Side-by-Side Comparison
Structural & HVAC
Concrete Anchors vs. HVAC Duct Sizes
Comparing 2 standards across 20 specifications. 20 key differences identified.
Comparing:
Concrete Anchors
HVAC Duct Sizes
Heavy-duty concrete anchors are categorized into mechanical expansion anchors (Wedge and Sleeve), drop-in anchors, and concrete screws (Tapcons), specified by drill bit diameter, minimum embedment depth, and tensile pullout / shear load capacities.
Standard residential and commercial HVAC duct dimensions are specified by round spiral diameter (4 to 20 inches) and equivalent rectangular cross-sections based on airflow capacity (CFM) at 0.10 inches water column friction loss per 100 feet.
Specification Comparison Table
20 Parameters| Parameter / Spec | ||
|---|---|---|
|
Governing Code
|
ACI 318-19 Chapter 17 Anchoring to Concrete / ICC-ES Acceptance Criteria | — |
|
Wedge Anchor Drill Rule
|
Drill bit diameter MUST match nominal anchor diameter (e.g. 1/2" bit for 1/2" wedge anchor) | — |
|
Tapcon Screw Drill Rule
|
Drill bit is 1/16" smaller than screw dia (e.g. 5/32" bit for 3/16" Tapcon; 3/16" bit for 1/4" Tapcon) | — |
|
1/4" × 3-1/4" Wedge Anchor
|
Min Embed: 1.125 in | Tensile: 1,800 lbs | Shear: 1,600 lbs in 4,000 psi concrete | — |
|
3/8" × 3-3/4" Wedge Anchor
|
Min Embed: 1.625 in | Tensile: 3,400 lbs | Shear: 3,200 lbs in 4,000 psi concrete | — |
|
1/2" × 4-1/4" Wedge Anchor
|
Min Embed: 2.250 in | Tensile: 5,600 lbs | Shear: 5,100 lbs in 4,000 psi concrete | — |
|
5/8" × 6" Wedge Anchor
|
Min Embed: 2.750 in | Tensile: 7,800 lbs | Shear: 8,200 lbs in 4,000 psi concrete | — |
|
3/4" × 7" Wedge Anchor
|
Min Embed: 3.250 in | Tensile: 11,200 lbs | Shear: 12,500 lbs in 4,000 psi concrete | — |
|
Substrate Suitability
|
Wedge anchors: Solid poured concrete ONLY (Never use in hollow CMU cinder block or brick) | — |
|
Governing Standards
|
— | SMACNA / ACCA Manual D Residential Duct Systems |
|
Standard Sizing Metric
|
— | Cubic Feet per Minute (CFM) at 0.10" w.g. / 100 ft friction rate (Residential) / 0.08" (Quiet) |
|
4" Round Duct
|
— | Capacity: ~30 CFM | Small bathrooms, range hood make-up air |
|
5" Round Duct
|
— | Capacity: ~50 CFM | Small powder rooms, walk-in closets |
|
6" Round Duct (Standard Branch)
|
— | Capacity: ~100 CFM | Standard 10×12 ft bedrooms |
|
7" Round Duct
|
— | Capacity: ~150 CFM | Master bedrooms, medium living areas |
|
8" Round Duct
|
— | Capacity: ~200 CFM (0.5 Ton A/C) | Large master suites, kitchens |
|
10" Round Duct
|
— | Capacity: ~350 CFM (~1.0 Ton A/C) | Open living rooms, main branches |
|
12" Round Duct
|
— | Capacity: ~550 CFM (~1.5 Ton A/C) | Main trunk lines |
|
14" Round Duct
|
— | Capacity: ~800 CFM (2.0 Ton A/C) | Main central supply trunk |
|
Airflow Rule of Thumb
|
— | 1 Ton of Air Conditioning = 400 CFM of airflow |