Tag: curtain fabric

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Contract Curtain Fabric Specification: A Designer’s Guide

Contract curtains are governed by a different fire standard from upholstery, and by a set of practical decisions, fullness, lining, drop, and light control, that determine both cost and performance. This guide covers what a designer needs to specify contract curtains correctly. For the upholstery fire standard, which is separate, see our BS 5852 Crib 5 guide.

The Curtain Fire Standard: BS 5867

Contract curtains are governed by BS 5867 Part 2, not by BS 5852 Crib 5, which applies to upholstery. The two are not interchangeable: a Crib 5 upholstery certificate does not qualify a fabric for contract curtain use, and a curtain certificate does not qualify a fabric for seating. BS 5867 Part 2 has two relevant types. Type B is the standard requirement for most contract environments, hotels, offices, public buildings. Type C adds a launderability pre-conditioning stage and applies where curtains are laundered repeatedly, principally healthcare cubicle curtains washed at 71 degrees Celsius. Specify the type by environment: Type B for general contract, Type C for healthcare and anywhere curtains are regularly laundered.

Most decorative curtain fabrics need topical FR treatment to meet BS 5867. Some inherently fire-resistant fabrics, notably Trevira CS, meet it without treatment. For which fibres can be treated and how, see our FR treatment and fibre compatibility guide and how FR treatment works guide. For the BS 5867 test method and the Type B and Type C wash-cycle detail, see our BS 5867 standard explained.

Light Control: Blackout, Dimout, and Sheer

Light control is specified separately from the face fabric and is usually delivered by the lining. Blackout blocks effectively all light, either through a face fabric with a blackout coating or, more commonly, a separate blackout lining. It is the standard for hotel bedrooms. Dimout reduces light substantially without eliminating it, suitable where full blackout is not required. A sheer or voile controls privacy and glare while admitting daylight, and is often layered with a heavier curtain or a separate blackout blind. Specify the light-control requirement by room: blackout for bedrooms, dimout or sheer-plus-blind for living and meeting spaces.

Fullness and Fabric Quantity

Curtain quantity is driven by fullness, the ratio of flat fabric width to finished curtain width, and by drop. A typical contract fullness is between 2 and 2.5 times the track width for a gathered or pencil-pleat heading, meaning a 3-metre track needs 6 to 7.5 metres of fabric width across the required drops. Wave and wave-style headings often use around 2.2 times. Sheers are frequently fuller, up to 3 times, to read well against the light. Drop is the finished length plus hem and heading allowances. For patterned fabric, add the pattern-repeat allowance on top: see our pattern matching guide for the method, and our fabric quantity guide for upholstery estimates.

Light Fastness for Curtains

Curtains at a window take direct and sustained sunlight, so light fastness matters as much as it does for upholstery in a bright room. A south or west-facing window fades a curtain at the fold lines before the body of the fabric shows change, producing an irregular striped effect that only full replacement corrects. For curtains in sun-exposed positions specify ISO 105-B02 grade 6 or above. For the full grading detail, see our light fastness and Blue Wool Scale guide. For the full specification library organised by environment, application, and performance need, see our fabric buying guide by purpose.

Quick answers

What fire standard applies to contract curtains?
Contract curtains are governed by BS 5867 Part 2, not BS 5852 Crib 5, which applies to upholstery. Type B is the standard requirement for most contract environments such as hotels and offices. Type C adds a launderability pre-conditioning stage and applies to curtains that are regularly laundered, principally healthcare cubicle curtains. A Crib 5 upholstery certificate does not qualify a fabric for curtain use. Most decorative curtain fabrics need topical FR treatment to meet BS 5867, though inherently fire-resistant fabrics such as Trevira CS meet it without treatment.


What is the difference between blackout and dimout curtains?
Blackout blocks effectively all light, delivered either by a face fabric with a blackout coating or, more commonly, a separate blackout lining, and is the standard for hotel bedrooms. Dimout reduces light substantially without eliminating it, suitable where full blackout is not required. Both are usually specified through the lining rather than the face fabric, so the decorative fabric can be chosen independently of the light-control requirement.


How much fabric do I need for contract curtains?
Curtain quantity depends on fullness and drop. A typical contract fullness is 2 to 2.5 times the track width for a gathered or pencil-pleat heading, so a 3-metre track needs 6 to 7.5 metres of fabric width across the required drops. Sheers are often fuller, up to 3 times. Add hem and heading allowances to the finished drop, and add the pattern-repeat allowance on top for patterned fabric.

To request cuttings for a curtain project, visit KOTHEA.com/cuttings.

