PEC EPE Textile cheat sheet
PEC EPE Textile · Keep the key ideas within reach.
Textile Engineering
Yarn count conversion: English cotton count (Ne) = 840 yd/lb; Tex = 590.5 / Ne; Denier = 9 × Tex; 1 Tex = 1 g/1000 m.
Twist multiplier (TM) = turns per inch (TPI) / √Ne; TM = TPI / √(cotton count). For metric: TM = TPM / √(Nm).
Fabric cover factor (K) for woven: K = (threads per inch) / √(yarn count in Ne). For plain weave, K_fabric ≈ K_warp + K_weft − (K_warp × K_weft)/28.
Tensile testing: breaking strength (N) = (load at break) / (linear density in tex) × 1000 for tenacity in cN/tex; tenacity (cN/tex) = (force in cN) / (tex).
Color measurement: K/S = (1−R)² / (2R) from Kubelka-Munk; reflectance R is measured at λmax; color strength (K/S) proportional to dye concentration.
Fabric drape coefficient = (projected area of draped fabric − area of supporting disk) / (area of specimen − area of disk).
Air permeability (mm/s) measured at 100 Pa pressure differential; depends on fabric porosity, thickness, and yarn twist.
Pilling resistance rated 1–5 (5 = no pilling) using Martindale or Random Tumble testers; pilling increases with loose fibers and low twist.