For the modernization of the painting department at PrJSC “Ob’iednannia Prohres”, TWEKO delivered an open-type two-zone water wash spray booth with a 4500×4500 mm working area. The system includes two water wash exhaust units, an integrated water-flooded floor system across the entire painting area, and a separately installed supply thermo-ventilation unit (TVU) equipped with a 60 kW electric heating section. The solution provides controlled vertical airflow, stable air exchange, and compliance with fire and electrical safety regulations.
About the Client
PrJSC “Ob’iednannia Prohres” is a Ukrainian structural steel manufacturer operating its own production facilities with a full-cycle metal fabrication and processing workflow. The company produces large-scale steel elements for industrial and civil construction projects, including load-bearing frames, assembly units, and structural components.
Due to the significant dimensions and weight of the products, production requires an open spray area allowing unrestricted crane handling of oversized structures. To ensure consistent coating quality and safe working conditions, the company required a local exhaust ventilation (LEV) system with controlled airflow and efficient capture of paint overspray.
Project Objectives
- Establish an open 4.5×4.5 m spray zone for oversized steel products.
- Install two water wash exhaust units with externally mounted fans.
- Provide uniform top-down air supply via a ceiling distribution frame.
- Integrate a full-area water-flooded floor system.
- Install a separate TVU with a 60 kW electric heating section.
- Ensure compliance with PUE requirements and Class V-IIa hazardous area standards.
Solution
A two-zone spray booth based on the FKG-4.0 model was installed and adapted to the customer’s facility layout. The working area is formed by a structural steel frame with ceiling-mounted supply air distribution. Total exhaust frontage width — 4600 mm. Working zone depth — 4500 mm. Working height — 3480 mm.
The exhaust units are mounted externally to reduce indoor noise levels and enhance fire safety. Exhaust air is discharged through ductwork (manufactured by the customer) with a minimum cross-sectional area of 0.16 m².
The supply thermo-ventilation unit (overall length 2770 mm) is equipped with an 11 kW fan motor and a 60 kW electric heating section. The heating system is divided into three stages to ensure phased electrical load distribution.
Key System Components
- Water wash exhaust units — 2 units. Provide capture of paint overspray and water-based filtration of aerosol particles.
- Externally mounted exhaust fans — 2 units. Discharge filtered air outside the building, reducing indoor noise levels and minimizing ignition risk.
- Water-flooded floor system with grated collection tanks — 4 units. Collect paint residues, ensure liquid circulation, and prevent contamination buildup in the working area.
- Supply thermo-ventilation unit (TVU) — 1 unit. Delivers filtered and heated air to the working zone through a ceiling distribution system.
- Electric heating section — 1 unit. Maintains the painting temperature regime (≤23.5°C) with staged power control.
- Submersible pumps — 4 units. Ensure water circulation within the water wash and floor system.
Technical Specifications — FKG-4.0 Spray Booth
| Parameter | Value |
|---|---|
| Overall Dimensions | |
| Exhaust unit dimensions (without fan) | 3 820 × 600 × 1 930 mm |
| Working zone dimensions | 3 800 × 1 930 mm |
| Aerodynamic Parameters | |
| Airflow in painting mode | up to 10 000 m³/h |
| Air velocity through exhaust unit | 2.5 m/s |
| Air velocity in working zone | 0.15–0.25 m/s |
| Ventilation Equipment | |
| Exhaust fan motor | 4 kW / 1000 rpm |
| Supply fan motor | 11 kW / 1500 rpm |
| Other Technical Parameters | |
| Electric heating section | 60 kW |
| Submersible pump | 2 kW |
| Power supply | 380 V / 50 Hz |
| Total connected load | 90 kW |
| Equipment weight | 1 540 kg |
Operating Principle
Supply air is delivered from above through a ceiling air distribution frame, forming a uniform vertical airflow within the working area. A controlled air velocity of 0.15–0.25 m/s ensures stable coating application without turbulence or secondary contamination.
During spraying operations, paint overspray is directed by the airflow toward the front water wash exhaust units. At the water curtain face and spray zone, primary capture of paint particles occurs through water-based filtration.
Additional purification is provided by a fiberglass Paint Stop filter, after which the filtered air is discharged outside the building by the exhaust fans.
The integrated water-flooded floor system collects residual paint and ensures continuous liquid circulation via submersible pumps, maintaining stable water wash operation and minimizing contamination buildup within the working zone.
Maintenance and Safety
The system complies with GOST 12.2.003-74 and PUE regulations. Exhaust fans are installed outside the workshop to reduce ignition risk. All metallic structures are properly grounded.
The preventive maintenance schedule includes cleaning of water floor collection tanks, replacement of filtration media, and routine inspection of pumps and ventilation equipment.
Results
- Established a 4.5×4.5 m working zone for oversized steel structures.
- Stable and controlled vertical airflow.
- Efficient water wash capture of paint overspray.
- Reduced indoor noise due to external fan installation.
- Compliance with explosion and fire safety requirements.
Summary
The project for PrJSC “Ob’iednannia Prohres” delivered an industrial open-type water wash spray booth for processing large-scale steel structures. The system integrates water wash filtration, a full-area water floor, and a ceiling-mounted supply air system with electric heating, ensuring stable and safe operation of the painting department.
