Do you know what size air compressor you need for your facility? Calculating compressed air requirements may seem complex, but it’s important to understand your needs before installing a new compressed air system. Here are four ways to calculate compressed air requirements for your facility.
Why Proper Sizing for Compressed Air Systems Matters
Air compressors come in a range of sizes and styles to suit a variety of needs. A small auto repair shop with a handful of tools will not need the same volume of compressed air as a large manufacturing facility using compressed air to run dozens of production lines. But in between these two extremes, there are a number of variables that impact the size of the compressor needed.
The costs of getting this calculation wrong can have consequences. Both over-sizing and under-sizing your equipment will impact your bottom line.
- If the air compressor is underpowered for your needs, it will result in unexpected downtime or may not serve production at all. The resulting productivity losses can be many times the cost of a larger compressor. Removing and replacing an inadequate system, or adding additional compressors after the fact, will be much more expensive than simply getting it right the first time.
- On the other hand, an air compressor that is larger than you need drives up energy, maintenance and operating costs in addition to the initial purchase price. Unless you are planning for rapid growth, it doesn’t make sense to buy a more expensive system than you really need.
Facilities using compressed air need to find a system in their “Goldilocks” range: not too big, and not too small, but just right.
Calculating Compressed Air Requirements for a New Facility
Calculating compressed air requirements for a brand-new facility presents special challenges. Without historical or baseline data, systems engineers must rely on estimates based on the technical specifications for the equipment planned for the facility. Entering this information into a spreadsheet will help you calculate the maximum CFM requirements for the facility. For each piece of equipment, you will need to know:
- The minimum and maximum CFM required
- Minimum PSI requirements
- The amount of time that production equipment will be running on each shift
In addition, you will need to consider how many machines will be running at the same time. For example, a fabrication shop may have multiple air-powered machines, including grinders, sanders and presses. However, the likelihood that all of them would be in use at once may be very lowl. Considering the number of machines running simultaneously, and the duration, will help system designers avoid over-engineering the compressed air system.
This method tends to result in over-estimating the CFM requirements for a facility, especially when there is a mix of manual and automatic equipment. However, it is still the best way to start when calculating CFM requirements for a new facility. An experienced compressed air system engineer can help you get a more accurate estimate of your needs.
Calculating Compressed Air Requirements for Existing Facilities
When replacing or supplementing a compressed air system in an existing facility, system engineers have more options. There are several methods that can be used to calculate actual compressed air usage in the facility. This will result in a more accurate calculation of CFM requirements than can be made with estimates based on machinery specifications.
- The simplest method involves compiling pump-up timings and on/off or load/unload timings in order to determine compressor system efficiency and remaining capacity. This works well as a rough estimate in environments where air usage is fairly stable throughout the day or for an instantaneous snapshot.
- Data logging, in which system pressure and CFM demand are recorded across multiple shifts, provides hard data which can then be broken down to show the minimum and maximum CFM requirements and energy consumption. This enables more accurate calculations in environments with varying demands and multiple shifts of operation.
- Flow meters can be installed on individual pieces of equipment or complete systems to provide an instant reading of actual usage. For a more accurate reading, a receiver tank should be installed near the flow meter to even out peaks and valleys in the data.
Selecting the Right Compressed Air System
These are just a few of the methods that our experienced compressed air system engineers use when sizing compressed air systems for our customers. These methods are backed up by decades of experience in compressed air system design. In addition to performing calculations, we can compare your facility to similar-sized operations within your industry to ensure that you have the right size system for your specific application.
Many sellers simply send a quote based on basic rules of thumb, without performing detailed calculations. Often, this results in a quote for a compressed air system that is either under- or over-sized for your application. At Fluid-Aire Dynamics, we believe that it’s worth the time to calculate your actual needs and make sure you understand how we are coming up with our recommendations. Our goal is to design a compressed air system that is “just right” for your facility.