Wind Fences for Dust Control

Wind erosion causes an estimated 30 percent of stockpile dust emissions. Reducing the wind speed over the stockpile results in less dust. DustTamer Wind Fence material is designed to reduce wind speeds up to 90 percent within the sheltered area.

Why a Wind Fence?

Wind blows across the surface causing particles to move and ultimately lift off. This airborne dust then travels where it can be inhaled or deposited for future lift off.

Illustration of dust lifting off a stockpile

The size of particles that lift off is related to the wind speed. The following table provides a theoretical guide of wind speed required to lift off particles of different sizes and densities. It is important to note that the lift off of larger particles exposes more smaller particles to the wind increasing the total volume of dust, particularly respirable PM10 particles.

Material	Density	1 Micron Particle	10 Micron Particle	100 Micron Particle
Coal	800 kg/m3	0.8 m/s	2.6 m/s	8.3 m/s
Dirt	1300 kg/m3	1.1 m/s	3.4 m/s	10.6 m/s
Iron Ore	2200 kg/m3	1.4 m/s	4.4 m/s	13.8 m/s
Lead	3200 kg/m3	1.7 m/s	5.3 m/s	16.6 m/s

By controlling wind speeds, it is possible to control levels of particulate matter in the air. Using a Wind Fence to reduce the speed of the wind reduces the lift off of larger particles preventing exposure of more smaller particles.

Illustration of dust lifting off a stockpile with a wind fence protecting it

Why a Wind Fence and Not a Wall?

If a solid wall is used as a wind break, two different pressure zones are created as wind movement towards the wall increases. Impermeable materials such as a solid wall only deflect wind, not reduce it, creating a low pressure area in front of the structure which increases turbulence and causes more dust to lift off the surface.

dust lifting off a stockpile with a solid wall showing turbulent wind in front of stockpile

If a porous material is used, high velocity wind that moves toward the stockpile is reduced as air passes through, equalizing air pressure on either side of the barrier. A Wind Fence which reduces the wind speed in the protection zone does a better job at preventing dust lift off.

Illustration of dust lifting off a stockpile with a porous wind fence protecting it

Wind Fence Material & Attachment Systems

Wet Earth offers two different Wind Fence material types which have very different attachment systems. Both products have a similar wind reduction (based on their porosity) capability and are both quality long lasting systems. The DSI Dust Tamer solution uses a polyester material that has long strands. This material is secured to the support directly. The Dust Tex Net solution uses a HDPE mesh material that is secured to cables on 4 sides. The following summarises these different products and their securing systems.

DSI DustTamer Wind Fence Fabric & Attachment System

DustTamer Fabric is specifically designed for use as a wind reduction material. It is knitted from industrial grade woven polyester, resistant to UV rays, inclement weather, and temperature extremes. It’s unique ability to be stretched and tensioned to over 250 kg of pull prevents "flagging” of the material and consequential damage due to abrasion.

The fabric is 150cm or 90cm wide and is installed horizontally, spanning support columns as wide as 8m apart. DustTamer 6510 is 30% porous (90% wind reduction) and 6517 is 50% porous (75% wind reduction). The DustTamer material DOES NOT require any cable supports.

DustTamer fabric has been used for over 30 years as a wind reduction tool. A study of this fabric’s effectiveness was jointly conducted by the National Oceanic Atmospheric Administration and North Carolina State University and published in the Journal of Air Pollution Control in 1988.
DustTamer fabric image

Special Features of the DustTamer System

ACE polyester fabric is highly resistant to the elements (same fabric as used for towing and lifting)
Knitted design is so strong that it is self-supporting for spans up to 8m, no cables required
Fabric can withstand very high wind loads without damage (in excess of 200 km/hr) therefore DustTamer will work in high wind conditions when you need it most
Permanent installation with no maintenance required. The system is built to last for 20 years or more.
Slotted fabric design is self-cleaning as the vertical filaments will move with slots 27mm long.
Simple attachment hardware, no cables, heavy hardware or clips to install or maintain after installation due to stretching

DustTamer Wind Fence Securing Mechanism

Stand-Off Brackets

We provide specifically designed metal brackets to "stand off” the fabric from the support columns. This prevents the fabric from coming into contact with the post. They also provide a material that is thin enough to allow self-drilling/tapping attachment screws to penetrate the metal without pre-drilling. This makes installation significantly easier when attaching the fabric to the support columns.

Lock Bars

Anodized aluminium lock bars are available in lengths that match the fabric width (90cm or 150cm). They are used to "pinch” the wind screen fabric against the stand-off brackets. The lock bars are pre-drilled to accommodate self-drilling/tapping screws.

Tie Wraps

Fabric ties are usually installed at 60cm intervals on centre to tie the fabric together. This prevents fabric wear between horizontal fabric runs.

Photos of DustTamer securing system

Dust Tex Net Wind Fence Fabric & Attachment System

The Dust Tex Net is secured to cables which are hung between supports. The fabric is 300cm wide and is installed horizontally, spanning support columns as wide as 30m apart. We generally recommend 20m support spacing.

The fabric is secured to cables on the side and bottom by clips that release in high winds (eg >90 km/hr). This means that the support structure only needs to be designed to support these wind speeds which can significantly reduce the installation cost in locations where there is potential for high winds. If the location regularly has winds above this speed then the reduction in installation cost may be mitigated by the requirement to regularly reattach the bottom and sides of the material.

The Dust Tex Net system can also be used as a Dust Fence to capture dust. In this case a low porosity fabric (5% to 10% porosity) is used so that the mesh is small enough to capture dust particles and the wind speed reduction is significant enough for dust particles to fall out quickly.

Dust Tex Net Wind Fence Material

The Dust Tex Net is designed to be self cleaning, resist UVA rays and doesn’t lose its colour. It also maintains its mechanical characteristics for at least 5 years. The wind that brings dust onto the Dust Tex Net will also dry and shake the Dust Tex Net causing the dust to fall to the base of the net itself.

Dust Tex Net looks like shade mesh which is commonly used for small scale dust walls. Dust Tex Net is different from shade mesh in the following ways:

Dust Tex Net is non sparking and non flammable, ideal for coal
Dust Tex Net is self cleaning through the action of the wind
Dust Tex Net has electrostatic attraction of dust particles

Dust Tex Net Wind Fence Securing Mechanism

The Dust Tex Net installation system provides additional benefits:

up to 55m high walls
up to 30m spacing between supports
Safety material release in very high winds reducing structural support requirements and costs
Clips stay secured to cable after release so no airborne projectiles
Easy and quick installation and re-securing and replacement of material

This photo of a demonstration unit shows how the Dust Tex Net is secured, although in most applications the top of the material would be permanently secured (cable runs through mesh seam) and would not have the release clips.

$Dust Tex Net Wind Fence Installation System$

Wind Fence Installation Photos

$Dust Tex Net Wind Fence with A-frame supports$

Steel beam style posts flanged to concrete foundation

Round steel posts flanged to concrete foundation with matrix style bracing

Round steel posts driven into the ground

Round timber posts concreted into the ground

Dust Fence vs Wind Fence

Wet Earth also offers the Dust Tex Net Dust Fence. This page discusses the differences between Wind Fences and Dust Fences.

More Information on Wind Fences

If you have a particular dust control application you would like to discuss or would like more information then please call us on +61 2 6062 3300 or send an email to sales@wetearth.com.au.