Manufactured in-house

MVWS Nozzle

Open, non-automatic directional spray nozzles discharging a uniformly filled cone of medium-velocity droplets. They apply water to vertical, horizontal, curved and irregular surfaces to cool them and stop heat being absorbed from an external fire.

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At a glance

Material: Brass or stainless steel 316
Maximum working pressure: 12 kg/cm²
K-factors: K-18 to K-102
Spray angles: 65° to 160°

Specification

Model	MVN-B (brass) or MVN-S (stainless steel 316)
Type	Open (non-automatic), directional
End connection	½" NPT (ANSI B1.20.1) standard; ½" BSPT optional
Maximum working pressure	12 kg/cm²
Design pressure	12 kg/cm²
Effective working pressure	1.4 to 3.5 kg/cm²
Minimum operating pressure	1.4 kg/cm² (20 psi)
Operating temperature	4 °C to 65 °C
K-factors (metric)	K-18, K-22, K-30, K-35, K-41, K-51, K-64, K-79, K-102
Spray angles	65°, 80°, 90°, 100°, 110°, 120°, 140°, 160°
Accessories	Strainer and/or blow-off cap (optional)
Finish	MVN-B: natural brass, nickel-chrome plated or electroless nickel plated. MVN-S: natural
Weight	Approx. 162 g (nozzle assembly)
Standards	UL 2351, NFPA 15

K-factor and discharge

K-factor (metric)	K-factor (US)	Orifice, mm (nominal)	Flow at 1.4 kg/cm², LPM	Flow at 2.0 kg/cm², LPM	Flow at 3.5 kg/cm², LPM	Flow at 12 kg/cm², LPM
K-18	1.26	6.2	21.3	25.5	33.7	62.4
K-22	1.54	6.7	26.0	31.1	41.2	76.2
K-30	2.10	7.2	35.5	42.4	56.1	103.9
K-35	2.45	7.8	41.4	49.5	65.5	121.2
K-41	2.87	8.8	48.5	58.0	76.7	142.0
K-51	3.57	9.6	60.3	72.1	95.4	176.7
K-64	4.48	10.2	75.7	90.5	119.7	221.7
K-79	5.53	11.8	93.5	111.7	147.8	273.7
K-102	7.15	13.6	120.7	144.2	190.8	353.3

Q = K × √P, Q in LPM and P in kg/cm². US K-factor = metric K-factor ÷ 14.2745. Other K-factors on request.

Material of construction

Component	MVN-B (brass)	MVN-S (stainless steel 316)
Housing (yoke)	Brass IS:291 Gr.1 (equivalent ASTM B21)	ASTM A351-CF8M (SS 316); CF3M (SS 316L) optional
Nozzle	Brass IS:319 Gr.1	ASTM A479 TP 316
Deflector	Brass IS:291 Gr.1	ASTM A351-CF8M (SS 316)
Screw	ASTM A479 TP 304	ASTM A479 TP 304
Strainer (optional)	Copper	Stainless steel 316 / 316L
Blow-off cap (optional)	Elastomer	Elastomer

Equivalent specifications are indicative only.

Dimensions

Dimension	mm
Overall height, without strainer	73 ± 0.5
Strainer projection (optional)	13
Thread length, ½" NPT	14
Hexagon, across flats	22
Deflector diameter	Ø 26
Yoke width, plan	30
Yoke end radius, plan	R 20

Tolerances on untoleranced dimensions to IS:2102 (M). Reference drawing DTL-MVWS-NOZ-P1.

Spray coverage

Spray angle	Coverage Ø at 1 m	Coverage Ø at 3 m
100°	2.4 m	5.4 m
120°	3.5 m	6.9 m
140°	4.9 m	7.5 m

Vertical downward spray at an average inlet pressure of 2.0 kg/cm², still air. Patterns for 65°, 80°, 90°, 110° and 160° on request.

Construction & operation

MVWS nozzles are open (non-automatic) directional spray nozzles for fixed water spray (deluge) systems protecting special hazards. An external deflector discharges the water in a directional cone of fine droplets, distributed uniformly over the surface to be protected.

They apply water to exposed vertical, horizontal, curved and irregular surfaces; cool those surfaces and prevent excessive absorption of heat from an external fire, avoiding structural damage and the spread of fire; and control or extinguish the fire, depending on the water design density the applicable code requires.

Because the design intent of water spray systems varies considerably, the nozzle is made in several combinations of K-factor and spray angle, and may be oriented in any position the hazard requires.

Operating pressure

The minimum desirable pressure for a reasonable spray pattern is 1.4 kg/cm², and a change in pressure between 1.4 and 3.5 kg/cm² does not change the spray angle considerably. Published patterns are at an average of 2.0 kg/cm² in still air and apply between 1.4 and 4.2 kg/cm²; above 4.2 kg/cm² the pattern draws inward and the coverage area decreases. Consult DTL for pressures up to 12 kg/cm².

NFPA 15 requires a main pipeline strainer for systems using nozzles with an orifice smaller than 9.5 mm (⅜ inch) — K-41 and below — and wherever the water is likely to contain obstructive material.

Installation and maintenance

Handle with care; store and ship in the original packing only.
Do not install a nozzle that is visibly damaged.
Apply Teflon tape or a soft thread sealant to the male thread of the nozzle only.
Hand-tighten into the fitting, then use a nozzle wrench. Excessive torque can damage the arms and deflector and affect the spray pattern.
Optional blow-off caps keep foreign material out of the waterway; the minimum operating pressure with a cap fitted is 1.4 kg/cm² (20 psi).
Outdoors, the system designer must allow for wind velocity and any field obstructions affecting the pattern.
Have authorised personnel inspect the system regularly for atmospheric effects and internal or external obstruction.
Operate the system at full water flow at least twice a year, or as NFPA or the authority having jurisdiction requires.
Design water spray systems to NFPA 15 and/or the applicable authority having jurisdiction.

Marking

Each nozzle body is marked with the DTL trademark, its K-factor and the year of manufacture.

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