29 CFR §1926.250

1. (a)General.
   1. (1)All materials stored in tiers shall be stacked, racked, blocked, interlocked, or otherwise secured to prevent sliding, falling or collapse.
   2. (2)
      1. (i)The weight of stored materials on floors within buildings and structures shall not exceed maximum safe load limits.
      2. (ii)Employers shall conspicuously post maximum safe load limits of floors within buildings and structures, in pounds per square foot, in all storage areas, except when the storage area is on a floor or slab on grade. Posting is not required for storage areas in all single-family residential structures and wood-framed multi-family residential structures.
   3. (3)Aisles and passageways shall be kept clear to provide for the free and safe movement of material handling equipment or employees. Such areas shall be kept in good repair.
   4. (4)When a difference in road or working levels exist, means such as ramps, blocking, or grading shall be used to ensure the safe movement of vehicles between the two levels.
2. (b)Material storage.
   1. (1)Material stored inside buildings under construction shall not be placed within 6 feet of any hoistway or inside floor openings, nor within 10 feet of an exterior wall which does not extend above the top of the material stored.
   2. (2)Each employee required to work on stored material in silos, hoppers, tanks, and similar storage areas shall be equipped with personal fall arrest equipment meeting the requirements of subpart M of this part.
   3. (3)Noncompatible materials shall be segregated in storage.
   4. (4)Bagged materials shall be stacked by stepping back the layers and cross-keying the bags at least every 10 bags high.
   5. (5)Materials shall not be stored on scaffolds or runways in excess of supplies needed for immediate operations.
   6. (6)Brick stacks shall not be more than 7 feet in height. When a loose brick stack reaches a height of 4 feet, it shall be tapered back 2 inches in every foot of height above the 4-foot level.
   7. (7)When masonry blocks are stacked higher than 6 feet, the stack shall be tapered back one-half block per tier above the 6-foot level.
   8. (8)Lumber:
      1. (i)Used lumber shall have all nails withdrawn before stacking.
      2. (ii)Lumber shall be stacked on level and solidly supported sills.
      3. (iii)Lumber shall be so stacked as to be stable and self-supporting.
      4. (iv)Lumber piles shall not exceed 20 feet in height provided that lumber to be handled manually shall not be stacked more than 16 feet high.
   9. (9)Structural steel, poles, pipe, bar stock, and other cylindrical materials, unless racked, shall be stacked and blocked so as to prevent spreading or tilting.
3. (c)Housekeeping. Storage areas shall be kept free from accumulation of materials that constitute hazards from tripping, fire, explosion, or pest harborage. Vegetation control will be exercised when necessary.
4. (d)Dockboards (bridge plates).
   1. (1)Portable and powered dockboards shall be strong enough to carry the load imposed on them.
   2. (2)Portable dockboards shall be secured in position, either by being anchored or equipped with devices which will prevent their slipping.
   3. (3)Handholds, or other effective means, shall be provided on portable dockboards to permit safe handling.
   4. (4)Positive protection shall be provided to prevent railroad cars from being moved while dockboards or bridge plates are in position.