Xenon Arc Light Fastness Testing ISO 105-B02
topic
Xenon arc light fastness testing (ISO 105-B02, AATCC 16) irradiates textile specimens under a xenon arc lamp with daylight-simulating filter (Suprax, Soda-lime glass combination filtering below 290 nm UV) maintaining specimen blackboard temperature 45 ±3°C and 40 ±5% RH at 0.51 W/m²/nm irradiance at 340 nm. Test chamber capacity: 12–24 specimen positions in rotating carousel (Atlas Ci4000, SDL Atlas Xenotest 220+, Q-Sun Xe-3) each holding one specimen (45 mm × 110 mm) in black card mask exposing half to light and protecting half for grey scale comparison. Exposure duration: specified in AFU (1 AFU = standard daylight exposure equivalent), kJ/m² at 340 nm, or hours. Standard exposure levels: grade 4 assessment: 20 AFU ≈ 200 kJ/m²; grade 6: 80 AFU ≈ 800 kJ/m²; grade 7: 160 AFU ≈ 1,600 kJ/m²; grade 8: 320 AFU ≈ 3,200 kJ/m². Blue Wool Standards (BW L2–L9, SDC, ISO 105-B01): dyed wool reference specimens scaled in light fastness 2–9 grade equivalent, used as concurrent exposure monitor to verify correct irradiance delivery — at correct exposure dose BW L4 should reach grade 4 boundary. Xenon arc lamp replacement: lamp output degrades 15–25% over 1,500 hours — radiometer monitoring at 340 nm with automatic irradiance compensation (xenon lamp dimming control) maintains constant irradiance ±2% — expired lamp replacement mandatory when compensation >30% to maintain test validity. Temperature-humidity effect on light fastness: high humidity (>60% RH) accelerates fading of some reactive dyes by 20–30% on cotton (hydrolytic acceleration); low humidity (<30%) reduces fading — humidity stabilisation in modern xenon chambers to ±5% RH critical for inter-laboratory reproducibility. AATCC 16 Option 3 (xenon arc, alternate wetting, 1.10 W/m² at 420 nm): different filter and irradiance standard than ISO 105-B02 — AATCC results not directly equivalent to ISO grade due to spectral and irradiance differences.
Role
Xenon arc light fastness testing is the accelerated laboratory simulation of outdoor sunlight fading — providing in 20–200 hours the exposure prediction that would require 6 months to 5 years of outdoor exposure to accumulate naturally, making xenon arc testing the essential quality gate for fashion, furnishing, and automotive textile colour approvals where seasonal design cycles require fastness data within weeks rather than years.