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Double Width Sheers

Double width sheer fabric
Double width sheer fabric
Double width sheer fabric

When considering sheers for window treatments it is often worth bearing in mind that there are many double-wdth sheers available from many suppliers including, of course, ourselves. Double width sheers are worth special consideration as they offer:

1. Cheaper make up costs as there can be less work involved in using a wider fabric;
2. The ability to improve the overall aesthetic look – as there are fewer seams; and
3. The ability to be railroaded (ie made up with the pattern going the ‘other’ or the ‘wrong’ way. A width of 300cm or thereabouts is often sufficient for many drops (lengths) and this can eliminate the need for any seams.

Some of the best ideas are often the simplest.

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Curtain Fabric Static

Another grey mohair velvet, luscious upholstery
Grey Mohair Velvet Upholstery
Grey Mohair Velvet Upholstery

If you are unfortunate enough to have created beautiful curtains that are plagued by static problems then please read on.

Fortunately static is rarely noticed when curtains are hung, this is partly because of the chosen combination of materials and partly also because the weight of the material overcomes the weak power of static electricity. However if you do have this rare problem then you have already invested a lot of time, effort and money into buying curtain material and having them made up and hung. Do you have to start again?

Before answering that dreaded question it is important to understand what causes the problem in the first place. There is little point in re-making the curtains if the same problem is going to happen again.

Static is a natural phenomena. The main way in which static is created is when two materials are rubbed together causing an excess electrical charge on their surfaces. It is not, however, caused by the friction itself and it is not caused because a material is synthetic/man-made.

All materials differ in their propensity to cause static. It takes the properties of TWO materials to cause static; one must be good at giving up ‘electrons’ and the other good at receiving ‘electrons’. The better that each of the materials are at giving/receiving ‘electrons’ then the more static there will be. For any scientists reading, you might remember that this is measured by The Triboelectric Series.

On the Triboelectric Series; hair, wool, glass, nylon and fur are good at giving up electrons. Whereas silk, paper and cotton are at the other end of the scale and are bad at giving up electrons. Conversely; wood, metals, polyester and styrene are bad at attracting electrons whereas at the other end of this side of the scale polyurethane, polyethylene, vinyl/PVC are good at attracting electrons.

Thus a combination of PVC and hair would produce the most static whereas cotton and wood would produce the least. If you think about combing your hair then this should ring true.

Polyester is very similar to gold, platinum, brass, silver, nickel and copper in its static generating properties. Whereas, cotton is one of the lowest materials on the scale.

So the first lesson, bearing in mind the above, is that the choice of materials ie the curtain and the lining are critical. Also any surface that the curtain comes into contact with is important. So the second lesson is to consider the location.

Let’s turn now to how the curtain is made up. An experienced, professional curtain maker should know how to avoid the static problem.

Taking an example of a mixed composition fabric. Let’s say 40% cotton, 40% viscose and 20% polyester. And let’s also say that the material is loosely woven and has movement. Looking at such a fabric an experienced curtain maker would say that the fabric ‘needed taming’ and that a light cotton inter liner should be used. In addition to that the following details should be followed:

• The interlining should be locked in with 3 inch stitches. This should not be knotted;
• At the leading edge the interlining should be serged and locked in;
• The hem should be herring bone stitched. The stitches should not be too large and should not catch the face fabric; and
• Because of the nature of the fabric, the hem should slightly break on the floor.

These are not generic solutions to all curtain static problem. But they should be considered by the curtain maker.

So we have seen that: the choice of material; how the design works when hung; and how the curtain is made up, all have impacts on the creation or dissipation of static.

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Shimmering Upholstery

White Textured Upholstery on Contemporary Chair
White Textured Upholstery on Contemporary Chair
White Textured Upholstery on Contemporary Chair

 

New for Spring 2015, striking and shimmering design beautifully upholstered on an occasional chair.

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Textured Upholstery & Sheers

White Textured Upholstery on Contemporary Sofa
White Textured Upholstery on Contemporary Sofa
White Textured Upholstery on Contemporary Sofa

Some farbics beautifully arranged from our Spring 2015 Collection. A vey nice (we think) staged image in a set full of light diffused from some white souble-wodth sheers. 3 differing and contrasting cushions arranged off-centre on white contempoary seating

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Fabric Tips #13: Velvet Curtain Making

Image by tenz1225 via Flickr

Here are some additional pointers to consider when you are making a curtain using a velvet. Remember that a velvet is just a type of fabric and the fibre(s) that the velvet is made from is important.

So for example, we would always recommend that you line a curtain. This gives a superior appearance but also reduced the amount of light going through the fabric hence limiting as much as possible the effect of any fading.

If the velvet has a pile that can be flattened in one direction then we would recommend that you have the pile going downwards for SHINY velvet fabrics and PATTERNED VELVETS.

If however you make up the curtain with the pile upwards then this will deepen the colour so you could make the curtains this way for cotton velvets and Trevira Velvet and Mohair velvets.

