When you walk onto a high-rise construction site and look up, you usually see layers of heavy-duty debris netting tied to the scaffolding. It is one of the most passive pieces of safety equipment on the job-just a giant woven net that sits there waiting to catch a dropped wrench or a falling piece of formwork. Because it just hangs there, it rarely gets the maintenance attention that a power tool or a safety harness gets. But treating debris netting as a "set it and forget it" item is a massive mistake that has led to several near-misses and fatalities in the industry.
The primary enemy of safety netting is ultraviolet light. Almost all high-quality construction netting is made from high-density polyethylene (HDPE). While HDPE is incredibly strong when it is new, it is highly susceptible to UV degradation. When the plastic is baked by the sun for months, the polymer chains break down. The netting doesn't necessarily rip or tear when this happens; instead, it becomes brittle. A section of netting that looks perfectly fine to the eye can lose up to 70% of its tensile strength just from sun exposure.
This is why you cannot simply look at a net and decide it is safe. Every debris net should have a small tag stitched into the border that states its manufacturer and its expected lifespan under UV exposure (usually about one to two years for standard netting, though some treated nets last longer). If that tag is faded, torn off, or missing, the net should be immediately removed from service, because you no longer have a verifiable warranty of its strength.
How the net is stored when it is not in use also dictates its lifespan. Far too often, crews take down a section of netting, ball it up, and throw it in a pile on the ground until they need it again. Folding and creasing the netting in the same spot over and over damages the intersecting knots. When a heavy object hits a net with damaged knots, the force isn't distributed across the web; the knots simply unravel, and the object punches right through. Netting should be folded in an accordion style, rolled up, and stored completely out of direct sunlight, preferably in a dark storage locker. Furthermore, never use the net to hold or store loose materials, tools, or debris while it is hanging. The extra weight causes the mesh to stretch permanently, lowering the sag and reducing its ability to absorb the kinetic energy of a falling object when an accident actually happens.
