RA. Medium Velocity Fixed Spray Nozzle

Model: EM CB, EM CBS, EM C, EM CS, EM CE
K-factor: 18 (1.26), 22 (1.54), 30 (2.10), 51 (3.57), 64 (4.48), 79 (5.53), 102 (7.14)
Spray Angle: 120°, 140°
Thread: 1/2” BSPT
Maximum Working Pressure: 175 psi (12 bar)
Minimum Operating Pressure: 20 psi (1.4 bar)
Strainer: Copper, Stainless Steel (Optional)
Nozzle Material: Brass, Stainless Steel, Aluminium Bronze
Finish: Natural Brass, Bright Brass, Chrome Plated, White Plated, Nickel Plated, Electroless Nickel Plated, Epoxy Coated
Standard: NFPA 15
Approval: UL Listed
View technical datasheet for more information

EMACO Reverse Action Fixed Spray Nozzle is an open type water spray nozzle used in fixed fire protection systems. It is typically installed in water spray systems where water is applied directly over exposed equipment or structural surfaces during a fire.

Unlike conventional spray nozzles, a reverse action nozzle discharges water in the opposite direction. Water hits the deflector, then gets redirected outward and spreads over the surface that needs protection. This reverse discharge feature allows water to be applied more effectively over surfaces that may be difficult to cover with standard spray nozzles.

Reverse action spray nozzles are commonly used in medium velocity water spray systems designed according to NFPA 15. These systems are primarily used for equipment cooling and exposure protection. The spray distributes water across the exposed surface to limit heating up and fire spread.

In a typical installation, the system is activated through a deluge valve. When the valve opens, water flows through the piping network and reaches the open spray nozzles. The reverse action nozzle then distributes water across the hazard surface in a controlled spray pattern.

Water spray systems are commonly installed in industrial facilities where exposed equipment requires cooling during a fire. The nozzle can be oriented in different positions so that the spray pattern properly covers the protected area.

Typical applications include:

Transformer protection systems
Cable tray protection
Petrochemical process equipment
Steel structure cooling
Tank farm exposure protection
Power generation facilities

The nozzle may be installed in different orientations depending on the required coverage area. Spray angle and K-factor selections allow the system designer to achieve the correct water distribution pattern for the hazard being protected.

The nozzle is typically installed in fixed water spray systems or deluge systems designed according to NFPA 15.

Design Specifications:

1/2″ BSPT threaded connection
Open type reverse action fixed spray nozzle
Working pressure 12 bar (175 psi)
Spray angles, 120° and 140°
Discharge K-factor from 18 to 102 (1.26 to 7.14)
Constructed from brass, stainless steel, or aluminium bronze
Natural brass, bright brass, chrome-plated, white-plated, nickel-plated, electroless nickel-plated, epoxy coated finish options
Optional strainer with certain models
Optional blow-off plug
Designed for installation in NFPA 15 water spray fire protection systems
UL Listed Reverse Action Spray Nozzle

1. Why use a reverse-action nozzle instead of a standard MV nozzle?

Reverse-action nozzles direct water opposite to the inlet direction, allowing better coverage on vertical, curved, or underside surfaces. They provide more efficient cooling for tank shells, pump casings, valve gear, and complex machinery that standard nozzles cannot reach evenly.

2. Can this nozzle work with seawater or corrosive water sources?

Yes. When using seawater or chemically treated water, nickel-plated or special corrosion-resistant versions are recommended. These prevent metal deterioration, scaling, and orifice deformation, ensuring long-term accuracy of the spray pattern.

3. How do engineers select the correct model and K-factor?

Selection depends on hazard level, required water density, coverage area, and operating pressure. Engineers evaluate heat radiation, fuel type, environmental wind, and nozzle mounting height. EMACO provides curve data and application assistance to match project needs.

4. Do reverse-action nozzles require frequent servicing?

They require minimal servicing but should be visually inspected and flushed periodically to remove debris. Plants using untreated or seawater should schedule more frequent flushing due to sediment buildup affecting discharge geometry.

5. Can this nozzle be installed in existing deluge systems without changes?

Yes. With available thread standards (BSP or NPT) and a wide K-factor range, the nozzle can replace or upgrade existing units without altering pipework or hydraulic system performance. It easily integrates into legacy deluge systems with minimal modifications.

Certification and Accreditation Partners

Protect your home, family, and business with industry-leading fire safety solutions—because seconds matter. From advanced smoke detectors to professional-grade extinguishers and smart alert systems, we’ve got you covered.