Beside the obvious likelihood of them falling, it sounds like a major fire waiting to happen.

ALARP RA Time?

Is your insurer aware of this? I would give your broker a call if I were you and put it by them to be sure you are covered.

30 high is common, I believe. We stack ours 30 high and have not had an issues, I know others who do the same. We can get a stack of 15 empty pallets onto a trailer during empty pallet collections, hence why multiples of 15 are used. We would not go any higher than 30. Consider segregation from other MHE activity and security to prevent unauthroised access / arson. Our company policy (dictated by an insurance requirement) is for empty pallet stacks to be at least 6m from the building. Only good condition pallets should be stacked like this and stacks should be checked routinely.

Thanks for everyone's help. Our insurers are aware of this arrangement and have also stated a 3m to building gap. (Although in my experience of fire this isn't enough.) I shall have a chat with them and see where we go from here. But if 30 high is usual then that's good enough for me.

I don't read the guidance in that way, the characteristics of an empty pallet is somewhat different to a normal "load". I believe the spirit in which the guidance is written is for stock stored on pallets, not for empty pallet stacks. Can you substantiate? Our policy applies to internal and external stacks. The beauty of empty pallets is that they don't have as large a cross sectional area as say boxed goods, therefore they are not affected by wind uptake as a normal boxed load would be. To put it into perspective, my organisation has 9 Distribution centres throughout the UK, Wales and Scotland. We have been operating (with this policy) for over 15 years. We have never had an incident (even with the high winds in Scotland) of a pallet stack collapsing. Our policies and procedures are risk based, I've spoken to other retailers and we are not alone in adopting this policy, pulling joint figures together we assess the likelihood of an empty pallet stack collapse as very unlikely. Moreover, we don't live in a world of unlimited space, and if our pallet stacks were to be split in 2 this would introduce much more prevalent MHE / pedestrian collision risks. Totally disagree.