**6.3 Dry air or dehumidification technique**

The recently developed technique, specifically designed for suspension bridge main cable, focuses on keeping moisture away from the steel cable. In this technique, humidity is kept under 40%. The low humidity is maintained artificially by moving dry air through and along the length of the main cables of suspension bridges [6] (**Figure 27**).

**Figure 26.** *Corrosion inhibitors.*

Dry air is injected at low pressure into the main cable through inlet points provided at specific spacing along the length of the cable. This dry air is made to travel along the cable and exits at various outlet points provided along the cable length. The spacing of inlet and outlet points significantly influences the effectiveness and power consumption of the system.
