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:. Frequent Asked Questions:
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What does RLS™ meter stands for?
RLS™ meter refers to Relative Loss of Section Meter™. RLS™ is a registered trade marks of CMT(Instruments) Ltd.
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What is the measurement unit used?
The measurement unit is in LSU, Loss of Section Unit. It indicates the percentage loss of contiguous metal in the test area relative to the reference area. LSU is a registered trade marks of CMT (Instruments) Ltd.
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What is the technique used?
RLS™ test utilizes a special electromagnetic technique to acquire the necessary data, linked to an integral, embedded computer.
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Why use RLS meter?
It helps to quantify the overall corrosion levels of the columns, both internally and externally. It detects corrosion up to 100mm below ground without the needs for excavation (Non Destructive Test) . RLS meter enables those steel columns at risk to be rapidly identified and scheduled for action . Equally importantly, it allows those columns that are in sound condition to have their future monitoring economically scheduled . It assists owners in saving cost from unnecessary replacement of columns due to visual inspection. It helps to identify severely corroded columns that will otherwise be missed out by subjective visual inspection.
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Why visual inspection is not appropriate?
Visual inspection is subjective. It can't quantify the corrosion levels, therefore can't assess the severity of defects . It can't identify internal corrosion. Excavation is needed for below ground assessment .
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The instrument is capable of testing on which types of columns?
Any planted steel columns. Examples, streetlights, park and landscape lights, sign posts, gantries ,etc
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Why only detect upto 100mm below ground?
As identified and reported by Institute of Lighting Engineer of UK, this is one of the zone most vulnerable to corrosion (see ILE Technical Report No.22) . Defects at this zone due to corrosion are significant and catastrophic failure can occur as it is a pivot point of the planted column (see Structural Stability of Lighting Columns reported by Paul Withers , Chartered Civil Engineer) . The first 100mm below ground can hold enough water and oxygen to cause corrosion. Therefore, i f there are corrosion deeper below ground, then it'll be more serious near the ground surface .
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Will the surface coating such as bitumen, epoxy powder coating, galvanished coating affect the test?
No, it will not be affected by surface coating and therefore the coating do not need to be removed.
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What is the test procedure?
The procedure is to locate the search head against the column at a reference area least likely to have suffered corrosion. The instrument scans the area and a reference value, representing the bulk average mass of metal, is locked into the computer. The standard search head uniformly scan a 200mm by 200mm surface area.
 The head is then placed to the ground with its face against the column and a reading obtained proportional to the bulk average mass of metal within the reference area. The search head uniformly scan a 200mm wide area 100mm above its base to 100mm below ground level. The instrument is then move at 90° intervals around the column and readings obtained and held at each position. The four overlapping measurements cover the full circumference of the column. Thus, the quadrant suffering the greatest loss can be identified.
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