Mercury Vapour Lamps:
Osram UltraVitalux
 
broadband meter readings and thermal gradient  
iso-irradiance charts
spectrum - UV + Visible light
spectral analysis - photobiologically active UV

 

 

 

Lamp index :
 
 

Lamp Description

Osram UltraVitalux - also marketed under the brand name Radium Sanolux HRC 300-280
300watt, 230volt Self-Ballasted R40 mercury vapour lamp
Osram GmbH, Augsberg, Germany

Osram Ultravitalux 300-watt mercury vapour lamps are extremely powerful UV emitters which are used in industry for a wide range of paint curing and chemical processes, accelerated ageing and weathering tests. They have also been sold for many years as human tanning lamps, although recent European legislation governing the level of UV emission from tanning lamps has ended their sale for this purpose. Nevertheless, they have been used for upwards of 20 years as UVB lamps for reptiles in certain UK zoos, and are more widely used for this purpose in Europe, notably in Germany. Three different boxes in which these lamps have been sold are shown below.

Lamp refs: BO1,BO2,BO3,BO5,BO6,BO7 (2005-2011)

Broadband Meter Readings

 
UV Index (Solarmeter 6.5) and Total UVB (Solarmeter 6.2) readings)   (BO1)
New lamp (110h use)                                Distance from lamp surface (cm)
40
60
80
100
120
140
160
180
200
220
UV Index
41.1
19.3
11.1
7.1
5.0
3.7
2.9
2.3
1.9
1.6
Total UVB (W/cm)
583
275
156
101
72
53
41
33
27
22

These lamps have an extremely high, hazardous UVI output at distances under 1 metre. NB: the total UVB figures may not seem particularly high in comparison to natural sunlight. This is due to the high photoreactivity of the predominantly short-wavelength UVB emission (see spectral analysis, below).

Longevity
Decay (reduction in UVI with use) (BO1) (BO5)
105 h (10 days normal use) 31% 24%
4000h (1 year) - estimate* (BO3)
68%

*lamp BO3 acquired after 1 year of use; estimate assumes initial output identical to lamp BO1

Electrical consumption (BO2) (BO6)
292 watts 296 watts
Colorimetry (from spectral data)
  (BO2) (BO6)
CCT (human eye) 3416K 3380K
CRI (Ra) (human eye) 4.8 3.1

 

Thermal Gradient  (lamp to surface distance = 120cm)
Surface temperature (C) measured with infrared non-contact thermometer, on open bench.
Distance from lamp to bench = 120cm. Time to equilibrate = 2 hours


At distances with a reasonably safe UVB output, this lamp cannot be used to supply infrared warmth for basking. Additional heat lamps will be necessary.

(BO7)

Distance from central point directly beneath lamp
0 cm 5 cm 10 cm 15 cm 20 cm 3 m (room temperature)
White wooden block
22.6
22.3
21.9
21.8
21.4
19.1
Unpainted wooden block
23.1
22.5
22.3
21.9
21.6
19.1
Black wooden block
24.0
23.2
22.9
22.6
22.3
19.1

Iso-Irradiance Chart       
The iguana (S-V length 40cm) is drawn to the same scale as the charts and is placed so that its eye level is 110cm beneath this lamp. This is to enable comparison between charts,
not necessarily to indicate a suitable lamp distance. This will depend upon individual species requirements.

Spectrum - UV plus Visible Light

Spectrum - UV in more detail

This spectrum has:

  • typical features of a mercury vapour lamp: extremely discontinuous spectrum ("spikes") very unlike sunlight.
  • no detectable UVC, but detectable borderline non-terrestrial UVB (wavelengths below 290nm).
  • very high solar-wavelength (290 - 320nm) UVB output, restricted to "spikes" at 289, 296, 302 and 313nm. These wavelengths are involved in vitamin D3 synthesis.
  • low short-wavelength UVA output (320 - 350nm). These wavelengths are involved in the control of vitamin D3 synthesis.
  • high long-wavelength UVA output, but restricted to one "spike" at 365nm - reptile vision includes long-wavelength UVA.
  • Visible light spectrum (wavelengths 400 - 750nm) restricted to only four colours - very poor colour rendering.

Spectral Analysis - photobiologically active UV (wavelengths from 270 - 350nm)

  • Some of these lamps emit detectable borderline UVC (280 -282nm) and all emit small amounts of non-terrestrial UVB (below 290nm). (These spectra are typical examples of all six lamps tested.)
  • There is a high proportion of UVB in the wavelengths which enable vitamin D3 synthesis in skin.
  • However, unlike natural sunlight, the spectrum also falls well within the action spectrum for DNA damage there is a higher risk of significant DNA damage. The short wavelength UVB will doubtless stimulate rapid pre-D3 formation, but there are risks involved; in certain circumstances these could outweigh the benefits.
  • The proportion of UVA from 320 - 335nm, important for natural prevention of excessive vitamin D3 synthesis, is extremely low. The health consequences of this are as yet unknown.

 

      

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