, residential sofas, headboards, cushions, and curtains in appropriate light conditions are all applications where correctly specified velvet performs excellently.

For velvet types and comparative performance, see our velvet types compared guide. For hotel velvet specification, see our hotel fabric specification guide. For alternatives in high-cleaning environments, see our faux leather types compared guide.

Request Samples

Order cutting samples of any fabric from our current collections. Trade accounts only.

Order Cuttings
Posted on

Pilling Resistance in Upholstery Fabric: A Guide for Interior Designers

Silk Velvet Upholstery Mohair

Pilling Resistance in Upholstery Fabric: A Guide for Interior Designers

What pilling is: Small balls of tangled fibre that form on the fabric surface through friction and use, altering appearance even when the fabric remains structurally intact.
The test: ISO 12945-2 Martindale pilling test, graded 1 to 5. Grade 5 is no change. Grade 4 is slight surface fuzzing. Grade 3 is moderate pilling. Contract minimum is grade 4.
Highest pilling risk: Short-staple fibre blends, loosely twisted yarns, natural-synthetic blends.
Lowest pilling risk: Long-staple natural fibres, tightly twisted yarns, high-density weaves, mohair velvet.

A fabric can achieve 80,000 Martindale rubs and still pill badly. Abrasion resistance and pilling resistance are distinct properties measured by different tests. A fabric that resists structural wear may nevertheless develop an unsightly surface of small fibre balls within months of use, fundamentally altering its appearance without any yarn breaking. For pile fabrics in particular, pilling can destroy the visual quality of a fabric long before its structural integrity is compromised. This guide explains what causes pilling, how it is tested, which fabrics carry the highest and lowest risk, and what to specify to avoid problems in contract use.

For abrasion resistance and Martindale rub counts, see our Martindale rub test guide. For velvet types and their performance characteristics, see our velvet types compared guide.

What Causes Pilling

Pilling begins when individual fibres work free from the yarn structure through friction and mechanical stress. Loose fibre ends at the surface of the fabric are caught by adjacent surfaces and tangled together into small balls. These balls remain attached to the fabric by the fibres still anchored within the yarn, which is why they do not simply fall off. The ball continues to grow as more loose fibres are captured and incorporated into it.

The size and tenacity of pills varies by fibre type. Natural fibres produce pills that are relatively fragile and may eventually detach from the fabric surface through continued friction. Synthetic fibres produce pills that are anchored by stronger fibres that do not break under continued use. The pills grow, persist, and resist removal. This is why fabrics containing synthetic fibres often pill more visibly and permanently than pure natural-fibre fabrics.

Blended fabrics often pill worst of all. The short, weak natural fibres break loose from the yarn easily, producing the loose ends that form pill nuclei. The stronger synthetic fibres then anchor the pills to the fabric surface, preventing them from detaching. The result is persistent, anchored pills formed from natural fibre content but held in place by synthetic fibre anchors.

The Pilling Test: ISO 12945-2

Pilling resistance is tested to ISO 12945-2 using the Martindale machine with a different abradant. For pilling assessment, the fabric sample is rubbed against itself rather than against a worsted wool abradant. The machine runs for a defined number of cycles and the sample is then assessed visually against reference photographs and graded on a scale of 1 to 5.

Grade 5 indicates no change. Grade 4 indicates slight surface fuzzing or early-stage pilling, barely visible in normal viewing conditions. Grade 3 indicates moderate pilling, noticeable in normal use. Grade 2 indicates distinct pilling. Grade 1 indicates severe, dense pilling across the whole surface.

The test is typically run at 125, 500, 1000, and 2000 cycles. A fabric assessed at 2000 cycles with a grade of 4 or above is considered acceptable for contract upholstery use. The contract minimum is grade 4. A fabric achieving grade 3 at 2000 cycles will show noticeable pilling in use and is not appropriate for contract seating applications regardless of its Martindale abrasion count.

Fibre Types and Pilling Risk

Mohair. Lowest pilling risk of all natural-fibre velvets. The long-staple mohair fibre has fewer free ends per unit length of yarn than short-staple fibres. Fewer free ends means fewer pill nuclei. The smooth surface of the mohair fibre also means that free ends slide rather than tangle, reducing the rate of pill formation. Mohair velvet in contract grades typically achieves grade 4 to 5 at 2000 cycles.

Wool. Low to moderate pilling risk depending on fibre length and yarn construction. Merino wool pills less than coarser short-staple wool. Tightly spun wool yarns pill less than loosely spun yarns of the same fibre.

Cotton. Moderate pilling risk. Short-staple cotton varieties pill more than long-staple varieties such as Egyptian or Pima cotton. Cotton velvet is more susceptible to pilling than mohair velvet because cotton fibres are shorter and the pile construction exposes more free ends per unit area.

Linen. Low pilling risk. Linen is a long-staple bast fibre. The fibre length and relatively smooth surface reduce pill formation compared to cotton.

Polyester. High pilling persistence if it pills at all. Synthetic fibres anchor pills rather than allowing them to detach. When pills do form they are tenacious.

Natural-synthetic blends. Highest pilling risk in practice. Specifying blends for contract upholstery requires specific pilling grade confirmation, not just Martindale abrasion data.

Construction Factors That Affect Pilling

Yarn twist affects pilling directly. A high-twist yarn locks fibres into the yarn structure more firmly, reducing the number of free ends exposed at the surface. A low-twist yarn allows fibres to work free more easily. Two fabrics of the same fibre and weight can have very different pilling grades depending on the yarn construction.

Weave density affects pilling by controlling the movement of yarns at the fabric surface. A tight, dense weave restricts yarn movement and reduces the abrasion between adjacent yarns that generates free fibre ends.

Pile construction in velvet affects pilling through pile height and density. A short, dense pile has fewer exposed free ends per unit area than a long, open pile of the same fibre. Contract-grade velvet is typically specified with a denser, shorter pile than residential velvet partly for this reason.

Pilling in Use: What Clients Experience

Pilling in upholstery is most visible in areas of sustained friction — seat cushions where clothing rubs against the fabric, and armrests. In a hotel or restaurant environment, denim in particular is highly abrasive and accelerates pilling. Pilling is not repairable in the way that surface staining can sometimes be treated. A pilled fabric requires either mechanical depilling — a temporary intervention — or replacement. Brief clients on pilling risk at the point of specification, particularly for natural-fibre pile fabrics in contract environments.

