Our first question this month asks about Shelving Safety and our second is looking for advice on using nuts and bolts in addition to safety clips/locking pins.
Q. Shelving – Does shelving require to be bolted to the floor or secured in any way, can it be secured to another shelf? We are a factory environment but the area in question has light Forklift truck traffic, if any at all.
There is a chance that the shelving could be susceptible to other sources of damage such as pallet trucks. I’d appreciate you help as I can’t locate this in any guidance.
A. Shelving is designed for hand loading only and is not designed to take impact from fork lift trucks or similar pieces of mechanical equipment such as order pickers or even passing hand pallet trucks or bogies which can do severe damage to a shelving system when fully loaded due to their weight and speed.
Shelving can be free standing providing the height to depth ratio is less than 4 : 1 (height is distance from floor to top of topmost loaded shelf and depth is the width of the frame supporting the shelf, or twice that if it is a back to back system where both runs are coupled together, see SEMA Code of Practice for the design of low rise static steel shelving). Above that ratio and up to 6:1 it needs to be fixed down with the fixing capable of resisting 3kN in shear and 2kNin uplift. Above 6:1 specific calculations need to be made.
Shelving sometimes gets fixed to a building wall for stability however be aware that block walls do not resit transverse forces readily and the building designer should in theory be asked to confirm that his building will accept the forces involved. Mostly they will refuse to do this as it is extra responsibility on their insurance cover!!
If you are running even light fork truck traffic close to a shelving system we would urge precautions be taken to prevent impact. Armco type barriers or Dragons Teeth both work well in this regard. If this is not possible then you need to consider a more substantial product such as pallet racking decked out to act as shelving in this particular situation. Please note that all ‘pallet racking needs’ to be fixed down!
Use of Nuts & Bolts
Q. I am hoping you can advise on the use of nuts and bolts in addition to safety clips/locking pins on warehouse racking.
A. Nuts and bolts used as general substitutes for locking pins in racking are not recommended by SEMA or any Manufacturer of racking as far as we are aware. The locking pin is designed as a kind of fuse to allow the beam to dislodge from the upright at an upward force of over 1/2 tonne. Plainly this is within the capacity of most lift trucks so the intention is that the beam dislodges from the upright before the force becomes so great that the upright is seriously damaged and can also collapse the whole bay and possibly also the adjacent bay as the collapsing frame allows the ends of the beams to sink and rotate about the next upright, and so on, perhaps causing a progressive failure along a whole run of racking.
Even if the nut and bolt are selected in line with this 1/2 tonne shear limit the effect of having a nut and bolt connection prevents the beam moving away from the face of the upright and allowing it to disengage from the upright so the connector lugs continue to exert moment on the upright.
What is intended here is that an accidental over-lift from a truck results in a single aperture being destroyed resulting in a couple of pallets being dislodged rather than having a complete bay collapse followed by whatever the progressive failure might bring. Experience of many collapses indicates that the rack does perform as described.
In some circumstances (such as the front beam of live storage systems for instance) the risk of not bolting is deemed to be greater than of doing so, given that the forces from stopping pallets running down the inclined rollers is substantial however this is one of the few exceptions to the rule of using manufacturer approved locking pins.
The 2018 SEMA Safety Conference is scheduled for 1st November; at the National Motorcycle Museum, Solihull.
SEMA Rack Safety Awareness and Inspection Courses are aimed at end users, giving an in-depth look at the need for inspections, how to conduct an assessment and what actions to take when this is completed.
SEMA Approved Rack Inspectors Qualification is aimed at professionals who conduct rack surveys as an integral and significant part of their duties. It involves delegates in undertaking an in-depth SEMA Course, together with an examination and practical assessment.
SEMA runs a USERS Club designed to be of benefit to purchasers and users of storage equipment. Members receive newsletters, access to specialised events and discounted rates on publications and codes of practice.