Kaishan USA | June 4, 2025 | Uncategorized
Like an athlete training to perform at higher elevations, you must prepare for altitude effects on compressors.
When 19-year-old Jim Ryun broke the world record for the one-mile run in 1966, one of the marquee events in track and field, it looked like he had a lock on Olympic gold in two years. By the time he reached the starting line in 1968, he was the world record holder in the 880-yard run and the one-mile run, as well as the metric equivalents for those distances.
Unfortunately, he finished second in the metric mile (1,500 meters) and did not place in the 800-meter event. He was hit by a double whammy: Mexico City’s 7,300-foot altitude and wily Kipchoge Keino, who grew up and trained in Kenya, where 7,000-foot altitudes are routine.
If one of America’s premier middle-distance runners experienced problems, we shouldn’t be surprised by the altitude effects on compressors. Let’s talk about the impact of altitude on rotary screw compressors.
Those factors, combined, have a significant impact on your compressor.
High-altitude air affects your compressor’s efficiency and performance, as well as its capacity to produce air pressure and flow. We’ll start with the impact on flow.
With less density and fewer air molecules available, an air compressor in Denver can capture and compress less air and deliver less flow than the same compressor in Houston.
That difference can be significant. Let’s say, for instance, that you have added up all rated flows your end users need, and you determine that you’ll need your compressor to deliver 1,000 CFM. That’s great if you’re at sea level. Say, New Orleans.
But if you’re somewhere in Colorado at 10,000 feet, there are fewer air molecules to compress. So, that same compressor that gave you 1,000 CFM in New Orleans will only give you 600 CFM. You’ll need a compressor capable of delivering 1,500 or 2,000 CFM at sea level to meet all your requirements.
Higher elevations, like this one in Colorado, can be picturesque. But they pose challenges for compressed air systems.
Recognizing the significant impact elevation has on compressor capacity, compressor manufacturers have adopted standards to allow “apples-to-apples” comparisons of their models and those of other manufacturers, taking site conditions out of the equation:
Only the compressor is rated in ACFM. Dryers, filters and all downstream equipment are rated in SCFM.
Lower ambient air pressure means your compressor must work harder to generate the pressure you need. If the air pressure is 14.69 pounds per square inch in New Orleans and 12.22 in Denver, your compressor has to make up the difference. For the most part, an air tool in Denver needs the same 80 PSIG of pressure it requires in Miami.
Altitude even impacts two-stage units like Kaishan’s KRSP2 premium rotary screw air compressor, requiring higher compression ratios, especially in the first stage.
Because fewer air molecules enter at a lower pressure, your compressor at altitude will have to work harder and generate more heat to produce the same amount of pressure and flow as at sea level.
Because the air is less dense, there are fewer air molecules to remove heat. Once again, your compressor must work harder to maintain the target temperature.
The effects of altitude are not limited to your compressor and the airend. They will also change the performance of your motor and cooling equipment.
Your compressor will need a larger motor to do the increased work required to generate the pressure and flow. As with the compressor, the motor will generate more heat and have less cooling capability, so you will need a motor rated for high altitudes.
Because the air is thinner at higher elevations, you may need to increase the size of your air inlet valve to bring more air molecules.
You may need to increase the size of your air inlet valve to compensate for the thinner air at higher elevations.
As mentioned, altitude will impact the cooling capabilities of an air-cooled machine (but not a water-cooled compressor). You’ll need to oversize your fans and heat exchangers.
Even your electrical components will be impacted. Your starters and other electrical equipment must be oversized to dissipate heat into thinner air.
If you use the same components at 10,000 feet as you use at sea level, your system may overheat.
Do we have high-altitude compressors? Not really, but there are a host of steps we can take to make sure your compressor runs well at higher elevations, including:
Altogether, these combined impacts could require as much as a 40% increase in compressor capacity at higher altitudes, according to Compressed Air Best Practices.
We recently sold a compressor to a Colorado gold mine where they could have used a 200-HP compressor if they were at sea level. But because they were at 11,000 feet, we had to specify a 350-HP unit with a 400-HP cooler pack, larger fan, heat exchanger, motor, starter and drive. We oversized everything, and it’s been running well.
Sizing a compressor to account for your elevation illustrates the value your local compressed air consultant can offer. They know your area and the unique challenges of delivering compressed air.
Your local compressed air professional can help ensure that your air compressor is sized correctly for your elevation.
Kaishan USA is fortunate to work with a nationwide network of independent distributors, who can provide on-site help and consultation to answer any questions about how your particular elevation will impact the operation of your compressed air system.
We choose to partner with independent, local professionals because it's the best way to ensure you have access to factory-trained air compression experts who can service your air compressor system without a problem. They offer expert guidance, faster response times and personalized support tailored to your needs. They don't just sell compressors—they build relationships, ensuring you get the right system, reliable service and quick access to parts when you need them most.
With factory-trained technicians and a deep understanding of industrial applications, they know how to maximize efficiency and minimize downtime. When you buy through Kaishan, you're getting more than a product—you're getting a local partner who cares about your business and wants to see it succeed.
Making sure your rotary screw air compressor is sized and equipped for your altitude is critical to the operation of your compressed air system and all the processes that rely on that system. If you need help adapting your compressed air system to your elevation, get in touch with the experts at Kaishan. Contact us today.
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