Capiscum

Thanks bankruatsteve. I have some confidence that fire is not an issue, especially after topping the downlight system with a dummy batt and seeing that the heat around the point of contact was not too intense. But I am no expert, so it is good to hear your take on the fire issue also. My secondary concern is about significantly decreasing the life of the bulb if the immediate area gets too hot, however I am hopeful that the air space around the bulb will be sufficient for reasonable heat dissipation to occur. Big thanks to all those responded.

Thanks Yellowtail, good point, however the insulation has already been put in place. One of the 2 upstairs rooms cannot be accessed from above (flat roof directly above) and so the ceiling would have to be opened up from below and the batts removed, with holes cut into the batts, and then replaced. SimpleMan555's post above seems like a simple solution.

Many thanks for the responses, I appreciate the time taken to reply. I have a further question on the topic of insulation, but in combination with LED down lights. I have read forum posts on TV with regard to SCG Stay cool and flower pots etc, making space for heat to dissipate from down lights. The 15 cm Stay Cool batts that I had installed do not sit directly on top on the ceiling, they are propped up somewhat by C-lines and other struts. Although they are not exactly flush, they prevent a lot of heat coming through. Soon the new downlights will be hooked up, however I have read that LED bulbs lifespan is shortened by over heating. Here is a poor sketch of what the situation will look like: Here is a picture of the downlight itself getting tested out (just on the floor, not yet in the ceiling). The height of this set-up is about 8 cm. Another shot of the downlight (is the black rectangle the driver?) My question is this - if the aluminum encased SCG batts sit on top of the ceramic cap, will that cause excessive heat build up in the bulb ? The heat sink area was too hot to touch for more than a second, however the black ceramic cap was quite cool. I believe aluminum and fiberglass have melting points of above around 500°C, so I don't think combustion is an issue, but I would like to hear others thoughts on this. There will be plenty of air space on all sides of the bulb, the batts only sit above the bulb. I tried to do a test by placing some foil directly onto the ceramic cap, and then weighing it down somewhat to mimic a batt laying on top: The area of contact between the top of the ceramic cap and the foil did not seem very hot, but I only ran this for about 30 minutes and the box was not overly heavy. The hottest area of the bulb is about 3-4 cm from the foil above. One option could be to place an object like an aluminum cup (or 2) not far from the bulb, in order to prop up the batt and allow a little more air flow over the top of the ceramic cap: Not sure the workers doing the renovations have dealt with down lights and insulation in combination before. With no renovating/building experience myself, I am not sure if I am being overly cautious/concerned or not cautious enough. Any thoughts or suggestions would be gratefully received.

Have just had some SCG Stay Cool ceiling insulation installed, but some of the ends of the foil bags are not sealed. How likely are fiberglass particles to suspend into the air ? We have bathroom vents, that vent into a service shaft (it is a condominium). This space connects to the ceiling space. Any thoughts from the seasoned DYI folks out there? many thanks