These are general guidelines and it is not necessarily wrong if you make up the curtain ‘the other way’ just so long as you understand the implications to the finished look and performance of the material.

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Fabric Tips #12: Rolling a velvet

Image via Wikipedia

You’ve just ordered a new velvet and unrolled it to admire your purchase. But how do you re-roll it?

When you roll almost any fabric you should have the face on the inside. With a velvet this is the pile so you have the pile on the inside.

Some, but not all, velvet piles stand straight up others will ‘lay down’. for the former it does not matter which way you then roll the fabric (provided the pile is on the inside). However for typically longer pile which lays down (ie you can brush it flat with your hand in one direction only) then you should roll the fabric down the pile as you return it to its roll.

Hopefully that made sense. Good luck.

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What Is Sanforisation? Sanforised and Sanforising Explained for Interior Designers

What Is Sanforisation? Sanforised and Sanforising Explained for Interior Designers

What it is: A mechanical pre-shrinking finishing process applied to woven fabric before it leaves the mill. Named after Sanford Lockwood Cluett, who patented the process in 1930.
Which fabrics: Most commonly applied to cotton and linen. Also used on some cotton-blend upholstery and shirting fabrics.
Why it matters: Fabric that has not been sanforised may shrink when used in curtains or upholstery that are subsequently washed or exposed to moisture. Sanforised fabric has been pre-shrunk to defined limits at the mill, reducing but not eliminating subsequent shrinkage.
On the label: Sanforised is a registered trademark. Fabric labelled Sanforised has been tested and certified to shrink no more than 1% in either direction. Sanforised-Plus is the rating for fabrics with even greater dimensional stability.

Sanforising is a mechanical finishing process applied to woven fabric to reduce the shrinkage that would otherwise occur when the fabric is exposed to moisture or heat after making up. Interior designers encounter the term on fabric data sheets and labels, most commonly on cotton and linen upholstery and curtain fabrics. Understanding what it means and what it does not guarantee is a practical specification consideration.

How the Process Works

Sanforising passes the woven fabric through a machine that compresses it mechanically in the warp direction — along the length of the fabric. A rubber blanket is stretched and then released, and the fabric is carried through this process so that the yarns are forced into a more compact arrangement in the warp direction before they are set by steam. The result is a fabric whose yarns have already been displaced into the position they would naturally move to if the fabric were washed. When the finished curtain or upholstered piece is subsequently washed or exposed to moisture, the fabric has less remaining tendency to shrink because the displacement has already occurred.

The process addresses warp shrinkage — shrinkage along the length of the fabric. Weft shrinkage — shrinkage across the width — is controlled by a separate process called tentering, in which the fabric is held to a defined width during drying and heat setting. Sanforised fabric has typically been through both processes.

What Sanforised Means on a Label

Sanforised is a registered trademark owned by Cluett, Peabody and Co. Fabric carrying the Sanforised mark has been independently tested and certified to shrink no more than 1% in either the warp or weft direction when washed. This is the residual shrinkage after the sanforising process — fabric may still shrink by up to 1% in each direction, but no more.

Sanforised-Plus is a higher standard, certifying residual shrinkage of no more than 0.5% in either direction. It appears on some high-quality cotton fabrics and performance linens.

Fabric described as pre-shrunk rather than Sanforised may have been through a similar mechanical process but without independent certification to the same standard. The level of residual shrinkage permitted under a pre-shrunk claim is not standardised.

What It Does Not Guarantee

Sanforised certification applies to shrinkage caused by washing. It does not address all the dimensional changes that fabric may undergo in use. Natural fibre fabrics — cotton and linen in particular — absorb and release atmospheric moisture as humidity changes. This hygroscopic behaviour causes minor dimensional changes that are distinct from washing shrinkage and are not addressed by sanforising. In environments with significant humidity variation — a room that alternates between very dry and very damp conditions — even sanforised linen or cotton may show minor dimensional change over time.

Sanforised certification also does not address the relaxation shrinkage that may occur in curtains hung under their own weight over time, particularly in heavy cotton or linen fabrics. This is a tension-release effect rather than a moisture-induced shrinkage and is unrelated to the sanforising process.

Relevance for Upholstery Specification

For upholstery fabrics that will not be washed — most contract upholstery is dry-clean or spot-clean only — sanforised certification has limited direct relevance to the face fabric performance. Where it matters most is in curtain fabrics that will be laundered, and in loose covers and cushion covers in domestic settings where machine washing is planned.

For linen upholstery fabrics, the dimensional stability of the fabric during making-up is more practically significant than its washing shrinkage. A fabric that relaxes or distorts during the tension applied in upholstery construction will affect the alignment of the finished piece regardless of its sanforised status. Confirm dimensional stability under tension with the supplier for any linen or cotton fabric being used in tight upholstery applications.

