Calculate the Air Consumption Required to Fill a Tire (CFM)

Your question makes no sense. Any rate value will work. It's just that lower rates will take longer time to fill. Are you in a hurry to fill? Use 100 cfm. But remember to stop when the tire pressure reaches your desired pressure range.

Perhaps you meant what volume (in cubic feet) is required. Since you want 8 atmospheres, multiply the volume of the tire by 8.

Divide this volume by the fill rate to get time to fill (in minutes) CF/CFM = (value) minutes.

This is the info I have

I need to buy an air compressor

I have the inventory of pneumatic tools that we have working so I have the total CFM for all of them.

Additional to this I need to calculate the air consumption required to inflate 20 bridgestone tires (size 11r24.5) at the same time (each tire must be inflated in 5 minutes). the air pressure rate we need is 120 psi.

- I got the CFM for pneumatic tool

- I need to know the CFM to inflate the tires

- Other guy is working in calculate the air piping, also have to will get the CFM

Pneumatic tools + process of inflation of tires + air piping = air compressor required

I am a computer engineer and I'm not familiar with this job, but I was assigned to this so I will appreciate your help on this

Dose your system have an air reciver. The size of the air reciver would alter the amount of available air to inflate the tyres.

The pressure in the air reciver will be more than what is needed to inflate the tyre but the time would depend on the size of the filling pipe to the tyre, and the size of the tyre valve hole. This valve will be the limiting factor to your question. How much air can you pass through this valve in how much time.

From the tool inventory determine which consumes the highest rate of air as the worst case.

Determine how many tools from the inventory will consume air simultaneously (Do not spec for those on the bench).

Determine the volume of the tire in CF.

Determine how many of the twenty tires are to be filled simultaneously.

Add the consumption of tools and tires during the worse case demand.

Divide the tire volume by 5 minutes to obtain the rate for one minute.

Add them up (sum tools in CFM plus tires CFM).

Multiply the rate by a factor of safety (say 2x or 3x)

Procure a compressor whose specification exceeds this rate at 120 psi plus the buffer (say 30 psi) to account for line losses from the tank to the various nozzles. You mentioned someone else is sizing the piping. Talk to that person.

The larger the compressor tank volume is and the more tank pressure exceeds 120 psi, the less frequent the compressor will have to run during peak consumption periods.

Make sure you take heat and water vapor condensation into consideration.

Compressed air is one of the least cost effect operations in any production area and the most miss understood item used in shops. One must be careful not to undersized the unit and on the other hand oversizing waste energy in the operations as well. Same goes with the use of receiver tanks. Too large and system works harder to get up to pressure. To small and compressor is working harder as well.

Sounds like you are setting up a repair shop of some kind from what I see written. If this is the case how many work bays. Are there to be air/oil lifts? At any rate, most of the large shops I have worked in or set-up if you like, use a compressor in the 30 - 40 HP range. Which produces in the area of 100 - 140 CFM depending on the compressor manufacture.

Hope this helps.

WOW! Bad day for questions!

Any reasonable compressor of any CFM output will eventually fill a Bridgestone tire to 100-120 psi.

If you have the time and inclination, you can calculate the number of cubic feet of air (at standard temperature and pressure) to fill the tire, based upon the calculated volume of the tire. You can calculate the volume of the tire as being close enough to 75% of the that of a rectangular prism formed from the average circumference (the circumference half way between rim and tread) times the width and height of the tire cross section.

Some thing to think about when considering compressor--not only cfm but also pressure. any compressor will eventually fill your tire if it can produce 100psi but if you have higher pressure, say 175 psi, you will fill your tire much faster. If you have higher pressure than you require, flows higher to lower pressre.