What Is an Air Receiver Tank: Full Guidelines

A properly sized air receiver tank can reduce your compressed air system's energy costs by up to 20% while extending equipment life significantly. Yet many facilities operate with undersized or poorly maintained storage tanks, leaving efficiency gains on the table. Whether you're designing a new compressed air system or optimizing an existing one, understanding air receiver tanks is essential for maximizing performance and protecting your investment.

Fluid-Aire Dynamics provides expert guidance on compressed air system design to help you select and configure the right storage solution for your facility.

What Is an Air Receiver?

An air receiver (sometimes called a compressed air storage tank or air compressor tank) is a pressure vessel designed to receive and store compressed air after it exits the compressor. This reservoir gives you a reserve of compressed air that you can draw on without running your compressors continuously.

Air receiver tanks come in a range of sizes and in both vertical and horizontal configurations. They are a type of pressure vessel that holds compressed air under pressure for future use, acting as a critical buffer between your compressor and the fluctuating demands of your facility.

The Purpose of an Air Receiver Tank

Air receivers play an essential role in your compressed air system. Beyond simply storing air, they help your entire system run more efficiently. The air receiver tank serves three main functions:

Temporary storage: Provides a reservoir of compressed air for short, high-demand events such as sandblaster bursts, dust collector pulses, or blowgun use.

Compressor control stability: Stabilizes system pressure, allowing compressor controls to operate within a steady pressure band.

Secondary heat exchange: When used as a "wet tank," acts as a heat exchanger that increases the efficiency of your air dryer by pre-cooling compressed air.

Compressed Air Storage

The primary role of an air receiver tank is providing temporary storage for compressed air. Think of your air receiver like a battery for your compressed air system—except it stores air instead of electrical energy. This stored air is available even when the compressor is not running, reducing sudden demands on your equipment and prolonging system life.

Storing compressed air allows the system to average out peaks in demand over the course of a shift. Using an air receiver may also allow you to use a smaller horsepower compressor for larger jobs, reducing capital equipment costs.

Compressor Control

The air tank provides steady pressure for compressor controls, eliminating short-cycling and over-pressurization. Uneven compressed air utilization causes rapid cycling of the compressor controls as the unit turns on and off to meet moment-by-moment demand.

Each time the system turns on and off (or loads/unloads) is called a "cycle." Keeping these cycles as long as possible is better for the compressor motor. Over time, frequent short cycling leads to premature failure of switches and other compressor components. Rapid cycling can result in excessive wear of the motor contactor or even a direct motor short from winding insulation breakdown.

Heat Exchanger

As air is compressed under pressure, its temperature increases according to the Pressure-Temperature Law. Depending on the type of compressor you are using, discharged air may be as hot as 150°F - too hot for most air-operated equipment to use directly.

Hotter air also contains more moisture, which will condense in control lines and tools if not removed. The air receiver tank acts as a secondary heat exchanger; as air sits in the tank or slowly flows through it, it cools down, allowing some of the moisture to condense, and decreasing the thermal load on your air dryer. 

 

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Efficiency Benefits of Air Receiver Tanks

Adding an air receiver tank significantly improves the efficiency of your compressed air system through multiple mechanisms:

Reduce Waste of Compressed Air

As the compressor cycles on and off, air can be wasted. Every time a rotary screw compressor unloads, the sump tank (oil tank) is vented, releasing compressed air. Over time, this adds up to a significant volume of compressed air that could otherwise power your processes. A properly sized storage tank reduces frequent cycling and venting. 

A study conducted by the Compressed Air & Gas Institute (CAGI®) showed that a system with 1 gallon of receiver tank storage per CFM, operating at 40% capacity, was able to decrease their energy usage by over 20% by upgrading to 10 gallons of storage per CFM. 

Source: Compressed Air Best Practices

Reduce Operating Pressure

An air tank allows you to reduce the system pressure at which your compressor operates. Without stored compressed air to draw on, the system must operate at higher PSI to always meet peak demands; essentially running as if your facility is always at maximum demand.

On average, every 2 PSI increase in system pressure increases energy demand by 1%. This can add hundreds or thousands of dollars to your energy bills annually. An air receiver tank evens out demand peaks, allowing you to meet intermittent high-demand periods without increasing overall system pressure.

