Scaffold Load Capacity Under OSHA Standards
Under OSHA 29 CFR 1926.451, scaffolding must be capable of supporting at least 4 times the maximum intended load. The practical working ratings are 25 psf for light-duty, 50 psf for medium-duty, and 75 psf for heavy-duty applications. Multiply the platform area by the psf rating to find the total allowable load.
A recommended working load of 80% of the maximum provides a safety buffer for dynamic loads — vibration, impact from tools, and workers moving on the platform. Always include the combined weight of workers, tools, and materials when checking against the working load limit.
Scaffold erection and inspection must be performed by a qualified person before each work shift. Never overload a scaffold, and remove all materials from the platform when work is stopped. Secure the scaffold against wind loads if left standing overnight.
Frequently Asked Questions
OSHA requires scaffolds to be erected, moved, dismantled, or altered under the supervision of a competent person. Many states require scaffold erectors to have specific training or certification.
OSHA requires guardrails or personal fall arrest systems for all scaffold work platforms 10 feet or higher above a lower level.