well sir does candel fire emits IR around 1-2um? I'm not familier with physics laws you mentioned.I think your best bet is to look at wavelengths around 1-2 um. According to Incropera and DeWitt's Fundamentals of Heat and Mass Transfer there's very little emission under 2 um for bodies at 300 K.
All materials emit all wavelengths, but there's a characteristic peak that's a function of temperature alone. For room temperature objects, it looks like the peak is around 10 um. For a candle flame, 1-4 um.
thankyou very much both of you sirsYes, with a typical candle color temperature of about 2000k, by my calculations 2um should be reasonably close to the peak wavelength emitted.