Electrostatic Control and Humidity

Electrostatic charge builds up when there is rubbing between different materials.  This charge is undesirable in many cases.  Electrostatic charge accumulation can result in sparking which has a risk of fire.  It can also result in jamming of papers in printers.  In the textile industry, the fabric which passes through the machines can get stuck due to charge accumulation.  Charge accumulation also results in dust accumulation on surfaces which is an area of concern in the painting industry.  Charge accumulation and electrostatic discharge can destroy electronic components.

Hence, control of electrostatic charge accumulation is vital in many industries.  Humidity plays an important role in electrostatic control.  When the air is humid, a thin layer of moisture appears on the surface of the material.  This increases the surface conductivity.  This ensures that the charge which accumulates on the surface is dissipated through the conductive layer of moisture.

When dry air blows over insulating materials, it can itself cause charge build up.  

A humidity of 40 to 60 percent can help reduce charge build up.  Relative humidity lower than 30% can result in high levels of charge.  However, if the relative humidity is too high it can result in corrosion.  Hence, any humidity control system should be closely monitored.