Research review - the latest developments

15 May 2020



With the world still in the grip of the novel coronavirus, Covid-19, LTC Worldwide disseminates the latest information available for the laundry sectors on this and other subjects of concern to the industry


This month we look at the latest information available as the laundry sectors battle with the Coronavirus and its knock-on effects on our industry.

We cover the following topics:

  • Low temperature washing and dealingwith the Coronavirus.
  • Implementing the latest detergent research.
  • How does the textile specification affect performance?
  • How to reduce the risk of laundry fires.
  • Minimising plastic debris from synthetic fibres in the oceans.

Ground-breaking research from around the world is of little use until it is implemented, and the benefits realised. Let’s look at just what is needed.

Conclusion

There is no limit to man’s ingenuity and the progress this year in the laundry and rental sector bears witness to this


LOW TEMPERATURE WASHING AND DEALING WITH THE CORONAVIRUS

The Coronavirus, Covid-19, is just one example of a difficult to kill micro-organism with serious, occasionally lethal, effects on the general population. Research by detergent suppliers has quite rightly addressed not only Covid-19 but also the Norovirus, Clostridium difficile, Bacillus cereus and a host of other species which tend to survive normal laundering. One solution being looked at by many textile rental operators is to design thermo-chemical processes which deal effectively with each of the main hazardous bugs mentioned, perhaps in the very reasonable belief that this will reduce future risks.

The results of the latest research by detergent suppliers, taken together, display a progressive move away from reliance on sodium hypochlorite for either bleaching of stains or for disinfection. This appears to have been driven by the difficulty of controlling chemical damage (and therefore shortened linen life) in textile rental. The problem of creating irremovable stains on healthcare work (because of the reaction between sodium hypochlorite and chlorhexidine antiseptic) has been spreading to hospitality linen (because chlorhexidine is now an ingredient of many skin products used by hotel guests). Processes based on peracetic acid are now widely available and have been demonstrated independently to be effective, but these do rely on disciplined process control and operation. Quite separately, there are also processes available which employ the undoubted disinfection power of ozone, but these too require systematic and methodical implementation. Locally generated ozone appears to work best, but again dosages, temperatures and concentrations need to be professionally controlled. Processes tested in independent research institutes still need to be validated under local laundry conditions.

Modern, laundries, with computer-controlled equipment, are well placed to deliver the quality of management required and perhaps the present turmoil engendered by Covid-19 will be the forerunner of some major changes. This may be more difficult to achieve in on-premise laundries and there perhaps could and should be a move away from these to textile rental. The time appears to be coming when the professional launderer has to market (vigorously and with authority) their ability to deal with the full range of infections and to assure each customer of their ability to process work in accordance with a validated disinfection process. Hotels and restaurants are rightly risk-averse and would recognise this claim, even if they jibbed at paying for it. As we emerge from the Coronavirus pandemic might be the ideal timing to raise this aspect of the marketing offer.

TEXTILE SPECIFICATIONS AND THEIR PERFORMANCE RELATIVE TO USE

Rental operators in Europe and North America are now developing textile construction standards which consistently deliver a target average life of around 120 wash and use cycles. For terry towels, for example, this is achieved by attention to factors such as the distribution of fibre length in the spun yarns, the twist for the pile yarns and the design of the seam stitching. This has been accompanied by demand from the hospitality sector for ever thicker (and heavier) towelling to meet customer perceptions of luxury, resulting in higher costs for purchase and laundering and sometimes bottlenecks at the tumble dryers. This can be partially offset by varying the fibre content of the base weave, with polyester blends speeding drying and offering the side benefit of improved tear strength.

For sheeting the picture is more varied, with demand shifting to higher thread counts for improved drape and handle, but with the accompanying disadvantage of reduced tear strength, especially for single pick constructions. Some suppliers have countered this (very undesirable) feature with a textile finish which improves the initial tear strength, but work is still needed to find a finish which achieves this, but which still lasts for the life of the sheet.

The move to cotton rich appears to be delivering a useful contribution to reducing the carbon footprint, certainly of the high-volume central section of the rental market. The inclusion of 20 – 30% polyester fibres is also restoring some of the tear strength lost with higher thread counts (which necessitate finer yarns). Not al laundries have yet achieved the necessary calendaring conditions to cope successfully with cotton rich without thermal distortion and there does not yet appear to be any ironer design on the market able to dry cotton rich using 12 bar steam without some distortion. LTC has completed basic work to indicate how this could be done.

