What is the difference between class A and class B pressure washers?

Class A and Class B pressure washers differ primarily in their pressure output, flow rates, and intended industrial applications. Class A units typically operate at pressures exceeding 20,000 PSI (1,379 bar) with lower flow rates, making them ideal for ultra-high-pressure applications like concrete cutting and paint removal. Class B washers work at pressures between 3,000-20,000 PSI (207-1,379 bar) with higher flow rates, better suited for general industrial cleaning and surface preparation tasks.

What exactly are class A and class B pressure washers?

Class A and Class B pressure washers represent two distinct categories in industrial high-pressure water jetting equipment, each designed for specific operational requirements. These classifications help maintenance engineers and operators select the right equipment for their industrial cleaning needs.

Class A pressure washers are ultra-high-pressure units that operate above 20,000 PSI (1,379 bar). They feature specialised pumps, often plunger-type or intensifier systems, designed to generate extreme pressures while maintaining lower flow rates, typically between 2-10 gallons per minute (7.6-37.9 litres per minute). These machines excel at precision tasks requiring concentrated force.

Class B pressure washers operate in the high-pressure range between 3,000-20,000 PSI (207-1,379 bar) with higher flow rates ranging from 10-40 GPM (37.9-151.4 LPM). They use robust triplex or quintuplex pumps and are built for continuous operation in demanding industrial environments. The higher flow rates make them effective for washing larger surface areas and removing substantial debris.

Industrial standards from organisations like the Water Jet Technology Association (WJTA) define these classifications based on pressure ranges, safety requirements, and operational capabilities. Understanding these classifications helps you match equipment specifications to your specific cleaning challenges while ensuring compliance with safety regulations.

How do pressure ratings differ between class A and class B models?

The pressure specifications between Class A and Class B models show significant differences that directly impact their cleaning capabilities. Class A units generate pressures starting at 20,000 PSI (1,379 bar) and can reach up to 40,000 PSI (2,758 bar) or higher, while Class B models operate in the 3,000-20,000 PSI (207-1,379 bar) range.

Flow rate differences are equally important. Class A washers typically deliver 2-10 GPM (7.6-37.9 LPM), focusing power into a concentrated stream. This lower flow rate combined with ultra-high pressure creates enough force to cut through concrete, remove thick coatings, or perform hydro-demolition tasks. Class B units deliver 10-40 GPM (37.9-151.4 LPM), providing the volume needed to flush away debris and clean larger areas efficiently.

Pump technology varies significantly between classes. Class A systems often use intensifier pumps or specialised plunger pumps capable of generating extreme pressures. These pumps require precise engineering and robust materials to withstand the forces involved. Class B washers typically use triplex or quintuplex plunger pumps, which balance pressure generation with flow capacity and operational durability.

Motor specifications reflect these operational differences. Class A units may require 150-500 HP (112-373 kW) diesel or electric motors to drive their high-pressure pumps, while Class B models typically use 50-200 HP (37-149 kW) motors. Duty cycle ratings also differ, with Class B units often designed for continuous operation over extended periods, while some Class A systems may have intermittent duty cycles due to the extreme stresses involved.

Which industries typically use class A versus class B pressure washers?

Different industries select Class A or Class B pressure washers based on their specific cleaning challenges and operational requirements. Understanding these applications helps you determine which class best suits your facility’s needs.

Class A pressure washers find extensive use in specialised applications within the petrochemical industry. Refineries use them for removing hardened deposits from heat exchangers, cutting through coke buildup in delayed coker units, and performing concrete scarification during facility upgrades. Marine operations employ Class A units for removing marine growth from ship hulls and offshore platforms where extreme pressure is needed to cut through tough barnacle formations.

Class B washers serve as workhorses across multiple industries. Manufacturing plants rely on them for routine equipment cleaning, removing oil and grease from machinery, and preparing surfaces for painting or coating. In petrochemical facilities, they handle tank cleaning, pipe flushing, and general maintenance tasks. Marine applications include deck washing, cargo hold cleaning, and routine vessel maintenance where high flow rates efficiently remove salt deposits and general contamination.

