wrote:

I heard that GU10 230v lamps throw the heat forwards and other types,
including LV, throw the heat backwards. The forward throwing type is
better for fire safety in ceilings.

There are several issues here...

there is the issue of how much heat is generated by the fitting/bulb.
This tends to be more of a problem with reducing the life of the bulb
and transformer rather than being a direct fire risk IIUC.

(You are correct that the bulbs with aluminium reflectors tend to
project more IR forward. The dichroic ones will let more reach the
fitting (hence the fitting has to be designed to be able to take it).
You can get dichroic bulbs in both 240V and 12V).

Building inspectors are getting shirty about downlighters in ceilings,
wanting fireproof boxes around them. If a lamp throws heat forwards
then the fire aspect should not be an issue.

The more significant fire issue in many cases, is that fitting down
lighters requires a large(ish) hole be cut in the ceiling. This in many
cases breaching a fire resistant layer (i.e. the skim/plasterboard)
between habitable rooms. In these cases an intumescent hood can be
fitted to restore the integrity of the fire block.

Does anyone know what lamps are more safe than others in this respect?

Hard to choose on safety grounds... with a downlighter of any sort you
need enough space behind it. Given that the bezel of a non dichroic bulb
may get hotter, and hence be more of a touch hazard (if the ceiling is
low enough), I would lean toward the dichroic bulb. On aesthetic grounds
the dichroic bulb wins on several counts.

--
Cheers,

John.

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