Question

The Air permeability of a fabric increases linearly with increase in twist factor. This is due to

• A. The air space in the yarn is reduced
• B. The warp and weft cover factor is high
• C. The air space in the yarn is high
• D. The warp and weft cover factor is constant

Hint:

Higher twist factor leads to higher air space, and thus greater air permeability.

Answer 1

The Correct Option is C

Step 1: Understanding Air Permeability: Air permeability is the ability of a fabric to allow air to pass through it. It's a crucial factor for comfort, especially in clothing. 
Step 2: Understanding Twist Factor: Twist factor is a measure of the amount of twist in a yarn. Higher twist factor means a tighter, more compact yarn. 
Step 3: Relationship Between Twist and Air Permeability: As the twist factor increases (up to a certain point), the yarn becomes more open and porous, allowing air to flow through easily. But after reaching a certain level, increase in twist makes the yarn compact, thus reducing the air permeability. Thus the relationship is not exactly linear. 
Step 4: Analyzing the Options: 
 (a) The air space in the yarn is reduced: This is incorrect as increase in twist factor increases the air space. 
 (b) The warp and weft cover factor is high: This is not directly connected to the air permeability of yarn. 
 (c)The air space in the yarn is high: This is correct as higher twist factor makes the yarn more open. 
 (d) The warp and weft cover factor is constant: This option has no direct relation with the twist factor.