Scaffold Load Calculator - OSHA 1926.451 Load Capacity & Platform Loading Analysis

How It Works

1. Select Scaffold Type and Duty Rating

   Choose the scaffold type (frame, system, tube-and-coupler, or supported) and the duty rating: light-duty (25 PSF - painting, inspection), medium-duty (50 PSF - general construction), heavy-duty (50 PSF - bricklaying), or special heavy-duty (75 PSF - stone masonry, heavy material storage).

2. Enter Platform Dimensions

   Input the scaffold bay width and length, number of platform levels being loaded, and total scaffold height. The calculator determines the total platform area per level and the maximum allowable load per platform based on the duty rating and platform area.

3. Add Applied Loads

   Enter the number of workers (250 lbs per worker per OSHA), weight of tools and equipment, and weight of stored materials on each level. Be specific about material weights: brick, mortar, stone, steel, lumber, drywall, and equipment all have different unit weights.

4. Review Load Analysis

   See the total applied load, platform load in PSF, and comparison against the rated capacity. The calculator flags any platform exceeding its rated load. Also shows individual leg loads for base plate sizing and foundation bearing capacity checks.

5. Verify Tie and Bracing Requirements

   Based on scaffold height and configuration, see the required tie spacing per OSHA 1926.451(c)(1) and the horizontal tie force for wind load resistance. The calculator references the 4:1 height-to-base-width ratio requiring ties.

Built For

• Scaffold erectors verifying load capacity during scaffold planning before erection
• Construction site superintendents reviewing scaffold loading before allowing work to proceed
• Safety officers inspecting scaffolds and verifying that actual loading matches the engineered capacity
• Scaffold companies preparing engineering calculations for site-specific scaffold designs
• Masons and bricklayers determining maximum material quantities for scaffold platform staging
• General contractors evaluating scaffold duty ratings for subcontractor work scopes
• OSHA compliance officers checking scaffold loading during jobsite inspections

Features & Capabilities

OSHA Duty Rating Verification

Checks applied loads against OSHA 1926.451 scaffold capacity requirements. Light-duty scaffolds support 25 PSF, medium-duty 50 PSF (maximum 2 planked platforms), heavy-duty 50 PSF (maximum 3 planked platforms), and special heavy-duty 75 PSF.

Leg Load Distribution

Calculates the axial load in each scaffold leg from the combined weight of platforms, workers, materials, and scaffold self-weight. Compares leg loads against frame capacity and determines required base plate size for the supporting surface bearing capacity.

Wind Load Analysis

Estimates wind forces on scaffold frames, platforms, and enclosures (tarps, mesh, solid panels) based on wind speed and scaffold dimensions. Calculates tie forces and overturning moments for scaffolds with weather protection enclosures.

Foundation Bearing Check

Calculates the base plate bearing pressure on the supporting surface and compares against typical bearing capacities for soil, concrete, asphalt, and timber. Flags conditions requiring mudsills, base plates, or engineered foundations.

Material Weight Reference

Built-in weight database for common construction materials: brick (5 lbs each), mortar (130 lbs/cf), CMU block (35 lbs each), drywall (2 lbs/sf), plywood (2.5 lbs/sf), steel bundles, and equipment. Helps workers accurately estimate material loads before placing them on the scaffold.

Frequently Asked Questions