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What is SMACNA standard?

SMACNA standards help contractors reduce costs, anticipate technical requirements, and increase productivity and efficiency. SMACNA standards and manuals address all facets of the sheet metal industry, from duct construction and installation to air pollution control, energy recovery, and roofing.

Is standard for ducting?

This standard covers materials and constructional requirements of air ducts used for air conditioning and ventilation system (including gas exhausting system). The standards listed at Annex A contain provisions, which through reference in this text, constitute provisions of this stidard.

What are the duct pressure classes as per SMACNA?

SMACNA breaks down the sealing of commercial ductwork into three classes: A, B, and C. Class A applies to static pressure of 4″ wg or more and requires all transverse joints, longitudinal seams and duct wall penetrations to be sealed..

What gauge is standard ductwork?

Gage-It Right The thinnest acceptable sheet metal for ductwork used in a single dwelling is 28 gage or 0.013 and 0.018 inches for galvanized and aluminum, respectively. This measurement is for around duct smaller than 12 inches in diameter and a rectangular section no bigger than 8 inches.

How many chapters are there in Smacna?

There are nearly 100 local SMACNA Chapters across the United States, Canada, Brazil, and Australia that represent signatory sheet metal and HVAC contractors. Membership in a local chapter automatically extends your membership to SMACNA.

Is Smacna a union?

CAL SMACNA is a non-profit statewide trade association representing over 600 sheet metal and air conditioning contractors who employ more than 25,000 union employees and administrative personnel throughout the state of California. For more information on the services CAL SMACNA provides, visit

How do you measure insulated ducts?

Measure the diameter of the duct then divide it by 2 to get the radius. Square the radius then multiply the radius by Pi, or 3.14. This will give you square inches of the duct. Divide that total by 144 to get square feet of the actual duct.

What is Smacna Seal Class A?

SMACNA and Mastic on Rectangular Duct Class A applies to static pressure of 4″ wg or more and requires all transverse joints, longitudinal seams and duct wall penetrations to be sealed. Class B applies to static pressure of 3″ wg and requires all transverse joints and longitudinal seams be sealed.

What is the maximum operating pressure in an air duct system?

Usually the static pressure is limited to a maximum of 7 inches WC, and duct velocities are limited to 4,000 fpm. Systems requiring pressures more than 7 inches WC are normally unwarranted and could result in very high operating costs.

How many CFM is a 10 round duct?

325 CFM
CFM Sizing Chart For Metal Round Ducts (50-2,000 CFM)

Duct Size (Inches) Metal Duct Airflow (CFM)
7 inches 125 CFM
8 inches 180 CFM
9 inches 240 CFM
10 inches 325 CFM

What is the name of the Connecticut Smacna chapter?

The Associated Sheet Metal and Roofing Contractors of Connecticut.

When was Smacna established?

Established in 1950, SMACNA St. Louis serves member contractors and experts in four core industries across the greater St. Louis area: architectural, HVAC, industrial and residential.