Rack failures usually give notice. The trouble is that the notice is small: a slightly bowed column, a lock missing from one connector, a base plate that has started to rust from underneath. Walk your aisles with this list and you will catch most problems while they are still cheap to fix.
If you find structural damage: unload the affected bays, block the area off and keep it out of use until a qualified person has looked at it. Do not try to bend anything back into shape.
Uprights and Frames
1. A bent or bowed column
Uprights carry every level above them, so a bend is never minor. A widely used guideline treats a bend of more than 1/8 inch within any 3-foot length as out of tolerance. Measure with a straightedge; bends that look small from the aisle often fail that test.
2. Creases, tears or dents near the slots
Damage around the beam slots is especially serious, because the steel there is already cut away. A crease or tear can let the column fold under a fraction of its rated load.
3. Damaged bracing
The diagonals and horizontals between the two columns of a frame keep it stable. Bent, cracked or missing braces reduce what the frame can carry.
4. Base plate or anchor problems
Look for cracked or bent plates, missing or loose anchors, and plates that no longer sit flat. A frame without working anchors can shift or tip when hit.
Beams and Connections
5. Beams that stay bent when empty
Beams deflect a little under load by design; the common design limit is span divided by 180. A beam that sags noticeably more than that, or stays bent after unloading, has been overstressed and should be replaced.
6. Missing beam locks
Locks stop beams lifting out of their slots when a fork catches the underside. They are small, easy to lose and one of the most frequent findings in any inspection. Check every connector.
7. Bent or cracked connectors
If the connector at the end of a beam is bent or its weld is cracked, the beam will not seat properly and cannot be trusted at its rating.
The System as a Whole
8. Rows that lean
Sight down each row from the end. Frames should be plumb. A single leaning frame usually points to an impact. Several frames leaning the same way, with no damage, often point to the floor, which is common on the expansive clay under much of the Houston area. Either way, have it assessed.
9. Missing row spacers or ties
Spacers tie back-to-back rows together and keep them aligned. Missing ones leave each row to stand alone.
10. Signs of overloading
- Pallets heavier than the plaque allows
- Product stacked on top of the highest beam
- Pallets that overhang or bridge between bays
- Beams moved to new heights without an engineering check
11. Missing or unreadable load plaques
Operators cannot stay within limits they cannot see. ANSI/RMI MH16.1 calls for permissible loads to be posted conspicuously, and OSHA uses that standard as its benchmark.
12. Rust at the base
In humid and coastal buildings, from Webster to Galveston, corrosion concentrates at base plates and the bottom of columns near dock doors. Surface rust can be treated. Pitting or thinning steel is structural damage. Lift the edge of a plate or probe underneath; the top surface can look fine while the underside is gone.
After an Impact
- Stop work in the aisle.
- Unload the affected bays if it is safe to do so.
- Block off the area.
- Photograph the damage and record the time and location.
- Have a qualified person assess it before the bays are reloaded.
A Simple Inspection Routine
- Each shift: operators look over the rack in their area and report new damage.
- Monthly: a supervisor walks every aisle with a checklist.
- Annually: a qualified inspector produces a written report covering every component.
Our rack inspection and repair service provides that annual report and handles the repairs it finds. For how to decide between repair and replacement, see our repair-or-replace guide. Contact us to schedule an inspection.