Table 5.

Uncertainty budget for luminous intensity measurements

Source of uncertainty		Relative standard uncertainty (%)
		Type A	Type B
Illuminance Responsivity
	Scale uncertainty from Table 2		0.19
	Measurement noise	0.02
	Filter absorption		0.006
Lamp to Photometer Distance
	Size and construction of lamp		0.06
	Physical distance measurement	0.01
Geometrical
	Photometer transverse placement		a
	Photometer orthogonality		0.002
Lamp Operation
	Current regulation		0.03
	Aging (per hour)		0.1
Combined standard uncertainty		0.23
Expanded uncertainty (k = 2)		0.46

^aToo small to list.