1. UV rays

Ultraviolet radiation has a destructive effect on the insulation layer, protective coating of the outer shell, plastic parts, sealing adhesive, sealing ring and strip, and adhesive of the wires exposed to streetlights.

After the insulation layer of the wire ages and cracks, water vapor will penetrate into the interior of the lamp through the gaps in the wire core. After the aging of the coating on the lamp housing, the edge coating of the housing will crack or peel off, resulting in gaps. After the aging of the adhesive between electronic sealing colloids, sealing rubber rings, and structural components, it will also sequentially reduce the adhesive force, deformation, cracking, and reveal gaps, thereby reducing the waterproof performance.

2. High and low temperature

The outdoor temperature changes greatly every day. The surface temperature of the lighting fixtures can rise to 50-60 ℃ during the summer day, and drop to 10-20 ℃ at night. The temperature can drop to below zero on winter ice and snow days, and the temperature difference changes even more throughout the year. Outdoor street lights will experience accelerated aging and deformation of materials in high temperature environments during summer. When the temperature drops to below zero, plastic components become brittle and may crack under the pressure of cold air.

3. Thermal expansion and contraction

The outer shell of outdoor lighting fixtures may experience thermal expansion and contraction due to changes in temperature. Different materials have different coefficients of linear expansion, and glass and aluminum profiles may experience displacement at the junction. The process of thermal expansion and contraction is constantly repeated, and the relative displacement is also constantly repeated, which greatly damages the airtightness of the lamp. If the airtightness is poor, the waterproof performance will be greatly reduced.