Dose = irradiance × time
UV dose (fluence) is the ultraviolet energy delivered per unit area: irradiance at the target, in milliwatts per square centimetre, multiplied by exposure time in seconds, giving millijoules per square centimetre (mJ/cm²). It sounds elementary, and it is — the engineering difficulty is that neither factor is a single number in a real product. A dose claim in an enquiry names the point it is stated for — the design's own worst-case point among them.
Log reduction: what the dose is buying
The 40 mJ/cm² reference point
One reference figure recurs in drinking-water specifications: 40 mJ/cm² — the validated dose for NSF/ANSI 55 Class A point-of-use systems: ANSI's published summary of the standard's 2024 edition states the classification in one line — "Class A systems (40 mJ/cm2)". A specification that names a design dose states the point, the water quality and the flow it is quoted at, and the source-life basis behind it.
Water quality changes the arithmetic
UV transmittance (UVT) is the silent variable: the water's quality is a stated design input, not a discovery to make after launch. State the minimum UVT of the application water in the enquiry, and state whether the worst-point irradiance figures the design works to are computed or measured through that water — and in what test water, where a test basis is used.
Flowing water: exposure time from flow
For a flow-through design, state the flow rate, the chamber volume and the dose target in the enquiry; which device class answers those figures is established per model in that exchange.
Static water: exposure by cycle
Stored water inverts the problem: contact time is set by the hygiene cycle rather than by flow. Sizing uses tank volume, emitter placement and the duty cycle, stated in the enquiry alongside the dose target.
End-of-life and monitoring discipline
The sizing basis is stated in the enquiry: end-of-source-life output, not day-one output — for LED modules, the rated life point of the device class (company news describes Jason's mass-produced 10 mW line as rated at 10,000 hours — a company-published figure).
What the enquiry states
- The target organisms and the log credit the design names.
- The design dose (40 mJ/cm² — the NSF/ANSI 55 Class A validated dose — is one such figure) and the worst-case UVT.
- The regime the product runs — flow or static — with the flow or tank figures behind it.
- The end-of-life output basis the sizing assumes, not day-one output.
- The monitoring or replacement provision the design carries.
Ask what is recorded per model for the class you are sizing with, and bring the flow or tank figures to the enquiry.
Reference frameworks
The 40 mJ/cm² figure is stated directly in ANSI's summary of NSF/ANSI 55-2024 — "Class A systems (40 mJ/cm2)", in its words. The company's published chip range runs 255–340 nm, with the main production bands at 260–320 nm. The company's published lines pair those chips with disinfection modules and solution services for water, air and surface equipment. The company's own record at these bands runs from the UV LED production line it built on its own equipment in 2010 — the line that first produced 280 nm — to application products commercialised by 2012.
Worked example: a static reservoir
Take a dispenser reservoir of a few litres, treated by a static module on a repeating hygiene cycle. The example's design dose is set at the 40 mJ/cm² reference figure. Suppose the irradiance from the module window averages — over the volume's worst region, through the specified water quality — 0.2 mW/cm² at that worst point. The cycle time then follows by division: 40 ÷ 0.2 = 200 seconds, about 3.3 minutes. If the worst-point irradiance is lower — 0.05 mW/cm² in a larger or less clear tank — the same arithmetic gives 800 seconds, about 13 minutes. The levers, if the cycle must shorten, are placement, emitter count, and water path clarity. The example is illustrative rather than a product specification; for a real design, state the tank figures in the enquiry and ask what irradiance figures are recorded for the named module model.
Validation: proving the dose, not asserting it
Calculation is not validation. Buyers planning a validated product should say so at enquiry stage, and name the module configuration, monitoring provision and documentation the protocol will require.
Dose in standards language
The component supplier's part stays bounded: per-model ratings confirmed in the enquiry exchange; the compliance file itself, and the validation behind it, belong to the finished product and its maker. In this catalogue, the module classes a sizing conversation names are the six catalogued module products — a static water module, two lamp-tube module types, a light-bar set of four bars, and the J801 and J804 models.
Keep the dose file with the product
Finally, a housekeeping rule: retain the dose basis — target organisms, design dose, worst-point calculation, end-of-life assumption and validation result — in the product's technical file for its whole market life.
Stating a dose requirement in an enquiry
An enquiry names the target organism set and log credit, the design dose, the worst-case water quality the product must answer, the regime — flow or static — with the flow or tank figures behind it, and the end-of-life basis the sizing assumes. It asks what irradiance figures are recorded per model for the device or module class being sized with, and under what conditions they were recorded. The catalogue behind those module classes is the company's own: chips across 255–340 nm with more than 1,000 standard models, eight SMD package models in the 3535 and 6868 families, and the GaN MOCVD equipment line the company was founded to build. Company-published figures describe a team of 300+ people, 200+ patented products and 60+ customer application cases.
The tank figures behind a static dose
For a static product, the enquiry carries the tank figures the dose arithmetic runs on: the volume and material of the tank, the module mounting position the design allows, the target hygiene cycle, the water's expected quality range and any potable-water requirements the product must meet. The same message states the design dose and the end-of-life basis the sizing assumes. Quantities and programme timing belong in the same message.
The module side of a static design, in this catalogue: the module list names a static water module among six module products, and the published catalogue keywords name a water-tank sterilization module separately. Which model sits behind a given tank product is confirmed per model in the enquiry exchange. Water purification is the first of the company's published application case categories.