In any spray application. Whether you're cooling, cleaning, humidifying, or suppressing dust—droplet size is everything. It determines coverage, evaporation rate, efficiency, and impact. And the most influential factor in droplet size? Spray pressure.
This guide breaks down how pressure affects droplet size across nozzle types, with practical charts to help you select the right pressure–droplet combination for your application.
Why Pressure Directly Affects Droplet Size
Spray pressure is the primary factor that determines droplet size — but it doesn’t act alone.
The Rule of Thumb:
Higher pressure = smaller droplets
Lower pressure = larger droplets
But don’t forget: nozzle design and orifice size also influence droplet formation. That’s why identical pressures can yield different sprays across nozzle types.
Droplet Size vs Pressure (High-Pressure Fog Nozzles)
| Pressure (bar) | Droplet Size (µm) | Spray Behaviour | Typical Use |
|---|---|---|---|
| 10–20 bar | 50–80 µm | Coarse mist | Light dust suppression |
| 20–30 bar | 30–50 µm | Medium fog | Conveyor belt dust control |
| 30–40 bar | 20–30 µm | Fine fog | Dry fog systems |
| 40–60 bar | 10–20 µm | Ultra-fine fog | Cooling, warehouse humidification |
| 60–70 bar | <10–15 µm | Fast evaporation fog | Textile, pharma, precision humidity |
Best for: Dust suppression, fogging, HVAC cooling, precision humidification
Droplet Size vs Pressure (Full Cone / Hollow Cone Nozzles)
| Pressure (bar) | Droplet Size (µm) | Spray Pattern | Typical Application |
|---|---|---|---|
| 2–5 bar | 200–500 µm | Full cone | Irrigation, equipment washing |
| 5–10 bar | 100–200 µm | Hollow/full cone | Pesticides, process cooling |
| 10–20 bar | 50–100 µm | Hollow cone | Light misting for chemicals |
| 20–30 bar | 30–50 µm | Hollow cone | High-pressure dust suppression |
Best for: Irrigation, chemical spraying, mist cooling
Droplet Size vs Pressure (Low-Pressure Agri Nozzles)
| Pressure (bar) | Droplet Size (µm) | Spray Effect |
|---|---|---|
| 1–2 bar | 300–600 µm | Heavy soaking |
| 2–3 bar | 200–400 µm | Targeted irrigation |
| 3–5 bar | 100–200 µm | Fine misting for crops |
Best for: Greenhouse misting, nursery irrigation, drip prevention
Droplet Size vs Pressure (Washing & Cleaning Nozzles)
| Pressure (bar) | Droplet Size (µm) | Cleaning Effect |
|---|---|---|
| 10–30 bar | 200–500 µm | Basic rinsing |
| 30–70 bar | 150–300 µm | Medium-duty cleaning |
| 70–150 bar | 100–200 µm | Tough surface cleaning |
| 150–250 bar | Jet / stream | High-impact stripping |
Best for: Tank cleaning, CIP systems, industrial pressure washers
Pressure vs Application Matrix
| Application | Ideal Pressure | Target Droplet Size |
|---|---|---|
| Dust suppression | 20–40 bar | 20–50 µm |
| Dry fog systems | 30–60 bar | 10–30 µm |
| HVAC cooling | 40–70 bar | 10–25 µm |
| Humidification | 50–70 bar | 5–20 µm |
| Odor control | 20–40 bar | 20–40 µm |
| Irrigation | 1–5 bar | 100–400 µm |
| Chemical spraying | 5–20 bar | 50–150 µm |
| Industrial washing | 50–250 bar | >100 µm |
Important Technical Notes
1.Same Pressure ≠ Same Droplet Size
Different nozzle geometries atomize differently — a flat fan and a hollow cone will NOT behave the same at 20 bar.
2.Worn Nozzles = Larger Droplets
Worn orifice → higher flow
Larger droplets → wetting issues
Poor performance despite correct pressure
3.Filtration Preserves Atomization
Even minor clogging distorts the spray pattern. Always size filtration to nozzle micron specs.
Nozzle Selection Formula
Application
↓
Required Droplet Size
↓
Required Pressure Range
↓
Nozzle Type
↓
Material Compatibility
↓
Filtration