Frequently Asked Questions

What is the difference between pilling and abrasion?

Abrasion is the physical wearing away of yarn structure through friction, measured by Martindale rub count. Pilling is the formation of surface fibre balls through the tangling of loose fibre ends, measured separately by ISO 12945-2. A fabric can have a very high Martindale abrasion count and still pill badly. Both should be confirmed before specifying a fabric for contract use.

What pilling grade should I specify for contract upholstery?

Grade 4 minimum to ISO 12945-2 at 2000 cycles. For high-traffic environments, grade 4 to 5 is a more defensible specification. Always confirm the grade for the specific colourway being ordered, as pilling grades can vary between colourways in the same range.

Does mohair velvet pill?

Mohair velvet has the lowest pilling risk of any natural-fibre velvet due to the long staple length and smooth surface of the mohair fibre. Contract-grade mohair velvet typically achieves grade 4 to 5 at 2000 cycles. It is the most pill-resistant natural-fibre velvet available for contract upholstery.

Why do natural-synthetic blend fabrics pill so badly?

Natural-synthetic blends combine the pill-forming tendency of short natural fibres with the pill-anchoring strength of synthetic fibres. The result is persistent, anchored pills that grow with continued use. Blended fabrics for contract use require specific pilling grade confirmation before specifying.

For abrasion test method differences between Martindale and Wyzenbeek, see our Wyzenbeek vs Martindale guide.

For abrasion resistance, see our Martindale rub test guide. For velvet types and contract suitability, see our velvet types compared guide.

Request Samples

Order cutting samples of any fabric from our current collections. Trade accounts only.

Order Cuttings
Posted on

How FR Treatment Works: A Plain-English Guide for Interior Designers

Black Faux Leather Chair

How FR Treatment Works: A Plain-English Guide for Interior Designers

What FR treatment does: It slows or prevents the ignition and spread of flame by interfering with the chemistry of combustion at the surface of the fabric.
The two main methods: Back-coating (paste applied to the reverse — standard for upholstery Crib 5) and wet padding (chemical solution applied to the whole fabric — standard for curtain treatment).
Inherent vs topical: Inherent fire resistance is a permanent property of the fibre itself. Topical treatment is applied after weaving and can degrade over time, through cleaning, or through interaction with certain dyes.
Who can certify: Only a UKAS-accredited testing laboratory. No fabric company, designer, or treatment provider can self-certify.

Most interior designers who specify FR-treated fabrics regularly have never seen the treatment process and have only a general idea of how it works. This guide explains the chemistry and process in plain language — not to make designers into treatment specialists, but to give them enough understanding to ask the right questions, spot specification risks before they become problems, and explain FR compliance confidently to clients and contractors.

For which fibres can be treated, see our FR treatment and fibre compatibility guide. For dye types and their interaction with treatment, see our dye types and FR treatment guide. For the fire standards that require treatment, see our Crib 5 guide.

Why Fabrics Need FR Treatment

All organic fibres will burn if exposed to sufficient heat and ignition energy. The chemistry of combustion in textiles follows a consistent pattern. When a fibre is heated, its polymer structure begins to break down — a process called pyrolysis. This produces flammable gases. The gases mix with oxygen from the atmosphere and ignite, producing a flame. The flame generates further heat, which causes more pyrolysis, which produces more flammable gas, which sustains and spreads the fire. This self-reinforcing cycle is what makes unprotected upholstery and curtains a serious fire hazard in public buildings.

FR treatment breaks this cycle at one or more points. Depending on the type of FR compound used, it may prevent or delay pyrolysis, reduce the quantity or flammability of the gases produced, cause the fabric to form a carbonaceous char layer that insulates the underlying structure from the heat source, or dilute the flammable gases with inert gases that cannot sustain combustion. The goal in all cases is the same: to prevent the fabric from sustaining ignition and propagating flame when exposed to the ignition sources defined in the test standard.

The Two Main Treatment Methods

Back-coating. The standard method for upholstery Crib 5 treatment. The fabric is passed through a machine that applies a paste or emulsion of FR chemicals to the reverse face of the fabric. The paste is then dried and cured to fix the compound to the backing structure. The treatment sits on the back face and does not penetrate the face yarns. This is why back-coating, when correctly applied, does not alter the appearance or handle of the face fabric.

The FR compounds used in back-coating are typically phosphorus-based or halogenated compounds — most commonly brominated flame retardants applied in a paste that also contains a binder to hold the compound to the fabric. The phosphorus compounds work primarily in the solid phase: when heated, they decompose to form phosphoric acid, which causes the polymer to char rather than produce flammable gases. The halogenated compounds work primarily in the gas phase: they release halogen radicals that interrupt the chain reactions sustaining the flame.

Back-coating adds weight to the fabric — typically a few grams per square metre — and gives the reverse a firmer, slightly stiffer character. This can be an advantage in upholstery construction because the stiffer back helps the fabric behave consistently during cutting and making-up. It does not affect the face pile character of velvet or the handle of the woven face.

Wet padding. The standard method for curtain FR treatment and some lighter upholstery fabrics. The fabric is fed through a padder — a bath of FR chemical solution followed by rollers that squeeze the solution into the fabric structure under controlled pressure — and then dried and cured. The wet pickup is controlled to achieve the required chemical loading. Because the solution penetrates the whole fabric including the face yarns, wet padding can affect handle and, critically, can interact with certain dye types. See the dye types and FR treatment guide for the specific risks.

The FR compounds used in curtain wet padding are typically water-soluble inorganic salts — ammonium phosphate or ammonium sulphate compounds — applied in aqueous solution. These are effective for cellulosic fibres and work primarily by releasing inert gases when heated that dilute the flammable gas mixture around the burning fabric. They are less suitable for upholstery because they are water-soluble and would wash out in cleaning. Back-coating compounds are insoluble and more durable.

Inherent Fire Resistance vs Topical Treatment

The distinction between inherent and topical fire resistance is commercially significant and frequently misunderstood.

Inherent fire resistance is a permanent property of the fibre itself, arising from its chemical structure. Wool and mohair have inherent fire resistance because they are protein fibres with high nitrogen and sulphur content. These elements make the fibre self-extinguishing — when the ignition source is removed, the fibre stops burning. No chemical treatment is required and no treatment can be washed away. The fire resistance is permanent for the life of the fabric.

