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I believe that I can use the formula for conductive heat loss for a pipe or cylinder which is:

q = 2 π k (to - ti) / ln(ro/ri)

It’s a 6” diameter steel steam pipe with an uncoated surface temperature of 130 °C

After coating the pipe the temperature was reduced to 108 °C

I think the thermal conductivity of the steel pipe is 68 W/mK (should K be converted to °C?...and how would I do that?)

In South Africa we work in Watts and Kilowatts and °C and not Btu’s, °F or K.

I need to see how this formula works in a step-by-step calculation so that a ‘dumb ass’ like myself can understand it, explain it and use it again in future.

I’m also wondering how heat loss through radiation would come into the equation here?

This formula has caused me even bigger headaches which is:

P = ε б A (T⁴ - T⁴c)

It uses the Stefan Boltzmann constant which is: б = 5.6703 × 10⁻⁸ watt / m² K⁴

The emissivity of the steel pipe is 0.32 ...or is it 0.95? And what should the emissivity of the coating be...I would imagine, much closer to 0.1?

This formula will also require a step-by-step calculation in order for me to understand it.

If anybody on this forum is able to help and has the time to do so, the input will be greatly appreciated.