GB/T 22505-2008 English PDF (GBT22505-2008)

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GB/T 22505-2008: Inspection of grain and oils -- Sensory analysis environment-lighting
GB/T 22505-2008
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 67.040
B 20
Inspection of Grain and Oils - Sensory Analysis
Environment - Lighting
ISSUED ON: NOVEMBER 4, 2008
IMPLEMENTED ON: JANUARY 20, 2009
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the People’s Republic of China;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Terms and Definitions ... 4
3 Lighting Quality ... 5
4 Illuminance ... 5
5 Installation of Lighting Equipment ... 5
6 Maintenance of Lighting Equipment ... 6
Appendix A (normative) Light Color Quality Characteristics of Lighting for Grain and
Oil Inspection ... 7
Inspection of Grain and Oils - Sensory Analysis
Environment - Lighting
1 Scope
This Standard specifies the lighting quality, illuminance, installation and maintenance of
lighting equipment for the sensory inspection of grains and oils.
This Standard is applicable to the lighting for the sensory inspection of grains and oils.
2 Terms and Definitions
The following terms and definitions are applicable to this document.
2.1 North Sky Light
North sky light refers to the skylight seen from the north window that avoids direct sunlight
from 3 h after sunrise to 3 h before sunset.
2.2 Color Temperature
When the chromaticity of the light source is the same as that of a perfect radiator at a certain
temperature, the absolute temperature of the perfect radiator is the color temperature of the light
source. The symbol of color temperature is Tc and the unit is K.
2.3 General Color Rendering Index
General color rendering index refers to the average value of the special color rendering index
of the light source to the 8 colors specified by CIE, and the symbol is Ra.
2.4 CIE Standard Illuminants
CIT standard illuminants refer to a specific relative spectral power distribution incident on an
object as specified by CIE.
2.4.1 Standard illuminants A
Standard illuminants A refer to a perfect radiator with an absolute temperature of 2,856 K in
accordance with the international practical thermometric scale.
2.4.2 Standard illuminants C
Standard illuminants C refer to the average daylight with a correlated color temperature of about
6,774 K.
2.4.3 Standard illuminants D65
Standard illuminants D65 refer to the average daylight with a correlated color temperature of
about 6,504 K.
2.4.4 Standard illuminants D55
Standard illuminants D55 refer to the daylight with a correlated color temperature of about 5,503
K.
2.4.5 Standard illuminants D75
Standard illuminants D75 refer to the daylight with a correlated color temperature of about 7,504
K.
2.5 Illuminance
Illuminance is the luminous flux incident on a surface element at a point on the surface divided
by the area of the surface element, and the unit is (lx), 1 lx = 1 lm/m2.
3 Lighting Quality
3.1 Characteristics of Standard Lighting
It shall be equivalent to the color temperature and spectral distribution of north sky light. See
Appendix A for the specific requirements.
3.2 Requirements for Light Source
3.2.1 Correlated color temperature: 6,500 K  200 K.
3.2.2 General color rendering index: higher than 75.
3.2.3 The spectral distribution shall be as close as possible to the CIE standard illuminants D65
(Appendix A).
4 Illuminance
The illuminance on the surface of the entire inspection working area shall be within the range
of (750  100) lx, and the maximum shall not exceed 1,000 lx.
5 Installation of Lighting Equipment
5.1 The light source shall be able to provide the required lighting quality and illuminance.