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The
Use of Reflectors with Compact Fluorescent Lamps
(1)
Dome Reflectors and Brooder Lamp Fixtures
When
a compact fluorescent tube is fitted with a reflector, the
shape of the beam may be dramatically altered. We tested
both Arcadia and Zoo Med compact fluorescent lamps in three
different fixtures - an inexpensive polished aluminium dome
reflector, a brushed aluminium farmers' brooder lamp, and
a Zoo Med Clamp Lamp, which has a white porcelain interior
surface.
The
white porcelain Zoo Med Clamp Lamp
we used, with an 8.5-inch diameter dome, had very little
effect upon the output as measured from beneath the lamp.
The white porcelain interior does not, apparently, reflect
UVB light to any great extent.
However,
aluminium
surfaces appear
to be very efficient reflectors of UV light. Compact fluorescent
lamps have a comparatively large surface area. When most
of the light from all sides of such a lamp is gathered and
reflected downwards, as it is in a dome reflector, the resulting
beam may be extremely intense. In our trial, at all distances
between 6" and 22", the output was more than six
times greater beneath the lamp once either the
polished aluminium or brushed aluminium
reflector was fitted.
This
enormous increase in intensity is a mixed blessing and needs
to be handled with care. It might prove useful when supplying
UVB to sun-loving reptiles with high requirements. However,
it could well render the use of aluminium reflectors with
these lamps undesirable when housing some species of reptile
with lower UVB requirements.
We were
not able to test a brand new lamp in an aluminium reflector,
but we must consider the possibility that the combination
might produce a beam that is too intense for any reptile
at close range. We would therefore advise caution
in this case, if a UVB meter is not to hand.
(2)
The Arcadia Compact Lamp Reflector
 The
Arcadia Compact Lamp Reflector, (fig. 4) specifically designed
for the product, requires the lamp to be mounted sideways
in the vivarium. This has a screw-on plastic grille with
surprisingly thick bars, which fits over the front once
the bulb is installed.
We measured
the output of the Arcadia D3 Compact Lamp in the reflector,
both with and without the plastic grille in front of it.
We discovered that use of the reflector behind the lamp
effectively doubles the output of the lamp, as measured
from the front.
If
the grille is fitted, however, so much of the UVB (and visible
light) is then blocked by the thick bars that the output
is brought back to the same level as that of the bare lamp.
It is possible this effect was intended by the manufacturers;
there is no mention of the product increasing the output
of visible light or UVB on the packaging, instead it is
described as protecting the hobbyist from glare.
The
grille is, however, stated to protect reptiles from the
hot lamp. It is worth noting that all compact lamps do indeed
become hot during use. Using an infrared non-contact thermometer
we measured temperatures of 240 - 250°F at the base of both
Arcadia and Zoo Med compact fluorescent lamps.
The
temperature of the outside of the plastic Arcadia reflector
housing a working lamp was also measured. The hottest part,
behind the lamp, reached 1630F after 2 hours use. Clearly
these lamps do not provide sufficient heat to warm a vivarium,
but their heat output is not negligible.
Spread
Charts 2B and 2C
(above) show the Arcadia D3 Reptile Lamp with the Arcadia
Compact Lamp Reflector, both with and without the grille
on the front.
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Burning-in
of New Lamps
