Sign In

NMISA maintains a realisation of Coordinated Universal Time (UTC), called UTC (ZA), for South Africa, Eswatini & Lesotho. The current time is :  

South African Standard Time (SAST) is defined as UTC + 2 hours. The current time is : for South Africa, Eswatini & Lesotho. The current time is :

​​​​About

The Photometry and Radiometry section is responsible for maintaining the SI unit for luminous intensity, the candela, and to provide traceable radiometric and photometric measurements and calibrations in support of various industries and fields, such as: 

  • Lightin​​g

  • Aero​​space

  • Health a​​​nd Safety

  • Manufactu​​ring

  • Automoti​​ve industry

  • Agricult​​ure

  • Resea​rch

These measurements and calibrations impact aspects of everyday life such as energy-efficiency and quality of life. 

Key Facts​​​​​

The science of photometry and radiometry addresses the measurement of electromagnetic radiation. In more general terms, photometry concerns the measurement of light, i.e. the visible part of the electromagnetic spectrum. Measurements are performed in such a way that the response of the human eye to visible light is considered. Radiometry, on the other hand, concerns the measurement of electromagnetic radiation in the much wider spectral region ranging from the ultraviolet to the infrared part of the spectrum.

Photometric and radiometric measurements are important in a very diverse range of applications, including:

  • the lighting of homes, shops, factories, streets, and other public areas,

  • signaling for road, rail, sea and air transport,

  • process control in industries such as printing, plastics, textiles, paints, food, manufacturing and pharmaceuticals,

  • medical treatments such as phototherapy,

  • air and water disinfection,

  • curing of resins,

  • non-destructive testing (NDT),

  • earth-observation,

  • agriculture and

  • material characterisation.

​​As the number of applications increase, so does the need for increasingly accurate photometric and radiometric measurements of sources, detectors, and materials.​

The Photometry and Radiometry section offers measurement and calibration services that are categorised

  • Photometry

  • Properties of detectors (radiometry)

  • Spectral emission properties of sources (spectroradiometry)

  • Spectral properties of materials (spectrophotometry)

  • Spectrally integrated measurements for sources and detectors

Colour and other spectrally integrated measurements of materials (colorimetry). The Photometry and Radiometry section has close links with the International Commission on Illumination (CIE). This involvement is enhanced by participation in the activities of the Illumination Engineering Society of South Africa (IESSA) who represents the CIE in South Africa. IESSA keeps all stakeholders with interests in lighting and related matters informed of CIE recommendations and proceedings to ensure that the South African industry benefits from international developments. 

Furthermore, we participate in international key comparisons with other international laboratories, thereby maintaining the National Measurement Standards in photometry and radiometry as mandated through the Measurement Units and Measurement Standards Act (Act No 18, 2006) and assuring comparability internationally. Our internationally recognised calibration and measurement capabilities (CMC) are peer-reviewed and listed in the key comparison database(KCDB) of the International Bureau of Weights and Measures (BIPM).

We are also an accredited calibration laboratory with the South African National Accreditation Service (SANAS) according to the ISO/IEC 17025 international standard.

How we can help

The Photometry and Radiometry section can perform the following measurements and calibrations: 

Photometry:

  • Luminous intensity of sources 

  • Averaged luminous intensity of LED sources

  • Illuminance responsivity of illuminance/lux meters (photometers)

  • Luminous flux of sources

  • Illuminance of sources

  • Luminance of sources

  • Luminance responsivity of luminance meters

Properties of detectors:

  • Spectral power responsivity of broadband and black thermal detectors

  • Spectral irradiance responsivity of broadband and black thermal detectors

  • Spectral radiance responsivity of spectroradiometers

  • Optical/laser power responsivity

  • UV broadband irradiance responsivity (UV-A, UV-B, and UV-C meters)

Spectral emission properties of sources:

  • Spectral irradiance (various sources)

  • Spectral radiance (various sources)

Spectral properties of materials:

  • Spectral transmittance (regular and diffuse)

  • Spectral reflectance (-diffuse)

  • Spectral absorbance (regular)

  • Wavelength

Spectrally-integrated measurements for sources and detectors:

  • Correlated colour temperature of a source

  • Emitted colour of a source

  • Chromaticity response of a colorimeter

Colour and other spectrally-integrated measurements of materials:

  • Surface colour

  • Transmitted colour

  • Luminance factor​

Please check our SANAS schedule of accreditation for a list of accredited services:

https://www.sanas.co.za/Pages/index.aspx

We can also offer advice on your photometry and radiometry questions during product development or the research phase of your lighting or radiometry project. Please contact us to discuss your needs and how we can be of service.​

Development Proj​​ects

The development of measurement capabilities and standards that support industry is a key component of NMISA’s mandate in order to keep up with global developments.
 
