Figure 4. Test louver rig for sand louver testing at Thomas
Bell-Wright Independent Consultants, Dubai.
Figure 5. Close up of the sand louver free area under test.
SAND LOUVERS TO THE RESCUE
ANSI/AMCA STANDARD 500-L-
A NEW TEST STANDARD FOR SAND-RESISTANCE
Sand louvers are increasingly chosen as a solution by building
managers who struggle with wind-driven sand. The equipment
shields their building from sand before it becomes a problem.
When airstreams with windborne sand impinge on the face
of the louver blade, the terminal velocity of the airborne sand
particle is greatly reduced. Gravity pulls the particles to the
sloped louver sill before depositing them on the ground outside
the building, sweeping them away from the clean airstream
that passes through the louver blade gaps. (Figure 1).
Sand that is stripped from the airstream will fall to the bottom of the louver and exits via a sloped sill (Figure 2). Typically,
this sand simply then blows away.
Images courtesy of McGill Architectural Products.
There is no contesting that the prefiltering action of sand
louvers can provide significant savings in maintenance. But
building manufacturers must also be certain that sand louvers
perform as promised. It is important that there be a standard
way to put sand louvers to the test and evaluate their
effectiveness.
In January 2016, AMCA International published a new
test standard within its ANSI-accredited Standard 500-L,
Laboratory Methods of Testing Louvers for Rating3 (Figure
3). ANSI/AMCA Standard 500-L already contained rating
test procedures for air pressure drop, wind-driven rain and
other conditions. A test for wind-driven sand resistance was
Standard Test Dust Particle Size Distributions
120
Percent less than stated size (%)
ASHRAE
100
96
80
60
40
20
0
0.1
0.2
0.3
0.5
0.7
1
2
3
5
7
10
Mean Nominal Particle Diameter (microns)
20
30
50
70 80100
Figure 6. Standard test dust particle size distributions for different test procedures. Information courtesy of McGill Architectural Products.
24
Summer 2016
AMCA
inmotion
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Table of Contents for the Digital Edition of AMCA In Motion - Fall 2016