Flannel fabric, like any other upholstery material, can vary in its resistance to fading depending on several factors. It's not accurate to make a blanket statement that sofa flannel fabric is inherently less prone to fading than other fabrics, as the fading resistance is influenced by specific characteristics of the fabric, the dyeing process, and environmental factors. Here are some key considerations:

Dyeing Process:

The method used to dye the flannel fabric plays a significant role in its fading resistance. Fabrics that undergo high-quality dyeing processes, such as solution dyeing or vat dyeing, tend to have better colorfastness and are less prone to fading.

Fabric Composition:

Flannel can be made from various fibers, including cotton, wool, and synthetic blends. The type of fibers used can impact fading resistance. Some synthetic fibers may have enhanced color retention properties, while natural fibers like cotton can be more susceptible to fading.

Colorfastness Rating:

Fabrics are often tested for colorfastness, and they may be assigned a colorfastness rating. A higher colorfastness rating indicates better resistance to fading.

UV Resistance:

Fabrics treated with UV-resistant finishes can be more resistant to fading caused by exposure to sunlight. UV resistance helps protect the fabric from the deteriorating effects of ultraviolet rays.

Environmental Factors:

The environment in which the sofa is placed influences fading. Prolonged exposure to direct sunlight, especially in areas with intense UV radiation, can contribute to fading. Other environmental factors such as humidity and air pollution can also play a role.

Maintenance Practices:

Regular cleaning and proper maintenance can help preserve the color and appearance of flannel fabric. Removing dust and debris and addressing stains promptly can contribute to the fabric's longevity.

Dark vs. Light Colors:

Dark colors may be more prone to fading than lighter colors. If fading resistance is a concern, choosing lighter colors or patterns may be a consideration.

Indoor vs. Outdoor Use:

Fabrics intended for outdoor use are often engineered with additional features, including enhanced fading resistance. Indoor flannel fabrics may not be subjected to the same environmental stressors.

It's essential to consider the specific characteristics of the flannel fabric you're considering for your sofa and how it aligns with your expectations for fading resistance. 

Additionally, consulting with the manufacturer or retailer for information on the dyeing process, UV resistance, and care recommendations can provide valuable insights into the fabric's performance over time.

Ultimately, no fabric is entirely immune to fading, but selecting high-quality flannel and following proper care practices can help minimize the risk and prolong the vibrancy of the fabric.