What is the difference between cold and hot water jetting?

Cold water jetting uses water at ambient temperature to 60°C for industrial cleaning and surface preparation, whilst hot water jetting employs heated water from 60°C to 150°C to enhance cleaning power through reduced surface tension and improved grease dissolution. The choice between cold and hot water jetting depends on your specific application: cold water excels at paint removal and concrete work with lower operating costs, whilst hot water proves more effective for oil and grease removal despite higher energy requirements.

Understanding the basics of water jetting temperatures

Water jetting technology harnesses the power of high-pressure water streams, typically ranging from 500 to 3000 bar, to clean and prepare industrial surfaces. Temperature plays a fundamental role in determining how effectively these systems remove different types of contaminants and materials. The physics behind this involves how water molecules behave at different temperatures and their interaction with various substances.

Cold and hot water jetting work differently in industrial applications due to the molecular changes that occur when water is heated. At higher temperatures, water molecules move more rapidly, reducing surface tension and allowing the water to penetrate deeper into porous materials and break down stubborn deposits more effectively. This temperature difference creates distinct advantages for specific cleaning challenges.

The effect of temperature on cleaning power goes beyond simple heat transfer. When water temperature increases, its viscosity decreases, allowing it to flow more freely into cracks and crevices. Additionally, heated water accelerates chemical reactions, making it particularly effective at dissolving oils, greases, and other organic compounds that cold water might struggle to remove efficiently.

What exactly is cold water jetting and when should you use it?

Cold water jetting operates with water temperatures ranging from ambient (typically 15-25°C) up to 60°C. This method relies primarily on the mechanical force of high-pressure water to remove materials from surfaces. The pressure, rather than temperature, does most of the work in breaking bonds between contaminants and the substrate.

Common applications for cold water jetting include paint removal from steel structures, concrete demolition, and heavy-duty surface preparation in industrial settings. Marine vessels often require cold water jetting for removing marine growth and old coatings, whilst petrochemical facilities use it for removing scale deposits and preparing surfaces for inspection. The method proves particularly effective on tough, inorganic materials that don’t respond well to heat.

The advantages of cold water jetting make it an attractive option for many industrial operations. Lower operating costs stem from not needing heating equipment or additional fuel consumption. The simpler equipment requirements mean less maintenance and fewer potential failure points. Cold water systems typically offer greater portability and can operate in environments where hot water might create safety concerns, such as areas with volatile chemicals or temperature-sensitive equipment.

How does hot water jetting work differently?

Hot water jetting utilises water heated to temperatures between 60°C and 150°C, fundamentally changing how the water interacts with contaminants. The heat reduces water’s surface tension by approximately 30%, allowing it to penetrate deeper into materials and create better contact with surfaces. This enhanced penetration combines with the thermal energy to break down stubborn deposits more effectively than mechanical force alone.

Heat enhances cleaning power through multiple mechanisms. The reduced surface tension allows water to wet surfaces more thoroughly, whilst the thermal energy helps dissolve oils and greases by lowering their viscosity. Many industrial contaminants become less adhesive at higher temperatures, making them easier to flush away. The combination of pressure and temperature creates a synergistic effect that can reduce cleaning time significantly for certain applications.

Equipment requirements for hot water jetting include specialised heaters capable of maintaining consistent temperatures under high-pressure conditions. These systems need heat exchangers, temperature controls, and often diesel or gas burners to generate the necessary heat. Specialised nozzles designed to handle thermal expansion and maintain spray patterns at elevated temperatures are essential. The additional components increase system complexity but provide superior cleaning capability for specific applications.

Which method delivers better results for different industrial applications?

The effectiveness of cold versus hot water jetting varies significantly depending on the specific task at hand. For oil and grease removal, hot water jetting typically outperforms cold water by a considerable margin. The heat helps emulsify oils and reduces their adhesion to surfaces, making removal faster and more thorough. Conversely, paint stripping and concrete work often favour cold water jetting, as the mechanical force proves more effective than heat for breaking these harder, inorganic bonds.

Cost-benefit analysis reveals important considerations for choosing between methods. Hot water systems require 3-4 times more energy consumption due to heating requirements, translating to higher operational costs of approximately €50-100 per hour extra. However, hot water can reduce cleaning time by up to 50% for suitable applications, potentially offsetting the increased energy costs through improved productivity.

Safety considerations differ between the two methods. Hot water jetting presents burn risks to operators and requires additional protective equipment, including heat-resistant gloves and clothing. Steam production can reduce visibility and create slip hazards. Cold water jetting, whilst avoiding thermal risks, can generate higher noise levels due to the increased pressures often required to achieve similar cleaning results. Both methods require proper training and safety protocols to protect operators and nearby personnel.

How can DERC Salotech help you choose the right water jetting solution?

With over 40 years of expertise in both cold and hot water jetting systems, we understand the nuances of selecting the right technology for your specific industrial challenges. Our experience spans across diverse sectors including petrochemical refineries, marine vessels, and general industrial maintenance facilities, giving us unique insights into what works best for different applications and environments.

We provide customised solutions that consider your specific cleaning requirements, operational constraints, and budget parameters. Whether you need systems for routine surface cleaning or specialised equipment for challenging applications, our engineering team designs solutions that balance performance with practicality. Our systems accommodate both metric and SAE standards, ensuring compatibility with your existing infrastructure regardless of your global location.

Beyond equipment supply, we offer comprehensive training programs through our subsidiary to ensure your teams operate safely and efficiently. Our global support network across 55 countries means you’re never far from technical assistance or spare parts. To explore specific equipment options and discover how our water jetting solutions can optimise your operations, visit our products page where you’ll find detailed specifications and application guides for both cold and hot water systems.