How to Write a Fabric Specification: A Contract Guide

A fabric specification is the document that tells everyone downstream, upholsterer, contractor, client, fire officer, exactly what fabric is being used and what it must achieve. A vague specification is where contract projects go wrong. This guide sets out what a complete fabric specification contains and what certificates to require. For where each decision falls in the project timeline, see our RIBA Plan of Work fabric guide.

What a Complete Specification Contains

A specification that prevents disputes states every performance requirement explicitly rather than assuming it. The core fields are the fabric name and range, the fibre composition, the abrasion requirement as a Martindale figure, the fire standard in full (for example BS 7176 Medium Hazard, not just Crib 5), the cleaning code required for the environment, the light fastness grade, and the colourway with a dye-lot reservation instruction for larger orders. For patterned fabric, add the pattern type and repeat. For each requirement, state the standard and the figure, not a general word like durable or fire-safe.

State the Standard in Full

The most common specification weakness is naming a standard loosely. Crib 5 alone is weaker than BS 5852 Ignition Source 5 (Crib 5). Fire-rated is meaningless without the standard. A Martindale requirement should give the figure, 100,000 rubs, not high abrasion. The fuller the reference, the less room for a substitution or a dispute later. State the standard, the part, and the figure for every performance field.

What Certificates to Require

For any contract project, require the independent test certificate before the fabric is installed, not a supplier’s claim of compliance. For fire, that means the certificate from a UKAS-accredited laboratory naming the fabric, the filling used in the test, the standard, and the result. A verbal assurance or a product description is not a certificate. For a composite standard such as BS 7176, confirm the certificate names the specific foam, because the certificate is valid only for the fabric and filling combination tested. For marine work, require the IMO certificate for the relevant part. For how FR certification works and who can issue it, see our how FR treatment works guide.

Confirm the Composite and the Cleaning Regime

Two checks prevent most late-stage failures. First, confirm the foam or filling matches the fire certificate, since substituting a different foam invalidates it. Second, confirm the fabric’s cleaning code suits the environment’s actual cleaning regime, an S-coded fabric fails in a setting that uses water-based cleaning. Present the environment’s cleaning products to the supplier and get written confirmation of compatibility. For the cleaning implications in demanding settings, see our healthcare fabric guide and hotel fabric specification guide.

Request Cuttings Before Committing

A cutting confirms colour, handle, and quality before the fabric is committed to a scheme, and provides the reference sample for matching later deliveries against. Request cuttings early, and for a phased order retain the first-delivery sample to check subsequent dye lots. For cuttings, dye lots, and lead-time planning, see our lead times and colour matching guide. For the full specification library organised by environment, application, and performance need, see our fabric buying guide by purpose.

Quick answers

What should a fabric specification include?
A complete fabric specification states the fabric name and range, the fibre composition, the Martindale abrasion figure, the fire standard in full (for example BS 7176 Medium Hazard), the cleaning code, the light fastness grade, and the colourway with a dye-lot reservation instruction for larger orders. For patterned fabric it adds the pattern type and repeat. Every performance requirement should give the standard and the figure, not a general word such as durable or fire-safe.

What certificates should I require before installing a contract fabric?
Require the independent test certificate before installation, not a supplier’s claim of compliance. For fire, that is the certificate from a UKAS-accredited laboratory naming the fabric, the filling used in the test, the standard, and the result. For a composite standard such as BS 7176, confirm the certificate names the specific foam, because it is valid only for the fabric and filling combination tested. For marine work, require the IMO certificate for the relevant part.

Why does the foam matter for a fire certificate?
Contract fire standards such as BS 5852 Crib 5 and BS 7176 test the fabric and filling together as a composite, not the fabric alone. A certificate is valid only for the specific fabric and foam combination tested. If the project uses a different foam from the one named in the certificate, the certificate does not cover the installation, and new testing is required. Always confirm the foam matches the certificate before ordering.

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14 August 202614 August 2026

Mohair Velvet vs Cotton Velvet: Which to Specify

Mohair velvet and cotton velvet are the two natural-fibre velvets a UK designer chooses between most often. They look similar on a moodboard and perform very differently in a specification. This guide compares them across durability, fire rating, cleaning, appearance, and cost. For the full range of velvet fibres, see our velvet types guide.

The Core Difference

Mohair velvet has its pile woven from the hair of the Angora goat, a long, smooth, lustrous fibre of exceptional tensile strength. Cotton velvet has its pile woven from cotton, a shorter cellulose fibre. That fibre difference drives every specification distinction that follows: mohair is far more durable, carries an inherent fire rating, and has a directional sheen; cotton is softer in cost, matte in appearance, and needs treatment for contract fire compliance.

