Stockings and “Denier” (DEN)
The “Denier” is the unit of measurement that indicates the weight, in grams, of 9000 meters of thread or yarn used to make a sock.
So, what does it mean when you hear that a sock or pantyhose has a count of 40 DEN? It means that 9000 meters of yarn of those tights have a mass (“weigh”) of 40 grams.
To calculate the “denier” of a thread, you take any length of this thread, measuring its length (in meters) and its mass (in grams), and then applying the formula: mass divided by length multiplied by 9000.
Conversely, if you wish to know how long a thread used to make a single stocking, just divide 9.000 by its weight (in grams) and multiply it for the DEN number. From this you can easily understand that to create a single pair of socks several hundred meters of yarns can be used.
“Denier” – abbreviated as “DEN” – are traditionally used to indicate the degree of compression exerted by an elastic stocking.
Since a greater weight usually corresponds to a greater thickness of the yarn (or a greater amount of elastic material), a high degree of denier is associated with a higher compression, and the stock is thicker.
On packages of stockings and tights the word DEN preceded by a number expresses (indirectly) the different elasticity, that is, the different level of compression that the stocking or pantyhose has on the leg. Socks or tights from 40 DEN will have a milder compression than those from 70 DEN or 140 DEN.
A very similar alternative to the Denier is the Decitex (dtex), ie the weight (in grams) of 10 Km of yarn ( read about this topic on Wikipedia).
Millimeter of mercury (mm/Hg)
The most accurate and scientific way to indicate the compression of a sock is the use of “millimeters of mercury” (mm/Hg).
This unit of measure – which in the textile industry is more widespread than the “pascal” (Pa) – indicates exactly the pressure, just as it does for blood or atmospheric pressure, regardless of the yarn and the “weight” of the yarn.
No DEN / mmHg conversion standard is officially available in Italy. For this reason the same DEN value may correspond to different compression values.
In the case of the measurement in mm / Hg the reference value is the “compression at the ankle”.
This value is very important, especially in the case of graduated compression stockings, because in this case the pressure exerted by the yarn varies depending on the point at which it is measured.
The point where the compression is maximum is at the ankle, decreasing in the upper section.
RAL-GZ 387/1 Compression Classes
A useful reference to understand the DEN / mmHg conversion, and in particular the division of the compression socks into “classes”, can be provided by the German RAL-GZ 387/1, which comprehends:
Compression class: I
Compression intensity: Low
Pressure at the ankle in mmHg: 18 to 21
Compression in kPa: 2.4 to 2.8
Compression class: II
Compression intensity: Moderate
Pressure at the ankle in mmHg: 23 to 32
Compression in kPa: 3.1 to 4.3
Compression class: III
Compression intensity: High
Pressure at the ankle in mmHg: 34 to 46
Compression in kPa: 4.5 to 6.1
Compression class: IV
Compression intensity: Very high
Pressure at the ankle in mmHg: 49 and higher
Compression in kPa: 6.5 and higher
1 kPa equals 7.5 mmHg.
Graduated compression stockings in private label Sanyleg
Sanyleg’s private label elastic stockings include a wide range of products that is perfect for every kind of graduated compression need, from milder to preventive socks, from compression socks for sports to prevention lines for deep venous thrombosis, lymphedema and ulcers.
|Anti-embolism line||18-20 mm/Hg|
|Therapeutic Line (Therapeutic stockings available in Class I and Class II)||23-32 mm/Hg|
|Preventive Sheer Line||10-14 mm/Hg (about 70 den: moderate compression), 15-21 mm/Hg (about 140 den: high compression), 25-27 mm/Hg (about 280 den: very high compression)|
|Anti-ulcer Line||mm/Hg 40|
|Preventive Cotton Line||6-10 mm/Hg (low compression), 14-16 mm/Hg (moderate compression), 15-21 mm/Hg (high compression), 25-27 mm/Hg (very high compression)|
|Sensitive Feet Line||with no graduated compression|