Increase Dryer Efficiency

The heat exchanger function of the air receiver tank improves your air dryer's efficiency. As air passes slowly through the receiver tank, it cools. Cooler air can't hold as much moisture as warm air, so excess moisture condenses and falls out as liquid, draining from the valve at the bottom of the tank.

Wet vs. Dry Compressed Air Storage: What's the Difference?

When configuring your compressed air system, understanding the difference between "wet" and "dry" storage is crucial. The distinction refers to the tank's location in your system—there is no difference in tank construction or design.

Wet storage tanks are located before the air drying system. Air flows through the tank, entering through the bottom port from the compressor and exiting out the top to the dryer.

Dry storage tanks are located after the air dryers to store compressed air that has already been dried and filtered. Air does not need to flow through the tank for dry storage.

Advantages of Wet Compressed Air Storage

With wet air storage, the receiver tank is positioned between the compressor and the dryer:

• Increases dryer efficiency by allowing the air to cool down, and allowing excess water and to condense out before hitting the dryer

• Prolongs pre-filter element life since air going through the filter is cleaner and dryer than it would be directly from the compressor

• Eliminates compressor back pressure resulting in steadier pressure signals to the compressor controller, and preventing rapid cycling 

Advantages of Dry Compressed Air Storage

Dry air storage tanks provide supply air that is ready to use right out of the tank. Without a dry air tank, air from the wet tank must go through the dryer before use. During high-demand periods, the dryer risks becoming over-capacitated as the system tries to pull air through at higher volumes than the dryer is rated for, potentially leading to unwanted water in the air lines.

Finding the Right Ratio of Wet to Dry Storage

For most applications, the ideal ratio is 1/3 wet to 2/3 dry capacity.

For example, if you have 1,200 gallons of total storage:

• Wet storage: 400 gallons (1/3)

• Dry storage: 800 gallons (2/3)

Dry air is ready to use on-demand, while the wet air tank increases dryer efficiency and acts as a secondary reserve when dry air is exhausted. Dry storage needs to be greater than wet storage to minimize the risk of over-capacitating the dryer during high-demand periods.

Exception: Facilities with steady airflow without sharp peaks in demand may not need a dry storage tank, as air will simply flow through without being stored. In this case, all storage can be wet storage.

How Much Air Storage Capacity Do You Need?

The volume of storage capacity needed by a facility depends on several factors:

• Compressor capacity (CFM): Larger compressors typically require bigger receiver tanks

• Peak CFM requirements: Maximum demand periods may require more storage

• Consistency of airflow: Fluctuating demand requires larger tanks

• Diameter of piping: Larger piping carries more air and may necessitate larger tanks

• Distance to point of use: Longer runs may benefit from additional storage

• Air quality requirements: Some applications require specific tank configurations

Quick Sizing Reference Table

Flow Consistency Adjustments

• Facilities with very steady airflow: Storage can be reduced to 3 gallons per CFM. All storage should be wet storage.

• Facilities with high variability and large demand peaks: May require larger volumes of stored air. Testing to determine CFM at peak demand will be needed to calculate requirements.

Pipe Diameter Considerations

The pipes in your system also store air. For systems with pipework of 2" or greater diameter, it may be worthwhile to consider that volume in the calculation, as larger pipes provide additional storage capacity.

Air Tank Size Calculator

When sizing a tank for a point of use where demand exceeds compressor capacity:

1. Calculate the Air Deficit

Deficit CFM = Demand CFM - Compressor Capacity CFM

2. Find the Tank’s Capacity

Convert the tank's liquid gallon rating into cubic feet.

Tank Volume (Cubic Feet) = Total Storage Gallons x 0.134

3. Calculate Usable Stored Air

Determine the volume of "free air" available as the tank depressurizes from its maximum fill to your minimum required operating pressure.

Usable Stored Air (Cubic Feet) = Tank Volume (Cubic Feet) x (P1 - P2) / 14.7

Where:

P1 = Maximum tank pressure (PSIG)

P2 = Minimum usable pressure for the tool/application (PSIG)

14.7 = Atmospheric pressure constant 

4. Calculate Available Operation Time

Determine how long the system can run continuously before the pressure drops below the usable threshold.

