Posted 3 Jun 2024

Air pressure in a painting booth: what you need to know

The air pressure within a painting booth is a critical factor that must be carefully managed to ensure a safe working environment and high-quality finishes. A pressurized booth is engineered to minimize dust movement within the booth, thereby preserving the final appearance of the pieces being worked on. Air pressure influences overspray distribution, air filtration, and the prevention of external contaminants from entering, and it is affected by various factors.

Air pressure in a painting booth: what you need to know

Here are some important aspects regarding air pressure inside the painting booth.

Positive or negative pressure

A painting booth can be designed to maintain either positive or negative air pressure relative to the surrounding environment. Positive pressure means that the air inside the booth is slightly higher than outside, while negative pressure means it is slightly lower.

Controlling airflow in the painting booth can alter painting techniques and is crucial for maintaining proper airflow over the object being painted.

Before the digital era in the finishing industry, pressure settings had to be manually adjusted. Older booths (and some still in use today) feature a pressure gauge and an overpressure damper on the extraction motor, regulating pressure. This manual method can be time-consuming and requires attention. Fortunately, safety-conscious manufacturers like USI Italia have introduced digital control panels, frequency converters, and pressure transducers for easy adjustment of motor rotation (inlet and extraction) and booth pressure.

However, despite digitalization and automation, understanding the basic principles of adjusting air pressure in a painting booth remains important.

Positive pressure

A booth with positive air pressure aims to prevent dust and contaminants from entering. The air, generated by a more powerful supply motor than the exhaust motor, must be properly filtered to avoid escape through door joints. Positive pressure is often used to safeguard the painting process from environmental contaminants and is regulated by NFPA 33 in the United States.

Negative pressure

A booth with negative air pressure prevents harmful chemicals or vapors from dispersing outside the booth. Air is drawn in by an exhaust motor stronger than the supply motor, reducing operator exposure to hazardous substances. This configuration, mandated by OSHA Regulations, protects workers from volatile organic compounds (VOCs).

Pressure balancing

Maintaining proper pressure balance is crucial for air filtration and suction system functionality. Improper balancing can lead to filtration inefficiencies and overspray issues.

Factors influencing air pressure regulation include clogged filters, which make the extraction fan work harder, and objects within the booth, affecting pressure variation.

To ensure a safe working environment, air pressure should be constantly monitored and adjusted according to manufacturer specifications, paint recommendations, and safety regulations. Automatic control systems enable precise pressure adjustments, independent of the operator.

Accurate air pressure control is essential for a safe working environment, preventing flammable vapor ignition, and reducing the risk of harmful substance inhalation by painting staff.


In summary, controlling air pressure in a painting booth is vital for proper paint application, worker safety, and maintaining a clean environment. Balancing positive and negative pressure optimizes finishing results, ensures regulatory compliance, and reduces energy consumption in the painting facility.