Advice on Venting through the wall

[CG901]

I just bought a used Diedrich IR2.5 (2012) and am going to place it in my garage / shop for home roasting. For venting, Diedrich recommends manufacturers like Selkirk Sure-Temp, etc. My question is what is the most efficient way to vent. Ideally, one would use positive pressure double walled pipe which is fine for a commercial operation. Mine will be used for an hour or two every 3-4 weeks. That aside, to go vertical and through the roof, a series of 30 deg elbows is required to achieve 90 dgrees, some straight pipe, then a roof kit. This is possibly the best way but is it? I have seen a short horizontal pipe through the wall, then a short 90 degree elbow. Ths would not elevate the stack to roof or chimney height, but is that necessary unless you are in a production environment? Aside from my city's residential permitting process and building codes, for the best roaster operation and efficient airflow, does a short horizontal pipe get it done? Is a 90 degree elbow, then go vertical 12 ft more efficient? I don't expect to find HVAC engineers amongst the roasting community, but wanted to avoid having to hire an HVAC consultant. Thanks!

 

[BoldJava]

...Ideally, one would use positive pressure double walled pipe which is fine for a commercial operation. Mine will be used for an hour or two every 3-4 weeks...

That is advised not because of the size or roasting volume but rather in case of fire. Any time you are going through wood, it is advised. If a roast ever gets away from you, the double wall stainless will contain the fire, withstanding 1000.* Will save your garage. Spiral Manufacturing - Dual Wall Insulated Spiral Pipe & Fittings

Suggest posting on an HVAC forum for advice on the remainder of the questions you are asking (angles, runs, elbows, etc).

 

[sae]

whoever you buy the selkirk sure-temp from will be able to consult with the company and they can crunch the numbers to make sure it'll work.

 

[Hankua]

One issue not related to fire is the draw or negative pressure in the exhaust. I found this out last year as my temporary setup is next to a flat 30' north wall at home. In addition the roasting room has a slightly negative pressure than can pull the air in instead of out. When it's windy the air turbulence can change the pressure near my exhaust as well; affecting the roast dynamics.

Personally I'd just stub out the wall with a 90* and put a stainless rain cap on. (available from a fireplace/stove vendor)

Its good to have some sort of fresh air intake/ventilation in your roasting area.

 

[CG901]

One issue not related to fire is the draw or negative pressure in the exhaust. I found this out last year as my temporary setup is next to a flat 30' north wall at home. In addition the roasting room has a slightly negative pressure than can pull the air in instead of out. When it's windy the air turbulence can change the pressure near my exhaust as well; affecting the roast dynamics.

Personally I'd just stub out the wall with a 90* and put a stainless rain cap on. (available from a fireplace/stove vendor)

Its good to have some sort of fresh air intake/ventilation in your roasting area.

Thanks for all the great suggestions. I decided to go with a straigh 4 ft section of Selkirk Sure-Temp UT which will go directly out the back of the cyclone horizontally through the wall and protrude about 2.5 ft. The tip is on the downwind side of the building, so little chance of wind entering and creating a backdraft. I will not use a 90 deg elbow with a rain cap on the end. I should have zero pressure build up since I am not using elbows or long sections of pipe to exit on roof level. I think this is a good compromise.

 

[expat]

You're probably doing this but just in case you're not . . . make sure to put some kind of screen on your exhaust pipe so that birds can't nest in there. This happened to me when we first set up our roaster. We got things set up and got busy and forgot about covering the end of the exhaust pipe and within a week we had a big nest in the pipe.

 

[peterjschmidt]

Gotta roast more frequently, Expat!