Surface preparation requirements often dictate class selection. When you need to achieve specific surface profiles for coating adhesion, Class A units provide the precision required. For general cleaning where volume and coverage matter more than cutting power, Class B equipment delivers better results. Consider your typical cleaning tasks: removing paint layers might require Class A pressure, while degreasing large equipment surfaces works well with Class B flow rates.

What safety features distinguish class A from class B equipment?

Safety systems in Class A and Class B pressure washers reflect the different risk levels associated with their operating pressures. Class A units require more comprehensive safety features due to their ultra-high-pressure operation.

Class A pressure washers incorporate multiple redundant safety systems. These include dual pressure relief valves set at different thresholds, automatic dump valves that activate if pressure exceeds safe limits, and emergency stop systems accessible from multiple positions. Many Class A units feature remote control operation, allowing operators to maintain safe distances during ultra-high-pressure tasks. Pressure gauges often include burst discs as final failsafe mechanisms.

Class B equipment includes standard safety features like single pressure relief valves, trigger safety locks, and thermal relief valves to prevent pump damage. While still robust, these systems reflect the lower risk profile of sub-20,000 PSI (1,379 bar) operation. Emergency stops are typically located on the control panel, and most units include unloader valves that divert flow when the trigger is released.

Certification and training requirements differ significantly between classes. Operating Class A equipment often requires specialised certification through organisations like WJTA, with comprehensive training covering ultra-high-pressure hazards, proper PPE selection, and emergency procedures. Class B operators need industrial safety training but may not require the same level of specialised certification. Your team’s existing qualifications and training capacity should factor into equipment selection.

How do maintenance requirements compare between the two classes?

Maintenance complexity and frequency vary considerably between Class A and Class B pressure washers, directly impacting your operational costs and downtime planning.

Class A units demand more frequent and specialised maintenance due to the extreme stresses of ultra-high-pressure operation. Pump seals and valves may require inspection every 100-200 operating hours, with complete rebuilds needed every 500-1,000 hours depending on usage intensity. High-pressure hoses and fittings need regular inspection for fatigue cracks or wear. The precision components in intensifier pumps require skilled technicians familiar with ultra-high-pressure systems.

Class B washers offer more forgiving maintenance schedules. Routine service intervals typically extend to 250-500 hours for basic maintenance like oil changes and filter replacements. Pump rebuilds may not be needed for 2,000-3,000 operating hours with proper care. Standard industrial maintenance staff can handle most service tasks, reducing your dependence on specialised technicians.

Spare parts availability and costs reflect these differences. Class A components are often specialised items with longer lead times and higher prices. A single intensifier pump seal kit might cost several hundred euros, while complete pump rebuilds can reach thousands. Class B parts are more widely available through industrial suppliers, with competitive pricing due to broader market demand. Consider establishing relationships with reliable suppliers who stock critical spares for your chosen equipment class.

Making the right choice: Which class suits your industrial cleaning needs?

Selecting between Class A and Class B pressure washers requires careful evaluation of your operational requirements, budget constraints, and long-term objectives. Start by analysing your most common cleaning tasks and the results you need to achieve.

If your operations involve removing extremely hard deposits, cutting concrete, or achieving specific surface profiles for critical coating applications, Class A equipment provides the necessary power. However, if you primarily handle routine cleaning, degreasing, and general maintenance tasks, Class B units offer better value through higher productivity and lower operating costs. Consider creating a task matrix listing your cleaning applications, required pressures, and frequency to guide your decision.

Budget considerations extend beyond initial purchase price. Factor in training costs, maintenance expenses, and potential downtime when calculating total ownership costs. Class A units require larger capital investments and higher ongoing expenses but may be essential for specialised applications. Class B equipment offers lower entry costs and operational expenses while handling most industrial cleaning tasks effectively.

At DERC Salotech, we understand that choosing the right pressure washer class is crucial for your operational success. Our extensive experience in high-pressure water jetting technology helps facilities across the petrochemical, energy, and marine sectors find tailored solutions. Whether you need ultra-high-pressure Class A systems or versatile Class B units, we provide equipment that meets both metric and SAE standards. Visit our products page to explore our complete range of industrial cleaning solutions and discover how our technical expertise can optimise your maintenance operations.