The flow of pure air or any other gas that is free of any particulate solids or liquid droplets/mist particles would not give rise to any appreciable electrostatic charge on the PVC pipe. However, if the conveying air contains solid particles or liquid droplets one would expect electrostatic charge generation, accumulation, and depending on the quantity of particles/droplets, electrostatic discharges. In the absence of a flammable atmosphere, electrostatic discharges from the PVC pipe would just be of a nuisance nature. However if a flammable gas/vapor exists, there could be a flash fire/explosion risk.

I suggest that the following steps are taken to eliminate/manage this risk:

• Ensure that the air intake is free of particulate solids/ liquid droplets
• Provide adequate ventilation for the area to prevent the formation of a flammable vapor/gas atmosphere
• One could also perform on-site electrostatic voltage/field measurements to quantify the electrostatic charging risk.