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IH calibration standards

Interwoollabs StampINTERWOOLLABS' activities have been crowned by official recognition from the International Wool Textile Organisation of its IH calibration standards as official I.W.T.O. calibration standards for Air-Flow, Projection Microscope, Laserscan and O.F.D.A. measurement apparatus.

The first series was established in 1972. It was the result of the most extensive testing and retesting that significant quantities of standard wool tops have been established. Limited to a maximum duration of 3 years, this series has replaced by seventeen further series, each of them having been valid for a period progressively reduced to 2 years. The 21st Series will be valid until 31 January 2018, with respective finenesses as follows:

21st SERIES OF IH-STANDARDS
(Valid : 01.02.2016 - 31.01.2018)

Standard Values to be used for the calibration of the Instruments for the fibre diameter measurements

S T A N D A R D   V A L U E S

  AIRFLOW
for AIRFLOW Calibrations
PROJECTION  MICROSCOPE
for OFDA and LASERSCAN
Calibrations
 
Standard
No.
Mean fibre
diameter
(µm)
Mean fibre
diameter
(µm)
Distribution
of fibre
diameter
(CV %)
Fibre
Curvature
(deg/mm)
1 PM not applicable 15.71 20.00 79
1 AF 16.46 not applicable not applicable not applicable
2 18.61 18.47 20.89 69
3 20.74 20.66 20.29 66
4 24.31 24.29 22.43 62
5 26.79 26.57 23.29 58
6 31.47 31.65 22.18 48
7 32.59 32.60 25.57 47
8 35.43 35.37 25.07 46

Eight Tops are required to calibrate Airflow (IWTO-6), Laserscan (IWTO-12) and OFDA (IWTO-47).

  • To calibrate Airflow Instruments, tops “1AF” and “2” to “8” only shall be used.
  • To calibrate Laserscan and OFDA instruments, tops “1PM” and “2” to “8” shall be used. Do not use top “1AF”.