IAN HANBY - CHARTERED ENGINEER
NEW BS DIRECTIONAL DUST GAUGE
This instrument is designed to measure dust flux, usually quoted as mg/sq m/day
CONTENTS OF KIT
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Main assembly consisting of quadruple collectors on plastic-coated steel stand with heavy-duty base plate
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4 x 1000ml HDPE collecting bottles with internal seal
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1 x 600ml wash bottle
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4 spare collecting bottles
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Calibration data
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Overall height 1.6m, weight approx 14kg
BENEFITS
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Collecting heads and stand manufactured in accordance with BS1747Pt5 for consistent performance
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Collecting heads made from heavy gauge uPVC to reduce vibration and improve dimensional stability
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Robust collecting bottles of white HDPE with red HDPE attachment caps
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Optional sighting device fitted with magnetic compass for ease of installation - only one needed for any number of gauges
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Optional squeegee of aluminium alloy and neoprene rubber to facilitate removal of dust
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Various baseplates or special-purpose stands available by arrangement
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Spares, including collecting heads, and repairs available
There is a popular misconception that these gauges measure dust deposition whereas they attempt to measure dust flux. This flux is the vector product of airborne particle concentration (mass per unit volume) and the horizontal component of the windspeed (velocity) and thus has the units of mass per unit area per unit time. It is unfortunate that the units of dust flux are therefore the same as those of dust deposition, adding to the confusion. It is NOT possible to convert readings obtained by the directional gauge into deposition rates as the calculation would require knowledge of particle size, particle concentration and wind velocity components, most of which are not known. Adding the flux from the four collecting heads does not magically convert this directional gauge into a deposit gauge as some practioners imagine.