Test Parameter	Description	Tolerance
Total Spectral Irradiance	Sum of energy for all spectral bandwidths at a target irradiance level on the test profile (diurnal curve or constant irradiance).	±4 percent or ±15 W/m² (whichever is greater) of the target irradiance.
Spectral energy Distribution	Energy within each spectral bandwidth at a single measurement point.	See Table 505.7-I tolerance for each bandwidth.
Irradiance Uniformity	Deviation between the measured and target irradiance at all measurement points on the target plane. The number of points shall be adequate to define irradiance variation across the target plane(s) to meet the specific test requirement.	±10 percent deviation from the target irradiance
Instrumentation	Pyranometer, pyrheliometer, or radiometer	See Annex B
Temperature	Chamber control	±2 °C (±3.6 °F)
Air Speed	Across the test item	1.5 to 3.0 m/sec (300 to 600 ft/min)