Operation Time (Minutes) = Usable Stored Air / Deficit CFM

For assistance with sizing calculations, use our CFM Calculator or contact our engineers for a system assessment.

Can the Air Receiver Be Stored Outdoors?

Compressed air receivers can be bulky, so many facilities prefer outdoor storage to save precious floor space. Outdoor storage also helps reduce strain on your HVAC system in warm weather, as the storage tank radiates heat that would otherwise raise temperatures in the compressor room.

However, outdoor storage only works in milder, non-freezing climates.

Climate Considerations for Air Receiver Storage

Outdoor storage is only appropriate for environments that stay above freezing year-round. In freezing temperatures, outdoor tanks can ice up and even rupture—a costly and potentially dangerous outcome. If your area experiences freezing temperatures during any part of the year, keep your tank indoors.

Tips for Outdoor Storage of Air Receiver Tanks

If storing your air receiver tank outdoors:

• Conduct frequent inspections to monitor for corrosion

• Address any corrosion signs immediately to maintain tank integrity

• In cooler weather, the tank generates some heat on its own, but if temperatures drop too far, freezing risk remains

• Consider insulating your tank and providing auxiliary heating during cold weather to prevent damage

Air Receiver Tank Internal Lining Options

There are three main options for the internal lining of your tank, each suited to different applications and budgets:

Steel Air Receiver Tanks

The majority of air receiver tanks are bare steel on the inside with a primer coating on the outside to reduce corrosion. The exterior paint is commonly matched to the compressor equipment. A basic steel tank works well for most applications and is the least expensive option. However, they may be prone to corrosion if too much liquid is allowed to build up inside the tank.

Epoxy Coated and Galvanized Air Receivers

Some air receivers have treated interior linings to reduce corrosion and contamination in the air stream:

• Epoxy coatings are sprayed onto the interior as a liquid and cured into a tough, anti-corrosive coating, creating a moisture-proof barrier between the air and the base metal

• Galvanized tanks are treated with a protective zinc coating that halts rust formation by reacting chemically with corrosive agents before they reach the base metal

Both methods provide long-lasting protection but add to cost and lead time. Coated or galvanized tanks are better at maintaining air purity because they reduce the risk of corrosion-caused particulates entering the airstream. Applications needing higher purity air, or users concerned about longevity, should consider these options.

Stainless Steel Air Receivers

Stainless steel air receivers are primarily used for specialty applications where very high-purity air is required. They are the most expensive option but offer exceptional durability, corrosion resistance, and air purity. Hospitals, laboratories, electronics manufacturers, and other high-purity applications should consider stainless steel tanks.

Air Receiver Accessories

Air receiver tank accessories are essential for safety and operation. While the tank itself is a large sealed metal tube, all tanks must have at minimum: a drain, a gauge, and a pressure relief valve.

Essential Accessories

• Pressure gauges: Provide visual indication of interior air pressure. Essential for monitoring pressures and ensuring the tank is not under stress from over-pressurization.

• Pressure relief valves: Required for all air receivers per OSHA and ASME guidelines. Opens automatically to release air if pressures are too high, minimizing rupture risk from over-pressurization. Must not exceed the tank's ASME-rated pressure.

• Manual drain valve: Basic drain for releasing accumulated liquid from the tank bottom.

Recommended Upgrades

• Electronic auto condensate drain: Programmed to open at set intervals, eliminating the need for daily manual draining.

• Zero air-loss condensate drains: Use a float mechanism to control drainage, opening only when needed. Saves energy and reduces air loss from the tank compared to timed drains.

• Anti-vibration pads: Recommended if the compressor is mounted on top of the tank. Absorbs vibrations from the compressor motor and reduces fatigue on the tank.

ASME Certification for Air Receiver Tanks

All air receivers used in industrial applications must be certified by ASME for safety and performance. This is not optional, it's essential for compliance and safety.

What Are the ASME Standards for Air Receivers?

The American Society of Mechanical Engineers (ASME) sets engineering codes and manufacturing standards for pressure vessels, including air receiver tanks. The ASME Boiler and Pressure Vessel Certification Program establishes rules governing design, fabrication, assembly, and inspection of pressure vessel components during construction.

