1. The exposure from any single pulse in a train of pulses shall not exceed the exposure limit value for a single pulse of that pulse duration. 2. The exposure from any group of pulses (or sub-group of pulses in a train) delivered in time t shall not exceed the exposure limit value for time t. 3. The exposure from any single pulse within a group of pulses shall not exceed the single-pulse exposure limit value multiplied by a cumulativethermal correction factor Cp=N-0.25, where N is the number of pulses. This rule applies only to exposure limits to protect against thermal injury, where all pulses delivered in less than Tmin are treated as a single pulse. Parameter Valid spectral range (nm) Value Tmin 315 < λ ≤ 400 Tmin = 10-9 s (= 1 ns) 400 < λ ≤ 1050 Tmin = 18 - 10-6 s (= 18 μs) 1050 < λ ≤ 1400 Tmin = 50 - 10-6 s (= 50 μs) 1400 < λ ≤ 1500 Tmin = 10-3 s (= 1 ms) 1500 < λ ≤ 1800 Tmin = 10 s 1800 < λ ≤ 2600 Tmin = 10-3 s (= 1 ms) 2600 < λ ≤ 106 Tmin = 10-7 s (= 100 ns)
