Safe distance for t5

I was wondering what the safe distance for a couple 54w T5 bulbs would be. I have them just about 3 inches away right now. I can also turn on 6 bulbs. Would this change the distance? The temperature is cool, just about 70-80F right under the bulb.

How about 600w HPS? Could the light be about 7 or 8 inches away from the top branches? The temperature would be stabilized around 80F during flowering.

3" the more light the better

Keep my t-5's about 1.5" away and have the fan blowing right into the canopy

i had mine less than an inch away and the leaves where touching the lights

3 days later they died

keep them about 2-3 inch away

dont bring the t-5s closer than 3" from the top of your plant. mh and hps lights have to stay a considerable distance away. just keep in mind the ideal temp for growing is 75f during the day and 65f at night. slight temp fluxes r ok, but dont let the temp rise above 80f.