Trevira CS is an inherently flame-retardant synthetic fibre. The flame-retardant chemical is incorporated into the polyester polymer during fibre production, not applied to the surface afterwards. Like mohair, the fire resistance is permanent and survives cleaning.

Topical treatment applies FR chemicals to the fabric after it has been woven or knitted. The chemicals are not part of the fibre structure — they sit on or within the fabric surface. This means they can potentially be degraded by cleaning, by mechanical abrasion over time, or by interaction with atmospheric pollutants or incompatible dyes. The degree to which this happens depends on the specific FR compound, the fabric construction, and the cleaning regime.

Back-coated fabrics retain their FR properties well under normal contract cleaning conditions because the back-coating compound is insoluble and mechanically fixed to the backing structure. The relevant risk is the dye interaction problem in wet-padded fabrics described in the dye types guide rather than the physical removal of the compound.

For contract environments where cleaning frequency is high — healthcare, transport seating, hotel restaurants — the distinction between inherent and topical certification carries practical weight. A fabric whose fire resistance survives aggressive cleaning without needing re-treatment or re-certification is operationally simpler and more reliably compliant over its full service life.

The Testing and Certification Process

FR treatment produces a claim of compliance. The claim must be verified by an independent test before it has any legal or commercial standing.

The test is conducted by a UKAS-accredited testing laboratory. The fabric and, for composite tests such as BS 7176, the filling material as well, are prepared and tested against the relevant ignition sources. For BS 5852 Crib 5, the ignition source is a wooden crib of defined dimensions and mass placed at the junction between a test seat and back assembly made from the fabric and a standard filling. The assembly must show no sustained flaming or progressive smouldering after the crib has burned out.

If the assembly passes, the laboratory issues a test certificate. The certificate identifies the fabric by name or reference, the filling used in the test, the standard tested against, and the test result. This certificate is the document that a designer must obtain from the fabric supplier and retain as evidence of compliance for the project.

A fabric supplier’s claim that a fabric is Crib 5 compliant without a certificate from a UKAS-accredited laboratory is not sufficient for contract specification. The Regulatory Reform (Fire Safety) Order 2005 requires the responsible person for a building to be able to demonstrate that furnishings comply with the applicable standard. A verbal assurance or a product description are not adequate evidence. The test certificate is.

What FR Treatment Cannot Do

Understanding the limits of FR treatment is as important as understanding what it achieves.

FR treatment cannot make a fabric fireproof. No textile can be made completely non-combustible by topical treatment. FR treatment reduces ignitability and slows flame spread sufficiently to meet the defined test standard. In a real fire involving sustained heat and ignition energy beyond the test conditions, treated fabric will eventually burn.

FR treatment cannot compensate for incorrect installation. A Crib 5-certified fabric used without the foam specified in the test certificate does not maintain its certification. The certificate is issued for the specific fabric and filling combination tested. Substituting a different foam invalidates the certificate for that assembly.

FR treatment does not substitute for structural fire safety. The fire resistance of the building fabric — walls, floors, doors, compartmentation — is a separate matter from the fire safety of soft furnishings. FR upholstery fabric is one element of a fire safety strategy, not a substitute for the rest of it.

FR treatment does not make a fabric immune to cleaning degradation permanently. Back-coated fabrics are durable under normal cleaning conditions, but cleaning with inappropriate chemicals — very high pH alkaline cleaners, solvents incompatible with the binder system — can over time affect the integrity of the coating. The cleaning code on the fabric data sheet should be followed.

What Happens When a Treated Fabric Is Cleaned

The question designers are most frequently asked by clients is whether the FR treatment survives cleaning. The answer depends on the treatment method and the cleaning agent.

Back-coated upholstery fabrics coded S (solvent clean only) should not be cleaned with water-based products. The binder system holding the back-coating to the fabric may be water-sensitive. Repeated water-based cleaning of an S-coded back-coated fabric can progressively weaken the adhesion of the coating. The FR compound may remain present but its mechanical adhesion to the fabric is reduced.

Back-coated fabrics coded W or WS can be spot-cleaned with water-based products without significant effect on the back-coating, provided the products are not strongly alkaline. Hotel-grade alkaline cleaners applied repeatedly can over time affect the coating. This is one of the reasons to prefer inherently fire-resistant fabrics for hotel environments with high-frequency professional cleaning. See our hotel fabric specification guide for practical guidance on this.

Wet-padded curtain fabrics treated with water-soluble inorganic salt compounds are water-sensitive by nature. The standard BS 5867 Part 2 Type B test includes a water-soak stage precisely to assess whether the treatment survives cleaning. A fabric that passes this stage has demonstrated that its treatment survives a defined level of water exposure. This does not mean the treatment is permanent under repeated laundering. For healthcare curtain applications requiring Type C certification, a more rigorous laundering pre-conditioning is included in the test.

The Treatment Supply Chain

Understanding who is responsible for what in the FR treatment supply chain helps designers avoid the most common specification failures.

The fabric supplier is responsible for knowing whether their fabric can be treated, which treatment method is appropriate, and which treatment providers have successfully treated their fabric before. A good fabric supplier maintains this information and can advise the designer before the fabric is ordered.

The treatment provider applies the FR compound and, in most cases, arranges testing through a UKAS-accredited laboratory. The treatment provider issues the test certificate. They are responsible for the quality and consistency of the treatment and for ensuring the treated fabric meets the specified standard.

The designer is responsible for specifying the correct standard for the project, confirming that the fabric supplier and treatment provider can meet it, and obtaining the test certificate before the fabric is installed. The designer cannot certify compliance — only the testing laboratory can do that — but the designer is responsible for ensuring the certified fabric is what is installed.

The contractor or upholsterer is responsible for installing the certified fabric with the certified filling. Substituting materials without re-testing invalidates the certificate. The contractor should be briefed on this before work begins.

Frequently Asked Questions

Does FR treatment change how a fabric looks or feels?

Back-coating, correctly applied to the reverse of an upholstery fabric, does not alter the appearance or handle of the face. The back will feel slightly firmer and heavier but the face pile character and surface quality are unchanged. Wet padding for curtain treatment can affect the handle of lightweight or delicate fabrics — sheers in particular may feel slightly stiffer after treatment. Any fabric where handle or appearance change would be commercially significant should be sample-treated and approved before committing to the full order.

