As a result of involvement with both US-EPA and Environment Canada on their respective wetcleaning projects, it became apparent that additional practical experience with existing commercial sites was necessary.
In particular, it was clear that there was need to define the process parameters for professional aqueous textile cleaning to develop guidelines for professional aqueous textile cleaning and to demonstrate practical boundaries for these processes.
Through discussions held by the participating organizations (Environment Canada, R.R. Street & Co. Inc. and Langley Parisian Limited), it was determined that the test should be conducted at an existing, well established location. It was felt that a site such as this would yield more objective data with respect to the economical viability of wetcleaning. Further, it was decided that "state of the art" equipment would be used to maximize the potential for wetcleaning but that non-aqueous technology must also be available off-site to satisfy all customers.
The site was chosen as a result of the mix of articles being processed. It is located in a lower middle class/working class area. This tends to limit the number of complex, high-fashion garments received.
The plant has been established for approximately forty-five years and is relatively small. Annual sales are in the range of $160,000. This sort of low-volume plant is quite representative of many plants in North America. For the purposes of this study, the plant manager, who has many years of experience in the textile care industry, was instructed to use her experience and judgment to determine the proper cleaning method for each garment. Care labels were to be used as a guide, but could be overruled if necessary. It should be stressed that this decision was made in order to explore the boundaries of the process.
Because of the experience of the operator, it was felt that the risk was relatively minimal. Neither of the authors of this abstract advocate ignoring care labeling instructions in normal operational settings.
1. A total of 12,123 pieces were recorded for the purposes of this test from September 20, 1995 to March 31, 1996. A breakdown by fibre type is shown.
Wool 6.655
Cotton 2,267
Rayon 1,532
Synthetics 1,627
Silk/linen 42
Because the test period ran over the autumn and winter months, relatively few silks and linens were received. The low number of these garments (42) makes any results inconclusive.
2. Each fibre category is broken down into garments wetcleaned and drycleaned on percentage basis. Anecdotally, most of the results are fairly predictable, except for rayon which does no normally perform well in an aqueous environment.
Fiber % Wetcleaned % Drycleaned
Wool 43 57
Cotton 96 4
Rayon 67 33
Synthetics 80 20
Silk/linen 50 50
3. On an overall basis, 61% of garments received were wetcleaned with 39% being drycleaned. In retrospect, the demographics of the area and the nature of the work mix make this result fairly predictable.
4. & 5. These charts show what we feel is the theoretical endpoint for wetcleaning at this site. The data cover the period from January 1, 1996 to March 31, 1996. Because these are winter months, the volume is quite low (only 5,209 pieces). We hypothesize that this low value allows a considerable amount of time to be spent in making the decision on process selection.
Further, the operators had gained considerable skill with respect to the process in the first part of the test period. Approximately 75% of total throughput was wetcleaned during this period with drycleaning accounting for the remaining 25%.
Fibre % Wetcleaned % Drycleaned
Wool 66 34
Cotton 95 5
Rayon 91 9
Synthetics 73 27
Wetcleaned 75%
Drycleaned 25%
6. 7. & 8. Three representative formulae are shown. They are somewhat self-explanatory. It is interesting to note that we did not build in extensive dwell time. This has been done in some settings but we found that limiting the rotation speed of the cylinder to as little as 5 rpm was sufficient in most cases. A long dwell time formula is available but it is seldom used.
Process Time Temp Water Supply Mechanical action
(min) F Level RPM Rotate Dwell
(sec) (sec)
Wash 5 60 5" Detergent 5 10 3
(2 oz.)
Rinse 1 Cold 6" - 5 10 3
Finish 3 Cold 5" Sizing 5 10 3
(0.7 oz.)
Extract 1 - - - 400 - -
Process Time Temp Water Supply Mechanical action
(min) F Level RPM Rotate Dwell
(sec) (sec)
Wash 6 80 5" Detergent 5 10 3
(2 oz.)
Rinse 1 Cold 7" - 5 10 3
Finish 3 Cold 6" Sizing 5 10 3
(2.5 oz)
Extract 1.5 - - - 550 - -
Process Time Temp Water Supply Mechanical action
(min) F Level RPM Rotate Dwell
(sec) (sec)
Pre-Wash 2 100 7" Detergent 20 10 3
(2 oz.)
Wash 8 100 7" Detergent 20 10 3
(2 oz.)
