by Italo Pace
Most industrial laundries usually control their wash cycle by checking and comparing waste generated over a certain period of time. This system has a few gaps. Instead of being assessed immediately, the results are checked after a period of time that can vary from a week to a month, in order to prevent the analysis from being biased by the historical memory of the articles themselves.
I personally believe that the best way to check the wash cycle is to use EMPA 103 strips made by the EMPA Institute in St. Gallen (Switzerland). EMPA is a Swiss institution that studies materials and technologies used in different sectors, and employs 800 people.
The strips are made by sewing together several pieces of cotton pre-stained with different types of soiling agents. In the case of EMPA 103, these range from oil and grease spots to albumen and bleach stains. There is even a portion of cotton that has been bleached but not “brightened”.
The strip is placed in the washing machine and/or tunnel washer, then undergoes the drying and ironing cycle before being checked against the sample pre-selected by the laundry to represent its own “ideal cleaning standard”. The comparison reveals if the cleaning level achieved is satisfactory, unsatisfactory or above the desired standard.
Thereafter, wash cycle results are analyzed for each type of stain on the EMPA 103 strip, so that the laundry operator can determine the interventions required from the cleaning and detergents standpoint. The EMPA 300 strip will subsequently be used to evaluate the textiles wear and tear. Hence the EMPA 103 strip is used to test wash cycle quality and the EMPA 300 to check durability.
After the cleaning cycle has been verified or changed to meet the desired standard, you can start testing durability by means of the so-called “wash cycle stress test”. First, cut the EMPA 300 strip lengthwise in half, mark one piece “0 wash cycles” and set it aside. Once the other piece has undergone a single wash, dry and ironing cycle (1 wash cycle), cut it in half. Mark one half “1x” and store in a special place, then put the other half through 24 additional wash cycles. Thereafter, cut this in half, mark one piece “25x” and set it aside. Clean the other piece for a total of 50 wash cycles. Ultimately, 4 pieces of the original strip will remain: 1 with 0 cycles, 1 with 1 cycle, 1 with 25 cycles and the last with 50 wash cycles. All of them will be sent to the textiles institute for analysis of the following parameters:
- Organic stain content
- Ash content
- Tear resistance
- Degree of polymerization
- The standard cleaning quality desired and accepted by the market in which our company operates
- The weft yarn type
- The warp yarn type
- The number of warp threads/cm
- The number of weft threads (picks)/cm
- The type of weave patterns.
Verification of all this data will tangibly prove the usefulness of the test performed.