Engineering Strategies for Airborne Diseases

H V A C S Y S T E M S T R A T E G I E S

AIR DISINFECTION – UVGI DISADVANTAGES

Material Degradation

Some materials degrade under UVC. Sealants, filter material and filter supports can be impacted on HVAC system. • Organic filter fibers and Hepa filters have an average of 5-6% weight loss versus fiberglass filter weight loss of 25% • Other than structural damage, polyester filters may crumble to the touch and lofted fiberglass may irritate eyes (fibers becoming airborne within ductwork) under UVC exposure. • UVC resistance ratings shown on Table 8 per ASHRAE RP-1509:

A – No effect (aluminum tape, all organic materials experience mass loss)

B – Minor Effect (mainly cosmetic changes)

C – Moderate Effect (some cracking/pitting)

D – Severe Effect (structural damage, not recommended)

Courtesy of Table 8, ASHRAE RP-1509