Energy Efficiency – Solid state lighting
 

The Photometry and Radiometry section is developing measurement capabilities for light-emitting diode (LED) products that serve as energy efficient light sources. The move towards LED lighting is propelled by its high efficiency which promises savings in terms of energy and cost. In order to support the local lighting industry, accurate LED measurement methods and standards must be developed to ensure that its performance can be assessed correctly. The development and implementation of a national measurement capability for LED products to support the energy saving drive in South Africa is one of NMISA’s top priorities. The Photometry and Radiometry section can currently measure the following properties of small to medium-sized LED products:

Photometric and radiometric

  • Spectral power distribution

  • Spectral radiant/luminous flux[IR1] ,

  • Radiant/Luminous flux

  • Chromaticity coordinates (x, y), etc.,

  • Correlated colour temperature (CCT),

  • Colour rendering index (CRI),

  • Luminous intensity,

  • Averaged LED luminous intensity[IR2] [PDT3] ,

  • Irradiance/Illuminance,

  • Radiance/Luminance, 

  • Peak/Centroid/Dominant wavelength,

  • Purity,

  • ​Half width

Electrical
  • RMS current/voltage,
  • Power factor,
  • Luminous efficacy
Quality of Life – Improved NMS for UV radiometry

​​Staff members are also involved in various other development projects under the NMISA’s Quality of Life Programme. One of these projects is the improvement of the national measurement standards (NMS) for ultraviolet (UV) radiometry. Through this project, the NMSs and measurement capabilities for spectral irradiance and spectral responsivity are being extended into the UV. UV is an important tool in medical applications due to its disinfection properties and is used in UV germicidal irradiation (UVGI) devices to prevent the spread of infectious diseases. The need to accurately measure the UV content of lighting products is also important to ensure the safety of room occupants.

The Tea​m

​​Name and Surname
​Designation​ ​Email ​Telephone
Dr Liesl Burger
Section Head:Photometry and Radiometry
lburger@nmisa.org
+27 12 947 2782
Rheinhardt  Sieberhagen
Scientist:Radiometry and Spectroradiometry
rsieberhagen@nmisa.org
+27 12 947 2857
​Edwin Mofokeng
Scientist:Spectrophotometry and LED Radiometry
emofokeng@nmisa.org
+27 12 947 2747
Irma Rabe

Scientist: Photometry, Colorimetry, Radiometry

irabe@nmisa.org
+27 12 947 2763
​Pieter du Toit​

Scientist: UV Radiometry and Spectroradiometry
pdutoit@nmisa.org
+27 12 841 2846
Macdufe Mkabela 
Scientist:Spectroradiometry, UV Radiometry and Photometry​
mmkabela@nmisa.org​ 
+27 12 947 2790
Damian Nagura​
Engineer:Photometry and Radiometry
dnagura@nmisa.org
+27 12 947 2731

Events​

The Photometry and Radiometry section is actively involved in the local standardisation process and provides guidance on measurement methods in SABS technical committees.
 
Meetings for the LED Working Group of the SABS technical committee on Lighting and Optics (TC0064/SC01/WG01) are held at NMISA. For more information please contact the convenor pdutoit@nmisa.org.
 
We are also a member of the SANAS specialised technical committee (STC) on Photometry and Radiometry.
 
Industry and stakeholders are invited to technical advisory forums (TAFs) which inform the industry about our measurement capabilities and projects to keep NMISA’s goals in line with the industry’s measurement needs. The previous P&R TAF took place on 23 January 2019 https://en-gb.facebook.com/events/267479323959255/​

Conta​​ct

Email us at pr@nmisa.org