Coconut fiber has a thermal conductivity coefficient of less than 0.04 (W/(m-K)) and is therefore classified as an excellent thermal insulator. Compared to other traditional materials used as thermal insulators, coconut fiber has similar insulating properties.
Samples with coconut fiber are found to have identical thermal properties as other typical insulation materials (fiberglass and mineral wool).
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What are the properties of coir fiber?
Coir fiber is an abundant natural material, is used in agronomy as a substrate, is used in a wide range of products for industrial applications, and in construction has been used in the past as reinforcement in concrete elements.
However, coconut fiber has not been utilized in other types of structures.
Basically, Coconut fiber is a 100% natural fiber obtained from the mesocarp tissue of the coconut palm, a material composed of cellulose, hemicellulose, and lignin.
Physically, it corresponds to the shell of the fruit, is characterized by having a golden-brown color after drying, has an average length between 15 and 25 cm, is a hygroscopic material.
Has high mechanical strength, has a low density, and also has high natural durability (it is not affected by the action of rodents and insects, does not suffer the action of fungi when dry, and does not rot).
Among the properties of coconut fiber:
- density ranging from 1.15 to 1.46 g/cm3
- tensile strength between 131 and 220 MPa
- elasticity modulus between 4 and 6 GPa
It should also be noted that natural fibers have many advantages over man-made and synthetic fibers.
Natural fibers are not abrasive and do not damage processing equipment, do not cause skin irritation during handling and use.
They have good mechanical properties and the amount of energy required for their production is 80% lower than for the production of man-made and synthetic fibers.
Advantages and disadvantages of coconut fiber
The insulating effect of coconut fibers is to be located in the upscale area and is, therefore, to be assessed as advantageous. The thermal conductivity is approx. 0.04 to 0.05 watts per meter and Kelvin.
An insulation layer of around 18 centimeters is sufficient to meet the requirements of the Building Energy Act (GEG) with regard to the heat transfer coefficient for facade insulation with a U-value of 0.24 W / (m²K).
The insulation material is also open to diffusion and has a moisture-regulating effect. This means that the fibers remain odorless even after prolonged contact with moisture.
One of the negative things to consider is the above-average price of insulation made from coconut fibers. In addition, the ecological balance is worse than that of the other, regional, plant-based insulation materials due to the large delivery from Oceania.
Another disadvantage is the fact that, despite the addition of boron salts and ammonium phosphate, the coconut fibers are assigned to fire protection class B2, i.e. are classified as normally flammable.
Is coconut fiber insulation harmful to health?
The insulation made of coconut fibers consists entirely of natural materials and does not pose a risk to your health. You do not have to take any complex precautionary measures when installing and removing this insulation.
In particular, the good protection against mold contributes to the fact that the insulation made of coconut fibers can be classified as health-friendly. Only in fire protection does the insulation perform comparatively poorly.
Flammability and moisture regulation (risk of mold)
Coconut fibers are classified in fire protection class B2 and are therefore considered to be normally flammable. This means that the insulation material is ruled out for projects with increased fire protection.
However, insulation made from coconut fibers has very good properties for regulating moisture, so that the formation of mold is prevented.
Although coconut fibers are made from plant-based, renewable materials, the ecological balance of the insulation material is relatively poor.
One reason for this is the long transport route from overseas. Furthermore, mostly monocultures are grown for the production of coconut fibers, which have negative consequences for the soil and biodiversity.
What other natural fiber improves insulation?
Ecological insulations are the right choice, they are abundant, biodegradable, economical.
House insulation reduces energy consumption and the need to resort to air conditioning and heating. But not all materials are thermal insulators.
Here is a list of which natural materials work as thermal insulators.
Cellulose fiber from recycled paper
It is an insulating material obtained from recycled newsprint. The raw material is cellulose.
Its main characteristics are its hygroscopic qualities, resistance to fire and decomposition, recyclability or reusability, high mechanical strength, and insolubility in most ordinary solvents.
