Click on Droplet Test thumbnails below for enlarged views
According to NFPA 750, Standard for the
Installation of Water Mist Fire Protection Systems, 2000 Edition, drop size
distribution alone does not determine the ability of a spray to extinguish a
given fire and Scotch Mist® is an
advanced system whose nozzles produce a mist which benefits from a variety of
droplet sizes.
Drop size distribution, flux density and velocity are all involved in determining the ability of a mist to extinguish a fire in a given scenario [NFPA 750, Cl. A-1-4.21] and Scotch Mist® Blaster nozzles have been tested to establish this criteria. The tests were conducted at Spraying Systems Co. facility in Wheaton, Illinois, USA
The nozzles were tested in accordance with NFPA 750
Standard on Water Mist Fire protection Systems 2000 Edition and ASTM
E799 which require all measurements to be carried out at 1 metre distance.
Testing included volume flux measurements and drop size measurements at
various pressures, taken at numerous locations within the spray.
The one-component Aerometrics PDPA instrument used in this test has a
100-mWatt Argon-Ion laser to provide the light source. The transmitter
and receiver were mounted on a rail assembly with rotary plates. Size
range was adjusted to capture the full range of drops produced by the nozzle
and, for each test point, 10,000 samples were acquired.
This illustration shows a typical volume flux
contour plot, produced using Microcal's Origin 6.0 plotting software. The
volume of water collected in each pan was measured and the Origin software set
up to generate a 25x25 matrix to provide data for the contour plots.
The data
used for establishing Volume Flux Weighting was calculated by using Method 2 as
described in NFPA 750 and this illustration shows a typical plot.