Gas cylinders are the clearest case for purpose-built storage. A cage keeps cylinders upright and restrained, uses open construction so the store stays ventilated, segregates what needs segregating, and locks against theft — which also makes the site’s own storage arrangements straightforward to show an inspector. Cylinder handlers cover the other half of the problem, moving bottles around site without manual handling.
Pipe, conduit, rebar and section stock are the other recurring hazard. Loose lengths stacked against a hoarding roll, trap hands and get damaged. Pipe racks hold lengths in a defined bay, keep them off the ground, and let a single item be drawn out without destabilising the rest of the stack.
General material stillages cover everything else — fixings, formwork components, small plant, offcuts. Most of the value there is in stopping the drift towards loose piles that eats compound space and generates a tidy-up nobody has budgeted for.