The washroom is central to the laundry’s operation but it is one of the most expensive areas to run. It is essential that it is managed efficiently both to make sure that it meets production targets and to control its costs.

Each department in the laundry relies on the washroom to process its work correctly, send it out in the right sequence and deliver it to the next department on time and ready for processing.

Failure to manage the work flow correctly will adversely affect both productivity and costs. For example, if the washroom sends a constant flow of towels to the tumbler section and neglects to send out any sheets, then the ironer operators and their machines will be kept waiting, incurring costs without producing work.

This scenario will be even worse if the towels are too damp when they are sent out as they will take longer to dry, leading to a log jam of work waiting to be processed. Often the towels will fill all the available trolleys so that when the sheets are finally washed they have to stay in the machine waiting for transport to the ironers. This not only delays the washed sheets’ progress through the production line it could also delay any other loads that are waiting to be washed.

Although production planning through the washroom may appear quite logical, the situation described above occurs quite often.

It is therefore absolutely essential that the output from the washroom is carefully balanced to ensure that each department has enough work to produce a continuous flow through the plant. If an ironer is ­capable of producing 800 sheets per hour – at an average weight of 0.9kg per sheet this means that the washroom must produce an average of 800 x 0.9kg = 720kg/hour.

If a typical washer-extractor sheet program takes 35minutes plus 5minutes loading/unloading time, each washer can produce 1½loads per hour. Therefore, the washroom manager can allocate a specific number of machines, based on their capacity, to producing work for the ironer.

If each washer takes 100kg then each has a potential production rate of 150kg per hour. As the ironer line requires 720kg per hour, five machines should be constantly processing sheets to keep the ironer section productive.

In this situation with five machines processing sheets on a 40minute cycle, a load of work should be leaving the washroom every 8minutes so timing becomes critical and a poorly trained or poorly supervised washroom operator can destroy production.

Serious error

An untrained operator may try to save time by loading the machines at the end of the last shift of the day but this is a serious mistake.

When the operator switches on the machines in the morning, they will all call for water, steam and electricity and this sudden huge demand for utilities can be catastrophic for the whole laundry.

The steam pressure suddenly drops and this not only slows production for all steam-heated equipment but there is also a risk that the boiler will prime. This will contaminate the steam-line causing water logging and jamming in the steam traps and several other engineering problems.

Each washer will take longer to reach its target dip level and temperature and a 35minute wash cycle is suddenly extended to 45 or 50minutes.

As the washers were started round the same time they will also finish within a few minutes of each other. The operator can only unload one machine at a time so the last machine in the line will stand idle for up to 40minutes.

The production planning for the day has been destroyed by one well-meaning operator that did not understand the importance of sequencing and production planning.

Process design

The process design used for each classification must be checked carefully to ensure optimum production.

Many modern laundries have passed the responsibility for designing wash processes to their chemicals’ suppliers.

Programming the PLC or the machine’s computerised controls can be complex. Failure to maintain strict programming protocols can badly affect the wash process so it’s best to leave the programming to the detergent company as it is likely to be more familiar with the controls.

This does not mean that the wash process design should be left entirely to the detergent supplier without any input from the laundry management. Many wash processes are unnecessarily long or use excessive amounts of water and both errors can have severe financial consequences.

For example, only loads with medium to heavy soiling will need more than one wash stage but many wash programs use two separate stages. The first stage is carried out at 39 – 40C for 5minutes. The machine is then drained and more water, steam and detergent are added for a second wash at 71– 75C for 7– 8 minutes.

Stepped wash

However, a single “stepped” wash process will not only save time and money but will often give a significantly better result as well as reducing the number of pieces sent for re-wash.

A typical washer-extractor two-stage wash will use 25 – 30litres of water per kg dry weight of work processed – whereas a “stepped” wash process will reduce this by 4 – 5litres per kg. It will also save up to 30% of the steam required, shorten the elapsed process time by 5minutes or more and reduce detergent consumption by 25%.

Hotel and hospital sheets, for example, are rarely more than lightly soiled. They only need a single stepped wash process. The linen is processed at 39C for 3 – 4 minutes to remove protein soiling, then without draining the machine, the temperature is raised to 71– 75C and the line processed for a further 5 – 7 minutes to emulsify the oils and fats.

This stepped process shortens drain and refill times as well as reducing the time needed to reach the final temperature. The water temperature now only needs raising from 39C to 71 – 75C whereas fresh incoming water will only be at 15 – 18C.

Check the rinse

Rinsing is the next process to look at. If the laundry uses washer-extractors that can be programmed to give an inter-extract, then, depending on the alkalinity of the raw water and of the main wash water, it may be possible to use this feature after the main wash and between rinses to reduce the number of rinses from three to two. This could save at least a further 7litres per kg as well as the time taken by the third rinse, drain ­and fill.

When processing 100% cotton items, the water retained in the load after a wash and standard drain is around 2.8x the weight of the fabric so a 100kg load of cotton items will contain around 280litres of water. However, a 1minute inter-extract will often reduce this down to 1.5x the weight of the load.

If a 100kg load of cotton items is processed with a main wash working at a concentration of 800ppm alkalinity (calcium carbonate equivalent), then at the end of the main wash and standard drain the load will contain 280litres of water with a concentration of 800ppm alkalinity.

This means that 224g of alkalinity will be carried over and will need to be diluted in the first rinse.

If an inter-extract is used, the carry-over will become 150litres of water containing 800ppm of alkalinity so there will only be 120g of alkalinity to be diluted in the first rinse.

If the program uses a rinse dip in the ratio of 7:1, there will be 700litres of water to dilute that 120g of alkali.

Ignoring the raw water alkalinity, the carry-over from a normal drain should result in an alkalinity of around 320ppm versus the inter-extract carry-over which produces an alkalinity of 171ppm.

The same logic applies when an inter-extract is then also applied between the first and second rinse. So a normal drain would leave 128ppm at the end of the second rinse and a third rinse would be needed to avoid galling but if an inter-extract is used the concentration would be only 90ppm and a third rinse would not be necessary, thus reducing the cycle time.

Correct sequencing, a stepped process and the use of an inter-extract are just some of the ways to improve washroom productivity while also reducing the laundry’s operational costs.