The maximum permissible span for a 2x10 inch (nominal) solid sawn wood plank depends on the intended load. According to Appendix A guidelines, the maximum spans are as follows:
All load-carrying timber members of a scaffold, except for planks, should be a minimum of 1,500 lb-f/in² (stress grade) construction grade lumber. According to Appendix A to Subpart L, all dimensions are nominal sizes as defined by the American Softwood Lumber Standards unless rough sizes are specified.
Scaffold guardrail components must be equivalent in strength to specific lumber or metal dimensions. Appendix A to Subpart L provides the following minimum strength equivalents:
No, the guidelines in Appendix A to Subpart L are non-mandatory; however, they provide a starting point and acceptable methods for designing and building scaffolds that comply with the mandatory requirement that all scaffolds must support their own weight and at least four times the maximum intended load.
If you choose not to follow these guidelines for certain components, you must ensure your design and construction still meet the capacity requirements outlined in the mandatory standard, specifically OSHA 1926.451(a).
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