Calculating moisture retention, 6 calculating moisture retention – B&C Technologies IM Series Industrial Ironer User Manual
Page 23
3.3.6
Calculating Moisture Retention
Percent Moisture Retention is a measure the water remaining in the goods being processed. To
determine the water retention of flatgoods being processed do the following:
1. Pull a sample of 10 pieces from the middle of the pile (goods on top tend to be dryer and will
give false results).
2. Immediately weigh your sample of 10 goods and record that weight as ”W1”. 3. Pass them
through the ironer once and wait 5 minutes.
3. Weigh the sample again and record the weight as ”W2”.
4. Iron the sample goods a second time.
5. Weigh the sample a third time and record this as ”W3”.
From these weights one can find: 1) The dry weight of the laundry, 2) The moisture retention of
the ironed goods, 3) The initial moisture retention of the goods before ironing.
To calculate moisture retention, use the following formulas:
Moisture Retention (%) before ironing = (W1-W3)/ W3
Moisture Retention (%) after ironing = (W2-W3)/ W3
As a general guide: The Moisture Retention before ironing should be 30% to 50%. The Moisture
Retention 5 minutes after ironing should be 2% to 4%.
Fabric Weight is a major factor needed to determine the actual practical work rate for flat goods.
Fabric weight is typically expressed as g/m
2
(grams per square meter), lbs/yd
2
(lbs per square
yard), or oz/yd
2
(ounces per square yard). The fabric weight for the goods must be known to find
the proper ironing speed in the Work Rate Chart. The weight of the flatwork can be determined
easily by:
1. Measure the Length and Width of each of the 10 sample pieces used above. Multiply the
measurements for each sheet to find the total area of each piece (Area = Length x width).
2. Add the calculated area for all 10 pieces.
3. If the sheets are measured in inches, divide the sum by 1296 to convert to square yards (yd
2
).
4. Divide the total dry weight (W3 from above) by the area in square yards from step 3 to
calculate the weight.
Fabric weight = Total Weight (lbs) / Total Area(yd
2
)
13