Need help Planning Gas FP Venting

[Pamsfire]

If dialog below is to unclear I think I can figure it out using 45 degree distance if I knew the following:
1. What is the distance to subtract from the 45 degree distance for the two 45 elbows on each end?
Is 3.54" per 45 degree elbow correct?
2. What does using a 90 elbow add to the length? Is 7.3" on each end correct?
3. Is 1 1/2 subtracted from each pipe and elbow for joint overlap?
Venting for Kozy Heat Slayton using 5x8 double wall Selkirk venting. I need verification this routing will
work.(see attachment) It appears to meet the requirements in the Slayton install manual. I could
eliminate the second 90 elbow after the FP and replace it with two 45's if I could figure out the math.
I plan on using Selkirk as it fits with out an appliance adapter. I would like to use standard pipe if
possible, there is a 4-10" adjustable vent if necessary. 1" clearance from combustibles. Here are the
numbers necessary to do the math. horizontal from FP Vent connection O.C. through wall =18 3/4".
Horizontal from garage wall to center of 24" O.C. garage rafter is 43". Total horizontal run would
be from FP vent connection O.C. 18 3/4" +43"=61 3/4". Vertical from FP vent connection to bottom of
top sill on interior wall is 42 1/2". Add 3" for a double sill to 45 1/2" from FP to bottom of Garage rafter.
The garage rafters are 24" o.c. and run parallel to the FP.

 

[webby3650]

What is your reason for not wanting to use slip sections? It makes things so much easier, not to mention its often necessary to make the proper offset. This will be moved to the gas room shortly.

 

[Pamsfire]

What is your reason for not wanting to use slip sections? It makes things so much easier, not to mention its often necessary to make the proper offset. This will be moved to the gas room shortly.

If commonly used slip sections seem to be the answer. Having no experience with vent piping I thought slip sections were only used when there were no other options. What about flexible venting? That would solve all my problems. thanks tom

 

[webby3650]

The flex could only really be used if you were going up a few feet then straight out the wall to a horizontal termination. I'm not sure if the Slayton is approved for flex, we have installed a few, but we used rigid pipe straight up. Slip sections are very common, and it sounds like it is the answer to your problems.

 

[begreen]

According to the manual;

"For each additional 90° elbow used after first elbow, 3ft. (914mm) must be subtracted from maximum allowed venting. For each 45° elbow used, 1-1/2ft. (457mm) must be subtracted from maximum venting allowed."

The max horiz. distance will depend on whether this is nat gas or propane. Be sure to have adequate rise with the horizontal section. Keep it as short as possible and with proper clearances to any combustibles.