UV Intensity Comparison: Low-pressure vs Medium-pressure UV Lamps

Their UV intensity cannot be directly compared. We need to distinguish peak irradiance, 254nm monochromatic output, total UV radiation and energy efficiency.

Spectrum

Low-pressure lamp: quasi-monochromatic light, main peak at 253.7 nm.

Medium-pressure lamp: polychromatic spectrum ranging from 200–400 nm.

Power density & peak irradiance

Medium-pressure lamps have much higher power density (30~100 W/cm vs 1~3 W/cm), so the near-field UV peak intensity is far higher.

Energy efficiency at 254 nm

Low-pressure lamp: 30%~38% electrical power converted to 254nm UV.

Medium-pressure lamp: only 7%~12%.

Under the same power input, low-pressure lamps generate more 254nm germicidal UV.

Disinfection characteristic

Medium-pressure broadband UV can suppress microbial photoreactivation; low-pressure UV cannot