It is used as thermal insulation in roofs, floors, and vertical enclosures and as a fire protection material. It is applied with a machine that blows the product into the hollow spaces.
Wood fiber insulation panel
Wood fiberboards are insulating, ecological, and economical. The porous structure of its fibers favors vapor diffusion and the boards “breathe”, they are able to absorb sound waves and considerably improve impact noise damping.
They can absorb a large amount of water while retaining their dry material character.
In order for them to show their optimum insulating capacity, it is advisable to assemble them in a dry state.
Hemp thermosetting blanket
It is made from the hemp fibers joined together and the raw material is the cannabis plant or flax. It is fast-growing and, being a pest-resistant plant, it does not need pesticide protection.
It is presented in two forms: as an insulating hemp cellulose insulation protected with mineral salts or in the form of an insulating blanket.
It is inedible for insects and rodents and is permeable to water vapor.
It is used as a base layer in floating floors, as thermal and acoustic insulation in wood-framed ceilings, empty partitions, and for wall cladding by suitable methods.
Excellent thermal insulation with good hygrometric regulation capacity without loss of insulating qualities.
Perfectly adapts to the irregularities of the frame to ensure quality insulation.
Non-irritating and fully recyclable, it has good mechanical resistance and is a very durable material.
Sheep wool blanket
The use of wool as an insulating material involves cleaning treatments, protection against attack by xylophages and strengthening.
In its natural state, it has the disadvantage that it can be attacked by moths, but this can be avoided with treatment with sodium borate.
In addition, it absorbs moisture when it is excessive and releases it when the environment is dry. It is difficult to find an insulator that regulates humidity so well.
This wool can fix 33% of its weight in water and restore it when drying without losing its thermal capacities.
The mattress in sheets is a good thermal insulator, but it is a much better acoustic insulator, so it can be used for both functions.
It is the only ecological insulator resistant in humid environments. Non-irritating, recyclable, without any addition of glue.
The shredded cork has great insulation capacity, both thermal and acoustic, with conductivity coefficients ranging from 0.035 to 0.045W/m2K.
It is rot-proof and resists insect and fungus attacks, making it one of the most stable and durable materials in the plant kingdom.
It does not emit vapors or toxic particles, nor does it accumulate static electricity.
It allows walls and roofs to transpire and is also permeable to natural radiation (cosmo-telluric).
Feather is highly appreciated for its natural characteristics and performance in terms of insulation.
Manufacturers mostly use duck feathers that provide excellent thermal insulation both in summer and winter. Complying with the requirements of High Environmental Quality (HQE).
The ecological characteristics of insulating feathers contribute to the preservation of the environment through energy savings made in heating and air conditioning.
Using the remains of this textile industry and by means of transformation processes consisting of wetting and pressing the fibers, there are several companies that manufacture thermal and acoustic insulation for use in the construction sector.
This construction system incorporates great quality as thermal and acoustic insulation itself, so it is very suitable for self-construction.
Hard and generally translucent or transparent material resulting from the solidification of the molten mixture of silica sands, lime and sodium or potassium carbonate, which have a vitrifying, fluxing and stabilizing function, respectively.
It is a poor conductor of heat and electricity. It resists ordinary chemical agents and is attacked by hydrofluoric acid.
Geologically, expanded clay is an impermeable sedimentary rock with a powdery structure. The resistance conferred by the drying and firing process after mixing it with water has made it a material used throughout the ages for the manufacture of ceramic pieces: tiles, bricks.
Which is the better thermal insulator between coconut fiber or compacted straw?
Although ecological materials are considered as an alternative for thermal insulation, compressed straw, insulation material of natural origin often used in Europe in wooden structures, has a thermal conductivity coefficient of 0.065 (W/(m-K)).
Coconut fiber thus delivers a lower coefficient of thermal conductivity than compressed straw.
The composite section with coir fiber is therefore a sustainable alternative with low thermal conductivity.
It goes without saying that from a thermal point of view, wood structures can perform better than concrete and steel structures.