Rocket Heater Stovepipe Clearances

Hi Everybody,  I'm installing a 4" Dragon Heater Barrel Build in my little wooden house. The standard clearances for the single-wall stovepipe seem excessive for a rocket heater; and I need to save space. I'm imagining the usual clearances are based on pipes running 500 degrees or more, and that mine will be closer to 200 or less. Can anyone point me toward some information to help me work this out?

I'd also really love to vent it out the back wall at a 45 degree angle; but I've been told that would be asking for trouble.

Thanks for your time,
Sam

Hi Sam;  Welcome to permies!

I can't recommend this but... I did it... my exhaust pipe temps are 130 F or less no matter how long or hot the stove runs ... I have them passing  within an inch of wooden studs.  They have been this way now for over 5 years and there is zero sigh of pyrolysis happening.
Like I said I won't recommend doing it but... If you skin a piece of metal sheeting over any wood products, leaving an air gap between you should not have any issues.

Sam Del Vecchio wrote:Hi Everybody,  I'm installing a 4" Dragon Heater Barrel Build in my little wooden house. The standard clearances for the single-wall stovepipe seem excessive for a rocket heater; and I need to save space. I'm imagining the usual clearances are based on pipes running 500 degrees or more, and that mine will be closer to 200 or less. Can anyone point me toward some information to help me work this out?

I'd also really love to vent it out the back wall at a 45 degree angle; but I've been told that would be asking for trouble.

Thanks for your time,
Sam

In most cases, your home insurance would have the final word on this. If you don't have insurance, then I would personally consider sticking to the WETT standards.

The WETT standards call for 18" clearance to combustibles for single wall pipe, but this can be reduced significantly by installing a heat shields to protect combustibles that breach this clearance. An acceptable heat shield is a piece of 26ga sheet metal with a 1" space between it and combustibles. They are easiest installed by using 1" pieces of copper pipe as spacers and putting a screw through the sheet metal and copper pipe spacer install the wall behind. The heat shields have to be somewhat vertical so that air flow can happen behind (ie, warm air exits the top pulling cold air in from the bottom).

The whole reason for all this is to manage catastrophic events - for instance, if your stove isn't operating correctly, or there's a spot you can't clean out that catches fire in the pipe some day... perhaps all very unlikely with a rocket heater, but it would help me sleep at night.