Description
The HD® Medium Velocity Water Spray Nozzles
are open type (non-automatic) nozzles, designed
for directional spray application in fixed fire
protection system.
Medium velocity water spray nozzle has an
external deflector, which discharges water in a
directional cone shaped pattern of small droplet size.
The water is uniformly distributed over the surface to
be protected.
MV Nozzles are effectively designed to apply water
to exposed vertical, horizontal, curved and irregular
shaped surfaces to allow cooling to prevent
excessive absorption of heat from external fire
and avoid structural damage or spread of fire. In some
application nozzles may be installed to control or
extinguish the fire depending on water design density
as per applicable codes. The nozzle is used in deluge
water spray system for special hazard fire protection
application.
As the design and intent of specific water spray system
may vary considerably, MV nozzle is made available in
several combinations of orifice sizes (K-factors) and
spray angles.
The minimum desirable pressure to achieve a
reasonable spray pattern is 1.4 Kg./Sq.cm. The water
distribution pattern as shown in the graph in following
pages is at an average pressure of 2.0 Kg/Sq.cm. The
change in pressure between 1.4 to 3.5 Kg./sq.cm.
does not affect considerable change in spray angle.
The spray pattern shown is with indoor application.
System designer must consider wind velocity while
designing the system for outdoor application. Field
obstruction if any affecting the spray pattern of the
nozzle must also be considered. The nozzle may be
oriented to any position as deemed necessary to
cover the hazard.
UL
LISTED
®
OCTOBER, 2020 PAGE 2 OF 8 HD 108
HD FIRE PROTECT
PVT. LTD.
The Blow-off plugs can be used to prevent the
depositing of foreign materials in the water way of the
nozzles, which could interfere with discharge of the
spray nozzle. Blow-off plugs are optional and are FM
Approved. Blow-off Plugs have identification mark with
respect to K factor. For example, Blow off plug for
nozzle having K-factor 22 will have identification mark
of 22. Minimum operatiiong pressure for nozzle having
Blow-off plug is 1.4 Kg./Sq.cm (20 PSI).
The main pipeline strainer as per NFPA-15 is required
for system utilizing nozzle orifice diameter less than
9.5mm (3/8 inch), i.e.MV Nozzle having K-factor 41
and less, and also for the system water likely to
contain obstructive materials.
INSTALLATION & MAINTENANCE
The spray nozzle must be handled with due care.
For best results, the storage as well as any further
shipment shall be made in original packing only.
Nozzle which is visibly damaged should not be installed.
Use Teflon tape or soft thread sealant on male thread
of the nozzle.
The nozzles must be hand tightened into the
fitting. After hand tightening use Nozzle WrenchNW-M for wrench tightening in to nozzle
fittings. Excessive tightening torque may result
into serious damage to nozzle arms and the
deflector, which may affect spray pattern of the
nozzle and its performance.
It is recommended that water spray system be
inspected regularly by authorised technical
personnel.
The nozzle must be checked for atmospheric effects,
external and internal obstruction, blockage if any.
The system must be operated with optimum water
flow at least twice in a year or as per the provisions
of NFPA or local authority having jurisdiction.
It is recommended to design water spray system as
per guidelines of NFPA15 and/or AHJ.
The owner is solely responsible for maintaining the
water spray system and the components there in so
that it performs properly when required