Comparison by Specification Measure

Measure	Mohair velvet	Cotton velvet
Fibre	Angora goat hair	Cotton
Martindale rub count	80,000 to 100,000 and above	20,000 to 60,000 depending on construction
Fire rating	Inherent BS 5852 Crib 5 in correctly certified ranges, no treatment needed	Not inherent; topical FR treatment required for contract use
Cleaning code	S (solvent only)	S or WS depending on range and treatment
Appearance	High lustre with directional sheen and depth of colour	Matte to semi-matte, no directional sheen
Suitability	Heavy contract and residential upholstery	Domestic upholstery, cushions, curtains, headboards
Cost	Premium	Mid-range, plus FR treatment cost for contract use

Which to Specify

For heavy contract upholstery in hotels, restaurants, bars, and hospitality seating, mohair velvet is the sounder specification. It reaches 80,000 to 100,000 Martindale rubs, carries an inherent Crib 5 fire rating in correctly certified ranges without the cost or handle change of topical treatment, and its directional sheen gives the depth of colour associated with luxury upholstery. Confirm the inherent Crib 5 pass with an independent certificate for the specific range.

For domestic upholstery, cushions, curtains, and headboards where budget matters and use is lighter, cotton velvet is a sound mid-range choice. A well-constructed heavyweight cotton velvet reaches sufficient durability for general domestic and light contract use, but it needs topical FR treatment for any contract environment, which adds cost and can flatten the pile. Always confirm the specific Martindale figure, since cotton velvet quality varies widely.

For the fire treatment implications, see our Crib 5 guide. For durability figures, see our Martindale rub test guide. For the full specification library organised by environment, application, and performance need, see our fabric buying guide by purpose.

Quick answers

What is the difference between mohair velvet and cotton velvet?
Mohair velvet has its pile woven from Angora goat hair and reaches 80,000 to 100,000 Martindale rubs with an inherent Crib 5 fire rating in correctly certified ranges. Cotton velvet has its pile woven from cotton, reaches 20,000 to 60,000 Martindale rubs depending on construction, and needs topical FR treatment for contract use. Mohair has a directional sheen and depth of colour that cotton velvet does not replicate.

Is mohair velvet worth the extra cost over cotton velvet?
For heavy contract use, yes. Mohair velvet reaches far higher abrasion figures, carries an inherent Crib 5 fire rating without the cost and handle change of topical treatment, and lasts longer in daily multi-user settings. For lighter domestic use where budget matters, cotton velvet is a sound choice at lower cost, provided its Martindale figure suits the application and FR treatment is added where contract fire compliance is required.

Which velvet is more durable, mohair or cotton?
Mohair velvet is more durable. It reaches 80,000 to 100,000 Martindale rubs against cotton velvet’s typical 20,000 to 60,000, and its long, strong Angora goat fibre resists crushing and wear better than cotton’s shorter fibre. Mohair is the more reliable natural-fibre velvet for contract upholstery.

To request cuttings of any KOTHEA velvet, visit KOTHEA.com/cuttings.

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14 August 202614 August 2026

PVC vs PU Leather: Which to Specify for Contract Upholstery

PVC and PU are the two synthetic leathers a UK specifier will meet most often, and they are not interchangeable. This guide compares them across the measures that decide a contract specification: abrasion, fire certification, cleaning, cold performance, and cost. For the wider comparison including silicone leather, see our faux leather types guide.

PVC and PU: The Core Difference

PVC (polyvinyl chloride) leather is built on a plasticised PVC layer over a textile backing. PU (polyurethane) leather is built on a polyurethane coating over a textile backing. The base polymer is the difference, and it drives almost every performance distinction that follows. PVC is the more robust and chemically resistant of the two. PU is softer, more breathable, and closer to the handle of real leather, but generally less durable over a long service life.

Comparison by Specification Measure

Measure	PVC leather	PU leather
Abrasion (Martindale)	High; contract grades reach 100,000 and above, some over 200,000	Moderate; typically lower than equivalent PVC, prone to surface peeling over time
Handle	Firmer, can feel less natural	Softer, closer to real leather
Breathability	Low	Higher
Fire certification	Readily available with BS 5852 Crib 5	Available but less commonly certified to Crib 5
Cleaning	Wipe-clean, resistant to most cleaning agents	More sensitive to solvents and prolonged moisture
Cold-crack performance	Standard PVC can stiffen and crack in cold; cold-resistant grades available	Generally more flexible in cold, no plasticiser migration
Longevity	Long service life in high-use contract settings	Shorter; surface delamination is the common failure mode
Cost	Mid-range	Mid-range, can be higher for premium grades

Which to Specify

For heavy contract upholstery in hotels, restaurants, bars, healthcare, and transport, PVC leather is usually the sounder specification. It reaches the highest abrasion figures, is readily certified to BS 5852 Crib 5, and wipes clean, which matters in high-turnover and infection-controlled settings. Confirm the cold-crack grade for any exterior or marine application, since standard PVC stiffens in cold.

