Enter the scaffold dead load (DL, self‑weight per unit area) and the maximum intended live load (LL, workers/tools/materials per unit area) into the Scaffolding Load Capacity Calculator. The Basic tab estimates the minimum required scaffold/component strength using OSHA’s 4:1 requirement: Creq = DL + 4·LL. 

Scaffolding Load Capacity Calculator

Basic (OSHA 4:1)
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Enter any 2 values to calculate the missing variable (OSHA 4:1 rule: Creq = DL + 4·LL)

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Scaffolding Capacity (OSHA 4:1) Formula

The following example problem outlines the steps and information needed to estimate the minimum required scaffold/component strength using OSHA’s 4:1 requirement (support its own weight plus at least four times the maximum intended live load).

C_req = DL + 4*LL

Variables:

  • Creq is the minimum required scaffold/component capacity (per OSHA 4:1), expressed as a load per unit area (kg/m²)
  • DL is the dead load (self‑weight) per unit area (kg/m²) 
  • LL is the maximum intended live load per unit area (workers/tools/materials) (kg/m²) 

To estimate the minimum required capacity per OSHA’s 4:1 rule, multiply the maximum intended live load by 4, then add the dead load.

How to Calculate Scaffolding Capacity (OSHA 4:1)?

The following steps outline how to calculate the minimum required scaffold/component capacity using OSHA’s 4:1 requirement.

  1. First, determine the dead load (DL) per unit area (kg/m²). 
  2. Next, determine the maximum intended live load (LL) per unit area (kg/m²). 
  3. Next, use the formula from above: Creq = DL + 4·LL.
  4. Finally, calculate Creq (the minimum required capacity per OSHA 4:1).
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

DL (dead load, kg/m²) = 300

LL (maximum intended live load, kg/m²) = 500

Creq = DL + 4·LL = 300 + 4·500 = 2300 kg/m²