The construction industry is rapidly evolving and building schedules are crunched and moving faster than ever. As a result, there is exponentially more technology used in the office and onsite. You buy your field workers the best tools, software and devices to keep them on track and productive. Yet too few business owners and project managers give the same attention to the connection technology that accounts for much of the labor at job sites. 

When there are countless connection technology options for spiral duct systems, how do you find the right product for your team and application?

At Sheet Metal Connectors, Inc., our most popular connection technologies are Complete Seal and E-Z Flange because they save field labor and increase energy efficiency.

Complete Seal Duct Connection Technology

For smaller spiral duct, 3 to 16 inches in diameter, gasket connections are the clear choice. Complete Seal from Sheet Metal Connectors (SMC) creates an airtight connection without having to apply duct sealant to the transverse joints. This results in labor savings to the contractor and a clean, aesthetically pleasing system for the end user.

Since the initial release of Complete Seal in 2010, SMC’s customers have seen thousands of hours of labor savings on their projects. Manufactured from galvanized steel, Complete Seal fittings are spec ASTM A-653 (lock-forming quality). They feature a double-legged EPDM rubber gasket to guarantee an airtight fit when slipped into spiral pipe. Gaskets are mechanically fastened to fittings with a 180-degree hemmed edge. This hem gives added rigidity to the fittings, ensures that the gaskets will never slip out of place and creates a safe, rounded edge for the installer.

Complete Seal fittings are independently tested by a third party to meet the requirements of SMACNA leakage class 3 for -10” w.g. to +10” w.g. The EPDM rubber gaskets have operating temperature of -40 degrees to 250 degrees Fahrenheit. The flame spread and smoke developed is 0/5 in compliance with ASTM E-84-91A.

The Complete Seal end treatments are applied to the EZ Tap Takeoff Collar, the Super HETO (high-efficiency takeoff) as well as the rest of SMC’s energy efficient and time saving duct fittings.

Installing Complete Seal fittings is quick and easy. Simply insert the fitting into the spiral duct all the way up to the spiral stop bead. Secure in place with self-tapping sheet metal screws. Fittings will fit snugly inside the pipe to ensure a tight seal. Screws must be within one inch of the spiral stop bead and at uniform intervals not to exceed 15” along the circumference, and use a minimum of three screws must on all diameters 14” or less. Then, move along to the next piece of duct. No added sealant or caulk needed.

E-Z Flange Duct Connection Technology

Nearly any size or any material duct configuration can utilize the E-Z Flange Spiral Pipe System, including duct for stadiums. Materials include galvanized, paint grip, PVS, stainless steel and aluminum as well as single wall and double wall spiral duct and flat-oval duct applications. E-Z Flange can use either factory-installed or field-installed flanges on the ends of the spiral pipe and fittings.

Factory installed flanges attach by either spot weld or button lock, so there are no screws protruding into the air stream and are sealed internally making an airtight and aesthetically pleasing connection. .

The E-Z Flange spiral pipe system seals so tight that it outperforms both ASHRAE and SMACNA leakage class 3 testing from -10” w.g. to +10” w.g.

Assembling the E-Z Flange Spiral Pipe System requires applying a gasket to one flange, mating the two flanges together, and attaching the barrel clamp. This barrel clamp also allows the system to be disassembled and re-assembled for cleaning or easy changing of the ductwork configuration. Our clamp also saves you labor by allowing your field employees to make your connections with two simple carriage bolts rather than many screws around the circumference of the pipe.

The E-Z Flange system is available in two sizes. E-Z Flange Jr. is for smaller diameters, 6-24 inches, and is characterized by a 5/8 inch flange fabricated with 22-gauge material (field cut sets). This flange can be turned directly on your pipe and fittings at the factory which is ideal for dust collection, or in instances where field cuts are needed flanges can be spot welded, screwed, riveted or button punched. E-Z Flange Jr. comes with a SMACNA Rigidity Class A rating from the SMACNA Testing and Research Institute allowing lighter gauge fittings and pipe to work with heavier pressures.

Sheet Metal Connectors, Inc.’s larger 1.5” E-Z Flange is for diameters from 26– 120 inches. Fabricated from 16 gauge material it meets SMACNA Rigidity Class C per the SMACNA Testing and Research Institute. Attachment as well as joint assembly procedure remain the same as the Flange Jr.

Large diameter pipe and fittings are where the E-Z Flange System shines. Your labor savings will increase with the spiral pipe diameter. Customers save up to 40 percent on duct installation labor when utilizing E-Z Flange on their job site.

Whichever system is the best option for your application, they both save time on field installation and will result in a premier duct system that performs beyond SMACNA standards.


This article originally appeared in the Janurary 2020 issue of SNIPS magazine.