Downproofness of Fabric

• Air Permeability Air permeability describes breathability

  of  the fabric & may indicate downproofness.
• Downproofness Physical tumbling of the fabric filled with

  down/feathers determines downproofness.

  The next most common source of leakage is through the  

  fabric itself. Heavy, coated fabrics are almost always very  

  downproof whereas, very lightweight synthetic fabrics  

  and  damask & other patterned cotton fabrics allow more  

  material  to pass through. 

• Downproofness (FSTM 191-5530 & EN 12132-1).

  This involves physically testing the fabric to simulate the

  use of the product.

• Air Permeability (ASTM D737).

   Tests the amount of air that can pass through a fabric

   (e.g. breathability). Too much air passing through a

   fabric  can cause leakage whereas, too little air passing

   through  a fabric can cause odor problems due to

   incomplete  drying.

   more info:

   Air Permeability Conversion Factors

   Downproof FTMS 191 5530 vs IDFL Method

   Downproofness vs Air Permeability​​​​