Scaffold Load Calculator

OSHA 29 CFR 1926.452 requires that all scaffolds be capable of supporting their own weight plus at least four times the intended maximum load. OSHA categorizes scaffolds by load: light duty (25 lb/sq ft or less), medium duty (50 lb/sq ft), and heavy duty (75 lb/sq ft). The scaffold must be designed and inspected by a qualified person per OSHA 1926.451(d)(3).

Scaffold planks (scaffold-grade lumber) have rated working loads per OSHA 1926.452 and ANSI A10.8. A nominal 2x10 scaffold plank spanning 10 feet has a working load of approximately 50 lb/sq ft (medium duty). The load rating depends on species, span, plank width, and grade. Engineered aluminum and steel decks have published load tables from the manufacturer.

Bay load = (personnel count x 250 lb each) + material weight (lb) + equipment weight (lb). The total load per square foot = bay load / bay area (bay length x bay width). Compare the calculated load per sq ft to the scaffold system's rated deck capacity. Include a safety factor as required by OSHA (minimum 4:1 safety factor for scaffold frames).

OSHA 29 CFR 1926.451(a)(1) requires that each scaffold component (planks, frames, couplings) be capable of supporting, without failure, its own weight and at least four times the maximum intended load. This means a plank rated at 50 lb/sq ft working load must be capable of holding 200 lb/sq ft without failure. Never overload scaffolding or use damaged components.

OSHA 1926.454 requires that scaffold erectors and dismantlers receive training from a qualified person covering load capacities, scaffold erection sequences, fall protection, and falling object protection. Workers who use scaffolds must receive training from a competent person on hazard recognition, fall and falling object protection, and electrical hazards. Retraining is required when conditions change.