These rules include engineering standards for:

• Thickness of the tank body

• Welds and joints

• Connections and fittings

• Other structural components

An ASME certification stamp means the manufacturer has met all safety and engineering standards for their product.

Can I Buy an Air Receiver Without ASME Certification?

Non-code air receiver tanks should never be used, especially for industrial applications.

Some big box stores carry non-code air receiver tanks. While cheaper, they have not undergone the rigorous manufacturing processes and quality testing needed to ensure safety and reliability. Using a non-code air receiver tank puts lives at risk.

Can I Make a DIY Air Receiver?

Never attempt to build a do-it-yourself air receiver.

Some people may be tempted to convert old propane tanks, steel drums, or other vessels into air tanks by welding on fittings and valves. This is strongly advised against due to significant safety risks and legal regulations.

Air receivers operate under high pressure, and improper construction can lead to catastrophic failures, including ruptures that could cause serious injury or death. Professionally manufactured air receivers are built to stringent safety standards. Attempting DIY construction bypasses essential safety checks and violates legal standards, potentially leading to fines, insurance issues, and liability in case of accident.

Inspecting Your Air Receiver for Code Violations

If you're unsure whether your air receiver tank meets code requirements, have it inspected. Your local Fire Marshal may provide this service using ultrasonic metal thickness testing technology. If your air receiver does not pass inspection, it should be decommissioned and replaced immediately.

All air receiver tanks must also be inspected periodically once installed. OSHA does not mandate a specific testing interval, but annual inspection is recommended. Your insurance company or local governing board may have different requirements.

OSHA requires formal inspections be performed by an inspector holding a valid National Board Commission in accordance with the National Board Inspection Code. Manufacturers must keep records of formal inspections and make them available to OSHA representatives upon request.

Inspection includes:

• Review of current operating certificate

• Overall assessment of air receiver, piping, and other systems

• Visual inspection of vessel walls and support/mounting bracket welds for corrosion, cracking, denting, punctures, or weld failures

• Internal inspection using cameras or sensors

• Ultrasonic thickness readings where visual inspection is impractical

• Pressure relief valve verification

• Automatic or manual drain valve check

• Connected piping inspection

• Verification of proper tank securing (bolted to solid structure or concrete floor)

Between formal inspections, conduct frequent visual inspections for signs of corrosion, damage, or weld failure. Check drains daily and pressure relief valves monthly.

Air Receiver Safety

Air receiver tanks hold air under immense pressure, creating safety hazards if the tank is not up to code or properly maintained.

Causes of Air Receiver Tank Failure

Pressure vessels must withstand high internal pressures over long periods. Over time, corrosion, stress, and fatigue can make failure more likely. Common causes include:

• Faulty design or use of non-code tanks

• Operation above maximum allowable working pressure (over-pressurization)

• Improper installation

• Corrosion (internal or external)

• Cracking

• Weld failure

• Improper repair of cracks or leaks

• Exposure to extreme environmental conditions (freezing or overheating)

• Pressure relief valve failure

Air Receiver Occupational Hazards

High internal pressures make failure extremely hazardous. Cracking or weld failure can cause the tank to burst with explosive force, projecting large metal pieces or shrapnel at high speed. Air receiver tank failure may result in extensive facility and equipment damage and severe injury or death for nearby workers.

Maintaining Air Receiver Tank Safety

Follow all safety guidelines in your tank's owner's manual. To ensure safe operation, verify the following:

• The air receiver tank is ASME-certified

• Operating pressure stays within maximum allowable limits

• The pressure gauge is present and functioning correctly

• The tank is periodically inspected for corrosion, weld seam stress, cracks, wall thinning, and other defects

• An ASME-certified pressure relief valve is installed and working correctly

• The tank is drained frequently to prevent liquid accumulation

• All alterations or repairs are completed by certified professionals

• Operators receive proper safety training for air receiver tank handling

• The tank is properly secured by bolting to a solid structure or concrete floor

Consult the OSHA guidelines for pressure vessel safety for more information.

Air Receiver Maintenance and Draining

Regular maintenance and draining are crucial for air receiver longevity and performance. Air receivers should be drained daily—or more often depending on moisture levels—to remove accumulated water. This is especially important in humid environments where moisture buildup occurs quickly.

