Measurement Definition
Indirect yarn numbering units express the fineness of spun bast fibres by calculating the length of yarn contained within a standard unit of mass. International spinning mills designate the english lea with the symbol NeL to specify flax yarn dimensions across commercial contracts. One lea represents a length of three hundred yards, and the count signifies how many three-hundred-yard lengths weigh exactly one avoirdupois pound.
Higher numerical values correspond to finer yarns, while lower values denote coarse yarns suited for tarpaulins or heavy upholstery fabrics. The metric stops applying once yarns are converted into tex or metric count on continental European purchase contracts, where direct mass-per-length units replace imperial yardage.
Calculation Method
Standard laboratory skein testing determines yarn lea through skein winding and precision analytical balance weighing under conditioned atmosphere. Technicians wind a sample skein of one hundred and twenty yards on a wrap reel, expose the yarn to standard temperature and relative humidity for twenty-four hours, and weigh the sample in grams. The english lea count equals the product of length in yards and the constant 453.59, divided by the product of three hundred and the weight in grams.
When moisture regain deviates from the standard twelve percent allowance, spin technicians apply correction factors according to national textile testing protocols. Testing reports generated on the spinning floor record the nominal lea alongside actual lea, skein weight deviation, and single-end breaking tenacity.
Specification Threshold
Commercial contracts for wet-spun flax yarn establish strict tolerance envelopes around nominal lea counts to ensure warp consistency across rapier looms. Mill spinning rooms run flax roving into wet-spinning troughs to achieve fine counts, typically ranging between NeL 36 and NeL 80 for apparel fabrics. If delivered lots slip below contract lea, the fabric will finish over the targeted square-meter weight, altering handle and increasing export shipping costs.
Spinning mills record lea deviations on the final certificate of inspection, where yarn packages exceeding plus or minus five percent of target count undergo downgrading to domestic secondary markets.
