We have been receiving questions about how to choose the right version of Apyrum Liquid.

Generally speaking you can use Apyrum Liquid in any material that can be wetted or impregnated with water. If this is not true you can probably not use it. Apyrum Liquid is a water-based flame retardant that is used for impregnation of natural and mixed fibres and materials.

Apyrum 201 and 101 could potentially have a good function in most natural materials. The relevant question is what the requirements are regarding application process and final material properties.

To start with the material that shall be impregnated with a specific amount Apyrum that provides the fire retardant function that is required. We call this load. Generally the load is between 5% and 40% depending on application and requirement. (load is calculated as the weight of active substance in relation to total weight of substrate including active substance)

The questions that you have to awnsver is;

  • What load of active substance is needed to meet fire requirements?
  • Is 101 or 201 working better?
  • What impregnation method/process should be applied to reach the targeted load?
  • What concentration of Apyrum should be used and is wetting agent needed to reach the targeted load and functionality?
  • Is other material properties like hygroscopicity, tactile and functional properties of the substrate satisfactory?

These questions is a part of an iterative process that has to be tested and asked repeatedly until the system is optimised. You will notis that it is a tradeoff between.

ProductConcentrationWetting Agent
Apyrum 201-3030%No
Apyrum 201-30 wt30%Yes
Apyrum 201-5050%No
Apyrum 201-50 wt50%Yes
Apyrum 101-2525%No

Apyrum 201 Liquid is the standard or all-round flame retardant that has a high solubility and is available in a concentration as high as 50%. It produces an extreme char formation and gives a efficient flame retardancy in most natural materials. It is hygroscopic at high loads (amount of flame retardant in the material) that could make the material to seem a bit moist.
Apyrum 201 WA Liquid is produced with the same active substance as Apyrum 201 Liquid but with a wetting agent added to improve penetration during impregnation. It is often evident that the fire retardant is more efficient and other material properties are improved if the active substance is deeper and finer inside the substrate.

Apyrum 101 Liquid is a version of Apyrum that has a different active substance that has been specifically developed to be used in hemp, flax and wool and similar materials. It has a lower solubility compared with Apyrum 201 and is therefore only available in concentration of 25%. It could be more challenging to reach higher loads (of active substance) in the substrates. Apyrum 101 has not as strong charr formation and is less hygroscopic.