Anonymous asked in Home & GardenDo It Yourself (DIY) · 1 decade ago

air tools please help.?

what the difference between CFM AND SCFM?

I am trying to buy a new air compressor and i want to make sure that i am getting one powerful enough to run my pneumatic tools all of them list their air consumption at 5 to 8 CFM @ 90 PSI. the air compressor that i am interested in list it's air delivery at 11.7 SCFM @ 90 PSI. My local home depot associates were no help at all. so can somebody plain explain this to me.

7 Answers

  • KTB
    Lv 6
    1 decade ago
    Favorite Answer

    SCFM = Standard Cubic Feet per Minute. This means the units actual (normal) capacity. It will vary depending on sea level and etc.

    CFM (aka ICFM) = Inlet Cubic Feet per Minute (Cubic Feet per Minute). This means that it is used to figure how much air you have entering a compressor initially, and when you hook up things like filters, screens and such.

    ACFM = Actual Cubic Feet per Minute. This actually tells you how the unit is operating with all other factors figured in.

    *****The site above provides you with a free calculator to determine your actual rates and settings.*****

    In addition, it explains these definitions a little better. I am POSITIVE this is what you are looking for.

    Write to me if you have any questions. I'll be happy to respond in my best Neanderthal manner.

    Source(s): A GC
  • 1 decade ago

    Here you go:

    SCFM= Standard Cubic Feet per Minute.

    CFM= Cubic Feet per Minute

    ACFM=Actual Cubic Feet per Minute

    Now what this means is relatively simple as well, but a little confusing. The SCFM is a 'standard' measurement, which means that there is a rigid and repeatable scientific measurement for the amount of air a particular machine produces. What that means is that the US Govt requires that a standard measure apply to all air compressors regardless of size and shape and horsepower, so they defined how you have to measure it. It is basically this method:

    1- The air temperature must be 68 degrees Fahrenheit

    2- The relative humidity of the air must be 36%

    3- The air itself must be measured at sea level

    The SCFM and the CFM might be different for different compressors if say, one is manufactured to be used in Higher elevations (air is thinner) or if used in a wildly humid environment (florida summer) for instance.

    Now...for the rest of us that just want to run a paint sprayer, nail gun, or in your case an air tool, you really only need to know the CFM of the tool when operated and you will be fine. So if you take your 11.7 SCFM compressor (it's measured to do 11.7 CFM @ sea level, proper humidity etc..) and take it to Denver (mile high), you'll probably get a little less CFM, but not so much that you should worry. You will be fine with your compressor powering a pneumatic tool.

    The people who worry about SCFM vs ACFM are folks making very very tight tolerance machine parts that require a measurable air pressure to within very tight tolerances as well.

    The Wiki link below will tell you more, also if you google 'scfm vs cfm' you'll find lots of links that explain this much further.

    hope that helped.

  • 1 decade ago

    Never hear of SCFM but CFM is Cubic Feet per Minute. The biggest concern here is the PSI setting (Per Square Inch). Almost all air compressors have a regulator on them, and will pressurize to 120 psi, so if your tool calls for 90 PSI then you just adjust the regulator down to 90 psi.

    Also, when asking anyone questions at Home Depot, ask for the "Expert" for that department. i.e electrical expert, tool expert etc. When I do that, I always get the most knowledgeable person and usually learn something.

    Source(s): General contractor
  • 4 years ago

    Your air compressor is a source of power. Whether you're a weekend hobbyist or a business owner, you need the right-sized air compressor to power your air tools efficiently and properly. Selecting the right air compressor to meet your needs is simple, if you follow these steps. Pneumatic air tools require a volume of compressed air (CFM) at a specific pressure (PSIG) to operate efficiently - they do not require a specific horsepower. Ignore the horsepower rating when sizing and selecting a compressor. Add together the CFM requirements of all of the pneumatic tools you plan to run at the same time. Now, add another 25% for additional tools, future growth and eventual air system leaks. Be sure the motor characteristics of the compressor are compatible. Is your electrical supply single-phase or three-phase? What is the voltage? Residential and commercial buildings usually have single-phase, 115 volt, 60 cycle power, while industrial buildings often have a three-phase power supply. Small compressors should be used with an air receiver (storage tank). The receiver stores compressed air and minimizes the loaded run time of the compressor. The air receiver should be at least 5 gallons per CFM for optimal results. Take your CFM, maximum pressure, motor characteristics and receiver size requirements to your local compressor dealer or home improvement center and compare features among brands. Keep the quality factor in mind. You will certainly get what you pay for with air compressors.

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  • 1 decade ago

    CFM = Cubic Feet per Minute

    SCFM = Specific Cubic Feet per Minute

    PSI = Pounds Per Square Inch

    I have a large air compressor and a small (lighter one) to carry and I've found even my little one can handle all the tools I use, including a 16d nail gun. Unless you plan on running a framing crew with multiple guns, you'll be fine. Pick one that fits your needs, if you need a mobile one, go with a small lighter one, if you keep it in one spot in your basement or garage, go for the larger size.

  • 1 decade ago

    cubic feet per minute and square cubic feet per minute the scfm would be exponentially more volume but at the same pressure as pressure is regulated by a restriction to flow such as a restricted oriface. Immagine two lanes of trafic hindered by a wreck in one lane (cfm) now immagine the same wreck on a four lane highway

  • 1 decade ago

    Cubic Feet [per] Minuit =CFM

    Scfm is sq cubic ft per minuit, [Volume]

    Source(s): maint man
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