UV Required Intensity or Contact Time
Solves a target UV dose for whichever you are missing: intensity or contact time.
Example
You enter
- Target dose (mJ/cm²) 40
- UV intensity (mW/cm², 0 = solve for it) 10
You get
- Required exposure time 4.00 s
Checked against published worked examples from: ULTRAAQUA (UV system maker).
Details, formula, and sources
ScopeFrom a target dose, solve the operand you are missing - leave time blank for the required contact time (dose / intensity), or leave intensity blank for the required intensity (dose / time). A 40 mJ/cm^2 target at 10 mW/cm^2 needs 4 s of contact; at a fixed 8 s it needs a 5 mW/cm^2 lamp. USEPA UV Disinfection Guidance; the validated reactor dose and the state primacy agency govern compliance.
Formula or tablerequired_time_s = target_dose_mj_cm2 / intensity_mw_cm2; or required_intensity_mw_cm2 = target_dose_mj_cm2 / exposure_time_s (mW.s/cm^2 = mJ/cm^2).
Source and editionUSEPA UV Disinfection Guidance Manual (EPA 815-R-06-007) by name, the inverse of dose = intensity x time; no edition cycle.
Free accessThe dose relation is public; the validated reactor dose and the state primacy agency govern compliance.
What governsEstimate. Operator of record and primacy agency govern.
API field namestarget_dose_mj_cm2, intensity_mw_cm2, required_time_s
- Inverse relation time = dose / intensity, or intensity = dose / time; mW.s/cm^2 equals mJ/cm^2USEPA UVDGM
- Target a common validated target is 40 mJ/cm^2, editable to the validated reactor doseUSEPA UVDGM
- One unknown enter exactly one of intensity or time; the tile solves for the otherscope of this tile