Round duct is employed to attach in between fittings, components and flex duct. Manufactures generally inventory conventional lengths, but In case you have your own private spiral machine you may fabricate any duration. You have got the option of getting the air dispersed by linear vents, mounted orifices,  fixed nozzles https://ovalconduit79011.livebloggs.com/43138065/the-5-second-trick-for-oval-conduit