Disinfection CT Value Calculator
CT is the product of disinfectant concentration and contact time, and it is the only dose measure that treats a strong disinfectant and a weak one correctly: 2 mg/L for 30 minutes and 1 mg/L for 60 minutes deliver the same CT. Supply the residual concentration and the contact time to get the achieved dose, and a required CT from your disinfection reference to get the margin and the contact time the design needs. No required CT is built in, because the value depends on the organism and the jurisdiction.
Design parameters
The residual concentration and the contact time give the achieved CT on their own. The required CT is optional and is yours to state from the reference for your target organism.
Basis and limits
- CT = concentration × time. That equality is the reason CT is used: a weak disinfectant held longer is dosed the same as a strong one held briefly.
- A required CT is an engineer input. No organism and temperature table is built in, because citing the wrong one turns a credit into a false one.
- Zero residual gives CT of zero. Contact time by itself disinfects nothing.
- UV has no CT value. A UV dose is a separate calculation.
Workspace
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