comunque tutta la documentazione tecnica disponibile in rete indica che la massima resa dei tubi T5 la si ha a 35° C (temperatura aria circostante i tubi)
http://www.narva-bel.de/en/Products/...bHA8pyHG0g7pYC
"Lamps LT-T5 of the EQ and HQ series reach their maximum luminous flux at 35 °C of ambient temperature"
http://ecmweb.com/ops/electric_fluorescent_lamp_coming/
"One result of enclosing a smaller lamp with a relatively high output in a smaller fixture is heat — and lots of it. For that reason, the T5 lamp provides peak light output at 35°C (95°F) air temperature, whereas the T8 and the T12 lamp provide peak light output at a 25°C (77°F) ambient air temperature. Thus, in an indirect luminaire, where there is little or no air circulation, the T5 lamp can have a higher lumens-per-Watt efficacy than a T8 lamp of about the same wattage because of this thermal characteristic"
http://www.osram.com/_global/pdf/Pro.../130T015GB.pdf
"So the light output and the life time of the lamp were designed from the
beginning to an optimum of up to 104 lm/W. The maximum luminous flux of
the T5 lamps is at 35 °C"