“City Star” and “Country Star” telescoping ladders signal thermal chock exposition of aluminium:
Aluminium alloys used in ladders are high tensile alloys for lighter weight and greater strength. Because of this, these alloys have been heat treated when manufactured. This heat treating is done at about 315°C / 600°F to get the aluminium to its final tensile strength. If the aluminium ladder has been subjected to extreme heat exposure – even for a brief period -, the load capacity may be reduced even though the aluminium without surface treatments would show no sign of any change.
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