View Full Version : Direct Fire Kettle Question.....

2 Kilts Brewery
05-09-2011, 04:07 PM
Hey Guys,

We have a 8.5 barrel direct fired kettle that we are close to going into operation with. No matter who I talk to I cant seem to get a straight answer on what diameter pipe to vent the burners with and if it must be double wall, or some type of approved vent pipe. I was temped to just run 8 or 10 inch Type B Gas Vent but thought I would check here first.

Please advise? Peak burner BTU's is 450,000. Although when testing we never had to run anywhere near full throttle.

Thanks in advance for any thoughts or suggestions.



Capt. Bob
05-09-2011, 07:16 PM
Check with your local building inspector. We installed 6inch under the advise of the company installing the gas hook-up and had to replace with 8 inch per county code for 400K BTUs. We were not allowed to install ourselves. Had to hire a licensed contractor, also per code. Too big is also a no-no. You will want Type B double wall. Here's a good reference.

05-09-2011, 08:34 PM
Absolutely B vent.
Without calculations in front of me, I am thinking 8 inch. Check with the burner supplier. Design for full throttle. My CA building inspectors didn't care who installed it-luckily!
Don't forget the combustion air requirement, and know that a barometric dampener when correctly installed will help immensely.

05-11-2011, 06:51 AM
Every application is different and can be dictated by local code and/or manufacturer's specs. We have a 10bbl direct-fired kettle from Premier that uses a 300k BTU forced-air burner. Per Premier, we used 8" double-walled stainless ducting rated to 1000 deg F. If your exhaust temps are greater than 550 deg F after leaving the burner chamber, Type B, which uses an aluminum inner wall may not be suitable. I'd try to pin down the maximum exhaust temp where your ducting will connect to the kettle. Also, most installations I've seen that have 400-450K BTU burners use 10-12" exhaust ducting.

2 Kilts Brewery
05-11-2011, 08:17 PM
Thanks to everyone who posted. We are going to run 10" B Vent. Problem solved. Thanks to the Pro Brewer community. As always, a wealth of knowledge here.



09-18-2011, 08:16 AM
We just install a new kettle with 2 - 400,000 BTU burners. For both to exhaut into a single vent, we went with double walled 16". With one 450,000 BTU burner. Safe would be a 10" vent for a single burner.