How long does FR treatment last?

Inherent fire resistance is permanent. Topical back-coating is durable under normal contract conditions and will typically remain effective for the life of the fabric provided it is cleaned according to the cleaning code and not subjected to chemicals that attack the binder system. Wet-padded treatments are less durable and may require re-treatment after intensive cleaning or after a defined number of years in high-frequency cleaning environments. For healthcare curtains under BS 5867 Type C, re-treatment after a defined number of wash cycles is standard practice.

Can a fabric be re-treated after cleaning?

Yes, in most cases. Back-coated upholstery fabrics that have been in service for many years can typically be re-treated if the original treatment has degraded, though this requires removing the fabric from the furniture. Wet-padded curtain fabrics can be re-treated when they are laundered if the treatment has been removed. The re-treated fabric must be re-tested if a new certificate is required. Contact the original treatment provider for advice on re-treatment for specific fabrics.

What is the difference between Crib 5 and BS 7176?

BS 5852 Crib 5 is the test method — the specific ignition source and test procedure. BS 7176 is the specification standard for non-domestic upholstered seating that references Crib 5 and additionally includes the cigarette and match tests, a water-soak stage, and documentation of the specific hazard category and filling used. For hotel and contract upholstery, BS 7176 Medium Hazard is the correct standard to specify because it produces a more complete and defensible certificate than Crib 5 alone. See our Crib 5 guide and hotel fabric specification guide for full detail.

Can I self-certify that a fabric is fire retardant?

No. Only a UKAS-accredited testing laboratory can issue a valid fire test certificate. A fabric supplier, designer, treatment provider, or contractor cannot self-certify FR compliance. Under the Regulatory Reform (Fire Safety) Order 2005, the responsible person for a commercial building must be able to produce evidence of compliance. A test certificate from a UKAS-accredited laboratory is that evidence. A verbal assurance, a product description, or a supplier’s own claim of compliance are not.

For the fire standards requiring treatment, see our Crib 5 guide. For which fibres can be treated, see our FR treatment and fibre compatibility guide. For dye types and their FR interaction, see our dye types and FR treatment guide.

Request Samples

Order cutting samples of any fabric from our current collections. Trade accounts only.

Order Cuttings
Posted on

Light Fastness and the Blue Wool Scale: Fabric Specification Guide

Light Fastness and the Blue Wool Scale: A Complete Guide for Interior Designers and Specifiers

Light fastness is a fabric’s resistance to fading when exposed to light. For interior designers, it is one of the most practically consequential specifications you will make. A fabric that fades within two years in a south-facing room represents a specification failure regardless of how well it performs on every other measure. This guide explains how light fastness is tested, what the Blue Wool Scale grades mean, which grades to specify for different applications, and how light fastness interacts with fibre type, dye method, and room orientation.

This is the third in a series of technical specification guides from Kothea. The first covers the Martindale rub test and the second covers BS 5852 Crib 5 fire certification.
For why velvet in pale colourways in south-facing rooms is a specific light fastness risk, see our when not to use velvet guide. For colour naming, systems, and metamerism, see our colour naming and specification guide. For the companion test covering dye transfer and crocking, see our colour fastness and crocking guide.

What Light Fastness Means

Light fastness measures how much a fabric’s colour changes when exposed to light. It is not the same as colour fastness generally, which covers a broader range of stressors including washing, rubbing, and perspiration. Light fastness specifically measures the effect of ultraviolet and visible light on the dye or pigment within a fabric.

Fading occurs when light energy breaks down the chemical bonds in a dye molecule, altering its ability to absorb and reflect specific wavelengths of light. The result is a shift in the perceived colour of the fabric, which may manifest as bleaching, yellowing, or a change in hue depending on the dye type and fibre.

The speed and extent of fading depends on the fibre type, the class of dye used, the dyeing method, the intensity and spectrum of light the fabric is exposed to, and the presence of UV filtering in the glazing of the windows in the room.

Light fastness should not be confused with shade change in velvet, which is the apparent change in colour caused by pile being pushed in different directions through use. Shade change is a mechanical phenomenon and is not related to dye degradation or light exposure.

How the Test Works

The standard test for light fastness in the United Kingdom and Europe is ISO 105-B02: Colour Fastness to Artificial Light: Xenon Arc Fading Lamp Test. The fabric specimen is placed in a controlled chamber and exposed to a xenon arc lamp, which produces a spectrum of light representative of natural daylight at the D65 standard illuminant. This simulates the conditions of a south-facing interior window.

The specimen is assessed at intervals by comparing the degree of colour change against a set of eight reference fabrics known as blue wool references, numbered 1 to 8. These references are produced and calibrated by specialist manufacturers such as James Heal, who supply accredited test houses worldwide. Each blue wool reference is dyed with a different dye to produce a known and calibrated resistance to fading. Blue wool 1 is the most fugitive and blue wool 8 is the most resistant. Each successive reference is approximately twice as resistant to fading as the previous one, giving the scale a geometric rather than linear progression. The difference between grade 5 and grade 6 represents twice the resistance of grade 4 to grade 5, not an equal step.

The result awarded to the fabric is the number of the blue wool reference that most closely matches the degree of fading shown by the test specimen. A fabric rated at grade 5 has faded to a degree equivalent to blue wool reference 5 under the same exposure conditions.

The Blue Wool Scale: What Each Grade Means

Grade 1 indicates very poor light fastness. The fabric will fade rapidly under even moderate light exposure. No upholstery or curtain fabric should be specified at this grade.

Grade 2 indicates poor light fastness. Significant fading is expected within a short period. Not suitable for any interior application where appearance durability matters.

Grade 3 indicates moderate light fastness. Acceptable only for very low-light environments with no direct sunlight exposure. Not recommended for curtains or upholstery in standard residential or contract use.

Grade 4 indicates good light fastness and is the recognised minimum for interior furnishing fabrics. Suitable for residential upholstery and curtains in rooms with indirect or limited natural light. Not recommended for south-facing rooms with large glazed areas or for high-light contract environments.

Grade 5 indicates very good light fastness and is the recommended minimum for most residential upholstery and curtain specifications. Suitable for rooms with moderate natural light including east and west-facing rooms.

Grade 6 indicates excellent light fastness and is recommended for south-facing rooms, high-light residential environments, and standard contract interiors including hotels and restaurants.