Extract 1 - - - 400 - -
Rinse 2 Cold 7" - 20 10 3
Finish 3 Cold 6" Sizing 5 10 3
(2 oz.) 20 10 3
Extract 2.5 - - - 600 - -
9. It was determined at the outset that this project would only look at financial parameters that could be affected by the wetcleaning/drycleaning question. It was recognized that the vast majority of factors which determine the economic viability of a site have little if anything to do with the washing process, be it aqueous or non-aqueous. As such, we looked at productive labour costs at the site, excluding counter wages which, of course, do not change regardless of process. As might be expected, finishing costs are slightly higher in the current period (September 20, 1995 to March 31, 1996) then in the prior period (September 20, 1994 to March 31, 1995).
The plant operated in a dryclean-only mode during the prior period. The decline in number of pieces processed in the current period was due to a discount competitor opening for business in the neighborhood. This occurred on or about January 1, 1995. As a matter of interest, the piece counts for the periods January 1, 1996 to March 31, 1996 compared with January 1, 1995 to March 31, 1995 are virtually identical. Although the cost per piece is slightly higher for the current period, the results are fairly unremarkable.
Processing Costs, $Canadian
Source Current Period Prior Period
Total plant process wages 12,022 14,432
(excluding counter wages)
Outside processing wages 1,350 -
Total processing wages 13,372 14.432
Total pieces processed 12,123 13,439
Wage cost per piece, $Canadian 1.10 1.07
Current period= Wetcleaning
Prior Period=Dryclenaing
10. Energy cost differences, although significant on a percentage basis, are, from an overall perspective, immaterial. Process heat is supplied by a small (15hp) Scotch marine type HRT boiler equipped with flame retards. This unit was oil fired for both the current and prior periods although it has subsequently been converted to natural gas firing.
As might be predicted, fuel cost per piece is higher in the wetcleaning mode because of the non-volatile nature of water. The 15.7 cents per piece is probably understated because it does not include energy consumed to dry the drycleaned garments off site.
It is safe to say that this would add 2-3 cents per piece to this number. It should also be noted that the change to natural gas firing will reduce this number substantially, all of which should tell us that these costs are of relatively little consequence. At the beginning of the test period, a very inefficient electric water heater was replaced with a new gas fired unit. The savings are obvious. Again, these numbers demonstrate the high level of flexibility in dealing with costs in this area.
Source Current Prior
Period Period
FUEL OIL
Consumption, litres 5,948 5,287
Costs in $Canadian 1,907 1,654
Cost per piece $C 15.7 12.3
ELECTRIC ENERGY
Consumption, kwh 11,170 15,670
Costs in $Canadian 962 1,497
Cost per piece $Canadian 17.9 11.1
NATURAL GAS
Consumption, m3 663 -
Costs in $Canadian 172 -
Cost per piece $Canadian 1.4 -
Current period= Wetcleaning
Prior Period=Dryclenaing
11. The remarkable reduction in water consumption during the wetcleaning experiment can be explained by the fact that the old dry cleaning equipment was water cooled. As is often the case in Canada, because of low water costs, the cooling water ran continuously and was not re-circulated. The relatively cold winters in Canada make cooling towers problematic. This result is not really a commentary on the great efficiency of wetcleaning with respect to water consumption, but rather it is a commentary on the relative inefficiency of older drycleaning equipment. The 31.3 litres (8.1 US gallons) per piece used in wetcleaning is a relatively low number if compared to historical laundering standards. Ultimately, of course, water consumption levels are highly dependent on formula design so other tests may yield very different results.
Source Current Prior
Period Period
Waterc consumption, m3 379 566
Costs in $C per m3 0.73 0.70
Total water cost $Canadian 275 397
Total pieces processed 12,123 13,439
Cost per piece cleaned 2.3 3.0
Water consumption
Litre per piece 31.3 42.12
gallons per peice 8.1 11.0
Current period= Wetcleaning
Prior Period=Dryclenaing
12. We hypothesize that many items which have historically been drycleaned may, in fact, be wetcleaned with relatively little increase in finishing costs until a "threshold" limit is reached. We further hypothesize that this threshold level can vary drastically from site to site as a percentage of total throughput wetcleaned. Our own investigations, as well as earlier work done by Environment Canada, seem to confirm that once complex constructions (tailored garments) are wetcleaned, the threshold is quickly crossed. At the test site, because of work mix, this threshold occurred at a very high level of wetcleaning relative to drycleaning.
The results at this site should not be interpreted as being attainable at every site. A determination of the correct equilibrium for each site must be based on the criteria which will now be dealt with in the textile care spectra discussion. The test has been highly successful from an overall perspective. Few instance of consumer resistance have been encountered. Only four claims have been paid since the outset of the period, all on dry cleaned items.
The changes at the site have been dealt with only as a change in process rather than as a "green" or "environmentally friendly" change.
Date created: Oct. 10 96 Hal Horning hal@natclo.com