SSMA Nomenclature Guide: How to Read Steel Stud & Track Designations

What SSMA Nomenclature Means and Why It Is Used

Cold-formed steel (CFS) framing relies on a standardized identification system established by the Steel Stud Manufacturers Association (SSMA) and incorporated into American Iron and Steel Institute (AISI) standards.

Before industry-wide standardization, manufacturers used varying part numbers and regional trade terms (such as "light gauge stud," "drywall runner," or "tin can"), leading to ordering errors and plan misinterpretations. To eliminate confusion, the SSMA developed a unified, four-part alphanumeric designation system. This standard is recognized across North America and is codified in AISI S220 (for nonstructural framing) and AISI S240 (for structural framing).

Using standard SSMA nomenclature ensures that:

• Architects and Engineers specify exact structural properties without ambiguity.
• Estimators and Contractors take off materials accurately and order compatible studs and tracks.
• Building Inspectors easily verify code compliance and minimum steel thickness on job sites.

How SSMA Member Designations Are Structured

An SSMA designation consists of four distinct parts written in a specific order:

For example, in the designation 600S162-54:

1. Member Depth (First 3 or 4 Digits)

The first set of numbers indicates the web depth of the member in hundredths of an inch (1/100 in.).

• For Studs (S), the depth is the outside-to-outside web dimension.
• For Tracks (T), the depth is the inside-to-inside web dimension, allowing a matching stud to slide inside.

For fast quantity estimates, use our Steel Stud Calculator.

2. Member Style (Letter Character)

Directly following the depth digits is a single letter signifying the profile. AISI and SSMA standards recognize five fundamental style characters:

• S Stud or Joist: C-shaped profile with web, two flanges, and return stiffening lips.
• T Track: U-shaped profile with web and two unlipped legs.
• U Cold-Rolled Channel: Unlipped U-channels for bridging and bracing.
• F Furring Channel: Hat-shaped channels for ceilings and masonry walls.
• L Angle / L-Header: L-shaped profiles for utility angles and lintel headers.

3. Flange Width (Second Group of Digits)

The digits after the style letter represent the flange width (or track leg height) in hundredths of an inch.

Return Lips on Studs

Unlike track profiles, C-stud (S) profiles feature bent return lips along the outer edges of the flanges to provide torsional stiffness and buckling resistance. Standard return lip lengths per SSMA/SFIA standards:

4. Material Thickness in Mils (Digits After the Dash)

The numbers following the hyphen indicate the minimum base metal thickness of the steel in mils (1 mil = 1/1000 of an inch).

Under AISI S220 and AISI S240 standards, the minimum delivered base metal thickness must not be less than 95% of the design thickness.

Standard Steel Thickness Cross-Reference Table

SSMA Designation vs. Nominal Size vs. Actual Dimensions

In traditional lumber framing, dimensions are nominal (e.g., a "2×4" actually measures 1-1/2" × 3-1/2"). In cold-formed steel framing, members are designated by their exact actual dimensions.

Verified SSMA Designation Examples

SSMA Standard vs. Manufacturer-Specific Framing Systems

While SSMA nomenclature provides the industry baseline, major framing manufacturers produce proprietary product lines or "equivalent" (EQ) drywall systems. It is essential to distinguish standard SSMA designations from brand-specific product names on project submittals:

• Equivalent Thickness (EQ) Systems: High-strength steel drywall studs (such as ViperStud®, ProSTUD®, or Steeler ELITE) utilize thinner base metal with modified geometry or knurling to achieve limiting heights comparable to standard drywall studs. For example, a Viper 25 EQ stud has a design thickness of 0.0155 in. (15 mil) compared to the standard 25 gauge thickness of 0.0188 in. (18 mil).
• Proprietary Style Codes: Manufacturers often modify the style letter in their literature to denote custom shapes (e.g., Marino\WARE uses VS for ViperStud, VT for ViperTrack, SR for StudRite open-web studs, and JR for JoistRite).
• Standard SSMA Conversion: Even when proprietary names are used in sales literature, structural submittals and code evaluation reports reference testing under AISI S100, AISI S220, and AISI S240 standards.

Structural vs. Nonstructural Framing Considerations

Interior Nonstructural (Drywall) Framing

• Typical Thicknesses: 18 mil, 27 mil, and 30 mil (25, 22, and 20DW gauge)
• Primary Function: Gravity-load support for gypsum board only in interior partitions not exposed to axial loads or exterior wind pressure
• Steel Yield Strength: Typically manufactured from minimum 33 ksi steel

Structural Framing (Load-Bearing & Curtain Wall)

• Typical Thicknesses: 33 mil, 43 mil, 54 mil, 68 mil, 97 mil, and 118 mil (20STR to 10 gauge)
• Primary Function: Exterior curtain walls, axial load-bearing walls, floor joists, headers, and roof trusses
• Steel Yield Strength: Available in 33 ksi or 50 ksi. For structural members 54 mil (16 gauge) and thicker, building codes require the specifier to explicitly designate whether 33 ksi or 50 ksi steel is required.

Factory Web Punchouts

Standard C-studs (S) are manufactured with factory knockouts along the web centerline to accommodate electrical wiring and plumbing lines. Punchout spacing is indexed 12 inches from the member end, with intermediate punchouts spaced at 24 inches on-center.

• For studs larger than 2.5 inches deep: maximum punchout size is 1.5 in. × 4 in.
• For studs 2.5 inches deep or smaller: maximum punchout size is 0.75 in. × 4 in.

Step-by-Step Practical Example: Reading 600S162-54

Suppose you see 600S162-54 (50ksi) called out on a structural drawing set:

1. Identify the Web Depth (600): Divide 600 by 100 → 6.00 inches
2. Identify the Member Style (S): Stud/Joist — C-shaped with return stiffening lips
3. Identify the Flange Width (162): Divide 162 by 100 → 1.625 inches (1-5/8")
4. Identify the Thickness (–54): 54 mils → 0.0566 in. design (0.0538 in. min) → traditionally 16 gauge
5. Identify the Yield Strength (50ksi): 50 ksi high-strength steel

Common Mistakes When Interpreting SSMA Designations

Frequently Asked Questions

References & Authoritative Documentation

• Steel Framing Industry Association (SFIA): Technical Guide for Cold-Formed Steel Framing Products
• American Iron and Steel Institute (AISI):
  • AISI S100-16 / S2-20 — North American Specification for the Design of Cold-Formed Steel Structural Members
  • AISI S220 — North American Standard for Cold-Formed Steel Framing (Nonstructural Members)
  • AISI S240 — North American Standard for Cold-Formed Steel Structural Framing
• ASTM International: ASTM A1003, ASTM A653, ASTM C645, ASTM C955, ASTM C1007
• Manufacturer Technical Documentation: Marino\WARE Technical Framing Catalogs, ClarkDietrich Building Systems Technical Guides, Steeler Construction Supply Specifications