Fishing and Gear Technology (2+1) copy 1

Unit 4 - Yarn numbering systems/designation of netting yarn

4.2. Numbering systems

Direct system
In this system the length of the material is constant but weight varies. eg 1000m of yarn weigh 1 g. is1 Tex ( The tex system (Tex) specifies twine size in terms of weight in grams per 1000m of single yarn.) The tex system is recommended by international standards organization and is widely adopted and is expected to eventually replace other systems. The denier system (den or Td) which is also widely used specifies the size as weight in grams per 9000m of the yarn. Denier value is converted into tex by a multiplying factor of 0.111 and tex into denier by multiplying factor of 9.

Indirect system
This is usually used to express the size of the finished products. In this system the weight is kept constant and length varies.

The metric system
The metric system (Nm) designates the size as number of kilometers of yarn which weigh one kilogram is known as 1 Nm. Tex value is obtained by dividing 1000 by metric count and denier value by dividing 9000 by metric count.

The british cotton count
The british cotton count (Nc) is the number of hanks (840 yards) which weigh one pound. Equivalent tex and denier value to british cotton count can be obtained by dividing 590.5 and 5315 by British cotton count respectively.
Runnage system
Runnage system is expressed in terms of meters/kg, ft/lb, yards/lb etc and is mainly used for the finished products only.