For projects where handle and appearance are the priority and use is lighter, PU leather is the better choice. It feels closer to real leather and breathes better, which suits residential and boutique settings. The trade-off is service life: PU is more prone to surface peeling and delamination over years of heavy use, so it is less suited to the most demanding contract environments.

For cold-crack testing relevant to exterior and marine use, see our cold crack temperature testing guide. For the chemical safety and durability picture, see our faux leather sustainability guide. For the full specification library organised by environment, application, and performance need, see our fabric buying guide by purpose.

Quick answers

Is PVC or PU leather better for contract upholstery?
PVC leather is usually better for heavy contract upholstery. It reaches higher Martindale abrasion figures, is readily certified to BS 5852 Crib 5, and wipes clean, which suits hotels, healthcare, and transport. PU leather is better where handle and appearance matter more than service life, such as residential and boutique settings, but it is more prone to surface peeling over time.

What is the difference between PVC and PU leather?
PVC leather is built on a plasticised polyvinyl chloride layer and is more durable and chemically resistant. PU leather is built on a polyurethane coating and is softer, more breathable, and closer to the handle of real leather, but generally less durable. The base polymer is the difference and it drives their contrasting performance.

Does PU leather peel more than PVC?
PU leather is more prone to surface peeling and delamination over a long service life than PVC. This is the common failure mode for PU in heavy-use settings, which is why PVC is generally specified where durability over many years is the priority.

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29 July 202614 August 2026

Fabric Buying Guide by Purpose: Specification Guides for Interior Designers

This guide indexes the KOTHEA fabric specification library by purpose. It is organised three ways: by the environment a fabric is specified for, by the application it is used in, and by the performance requirement that governs the selection. Each entry links to a full guide covering the standards, test methods, and specification detail for that subject. Use it to move from a project requirement to the relevant specification guidance without reading the library in sequence.

By environment

The environment a fabric is specified for determines the combination of fire standard, durability, cleaning compatibility, and light fastness that applies. The guides below cover the principal contract and residential environments.

Hotel and hospitality

Martindale thresholds by room type, BS 7176 Medium Hazard fire certification, cleaning regime compatibility, and dye lot consistency across phased projects are covered in the hotel fabric specification guide. For the thermal and moisture behaviour of mohair in hospitality use, see the mohair thermal properties guide.

Healthcare

Disinfectant cleaning compatibility, BS 7176 fire certification, 100,000 Martindale durability, and infection control are covered in the healthcare fabric specification guide.

Marine and yacht

The IMO FTP Code, MCA MGN 580, and why BS 5852 Crib 5 is not interchangeable with IMO Part 8 are covered in the IMO marine fire standards guide.

Outdoor terraces and semi-outdoor spaces

Exposure mapping, solution-dyed acrylic, outdoor-rated faux leather, and light fastness by location are covered in the outdoor terrace fabric specification guide.

Poolside, spa, and chlorine-exposed areas

Why chlorine degrades fabric by a different mechanism than salt and UV, and what to specify for pool and spa surrounds, are covered in the poolside and chlorine-exposed fabric guide.

Acoustic and home cinema

How heavy velvet absorbs mid and high frequency sound and functions as an acoustic treatment is covered in the velvet sound absorption guide.

Contract versus residential

Why contract grade is defined by performance rather than by building type, and when a residential project needs a contract specification, are covered in the contract versus residential guide.

By application

The application a fabric is used in sets the abrasion, drape, and construction requirements independently of the environment.

Upholstery

The Martindale rub test, its classifications, and how it compares to the Wyzenbeek standard are covered in the Martindale rub test guide and the Wyzenbeek versus Martindale guide. Pilling resistance is covered in the pilling resistance guide, and the tactile character of the principal upholstery fibres in the fabric hand and tactile properties guide.

Curtains

Pattern repeat calculation and matching for curtains and upholstery are covered in the pattern matching guide. The applications where velvet is unsuitable, including several curtain and window conditions, are covered in the when not to use velvet guide.

Wall panels and headboards

BS EN 13501-1, BS 476 Part 7, the composite testing requirement for wall fabric, and the headboard fire standard ambiguity are covered in the wall panels and headboards guide and the BS 476 Part 7 guide.

By performance need

Where a single performance requirement governs the selection, the guides below address it directly.