For linen upholstery fabric specification, see our upholstery linen page. For fabric care and cleaning codes, see our fabric care symbols guide. For fabric hand and how natural fibres behave in use, see our fabric hand and tactile properties guide.

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What is BS5867 / BS 5867 part 2 type B? type C?

For the full guide to BS 5852 Crib 5 fire standards for contract upholstery, see: BS 5852 Crib 5: A Complete Guide for Interior Designers and Specifiers.

BS 5867 Part 2 Type B is the contract fire retardancy standard for curtains.

As an interior designer you do not need to understand the technical details of the test. However you are responsible for the project and must:

  • Confirm what standard is required for your project.
  • Specify fabric that meets that standard.
  • Prove that the fabric installed complies.

Here is what to do:

1. Determine the fire retardancy standard required. This may involve contacting the local fire officer. Confirm what documentation you need to provide.

2. Confirm with your fabric supplier whether the fabric inherently meets the standard or requires treatment.

3. On purchasing the fabric, specify the treatment required. Say to the fabric company: treat this fabric to BS 5867 Part 2 Type B and provide documentation confirming this has been done.

4. A treatment certificate confirms the fabric has been treated to the standard. It does not confirm the fabric has passed the test. For larger projects, arrange for your specific batch of fabric to be independently tested after treatment at a UKAS-accredited testing laboratory (not the treatment house). At the end of that process you will receive documentation confirming the fabric meets the standard.

Related: fire retardancy for contract upholstery, Crib 5 and BS 7176. For specifying contract curtains overall, covering light control, lining, fullness, and fabric quantity alongside this fire standard, see our contract curtain fabric specification guide.

Test Details

Test method

A sample of the fabric, vertically held, is exposed to a small flame. For Type B (hotels and similar) the ease of ignition is observed. It is noted whether the flame reaches any edge of the specimen and whether any burning pieces fall. For Type C (NHS environments) the fabric is further assessed for behaviour once the flame is removed but when the fabric may still be smouldering. The fabric is tested before and after laundering: Type B requires 12 wash cycles at 40 degrees; Type C requires 50 wash cycles at 40 degrees.

Type B performance criteria: The edges must remain completely intact and no burning debris should fall.

Quick answers

What is BS 5867?
BS 5867 is the British Standard for the flammability of fabrics used as curtains and drapes. Part 2 covers the fire performance of curtain and drapery fabrics in buildings. It is a separate standard from BS 5852, which covers upholstery: a Crib 5 upholstery certificate does not qualify a fabric for curtain use. BS 5867 Part 2 has two relevant types, Type B for general contract environments and Type C for healthcare.


What is the difference between BS 5867 Type B and Type C?
Both test a vertically held fabric against a small flame, before and after laundering. Type B, for hotels and general contract environments, requires 12 wash cycles at 40 degrees. Type C, for NHS and healthcare environments, requires 50 wash cycles at 40 degrees and additionally assesses the fabric once the flame is removed while it may still be smouldering. Type C is the more demanding standard and applies where curtains are laundered frequently.


Do contract curtains need to be fire treated?
Most decorative curtain fabrics need topical FR treatment to meet BS 5867 Part 2. Some inherently fire-resistant fabrics, such as certain Trevira CS constructions, meet the standard without treatment. As the designer you are responsible for confirming the required standard with the fire officer, specifying fabric that meets it, and proving the installed fabric complies with an independent test certificate from a UKAS-accredited laboratory.

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KOTHEA 2010 Fabric Collections

Finally! Our summer collections have been decided and we will begin to introduce the new designs and colourways throughout the remainder of this year. We have been inundated with new work in the first part of this year causing our blog posts to be curtailed and our ‘spring’ collection to nearly be an autumn/fall collection. Not that we really do seasonal collections in any case.

I will return later in another post to KOTHEA’s awesome sales figures for the financial year just finished. Most surprising, especially considering we are in the midst of a recession. We had our best ever year and by quite a large margin.

We expect some coverage of the new collections in World of Interiors and Elle decoration but, again, more on that at another time.

Where can you see our collections? Well, we are as elusive as ever but we are starting to digitize some images to our flickr feed (click the images on the right or here). The flickr update is ongoing, there is information on flickr now but some of the images are not final and some images do not have full associated descriptions / product details but we are woking on that this week. Our usual clients will receive the new collections in due course starting in late summer; if you need them more urgently for pressing projects of course we will be happy to oblige. Please get in contact in the usual way.

Not all are in production yet but most sampling is available now.

As a very broad summary we have:

1. New colours of several existing ranges including faux leather;

2. More velvets including patterned and crush;

3. Striped, double-width linens;

4. Upholstery weight linen; and

5. A few more interesting one-off designs in limited colourways like the one heading up this blog post.