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Posts tagged with “Sheets”

Bed Sheet Thread Count Testing

Thread counts are an important characteristic of top of the bed fabrics, both for consumers and technologists.

As commonly used in the United States the thread count, or “T number,” of a top of the bed (bed sheet) fabric is the sum of the ends (lengthwise yarns) per inch plus the picks (widthwise yarns) per inch contained in the fabric.

The most common woven fabric construction for top of the bed fabrics is the plain weave.  Light and scanning electron images of a lightweight 100% plain weave cotton sheeting fabric are shown below:

 

Light Microscopy of 100% Cotton Sheeting Fabric

 

Scanning Electron Microscopy of 100% Cotton Sheeting Fabric

 

Graphically, this is represented as:

 

Plain Weave

 

Another common woven structure for top of the bed products is the satin weave:

 

Satin Weave

 

Fabrics made of 100% cotton can always have their thread counts determined unambiguously using current definitions, as can intimate blends of cotton and polyester staple (polyester fibers cut up to a length similar to cotton). Top of the bed fabrics containing continuous filament yarns can be trickier to deal with, partially due to unclear definitions of how to count continuous filament yarns in top of the bed products, and partially because of the nature of continuous filament yarns.

The following shows the back of a top of the bed woven satin made with 100% cotton yarns. This fabric uses “10 pick insertion.”  10 individual picks are inserted into the shed (the temporary separation between the upper and lower warp yarns through which the filling is woven) of the loom before the harnesses of the loom alternate and a new shed is formed.

Several years ago ASTM updated the standard terminology for how plied yarns used in bed sheets are counted:

“ASTM D7023 06 (Reapproved 2012) Standard Terminology Relating to Home Furnishings:

thread count, n—in woven textiles as used in sheets and bedding, the sum of the number of warp yarns (ends) and filling yarns (picks) per unit distance as counted while the fabric is held under zero tension and is free of folds and wrinkles, individual warp and filling yarns are counted as single units regardless of whether comprised of single or plied components.

DISCUSSION—The thread count of sheets and bedding articles is frequently displayed on the outside packaging of such items, or utilized in advertising literature. The specific construction of the warp and filling yarns used to construct the fabric in such items may also be displayed. Examples:

“300 Thread count, 2 ply yarn.” A representation of “600 thread count” for this same product would be likely to mislead consumers about the quality of the product purchased.

“Finely woven 380 2 ply fabric.” The representation of “finely woven 760 threads per square inch” is considered to be misleading to the consumer.

The following shows the back of a top of the bed satin fabric made with a 100% polyester filament filling and 100% cotton warp.”

With filament filling yarns the presence of distinct separable yarns comprising a multiple pick insertion fabric can be hard to determine.

To find out more about bed sheets, Take A Video Tour Of An Indian Top Of The Bed Factory or contact us directly.

Vartest is an ISO 17025 Accredited Laboratory in Manhattan providing fast turnaround and technical drill down testing for all aspects of fiber, yarn, fabric and end product testing.