Grade 7 indicates very high light fastness. Recommended for environments with prolonged or intense light exposure including glazed atriums, conservatories, and south-facing hospitality spaces.

Grade 8 indicates the maximum achievable light fastness and is reserved for the most demanding light environments including marine, semi-outdoor, and direct sunlight applications.

Specification Thresholds by Application

For residential upholstery in rooms with limited or indirect natural light, grade 4 is the minimum acceptable threshold. For residential upholstery in rooms with moderate natural light, specify grade 5 or above. For south-facing rooms or rooms with large glazed areas, specify grade 6 or above. For contract upholstery in hotels, restaurants, and offices with standard glazing, specify grade 5 as a minimum with grade 6 preferred. For glazed atriums, hotel lobbies with skylights, or any environment with prolonged daylight exposure, specify grade 6 to 7.

For curtains, the same grading applies but the exposure is usually more direct and more sustained than for upholstery. A curtain fabric in a south-facing room should be specified at grade 6 or above regardless of whether the curtains are habitually closed or drawn.

For marine, yacht, or semi-outdoor applications, grade 7 to 8 is the appropriate range and specialist outdoor-rated fabrics should be specified rather than standard interior upholstery fabric.

The Effect of Room Orientation

Room orientation is one of the most underspecified variables in fabric selection. A north-facing room in the UK receives no direct sunlight at any time of year, and a grade 4 or 5 fabric is typically adequate. An east-facing room receives direct morning sun for a limited period. A west-facing room receives afternoon sun, which can be intense in summer. A south-facing room receives direct sunlight throughout the day from spring through autumn, with peak UV intensity between midday and 3pm.

The difference in light exposure between a north-facing and south-facing room in London over a twelve-month period is very significant. A grade 4 fabric that performs adequately in a north-facing study may show visible fading within eighteen months in a south-facing drawing room.

Always ask the client which direction the principal windows face and factor that into the light fastness requirement before specifying.

Fibre Type and Dye Method

Not all fibres accept dyes equally, and not all dyes are equally resistant to light degradation. The light fastness of a fabric is a product of both.

Silk is the most photosensitive natural fibre. Silk dyes are chemically susceptible to UV degradation, and silk fabrics typically achieve lower light fastness ratings than wool, cotton, or linen. Silk and silk velvet should be specified with caution in high-light environments, and the client should be advised of this limitation explicitly before specification is finalised.

Wool and mohair accept reactive and acid dyes that can achieve good light fastness ratings when correctly selected. Well-dyed wool upholstery fabrics typically achieve grade 5 to 6. Mohair, being a wool-derived fibre, has similar dye chemistry. Kothea’s Mohair Velvet Seven is tested independently to ISO 105-B02 and achieves grade 4 to 5 for light colourways and grade 5 to 6 for dark colourways. Darker colourways generally achieve higher light fastness grades because a greater proportion of colour loss is required before a visual change becomes perceptible.

Cotton and linen typically achieve moderate light fastness with standard reactive dyes. Pre-washed and solution-dyed cotton and linen can achieve higher grades depending on the dyestuff selection.

Polyester is inherently more resistant to UV degradation than natural fibres and typically achieves grades 6 to 7. Solution-dyed polyester, where colour is introduced into the fibre during extrusion rather than applied to the surface after weaving, achieves the highest light fastness ratings of any standard interior fabric and is appropriate for the most demanding high-light or semi-outdoor applications.

PVC and PU faux leathers are treated with UV-stabilising additives during manufacture and typically achieve high light fastness ratings. However, UV degradation of the substrate itself can cause surface cracking and loss of surface texture independent of colour change, which is a separate consideration for high-light environments.

What Light Fastness Does Not Measure

The ISO 105-B02 test measures colour change under controlled artificial light. It does not measure the effect of UV-filtering glass, which can significantly reduce UV exposure in modern double or triple-glazed windows. It does not measure the effect of cleaning on dye stability, which is covered by separate fastness tests. It does not predict how a specific fabric will behave in a specific room, because actual exposure varies by latitude, season, window orientation, glazing specification, and curtain or blind usage.

Low-e glazing and UV-blocking film can substantially reduce the UV component of light entering a room, extending the effective service life of a fabric beyond what the grade alone would suggest. If a client is refurbishing a property with high-specification glazing, this should be factored into the specification conversation.

Light Fastness and Crocking

Light fastness should not be confused with crocking, which is the transfer of dye from a fabric surface to another material through rubbing or friction. Crocking is measured by a separate test and graded on a different scale of 1 to 5. A fabric with good light fastness may still crock, particularly when wet.

For dark-coloured velvets in upholstery applications, crocking is a relevant concern particularly where light-coloured clothing is likely. Always check the crocking rating as well as the light fastness grade when specifying dark velvets for seating.

Kothea and Light Fastness

Mohair Velvet Seven from Kothea is tested independently to ISO 105-B02 and achieves grade 4 to 5 for light colourways and grade 5 to 6 for dark colourways, making it appropriate for moderate to high-light residential environments and standard contract interiors with adequate glazing.

For high-light environments, colourway selection is material. A dark colourway at grade 5 to 6 will outperform a pale colourway at grade 4 to 5 in a south-facing room. If the client’s brief requires a pale colourway in a south-facing room, this should be discussed explicitly and the light fastness limitation acknowledged before specification is finalised.

For full specification data on light fastness across the Kothea range, see the mohair velvet upholstery page or contact Kothea directly.

How to Specify Light Fastness

Ask the supplier for the ISO 105-B02 grade and confirm whether the test was carried out by an independent third party laboratory or self-declared by the supplier. Self-declared ratings without an independent test certificate should not be relied upon for contract projects.

State the required minimum grade in your specification as a labelled field. For example: Light fastness minimum grade 5 to ISO 105-B02. This makes the requirement explicit and verifiable.

Where the project involves south-facing rooms, large glazed areas, or a light-sensitive colourway, note this in your specification and confirm with the supplier that the grade applies to the specific colourway being ordered. Light fastness can vary between colourways within the same range, particularly between light and dark shades.

Frequently Asked Questions

What light fastness grade do I need for a south-facing room?

