What Is Trevira CS? Inherently Flame-Retardant Polyester Explained

What it is: Trevira CS is a brand name for a permanently flame-retardant polyester fibre manufactured by Trevira GmbH in Germany. The CS stands for Comfort and Safety.
How it works: The flame-retardant additive is incorporated into the polyester polymer during fibre production — it is part of the fibre itself, not a surface treatment applied afterwards.
Why it matters: The fire resistance is permanent. It cannot be washed out, worn off, or degraded by cleaning. Fabric made from Trevira CS does not require topical FR treatment to achieve contract fire standards.
Certification: Trevira CS fabric can achieve BS 5867 Part 2 Type B and Type C for curtains and BS 5852 Crib 5 for upholstery, depending on fabric construction.

Trevira CS is one of the most widely used inherently flame-retardant fibres in the UK and European contract interiors market. It is specified for curtains and upholstery in hotels, offices, healthcare facilities, and public buildings where fire compliance is required and the permanence of the fire performance is commercially important. This guide explains what Trevira CS is, how it differs from topically treated polyester, and where it is and is not appropriate to specify.

Inherent vs Topical Flame Retardancy

Standard polyester fabric does not meet UK contract fire standards without treatment. The two routes to compliance are topical FR treatment — applying chemical compounds to the fabric surface after weaving — or using a fibre with inherent flame retardancy built into the polymer from manufacture.

Trevira CS takes the second route. The phosphorus-based flame-retardant compound is added to the polyester melt during fibre extrusion. It becomes part of the polymer chain rather than sitting on or in the fabric surface. This means the fire performance is genuinely permanent — it survives laundering, dry cleaning, and normal use without degradation and without the re-treatment requirements associated with topically treated fabrics.

This permanence is the primary commercial advantage of Trevira CS over topically treated alternatives in high-frequency-cleaning environments such as healthcare curtains and hotel restaurant seating where laundry cycles are regular and frequent.

Fire Standards Trevira CS Can Achieve

Fabric woven from Trevira CS yarn can achieve BS 5867 Part 2 Type B for curtains and drapery, and Type C — which includes a laundering pre-conditioning requirement — making it appropriate for hospital cubicle curtains that are regularly laundered. This is the most demanding UK curtain fire standard and one that few non-inherent fabrics can meet reliably over repeated wash cycles.

For upholstery, Trevira CS fabric can be constructed to achieve BS 5852 Crib 5, though the specific fabric construction — weave density, pile height if applicable, and backing — affects the result. A fabric containing Trevira CS yarn is not automatically Crib 5 certified: the specific fabric as constructed must be tested and certified by a UKAS-accredited laboratory.

Trevira CS fabric also achieves good performance against the IMO fire standards used in marine and yacht interiors, making it a practical specification for vessels requiring FTP Code compliance. See our IMO marine fire standards guide for marine application requirements.

Where Trevira CS Is and Is Not Appropriate

Trevira CS is well suited to curtain fabrics in healthcare, hospitality, and institutional environments where BS 5867 Type C compliance and launderability are required simultaneously. It is also appropriate for acoustic panel fabrics and wall lining fabrics where a surface spread of flame classification is needed without reliance on topical treatment. For high-frequency-cleaning upholstery in healthcare environments, Trevira CS upholstery fabric is a practical alternative to silicone leather where a fabric aesthetic is preferred.

Trevira CS is standard polyester in all its non-fire properties. It does not have the tactile warmth of natural fibres, the lustre of mohair or silk, or the inherent sustainability credentials of wool or linen. For hospitality and high-end residential interiors where tactile quality and aesthetic warmth are the primary criteria, natural-fibre fabrics with independent fire certification are typically preferred over Trevira CS. For the distinction between inherent and topical fire resistance across fibre types, see our FR treatment and fibre compatibility guide.

Quick answers

Does Trevira CS need FR treatment?
No. The flame-retardant property is inherent to the fibre — it is part of the polymer structure from manufacture. Fabric made from Trevira CS does not require topical FR back-coating or wet-padding treatment to achieve its fire performance. This is what distinguishes it from standard polyester fabric, which would require topical treatment to meet contract fire standards.

Does Trevira CS fire performance survive washing?
Yes. Because the flame retardancy is part of the fibre polymer rather than a surface application, it is not affected by washing, dry cleaning, or abrasion. This makes Trevira CS particularly appropriate for healthcare curtains and other applications requiring regular laundering without re-treatment or re-certification.

Is all Trevira CS fabric automatically Crib 5 certified?
No. Trevira CS yarn has inherent flame-retardant properties, but the specific fabric woven from it must be tested and certified by a UKAS-accredited laboratory to confirm it meets the required standard for the specific application. The weave construction, pile height, and backing all affect the fire performance of the finished fabric. Always obtain a test certificate for the specific fabric being specified rather than assuming certification from the yarn specification alone.

For the Crib 5 standard for upholstery, see our Crib 5 guide. For curtain fire standards including BS 5867 Type B and Type C, see our hotel fabric specification guide. For inherent vs topical fire resistance across fibre types, see our FR treatment and fibre compatibility guide. For how FR treatment works, see our how FR treatment works guide.