NCB240 PVC elbows

[Jrv]

On the exterior intake/exhaust piping does it matter if long sweet or street 90s are used? Does one restrict airflow more than the other?
Thanks

 

[Fitter30]

3" PVC ell 7.9'
Long sweep 11.1'
https://www.engineeringtoolbox.com/pvc-pipes-equivalent-length-fittings-d_801.html
If your under max length it really doesn't matter if close use long sweep.

 

[Sponsor]

 

[Jrv]

I forgot to mention it’s 2in PVC pipe and I am well within the length specs.
Thanks

 

[Bannerman]

I am well within the length specs.

The length specs are not only the measured distance, but also the equivalent distance for each type of fitting.

The venting requirement specifications commence in page 43 of the NCB installation manual. Page 50 specifies each 2" 90 degree elbow is equivalent to 8 linear feet and 4 linear feet for a 45 degree elbow.
https://documentcloud.adobe.com/link/track?uri=urn:aaid:scds:US:e4596597-b449-4564-8742-417b93a65ddc

Page 44 specifies a street elbow is not to be installed directly into the NCB vent collar so as to direct exhaust gases to the exterior, but a length of straight pipe is to be utilized between the collar and street elbow.

https://documentcloud.adobe.com/link/track?uri=urn:aaid:scds:US:8f4daf10-26df-43df-8114-f7c93d47414c