Just how effective are insulated flasks and cups in preventing heat loss in severely cold weather?
The Consumer Council has conducted a test on 10 insulated flasks and 14 insulated cups to help consumers in their comparison and choice of these products.
The results indicated clear variations in the heat insulation performance of these seemingly identical utensils all made of stainless steel.
In the case of insulated flasks, some samples performed decidedly better than the others in heat insulation. After a test period of six hours, the best performer retained a temperature of 79.9℃ (a drop of 15.1℃).
The worst sample fared at 66.9℃ which is just short of the 70℃ minimum temperature requirement according to the European Standard (EN12546-1:2000).
For insulated cups, the variations in heat insulation performance (after two hours) was even more pronounced - from 44.4℃ to 83.6℃, a difference of 39.2 ℃ between the best and the worst samples. But unlike insulated flasks, the European Standard does not set minimum temperature limit for insulated cups.
In the test, all 10 insulated flask samples were of a vacuum type (the insulant is a vacuum); and among the 14 insulated cup samples, 10 were vacuum, two were with polyurethane insulant, and two were double layer stainless steel.
In general, the vacuum samples fared best in heat loss prevention, followed by the polyurethane insulant, and the double layer stainless steel.
The test could establish no direct correlation between their performance and price which ranged from $35 to $280, and $55 to $179 for insulated flasks and insulated cups respectively.
The test also revealed significant discrepancies between the claimed and measured capacities of the samples in accordance with the European Standard. The differences between claimed and measured capacities were 4% to 16% for insulated flasks and 2% to 26% for insulated cups.
All samples were judged to be satisfactory in their performance in relation to pouring, stability, thermal shock, stopper leakage, seal leakage, impact and handle.
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