Compressors
Breathing Air Compressors for Commercial Diving
A breathing air compressor supplies clean, filtered air to divers, either filling cylinders at high pressure or feeding a surface-supplied umbilical at low pressure. We supply diving compressors for sale or hire, new or used, shipped worldwide door to door.
Our high pressure range covers Bauer and Coltri Sub units for cylinder and bank filling, from compact single-phase machines to three-phase and silenced builds. Our low pressure range is our own iSubC line, from 12.5 to 33.3 CFM at 10 to 15 bar, in electric, petrol and diesel, alongside Quincy electric and diesel units. Supplementary filtration is available where duty cycle or ambient conditions demand it.
Specifying starts with the dive mode. Scuba, bailout bottles and storage banks need a high pressure compressor; surface-supplied work needs low pressure and high volume down the umbilical. Diver count and working depth set the CFM, and site power decides between three-phase, single-phase, petrol and diesel. For the panel the air feeds into, see our Control Panels and SRP range.
Tell us the dive mode, diver count, working depth and available power, and we will size a compressor and quote for supply or hire.
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High Pressure CompressorsBauer Breathing Air Compressor Model: PE 250-TB
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High Pressure CompressorsBauer Breathing Air Compressor Model: PE100-TB
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High Pressure CompressorsBauer Breathing Air Compressor Model: PE100-TW
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High Pressure CompressorsBauer Marina 320E Breathing Air Compressor
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High Pressure CompressorsBauer Oceanus-B Breathing Air Compressor
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High Pressure CompressorsColtri Sub ERGO 270 SH Breathing Air Compressor
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High Pressure CompressorsColtri Sub Ergo 280 DY & DY FA Breathing Air Compressor
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CompressorsColtri Sub ERGO 315 ET Breathing Air Compressor
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High Pressure CompressorsColtri Sub ERGO TPS 315 ET Breathing Air Compressor
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High Pressure CompressorsColtri Sub ERGO TPS 345 ET Breathing Air Compressor
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High Pressure CompressorsColtri Sub MCH16 ET Compact Breathing Air Compressor
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High Pressure CompressorsColtri Sub OPEN HD MCH 36 ET Three-phase Breathing Air Compressor
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High Pressure CompressorsColtri Sub SILENT HD MCH36 ET Three-phase Breathing Air Compressor
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High Pressure CompressorsColtri Sub SMART MCH11 EM Breathing Air Compressor
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High Pressure CompressorsColtri Sub SMART MCH16 ET Breathing Air Compressor
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Low Pressure CompressorsiSubC 12.5CFM 10 BAR Single Phase LP Compressor
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Low Pressure CompressorsiSubC 15CFM 10 BAR Petrol LP Breathing Air Compressor
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Low Pressure CompressorsiSubC 27CFM 10 BAR Petrol LP Breathing Air Compressor
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Low Pressure CompressorsiSubC 31CFM 15 BAR Three-Phase LP Compressor
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Low Pressure CompressorsiSubC 33.3CFM 10 BAR Diesel LP Breathing Air Compressor
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Low Pressure CompressorsQuincy 5120 25 hp Weg Electric Low Pressure Compressor
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Low Pressure CompressorsQuincy 5120 Deutz Diesel Low Pressure Compressor
Frequently Asked Questions
What is the operational difference between high-pressure and low-pressure diving compressors?
High-pressure (HP) and low-pressure (LP) compressors serve distinctly different roles in commercial diving. High-pressure compressors typically generate air at pressures exceeding 3000 psi (200 bar or more). They are strictly used for filling scuba cylinders, high-pressure storage banks, and diver bailout bottles. Conversely, low-pressure compressors operate at much lower pressures, usually between 10 and 15 bar, but deliver a significantly higher volume of air. These LP systems are used for surface-supplied diving, pushing a continuous, regulated flow of air directly down the diver’s umbilical.
Why is specialised multi-stage filtration critical for breathing air compressors?
Standard industrial workshop compressors are completely unsuitable for diving because they do not purify the air. Breathing air compressors are equipped with advanced, multi-stage filtration systems and chemical scrubbers. These stages meticulously remove moisture, oil vapour, and deadly contaminants like carbon monoxide and hydrocarbons from the ambient air. In a pressurised underwater environment, even microscopic levels of toxic gases become highly concentrated and lethal. Therefore, breathing air compressors must meet incredibly strict international air purity standards.
What role does CFM (Cubic Feet per Minute) play when selecting a commercial dive compressor?
CFM is the measurement of the volume of air the compressor can deliver over time. In commercial diving, the required CFM is not static. It increases drastically based on the diver’s working depth and their respiratory rate. As a diver descends, the ambient water pressure compresses the breathing gas, meaning they consume a larger volume of surface air with every breath. Selecting a compressor with a high CFM rating ensures that even under heavy physical exertion at maximum depth, the diver receives a continuous, unrestricted flow of air without “over-breathing” the system.
Can standard breathing air compressors handle mixed gas diving operations?
No, standard ambient air compressors are designed solely to compress and purify normal atmospheric air. Many deep commercial operations, such as saturation diving, require mixed gases like Heliox (a blend of helium and oxygen) to prevent nitrogen narcosis and oxygen toxicity. Handling mixed gases requires highly specialised, oxygen-clean gas boosters, mixing panels, and entirely separate compression infrastructure. Running high concentrations of oxygen through a standard air compressor introduces a catastrophic risk of combustion.
How often do commercial breathing air compressors require testing and maintenance?
Because they are classified as primary life-support equipment, commercial breathing air compressors are subject to rigorous, scheduled maintenance routines. Dive technicians must perform frequent oil changes, belt tension checks, and filter replacements based strictly on run-hours. Additionally, the output air must undergo mandatory periodic laboratory testing, often quarterly or biannually, depending on regional health and safety guidelines such as those set by the HSE or IMCA. These tests legally certify that the delivered air remains completely free of toxic impurities.