Removing moisture prevents internal corrosion, which can weaken the tank over time and lead to costly repairs or dangerous failures. Regular draining also ensures maximum tank capacity remains available for storing compressed air, improving overall system efficiency and reliability.

Maintenance frequency can be performed in the following way:

How to Drain Your Air Receiver

Draining is straightforward but should be done carefully:

1. Locate the drain valve: Typically found at the bottom of the air receiver tank

2. Open the drain valve: Slowly open to allow water, oil, and contaminants to flow out. Use a wrench or handle if manual. Be cautious—draining liquid may be under pressure and could spray out quickly

3. Monitor the drainage: Let the tank drain completely until only air is coming out, indicating all moisture has been removed. This may take a few minutes depending on moisture volume

4. Close the drain valve: Once fully drained, securely close the valve to prevent air leaks when the compressor restarts

Automatic and Zero-Loss Drain Valves

Automatic drain valves regularly discharge accumulated moisture without manual operation, ensuring consistent performance and reducing the risk of forgetting to drain.

Zero-loss drain valves remove moisture without releasing compressed air, maximizing energy efficiency and maintaining system pressure. These are particularly beneficial in high-demand systems or where minimizing downtime and energy waste is a priority.

Pressure Rating Considerations

When selecting your air receiver, consider the maximum output pressure your compressor can deliver. The tank’s maximum allowable working pressure (MAWP) must exceed the compressor’s maximum discharge pressure and comply with ASME requirements.

This safety margin ensures safety, accommodates pressure fluctuations, and allows for proper pressure relief valve function. It helps manage unexpected pressure spikes and maintains compressed air system integrity.

Pressure Rating Guidelines

Each air receiver must be equipped with a pressure relief valve to release excess pressure if it exceeds the tank's maximum rating.

Does Increasing Tank Pressure Increase CFM?

This is a common misconception. Higher pressure does not translate to increased airflow production (CFM). Higher pressure provides additional stored volume (like a bigger battery) only as long as pressure remains above your tool's required pressure.

This stored volume is useful only for short-term demand spikes. When consumed CFM exceeds compressor capacity, recovery time is required—otherwise pressure will continue to decay. At some point, the economy of a larger tank and recovery wait time is challenged by the fact that a larger compressor matching consumption to production may be the less costly route.

Remember: You can't consume more than you produce. Understanding minimum and maximum pressure requirements of your equipment is crucial. Use pressure regulators at the air receiver or point of use to maintain optimal pressure levels.

A good rule of thumb: every 2 PSI equals 1% of energy used. Keep system pressure according to your facility's actual needs for additional energy savings.

Can Your Air Receiver Help You Save Money?

An appropriately sized air tank improves system efficiency and can significantly reduce operating costs for your compressed air system.

Air Reservoir Benefits

Your compressed air receiver is like a battery for your facility, providing an extra air reservoir you can draw on during peak demand. This lets you reduce overall system PSI, resulting in lower energy costs. You may also be able to purchase a smaller compressor with lower CFM capacity by relying on your air tank for high-demand events.

Cycle Count Reduction

The air receiver tank reduces cycle counts by evening out peaks in compressed air demand. Lower cycle counts mean lower energy use and less wear on system components, extending compressor life.

Pulsation Dampening

The air receiver functions as a pulsation dampening device, absorbing the pulses of air discharged by the compressor. This reduces fatigue on piping and other system components.

Moisture Removal

As air cools in the receiver, excess liquid condenses and falls out. This means less work for the air dryer and reduced energy consumption.

Dirt Removal

Particulates can enter the airstream from upstream equipment like compressor valves and carbonized oil, or via internal system corrosion. Many particulates fall out with condensate in the air receiver tank, then drain away with the liquids. As a result, air entering the dryer is both cleaner and dryer than air directly from the compressor.

Your air receiver tank is an important component of your compressed air system. Having a properly sized air receiver ensures safe and efficient operation while providing a reservoir of extra power for periods of peak demand.

If you're not sure how much air storage capacity you need, or if you have questions about maintaining your tank for safe operation, the experts at Fluid-Aire Dynamics can help. We will perform an assessment of your compressed air usage patterns and recommend an air receiver tank that fits your needs.