Fabric Tips #10

Interior Designers are sometimes asked for the environmental credentials of their specification. Here are some figures that give you an idea of the greenness of different yarns used in fabric production. The figures show the energy consumption (per kilo in KWH) required to make the fibres. Of course this is far from the total carbon footprint of the finished delivered and fully made up cushion or sofa or curtain. But it is a starting point often covering the more energy intensive part of the process.

17 Wool
27 Viscose
32 Polypropylene
35 Polyester
69 Nylon

Clearly natural wool wins hands down!

As a side note, the “Campaign For Wool” should start to get media coverage throughout the rest of 2010 with the patronage of HRH Prince Charles. The society of British Interior Design are planning to give wool a big push “All we are saying is…give fleece a chance”. Their tagline. Great! Well it made me laugh!

Mohair Velvet, Silk Velvet: How to upholster using it

Silk Velvet Upholstery Fabric TextileMohair Velvet and Silk Velvet buyers consider this: You have just invested a considerable amount of money in a high quality silk velvet or mohair velvet. Are you really considering upholstering with it yourself. Use an experienced upholsterer who, to be brutally honest, should not need the instructions that follow.

Some velvets are woven with a nap others are not. It is not a problem either way. If there is a nap you need to know which way it goes as that affects the process of upholstering. When you run your hand down the mohair velvet or silk velvet the smoothed direction indicates the direction of the nap. Remember this, it is important.

I’m assuming that you have already checked that the fabric is not damaged and that each piece is from the same dye lot.

The nap should be upholstered downwards for:

– the back;

– the seat; and

– side surfaces.

The nap should be upholstered from the outside inwards for:

– arm rests.

How do you flip your cushions? Top to bottom or left to right?

Most people flip from top to bottom. It is therefore standard upholstering practice to upholster the front and the back the opposite way. IE when they are flipped over the nap is the same.

You should use a layer of wadding between the foam and the fabric. The wadding can be either cotton or synthetic it does not really matter but check with any fire rating requirements. Again check that you are using the right kind of foam but HR foam or cold foam are both fine.

However if the pile is vertical then we advise the additional use of a cotton slip-cover.

Going back to the foam for a minute we advise that you use white wadding. In certain circumstances it is possible that grey wadding will ‘bleed’ causing marks on your beautiful Mohair Velvet. For example this may be caused from moisture used in the cleaning process.

Always use wadding on the arm rests as a protective layer to help eliminate ‘sharp’ edges. Using wadding on arm rests will thus reduce wear and tear considerably.

For the piping never use synthetic piping cord, always use cotton piping cord. As with the arm rests this will reduce wear and tear by eliminating the ‘sharper edges’.

Again to reduce wear and tear also use the length of the fabric to make the piping. this will look better as well.

Happy Upholstering

For KOTHEA’s contract-grade ranges, see our mohair velvet upholstery page.

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.

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Fabric Tips #9

When using sheers think about double width fabric. Many sheer fabrics are available in double width. This reduces the number of joins you need to make and also may well allow you to run the fabric the ‘other way’ (ie railroaded)

Fabric Tips #7

When choosing a fabric for upholstery think about the finished sofa.

If you are planning to have piping (made by rolling the fabric) then make sure that your chosen fabric can be used in that way. It is sometimes hard to roll thicker fabric.

Also bear in mind that your upholsterer might be overly cautious. So, for example, people are often told that some Mohair Velvets cannot be used for piping when they usually can.

Fabric Tips #6

When your newly ordered fabric is delivered it will have the face rolled on the inside. This makes sense when you think about it. The roll will be transported and any damage caused during transit will be made first to the outside and that, when unrolled, will be the reverse/back of the fabric. So if there is minor damage the fabric can still be used.

However, if you fabric arrives and damage is apparent then:

1. Don’t cut it; and

2. Either reject it or get the courier to note the damage.

Fabric Tips #5

Be really sure what you are buying.

Ensure that the sample you have is the right way up. Mistakes are made. It could be back to front or rotated 90/180 degrees. Sometimes it is NOT obvious so check with the supplier.

Fabric Tips #4

If you are specifying upholstery fabric (especially) in a contract environment then look closely at the Martindale or rub test rating of your fabric. This measures abrasion and simulates ‘wear and tear’.

The following is taken from BS 2543 and shows the ‘intended duty’ of the fabric:

OD = Occasional domestic – 6,000 rubs

LD = Light domestic – 15,000 rubs

GD = General domestic – 20,000  rubs

HD = Heavy domestic – 25,000 rubs

SD = Severe domestic/general contract – 30,000  rubs

SC = Severe contract Abrasion performance – 40,000 rubs

Fabric Tips #3

Be precise about what lengths you need.

Rather than saying “Please can I order 24m of your black mohair velvet” be more specific to your requirements stating that, for example, you need 8 drops of 3m for wall panelling. This can sometimes even help the supplier as they know they can give you (from the same batch) some of the smaller lengths that they would not otherwise sell.