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October 11, 2010
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Question: Do I need to heat the wash water in my IBA?

With increased competition, rising operating costs and uncertain economic conditions, most in-bay automatic operators are looking for ways to save money without compromising wash quality. One issue that is often raised is the importance of heating water or how much the heat can be reduced without effecting wash quality. This is especially critical for touch-free washes.

First off, the only chemicals that should be heated are those actually used in the cleaning process — not the chemicals used for extra services, drying or rinsing.

The basic factors a carwash operator is able to control are:
  • Water quality;
  • Temperature;
  • Chemistry;
  • Time, and
  • Action.
These factors work together in the cleaning process. Change one and the others will be affected. It is wise when fine tuning an IBA to only change one factor at a time to ascertain exactly what effect the change has made. By changing more than one, you can never be certain what has worked and what hasn’t.

Water quality
While sometimes overlooked in the cleaning process, water quality is a key element. It can affect the overall performance of a wash and impact the type and amount of chemicals used, thus affecting the chemical cost of the process. Water quality refers to the hardness and total dissolved solids (TDS) present in the water.

Hardness is caused by the presence of several minerals; mainly calcium and magnesium and to a lesser extent, iron. Calcium and magnesium are dissolved in the water while other mineral traces generally remain in suspension.

Water hardness reacts with the surfactants and detergents in a cleaning product, creating a neutralizing effect. As water hardness increases, the effectiveness of a cleaning product decreases. Many cleaning products contain conditioning or additives that counteract the negative effect of hard water. These additives are expensive and are usually added only in sufficient amounts to compensate for medium-hard to hard water.

The only way to remove hardness from water is by using a water softener or an ion exchange system. The softener pulls out the dissolved calcium and magnesium and replaces it with sodium. Ion exchange occurs when hard water is passed through a water softening system that contains an ion exchange resin, a bypass and regeneration system and a brine tank that contains water with an excess of salt.

Soft water allows for a more efficient use of cleaning chemicals. It usually results in lower chemical costs and, in many cases, a cleaner vehicle. There is really no advantage to use soft water in the area of rinsing. Typically, hard water breaks down foam and creates a better atmosphere for a dryer or blower to work.

Total dissolved solids (TDS) refers to everything that is dissolved in the water including water hardness. It is what is basically responsible for water spotting along with chemical residue. TDS is measured in parts per illion (PPM).

Water spotting usually occurs when the TDS is greater than 50 PPM and there is no dryer. TDS is removed through a filtration process known as reverse osmosis (RO). Water that has passed through an RO system is used in a spot free rinse although some chemical companies also recommend its use in chemical applications.

Although this practice certainly can do no harm, RO water is much more expensive to generate than soft water and the benefit of using it in chemical applications is considered to be negligible at best.

Since there are many factors in answering this question, it is best to discuss the factors of cleaning and leave the decision on how much to reduce or eliminate the heating of water to each operator.

Temperature refers to three specific segments:
  • Ambient air temperature;
  • Ambient temperature of the vehicle’s surface; and
  • The temperature of the chemicals when they are applied.
Hot water enhances the cleaning ability of most chemicals. In the summertime, when temperatures rise and increase the ambient temperature of the vehicle’s surface, the operator may not need to heat the water as much or even at all. In the winter, the opposite is true.

In most cases, a temperature at the nozzle between 110° to 120° will provide the maximum cleaning power. The water should never be allowed to exceed 155°. Water that is too hot may adversely affect the chemistry of the cleaning product causing it to break down the solution.

An appropriate selection of chemical products used is critical in the cleaning process. The residual pH may also have an effect on the drying process. High residual alkalinity may create difficulties for your sealant or drying agent. On the other hand, a slightly acidic or neutral surface residual will enhance the drying process. In addition to an awareness of the residual effects of cleaning products, the flexibility of choice of cleaning products and the relationship of cost per car make the difference between clean vehicle and profitability.

Probably the most misused concept in our industry is the role of pH. It is represented as a progressive scale from 0 – 14, in increments by the power of 10. Aqueous solutions at with a pH less than seven are considered acidic, while those with a pH greater than seven are considered basic (alkaline) with 7 considered to be neutral. Extremes on either end can be dangerous.

An increase of pH from 10.0 to 10.2 is greater than an increase from 9.0 to 10.0. As you move toward either end of the scale, a slight increase is significant. The pH of a solution is an indicator of how acidic or alkaline a solution is — not the strength. Increasing or decreasing the dilution ratio does not significantly reduce the pH level of a solution. The dilution ratio itself is a much better indicator of cleaning capability than the pH level.

Chemicals used in the cleaning process depend upon the composition of the soils being removed. There are two different categories of soils: organic and inorganic. Organic soils originate from a living source such as vegetation or animal matter. They are best removed with an alkaline or high pH product. Inorganic soils originate from a man-made or synthetic, non-living source. Brake dust, mineral deposits, road salt, clay and abraded asphalt or concrete are examples of inorganic soils. They are best removed by acidic or low-pH products.

Time refers to the amount of contact time or dwell time chemical is given on the finish of the vehicle during the wash process before it is rinsed or followed by another application.

Dwell time may vary a great deal depending on the products you are using. The amount of dwell time is important because generally, if the application and dilution of a product is done properly, the longer contact it has with the surface the better the cleaning potential will be. It is especially critical in a touch-free IBA, although it also plays a major role in a friction unit.

Action refers either to the friction or the pressure and / or movement of the application of the IBA. Friction refers to the action of foam, cloth or brushes while the effect of high pressure water is called impingement or angle and pressure of contact with the vehicle’s surface.

In a friction wash, most of the cleaning is done by the action of the foam, cloth or brushes. Along with the chemicals, it loosens and lifts the soils from the vehicle’s surface allowing for easier rinsing. Although the role of product chemistry cannot be discounted, friction does the majority of the cleaning in a friction IBA and reduces the importance of the other factors in the cleaning process.

In a touch-free IBA, impingement is utilized to maximize the effect of chemistry in the cleaning process. While some give major credit for impingement in touch-free cleaning, the need for effective chemistry to loosen and lift soils from the vehicle’s surface is essential. Impingement alone without effective chemistry will not satisfactorily clean a vehicle. The elements of dwell time and appropriate dilution and application are more critical in a touch free IBA than one using friction.

In the end, the choice is yours
As you can see, any decision of how much heated water to use in your IBA is very much an individual decision based on the many factors of cleaning.

Changing the temperature of your wash water without adjusting the other factors of cleaning could significantly affect the performance of your IBA. In most cases, lowering the temperature of the wash water would require you to use more of the cleaning solutions to maintain your wash’s performance. It would be wise to involve your equipment and chemical distributors in that decision since they would best know how your IBA and products you are using work best.

Ron Holub has been involved in the carwash industry for almost 30 years. He has worked for several national carwash chemical companies, owned a carwash and detail supply company and been a general manager for a carwash chain.
He can be reached via email at:

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