HOW TO REDUCE THE RISK OF LAUNDRY FIRES

Historically, the industrial laundry sector in the UK has lost typically one or two large laundries each year to unexplained spontaneous combustion, with serious fires breaking out, often in the middle of the night, for no obvious reason. The result can be an insurance claim of over £5m per incident, with a consequent effect on premiums for the entire sector. There is now sufficient evidence to suggest that spontaneous combustion is probably the unfortunate consequence of an inadequate wash process. If oxidizable oils are not removed from textiles, then there is a risk that these will react slowly with the oxygen in the air (often in a warm pile of folded goods in the packing area). This chemical reaction is exothermic (it gives off heat) and it is this which warms up the pile so that it eventually reaches the auto-ignition temperature, perhaps over two hours later. The ignition hurls flaming textiles in all directions, giving the fire every chance to take hold and precipitate total destruction.

Leading chemicals suppliers have responded to this with modern emulsifiers which span the range of oxidizable oils, removing spa oils, printers’ solvents and garage greases with equal ease. There now needs to be a wider recognition that the solution to the laundry fire risk does not centre simply on fitting sprinklers to limit the damage. The risk can now be reduced at source very effectively. One quick method of assessing whether a laundry’s processes are adequate is to sniff the spa towels as they come out of the tumble dryer. If spa odours persist (or even worse, if there are rancid odours from breakdown of spa oils) then a better process is needed.

IMPLEMENTING THE LATEST DETERGENT RESEARCH

The common themes emerging from the research programmes of the leading suppliers of laundry chemicals include: The increasingly irresistible move to low-temperature washing, with a measurable impact on the carbon footprint of every rental laundry.

The tangible benefits of increased linen life offered by the novel low-temperature thermo-chemical processes now available, with average wash and use cycles attainable rising from around 120 towards a target of 200.

The ecological improvements resulting from reduced discharge of certain chemicals, particularly sodium hypochlorite, sodium metasilicate and various phosphates and other salts, into the environment.

The quality improvements now attainable using the latest chemical systems, especially with regard to protein soiling and staining and with the removal of spa oils and similar difficult contaminants.

The removal of some of the earlier problems with recycling of the heat in dirty wash water (notably lowering the risk of setting of protein stains in the pre-wash).

With linen replacement taking an increasing percentage of rental costs, the potential for increase in linen life has taken on greater importance. The reduction in textile degradation by washing at say 40C rather than 65C was theoretically predictable and early indications suggest that this is now being delivered. Accountants can now use their spreadsheet data to estimate accurately the average life cycle for items in each classification and so measure (in-house) how much is actually being saved (by totalling the number of rentals in a period and dividing this by the number of new items injected to maintain the service).

The drop to 40C or lower for the main wash has improved significantly the softening of protein stains (including bloodstains) in the prewash. Traditionally operated tunnel washers often had difficulty in maintaining a pre-wash which ran for at least 4 minutes below 40C to soften these stains sufficiently to get them all out in the main wash. This was frequently exacerbated by heat recovery creating warm rinse water, which again raised pre-wash temperatures. The move to low temperature appears to have solved this conundrum, to deliver much lower levels of residual staining.

The improvements now available with modern washing technology call for consistent process control. They need the skills of the professional launderer and the well-trained washhouse supervisor. Times, concentrations and temperatures are usually critical and will not tolerate the ‘twiddler’!

MINIMISING PLASTIC DEBRIS FROM SYNTHETIC FIBRES IN THE OCEANS

Environmentalists have rightly raised the issue of alarming accumulation of plastic debris in the world’s oceans. This includes polyester microfibres, which are released in large numbers, from small domestic washers right up to large tunnel washers. One enterprising and highly innovative laundry machine maker has designed and is now marketing a laundry filter design based on the principle of a hydro-cyclone (which works like a tiny spin dryer).

This should be capable of upscaling to industrial machines, delivering the capability of addressing the most difficult part of micro-plastic discharge to the environment. Achieving this might require some political will to mandate this relatively inexpensive add-on, but the means is nearly there.

IN-HOUSE TESTING: Dipslides enable in-house testing by the laundry for basic disinfection
TWO ROWS: A well-designed towel hem will have two rows of stitching and capture enough fabric either side of the stitch lines to prevent slippage
STAIN REMOVAL: Removal of protein stains demands requires a pre-wash which runs for at least 4 minutes below 40C
KEY DETAILS: Successful processing of cotton rich demands attention to key details


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