What is a good air permeability value for fabric?

Good breathability of a fabric is related to its material and construction. Breathability is the ability of air to circulate through a fabric and measures the ability of a fabric to expel moisture and perspiration, as well as its comfort.

Breathability is usually measured using two metrics: permeability and breathability. Permeability is the ability of water vapour to pass through a fabric per unit area and per unit time, and is usually expressed in grams/meter²/day (g/m²/day) or cups (g/100in²/24hr). Breathability, on the other hand, is the ability of air to pass through a fabric per unit area and per unit time, usually expressed as cubic feet per minute per square foot (CFM/ft²) or liters per square meter per second (L/m²/s).

Good breathability values for fabrics are relative, and different uses and environments will have different needs. For example, outdoor sportswear and high-intensity exercise require a high degree of breathability in order to wick away perspiration and keep you cool. In warm clothing or certain protective clothing, the breathability requirement may be lower in order to retain heat.

In general, better breathability usually requires the following qualities:

1. Breathable materials: Choose fibre materials with better breathability, such as cotton, linen and silk. These fibres have better moisture wicking and moisture removal capabilities.

2. Fabric structure: The structure and weave of the fabric will also affect breathability. For example, the design of openings or mesh in the fabric, the size of the lockstitch gaps, and the textile technology can all increase breathability.

3. Treatments and coatings: Some fabrics undergo special treatments or coatings, such as waterproof/breathable coatings (e.g. GORE-TEX), moisture-wicking layers or breathable membranes, which can balance the waterproofing and breathability properties of the fabric.

4. Wearing comfort: Good breathability is not only about the fabric itself, but comfortable wearing is also important. For example, proper fabric adaptation, garment design and seasonal adaptation can enhance wearing comfort and breathability.

Please note that breathability is a variable concept and its measurements and criteria may vary. When selecting fabrics, it is advisable to refer to product descriptions, test reports and compliance with local standards or regulations to ensure that the fabric you select meets your needs and expectations.