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What Keeps Feather & Down Warm? Fill Power is the Key Index to Determine Feather & Down Quality

1 What is down feather? What’s the purpose and scope?


The down feather of birds is a layer of fine feathers found under the tougher exterior feathers. Powder down is a specialized type of down found only in a few groups of birds. Down can absorb moisture and dampens, and it is one of the best thermal insulation materials in the world, we call it will “breathe”, down feather belonging to the green and environment-friendly natural warm material.

The down of our commonly used refers to the goose down and duck feather, which are mainly used in jackets, duvets, down jackets, pillows, and sleeping bags. In winter, these down products, as a must for cold protection, are loved by people. However, as a filling material, down has been “hidden” in it, it is difficult to judge its quality intuitively, so there is a variety of false publicity. So how on earth should we judge the quality of down?

2 Judging principle of keeping warm of down velvet

In down rings, many people think that Europe’s down is the best, this misconception of “origin = quality”, which has been publicized for a long time in the market, distorts the facts, and make the consumers mistakenly believe that only European countries such as France and Hungary have quality down. However, in fact, the quality of down has nothing to do with the place of origin. The most important index of down quality is the down fill power.

The down fill power is the down’s volume in per unit weight, the larger the volume, the more air locked, the warmer it is. In other words, the higher the fill power down, the same amount of down can fix a larger volume of air layer for heat preservation and heat insulation, down is lighter, to achieve an unparalleled warm weight ratio.

fill power down

In August 2017, 13 down samples from China, France, Hungary, and Poland were tested by the authoritative down testing laboratory (International Down & Feather Laboratory, IDFL) and Guangzhou Fiber Product testing Institute, GTT). The results showed that the highest quality of the 13 samples was gray duck feather duvet from Wu-Chuan, China, with a fill power of 22.1cm. The highest quality down sample of Europe is white goose down from Poland, with a fill power of 20.8cm, ranked fourth in 13 feather & down samples. The test results show that the down quality in other regions is no worse than that in Europe.

Down fill power is generally divided into 550, 600, 700, 800 and 900. In the same weight case, these kinds of different fill power down gives you a different feeling! As shown below:

feather&down jacket fill power

550 fill power down:
It is the most commonly used material with lightweight, thermal, and insulation, which wearing lightweight warmth.
600 fill power down:
It is widely applicable to different temperature conditions, which is warm, comfortable and easy to carry.
700 fill power down:
It is suitable for extreme cold conditions, pay more attention to keeping warm.
800 fill power down:
With ultra-high thermal insulation, outstanding expansion and compression, warmer at the same time can be lighter, there is no burden on the activities.
900 fill power down:
It is the highest quality down fill on the market at present, it not only has unparalleled warm-to-weight ratio, but also has good compressibility, super light weight, and has amazing thermal performance. Because of their limited number, most of them are used for outdoor top equipment.

3 How do I test the down fill power?

3.1 Test principle: Put a certain weight of down in a cylinder with a plate, check the down height in the natural state. At present, there are two units of down fill power: “centimeter (cm)” and “cubic inch per 30g (in³/30g)”, and their conversion constant is 28.77. For example, the down fill power value is 20.8cm, which is equivalent to 598in³. The common feather&down fill power tester is shown below


3.2 Test status: At present, the fill power test principle of each country and region is consistent, but there are some differences in the specific operation and parameters of the test. The main testing standards of down fill power are as follows: BSEN 12130 — test method for fill power of feather&down, JIS L 1903 — test method for feather&down, GB/T 10288 — down&feather test method, FZ/T 80001 — test method for washing feather&down, and IDFB — official analysis method of International Down&Feather Bureau.

The following table summarizes the eligibility limit requirements for a fill power of national standards (or labels), to make the enterprises understand and master the dynamics of fill power test standards in various countries as soon as possible, and deeply understand the conformity judgment and limit requirements of the standards. We hope to help enterprises organize production correctly, improve their ability to deal with technical barriers to international trade, and avoid claims and returns in international trade.

the eligibility limit requirements for fill power of national standards

The down fill power is a key index for determining the warm-keeping of the down. In order to solve the quality control problems of the down industry further and improve the quality of feather down products comprehensively, we should understand the standard terms correctly, standardize the test method, and improve the level of testing technology.

If you want to know more about the textile test, the related topics are as follows:

Test Standard Articles                    Textile Application Articles

Textile Property Articles                  Textile Related Articles

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