# Key Terminology

### CONVERSION FACTORS

Twist:

• Turns Per Meter (TPM) = Turns Per Inch x 39.37

Linear Density and Yield:

• Decitex = Denier x 0.9
• Meters Per Kilogram = Yards Per Pound x 2.0159
• Grams per 100 Meters = Denier/90
• Yards Per Pound = 4,465000/Denier
• Denier = 4,465,000/Yards Per Pound
• Decitex = 4,956,000/Yards Per Pound
• Cotton Count = 5315/Denier

Force:

• Newtons = Pounds Force x 4.448
• Tenacity and Breaking Strength
• Grams Per Denier = 1.132 x Centi-Newtons Per Decitex
• Centi-Newtons = Decitex x Centi-Newtons per Decitex
• Newton = Centi-Newton x 0.01

### TERMINOLOGY

TerminologyDefinition
Yarn Size:Denier and Decitex are the most commonly used measures of yarn size in the hose industry.
Denier:The weight in grams of 9000 meters of fiber. Denier is a direct numbering system in which lower numbers represent the finer yarn sizes.50, 2200, 3300 & 4400
Decitex:The weight in grams of 10,000 meters of fiber.
Cotton Count:Used as a measure on spun-polyester. The number of 840 yard skeins required to weigh one pound. Count is an inverse system in which lower numbers represent the heavier yarn sizes.
Yarn Tensile:The strength in pounds or newtons of a fiber as measured on a C.R.E. (constant rate of extension) tensile tester. The rate of extension is twelve inches per minute. In general, valid tensile tests are performed when the procedures outlined in ASTM D-885 are followed. The use of the newton is more technically correct since it is a measurement of force rather than of weight. To convert tensile to newtons multiply pounds by 4.45. One millinewton (mn) equals 102 grams.
Yarn Elongation:The hose industry normally uses the term elongation at break (Elong. @ Brk.) to indicate the percentage of length a fiber stretches before breaking. The Elong. @ Brk. figure is of use in designing a hose because it represents the property of the fiber at the rupture point, which plays a role in hose burst pressure.

Percent EASL (Elongation At Stated Load) is a better measure of how the yarn will perform in the hose since it can be specified at a total value close to its working load in the hose. The most common EASL used in the hose industry is Elongation at 10 lbs.

Percent LASE (Load At Specified Elongation) is sometimes the preferred test measurement. This reflects the load required to produce a given elongation.

Yarn Shrinkage:The acronym H.A.S. is commonly used as a term for yarn shrinkage. H.A.S. means free Hot Air Shrinkage. H.A.S. is expressed as a percentage figure. It indicates the percentage of free shrinkage as a fiber exhibits when heated at a certain temperature for a specified period of time under a specified amount of tension.
H.A.S. Testing:There are no established standards for test methods in the hose industry. The most widely used test is called the Testrite Method. The H.A.S. figures listed in the Beaver Manufacturing Company catalog were obtained using the Testrite Method.
Comments on Yarn Shrinkage:H.A.S. percentage figures provide only a partial indicator as to how a fiber will behave when braided or wrapped into a hose and then cured at various temperatures. Heat causes most fibers to develop a force of shrinkage which may be very low or very high depending on the fiber type and other factors. A particular fiber may have a high percentage H.A.S. under zero tension and a low shrinkage force. A low shrinkage force may translate into a low percentage H.A.S. within the hose because the hose tube may resist the H.A.S. with a force greater than the shrinkage force of the yarn. Within a hose a fiber with a high H.A.S. and a low force of shrinkage may actually shrink less than a fiber with a low H.A.S. and a high force of shrinkage.

Measuring the force of shrinkage requires different equipment. One method coming into prominence uses a Testrite instrument modified to employ an electronic strain gauge and digital readout. The yarn is held to constant length and the force developed during heating is measured by the strain gauge. Although force of shrinkage is a very important factor in fiber performance, very few hose manufacturers test the phenomenon.