The five fundamental spray patterns cover the full range of industrial spray applications. Choosing the wrong pattern — even with the right flow rate and pressure — produces inconsistent results because the spray geometry doesn't match the surface being treated.

Spray angle is the included angle of the spray cone measured at the nozzle tip. A 90° flat fan nozzle produces a spray that is 90° wide as it leaves the nozzle. The coverage width at the target surface is determined by the angle and the distance from the nozzle to the surface: Width = 2 × Distance × tan(Angle ÷ 2). A 90° nozzle at 12 inches from the surface covers approximately 24 inches. The same nozzle at 24 inches covers approximately 48 inches.

The tradeoff: as distance increases, coverage width increases but impact pressure at the surface decreases. For cleaning applications where impact energy matters, the optimal distance is the closest position that provides adequate coverage width — not the maximum possible distance. For coating and humidification applications where even distribution matters more than impact, a greater distance is often preferable because the spray has more room to develop a uniform pattern before reaching the surface.

For hydraulic spray nozzles, flow rate and operating pressure are linked by a fixed relationship: flow rate scales with the square root of pressure. Double the pressure and the flow increases by approximately 41%, not 100%. This means you cannot simply increase supply pressure to increase flow — the relationship limits how much flow increase is available from pressure alone, and at higher pressures the nozzle also begins to produce finer droplets and higher impact energy, which may or may not be what the application requires.

The correct approach: identify the operating pressure your system reliably delivers at the nozzle inlet — accounting for pressure drop in the supply piping — and then determine the flow rate required by your application. The combination of those two values determines the orifice size. Use the Flow Rate Estimator to check how your required flow at your operating pressure compares to catalog reference conditions.

• Measure or calculate pressure at the nozzle inlet — not at the pump or header. Pressure drop in supply piping can be significant, especially with small-diameter lines or long runs.
• Determine total required flow for the application — not just per nozzle. If 12 nozzles will run simultaneously, your pump must supply 12× the per-nozzle flow rate at the operating pressure.
• Check the catalog flow rate at your operating pressure, not at the reference condition. Use the flow-pressure formula or the Flow Rate Estimator to adjust.
• If the liquid is not water, adjust the catalog flow rate for specific gravity. Denser liquids flow at lower rates through the same orifice at the same pressure.

There are two separate material considerations in every nozzle: the nozzle body and the internal seals (if any). Both must be compatible with the liquid chemistry and temperature. A brass nozzle body that is compatible with a cleaning agent may have EPDM seals that are not — and the seal failure will cause a leak before the body corrodes. Check both.

Most NozzlePro spray nozzles use NPT (National Pipe Taper) threads — the standard in North American industrial plumbing. NPT threads are tapered, which means they tighten and seal as they are threaded together. The thread size refers to the nominal pipe size, not the actual thread diameter. A 1/4" NPT nozzle does not have 0.25" threads — the actual thread outer diameter is approximately 0.540". This is a frequent source of confusion when measuring existing fittings.

The most reliable way to identify an existing connection is to thread a known NPT fitting into the port and confirm the size that fits correctly. Trying to measure the thread diameter with a ruler is unreliable because nominal pipe sizes do not match actual dimensions at any standard size.

The orifice of a spray nozzle is precision-sized to deliver a specific flow rate at a specific pressure. As the orifice wears from liquid-borne abrasion, cavitation, or corrosion, it enlarges. A nozzle whose orifice has enlarged 15% delivers approximately 15% more flow than specified — and in a pattern that is wider and less uniform than the original. In a cleaning application, this means more liquid and water waste. In a coating application, it means too-thick or uneven film. In a humidification system, it means over-humidification.

• Establish a replacement interval based on operating hours, not appearance. A worn nozzle that still looks intact may be flowing 10–20% above specification. Test flow rate periodically — if flow has increased more than 10–15% above the new-nozzle spec, replace.
• Keep spare nozzles on the shelf. The cost of one production interruption from a failed or worn nozzle exceeds the cost of a year's supply of spares in almost every industrial application.
• Install a strainer upstream of nozzles in any system handling liquids with particulate content. A plugged orifice causes immediate performance failure. A 50–100 mesh strainer upstream of the nozzle prevents most clogging.
• Record the nozzle model number, orifice size, and installation date at each position. When a position underperforms, having this record eliminates guesswork about whether the installed nozzle is the correct specification.
• If you are cleaning a clogged nozzle, use a soft probe or soaking — never a metal pick or wire brush. Enlarging the orifice with a hard tool permanently damages the nozzle and increases flow above specification.