For a south-facing room in the UK, specify a minimum of grade 6 to ISO 105-B02 for both upholstery and curtain fabrics. South-facing rooms receive direct sunlight throughout the day from spring through autumn, which represents the most demanding light exposure condition in standard residential interiors. Grade 4, the minimum for interior furnishing fabrics generally, is insufficient for sustained south-facing exposure and will show visible fading within one to two years in most cases. If the glazing incorporates UV-blocking film or low-e coating, this will extend fabric performance, but grade 6 remains the appropriate specification baseline regardless of glazing.

What does a Blue Wool Scale grade of 5 mean for upholstery fabric?

A Blue Wool Scale grade of 5, tested to ISO 105-B02, means the fabric’s colour has faded to a degree equivalent to blue wool reference 5 under controlled xenon arc light exposure. Grade 5 is the recommended minimum for most residential upholstery specifications and is appropriate for rooms with moderate natural light including east and west-facing rooms. It is not recommended for south-facing rooms with large windows, where grade 6 is the appropriate minimum. Each grade on the scale represents approximately twice the light resistance of the grade below it, so the difference between grade 5 and grade 6 is significant rather than marginal.

Does silk fabric fade faster than other upholstery fabrics?

Yes. Silk is the most photosensitive of the natural upholstery fibres and typically achieves lower ISO 105-B02 grades than wool, mohair, cotton, or linen under equivalent conditions. The dyes used on silk are chemically more susceptible to UV degradation. Silk velvet and silk upholstery fabrics should not be specified for rooms receiving significant natural light without an explicit conversation with the client about this limitation. For high-light environments, mohair velvet or solution-dyed synthetic fabrics are more appropriate choices.

What is the light fastness rating of Kothea mohair velvet?

Kothea’s Mohair Velvet Seven is tested independently to ISO 105-B02 and achieves grade 4 to 5 for light colourways and grade 5 to 6 for dark colourways. For south-facing rooms, dark colourways at grade 5 to 6 are the appropriate selection from this range. For rooms with indirect or moderate natural light, light colourways at grade 4 to 5 are suitable. Contact Kothea to confirm the grade applicable to a specific colourway before finalising your specification.

Can UV-blocking glazing improve the effective light fastness performance of a fabric?

Yes. Modern low-e glazing and dedicated UV-blocking film reduce the UV component of light entering a room, which is the primary driver of dye degradation in interior fabrics. A fabric at grade 5 installed behind UV-blocking glazing will typically outlast the same fabric at grade 5 behind standard single glazing by a considerable margin. However, UV-blocking glazing does not eliminate UV exposure entirely, and the ISO 105-B02 grade should still be specified at the appropriate level for the room orientation. Treat the glazing specification as a factor that extends fabric performance, not as a substitute for adequate light fastness in the fabric itself.

What is the difference between light fastness and colour fastness?

Light fastness is a specific type of colour fastness that measures resistance to fading caused by light exposure, tested to ISO 105-B02 and graded on the Blue Wool Scale from 1 to 8. Colour fastness is a broader term covering resistance to colour change or transfer from a range of stressors including washing, rubbing (crocking), perspiration, and dry cleaning, each tested to a separate standard within the ISO 105 series and graded on a scale of 1 to 5. A fabric can have excellent light fastness and poor crocking resistance, or vice versa. For contract upholstery, both light fastness to ISO 105-B02 and crocking resistance should be checked and specified independently.

To request cuttings from the Kothea range, including Mohair Velvet Seven with independent ISO 105-B02 light fastness certification.

Request Samples

Order cutting samples of any fabric from our current collections. Trade accounts only.

Order Cuttings
Posted on

BS 5852 Crib 5: Complete Guide for Upholstery Specification

Brown faux leather chair from April Hamilton

BS 5852 Crib 5: A Complete Guide for Interior Designers and Specifiers

BS 5852 Crib 5 is the fire safety standard required for most contract upholstery in the United Kingdom. If you are specifying fabric for a hotel, restaurant, bar, office, healthcare environment, or any other commercial interior, Crib 5 compliance is the baseline expectation. This guide explains what the standard is, how the test works, the critical difference between inherent and topical certification, and how to specify correctly. For dye types and FR treatment compatibility — which dyes cause fading after treatment — see our dye types and FR treatment guide. For colour fastness and crocking specification, see our colour fastness and crocking guide. For hotel and hospitality projects see our hotel fabric specification guide. For wall panel and headboard applications, a different standard applies: see our guide to fabric for wall panels and headboards.For projects involving yachts or commercial vessels, a separate framework applies: see our guide to IMO marine fire standards for yacht interiors.

What Crib 5 Is

Crib 5 is shorthand for BS 5852 Ignition Source 5. BS 5852, titled Methods of Test for Assessment of the Ignitability of Upholstered Seating, is the British Standard that defines how upholstered furniture materials must behave when exposed to ignition sources of increasing intensity. The standard defines eight ignition source levels. The three that matter most in practice are Source 0 (a smouldering cigarette), Source 1 (a small flame equivalent to a lit match), and Source 5, which is the Crib 5 test.

The name comes from the wooden structure used as the ignition source. A crib is a small lattice of dry timber pieces, stacked five tiers high, weighing approximately 17 grams. The number 5 refers to the number of tiers. The crib is placed on the upholstery assembly and ignited. The test is designed to simulate an ignition event more intense than a match flame, comparable to a burning pile of paper, and is the realistic minimum for contract environments where furniture may be exposed to more severe ignition risks than a smouldering cigarette.

The Three-Stage Test

BS 5852 Crib 5 is not a single test in isolation. To achieve a Crib 5 certification, a fabric must first pass both the cigarette test (Source 0) and the match test (Source 1). Only materials that pass both of these lower-level tests are eligible to proceed to the Crib 5 stage. A material that fails the cigarette or match test cannot be certified to Crib 5 regardless of how it performs under the wooden crib.

For more detail on the cigarette and match stages of BS 5852, see our post on the cigarette and match tests.

In the cigarette test, a smouldering cigarette is placed in the crease between the seat and back of the upholstered test rig. The material must show no ignition and no progressive smouldering.

In the match test, a small burner flame is held against the upholstery for 20 seconds. The material must self-extinguish immediately and show no spread of flame.

In the Crib 5 test, the lit wooden crib is placed on the upholstered assembly. All flaming must cease within 10 minutes. The fire must not spread beyond defined limits or penetrate the filling material. There must be no self-sustaining smouldering after the crib has burned out.