Fire certification

BS 5852 Crib 5 is covered in the Crib 5 guide. How FR treatment works and which fibres can be treated are covered in the how FR treatment works guide and the FR treatment and fibres guide. Dye and FR treatment compatibility is covered in the dye types and FR treatment guide. The Building Safety Act 2022 documentation requirements are covered in the Building Safety Act guide.

Chlorine, UV, and salt resistance

Chlorine exposure is covered in the poolside and chlorine-exposed fabric guide. Light fastness and UV fading are covered in the light fastness and Blue Wool Scale guide. Cold crack temperature performance for coated fabrics in exterior and marine use is covered in the cold crack temperature testing guide.

Colour fastness and matching

Colour fastness and crocking are covered in the colour fastness and crocking guide. Colour naming, systems, and metamerism are covered in the colour naming and specification guide.

Chemical compliance and sustainability

UK REACH compliance is covered in the REACH compliance guide. Sustainability certifications are covered in the fabric sustainability certifications guide. Cashmere and mohair welfare certification is covered in the cashmere and mohair welfare certifications guide. Faux leather sustainability is covered in the faux leather sustainability guide.

Material selection

Velvet types compared across every specification dimension are covered in the velvet types guide, with mohair and cotton velvet compared directly in our mohair velvet vs cotton velvet guide. Faux leather types are compared in the faux leather types guide, with PVC and PU compared directly in our PVC vs PU leather guide.

Procurement and project planning

How much fabric a chair, sofa, or headboard needs is estimated in the how much fabric to upholster furniture guide. Contract curtains, covering the BS 5867 fire standard, light control, and fullness, are specified in the contract curtain fabric specification guide. How to write a complete fabric specification and what certificates to require is set out in the how to write a fabric specification guide. Definitions of the terms used across these guides are collected in the fabric specification glossary. Which fabric decision belongs at each project stage is covered in the RIBA Plan of Work fabric guide. Lead times, cuttings, dye lot reservation, and custom colour matching are covered in the lead times, cuttings and custom colour matching guide.

Quick answers

How do I choose the right fabric for a contract project?
Start from the governing requirement. Where a single environment sets the specification, such as a hotel, healthcare, marine, or poolside setting, the environment guide covers the full combination of fire, durability, cleaning, and light fastness standards that apply. Where a single performance requirement governs, such as fire certification or chlorine resistance, the relevant performance guide addresses it directly. Confirm the fire standard, Martindale threshold, cleaning code, and light fastness grade for the specific application before selecting a fabric.

What fire standard does my project need?
For most UK contract upholstery the standard is BS 7176 Medium Hazard, which incorporates BS 5852 Crib 5. Marine interiors follow the IMO FTP Code under MCA MGN 580, which is not interchangeable with Crib 5. Wall panels and headboards may fall under BS 476 Part 7 or BS EN 13501-1 depending on construction. The fire certification guides linked above cover each standard and when it applies.

How do I request samples of KOTHEA fabric?
Request cuttings of any KOTHEA fabric at KOTHEA.com/cuttings. Request cuttings early in the selection process, and where a scheme depends on several fabrics together, request cuttings of all of them so the combination can be assessed under the project’s lighting conditions before specification is finalised.

To request cuttings from the KOTHEA range, visit KOTHEA.com/cuttings.

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6 April 202628 July 2026

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.

Quick answers

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.

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Mohair Velvet Faux Leather Cashmere Throws Silks Linen Textured Upholstery

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Buying Guide by Purpose Crib 5 Fire Guide Martindale Rub Test BS 5867 Curtains Marine Fabric

6 April 202628 July 2026

Fabric Specification for Healthcare Environments: A Guide for Interior Designers

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.

Quick answers

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.

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6 April 202628 July 2026

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.

Quick answers

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.

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6 April 202628 July 2026

Pilling Resistance in Upholstery Fabric: A Guide for Interior Designers

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.

Quick answers

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.

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6 April 202614 August 2026

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

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.

UKAS-Accredited Treatment Providers

Textiles FR, based in Bradford, has operated since 1990 as both a flame-retardant finishing company and a UKAS-accredited test laboratory, combining treatment and independent testing under one roof. The company applies flame-retardant finishes and water and soil repellent treatments and conducts flammability testing to the British Standards covering furniture and furnishing fire safety.

Tek Treatments provides FR treatment and certification covering BS 5852 Crib 5, BS 5867 curtain standards, the IMO FTP Code for marine applications, and FAR/JAR standards for aviation.

Essex Flameproofing provides flame-retardant treatment for contract fabrics, including back-coating for upholstery and wall applications and treatment for curtains.

Quick answers

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.

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5 April 202628 July 2026

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.

Quick answers

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.

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Buying Guide by Purpose Crib 5 Fire Guide Martindale Rub Test BS 5867 Curtains Marine Fabric