The Composite Nature of the Test

This is the point most frequently misunderstood in specification. BS 5852 does not test the fabric in isolation. It tests the full composite assembly: the fabric cover, the foam or filling, and any interliner, all as they would be used together in the finished piece of furniture.

A fabric that achieves Crib 5 certification in one configuration with a specific foam may not achieve it when applied over a different foam. A certificate from a fabric supplier confirms the fabric was tested in a specific configuration. If the foam or filling used in your project differs from the foam used in the test, the certificate may not be valid for your application.

Always confirm with your fabric supplier the exact configuration under which the Crib 5 test was conducted, including the foam specification, before relying on that certificate for a contract project.

Inherent Versus Topical Certification

The single most important distinction in specifying a Crib 5 fabric is whether the certification is inherent or achieved through topical treatment. The practical consequences are significant.

Inherent Crib 5 means the fire resistance is a property of the fibre itself. The yarn from which the fabric is woven is non-combustible or self-extinguishing by its nature, independent of any chemical application. Mohair velvet is the primary example in the Kothea range. Mohair fibre is inherently resistant to ignition, and a correctly woven mohair velvet carries an inherent Crib 5 pass without any treatment being applied. The certification is permanent, unaffected by cleaning, does not alter the handle or surface appearance of the fabric, and carries no additional cost for FR treatment.

Topical or back-coated treatment is applied to a fabric that is not inherently fire resistant. The fabric passes through a bath of fire-retardant chemicals, which are bonded to the reverse of the fabric through a coating process. The resulting fabric can achieve a Crib 5 pass, but with three important caveats.

First, the BS 5852 standard requires a water-soak test as part of full certification. The fabric is soaked in water to simulate cleaning and then retested. Many fabrics that pass the dry Crib 5 test fail after the water-soak stage. An indicative test without the water-soak is not a complete Crib 5 certificate. Do not rely on an indicative certificate for contract projects without confirming with the client and fire officer that it is acceptable.

Second, the coating process can affect the appearance and handle of certain fabrics. Pile fabrics such as velvets are particularly susceptible. Immersion or back-coating can flatten the pile, stiffen the handle, or leave residue on the face of the fabric. This is one of the reasons mohair velvet with an inherent pass is preferable for contract use over cotton or linen velvet that requires treatment.

Third, a topically treated fabric may need re-treatment if cleaned by a method that degrades the coating. Professional cleaning must use methods compatible with the treatment. Confirm the appropriate cleaning regime with the treatment provider before specifying.

For a detailed guide to the treatment process and the difference between Crib 5 and BS 7176, see our post on FR treatment, BS 7176, and the Crib 5 test.

BS 7176 and Hazard Categories

BS 7176, Specification for Resistance to Ignition of Upholstered Furniture for Non-Domestic Seating, extends the BS 5852 framework by categorising different commercial environments into hazard levels and specifying the appropriate ignition source requirement for each.

Low hazard covers environments such as offices. Medium hazard covers hotels, theatres, and healthcare waiting areas. High and extreme hazard cover environments such as prisons, secure psychiatric units, and offshore installations.

For most hospitality and commercial interiors the relevant category is Medium Hazard, and the standard associated with it is effectively Crib 5. The practical difference between specifying to BS 5852 Crib 5 and specifying to BS 7176 Medium Hazard is that BS 7176 includes the water-soak stage explicitly and requires the certificate to document the specific end-use environment and foam specification. In complex or sensitive projects, specifying BS 7176 Medium Hazard rather than simply Crib 5 gives a more complete and defensible specification. The treatment applied to achieve both is the same.

When Crib 7 Is Required

Crib 7 follows the same principle as Crib 5 but uses a larger wooden crib, seven tiers high, producing a more intense ignition source. It is required in high and extreme hazard environments: primarily prisons, secure psychiatric units, and some offshore or industrial installations. The Regulatory Reform (Fire Safety) Order 2005 assigns responsibility for determining the appropriate hazard category to the responsible person managing the building, not to the designer or fabric supplier. If a project falls into a high hazard category, engage a specialist fire safety consultant before specifying.

Crib 5 fabric, when combined with an appropriate FR foam, can sometimes achieve a Crib 7 pass as a composite. This must be verified by testing and documented with the relevant certificate. Do not assume that a Crib 5 fabric will achieve Crib 7 without independent testing.

For a full explanation of Crib 7 and when it applies, see our post on what is Crib 7.

Curtain Fabrics and the Different Standard

BS 5852 applies to upholstery. Curtain fabrics are governed by a separate standard, BS 5867, which tests vertical hanging fabrics rather than upholstered composites. The two standards are not interchangeable. A curtain fabric certified to BS 5867 is not automatically suitable for upholstery use, and a Crib 5 certified upholstery fabric is not automatically certified for use as a curtain in a contract environment. Always confirm the correct standard for the specific application before specifying.

Kothea Fabrics and Crib 5

Mohair velvet from Kothea carries an inherent BS 5852 Crib 5 pass across all active mohair velvet ranges. The inherent certification means no treatment is required, no additional cost is incurred, the certification survives cleaning, and the handle and surface of the fabric are unaffected. The primary Mohair Velvet range achieves 100,000 Martindale rubs alongside its inherent Crib 5 certification, combining contract-grade durability with the highest fire safety standard for most commercial projects.

Faux Leather 3 from Kothea carries a BS 5852 Crib 5 certification alongside a Martindale rub count in excess of 200,000, making it among the most specification-complete fabrics available for severe contract environments including transport seating, healthcare, and hospitality.

Cotton velvet requires topical treatment to achieve a Crib 5 pass and is not supplied by Kothea with an inherent certification.

How to Specify Correctly

State the standard in full. Ask for BS 5852 Ignition Source 5 (Crib 5), not just Crib 5. The full reference removes ambiguity.

Confirm inherent or topical. Ask the supplier explicitly whether the certification is inherent to the fibre or achieved through topical treatment. If topical, ask whether the full water-soak test was completed and request the certificate confirming it.

Confirm the composite configuration. Ask which foam was used in the test. If your project uses a different foam, the certificate may not cover your specific application.

Use a UKAS-accredited treatment house. If your project requires a fabric to be treated, specify that treatment must be carried out by a UKAS-accredited company. This ensures the process is correctly executed and independently verifiable.

Request the full test certificate. An indicative result is not a certificate. For contract projects, require the independent test certificate before the fabric is upholstered.

Consider BS 7176 for complex environments. For hotel bedrooms, healthcare, or any environment where the hazard category is uncertain, specifying BS 7176 Medium Hazard rather than Crib 5 alone provides a more defensible specification at no additional treatment cost.

Crib 7: The Standard Above Crib 5

Crib 7 is the ignition source immediately above Crib 5 in the BS 5852 series. Where Crib 5 uses a wooden crib of approximately 17 grams with a specific timber species and construction, Crib 7 uses a larger and more severe crib of approximately 126 grams. The test assembly is the same — a seat and back pad covered in the fabric being tested — but the larger ignition source represents a significantly more demanding fire scenario.

Crib 7 is not widely required in mainstream UK contract specification. The environments where it is applicable include some prison and secure accommodation furniture, certain defence and government procurement specifications, and some highly specific public sector contracts where the risk assessment has determined that the standard Crib 5 level of protection is insufficient. It is also referenced in some transport seating specifications, though IMO standards apply in the marine context rather than BS 5852.

For most hotel, restaurant, office, and residential contract interiors, Crib 5 is the correct and sufficient standard. Specifiers who encounter a Crib 7 requirement should confirm with the project’s fire risk assessor whether it is genuinely required for the specific application, as it is a materially more demanding test and limits the fabric options available considerably. Very few standard upholstery fabrics carry a certified Crib 7 pass. Purpose-made fire-retardant fabrics with specialist construction and treatment are typically required.

If your project has a Crib 7 requirement, contact us directly to discuss suitable fabric options for the specific application.

For surface spread of flame requirements for wall and ceiling linings — a separate standard from Crib 5 — see our BS 476 Part 7 guide.

For fabric sustainability certifications including GOTS and Oeko-Tex, see our fabric sustainability certifications guide. For healthcare fire standards including BS 7176, see our healthcare fabric guide.

For how the Building Safety Act 2022 affects fabric fire certification documentation in higher-risk buildings, see our Building Safety Act and fabric specification guide.

Request Samples

Order cutting samples of any fabric from our current collections. Trade accounts only.

Order Cuttings
Posted on

Faux Leather Upholstery

Brown Faux Leather Upholstery Banquette
Brown Faux Leather Upholstery Banquette

Faux (or fake) Leather offers a great alterantive to leather. With Martindale rubs of over 100,000 this is a very safe choice for high use contract areas. It’s usually made of a pure cotton basecloth with a poly-cotton visible coating. There are many other animal skins that are mimiced in the same way and in many cases the finishes are convincing.

But why not just use leather?

Much leather production has now moved away from the West to areas with less stringent environmental laws and lower wage rates. This is where the problem lies.

Chromium based compounds are used in the tanning and curing process of real leather. They are thought to be carcinogenic as, in some European tanning factories, cancer rates were found to be up to 50% higher in workers than in the population as a whole. Furthermore there were higher incidences of Leukemia in children living in areas near the tanneries. Environmental problems are exacerbated by the siting of factories next to rivers; the significant amounts of discharge that are produced are fed into the water courses and then dispersed over wide areas. In more lowly regulated economies it is not unreasonable to believe that the situation is probably worse.

Moving towards a better leather requires that chromium use is stopped completely and that the water used in production is cleaned and re-used in the factory. Any tanins and dyes uses would preferably be plant based.

Food for thought: If you wear leather clothing on sweaty skin then chromium residues in the leather can rub off and enter the skin.

Posted on

Faux Leather on doors and walls

Brown Faux Leather Upholstery Banquette
Brown Faux Leather Upholstery Banquette

KOTHEA had two recent projects where we had to adhere Faux Leather vertically. This poses a more serious challenge than paper-based wall coverings due to both the weight of the fabric (nearly 1kg per linear metre) and the wear and tear when adhered to a door. Both installations were more involved than domestic ones as we had to consider firstly the use on a yacht in a marine environment and secondly the high levels of usage of a hotel.

So the adhesive needs to be strong.

A further set of issues to overcome are related to how the fabric might react to any chemicals in the adhesive. In both instances our fabric had a 100% cotton back coat with a vinyl mix visible layer. Superfically a conclusion could be drawn that most adhesives would be OK with the surfaces they are fastening to in these instances ie a natural wooden door and inert stone wall combined with the natural cotton back cloth. However the adhesive will almost certainly penetrate the back cloth. Becuase of this the use of a solvent based adhesive, such as Asceton, is most definately not recommended.

So the adhesive needs to be strong and water based.

After performing suitability tests in these instances we chose to use Mapei’s Adheselix VS45 . VS45 is an acrylic adhesive in water dispersion and has been used extensively by Mapei’s customers for PVC/foam wallcoverings and rubber flooring. An alternative of Adesilex G19 was also suggested for areas with more moisture but that was not necessary in these cases.

Posted on

Directory Listings Of Top Market Fabric Suppliers In The UK

555722790393613763_3d6571c7061dClick the fabric company name for their web site:

Abbot and Boyd 020 7351 9985
Altfield 020 7351 5893
Alton Brooke 020 7376 7008
Borderline 020 7823 3567
Brian Yates 01524 35035
Brunswig 020 7351 5797
Bruno Triplet 020 7823 9990
Chase Erwin 020 8875 7441
Colefax 020 7244 7427
Colony Fabrics 020 7351 3232
Donghia 020 7823 3456
Gainsborough Silk 01787 372081
Henry Bertrand 020 7349 1477
Jab 020 7349 9323
Jane Churchill 020 7244 7427
Jrobertscott 020 7376 4705
KOTHEA 020 8943 4904
Kravet 020 7795 0110
Lee Jofa 020 7823 3455
Lelievre 020 7352 4798
Manuel Canovas 020 8877 6400
Nobilis 020 7351 7878
Pierre Frey 0207 376 55 99
Robert Allen 01494 474741
Sacho Hesslein 020 7352 6168
Silk Gallery 020 7351 1790
Turnell and Gigon 020 7259 7280
Watts Westminster 020 7376 4486
Zimmer and Rhode 020 7351 7115
Zoffany 08708 300 350

Many of these fabric companies sell a wide range of products including: chenille, contract fabric, faux / fake leather, mohair velvet, linen velvet, cotton velvet, wool,  hand woven products, natural silk, cashmere and damask for upholstery, curtains and cushions.