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Air tool consumption and compressor sizing

Paste your tool list with consumption, quantity and usage. The page corrects for working pressure, applies simultaneity and allowances, and shows compressor flow, power and receiver volume.

Pre-sizing and estimating tool: results do not replace design, calculations or reports signed by a licensed professional, nor verification against the applicable codes and standards.

Pre-sizing
Tools
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Paste straight from Excel or separate with semicolons. Blank quantity and usage count as 1 and 100%. Consumption is the catalog value at the rated pressure below.

Pressures
Design factors
Compressor and receiver

Load/unload screw compressor at 100 psig: 17 to 20 kW per 100 cfm. Small piston units: 20 to 25.

—Required free air delivery (FAD)
—

Average consumption by tool

Rated consumption corrected for pressure, times quantity and usage factor.

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From the tool sum to compressor capacity

Each bar applies one factor: usage, simultaneity, leaks and expansion.

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Tools read

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Check the receiver with demand peaks →Annual cost of this compressed air →

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Method, assumptions and references

Equations used

Pressure correction: k = (p_actual + p_atm) ÷ (p_rated + p_atm); q_i = q_catalog,i × k
Average demand = Σ q_i × n_i × u_i; FAD = average × simultaneity × (1 + leaks) × (1 + expansion)
Input power = FAD × specific power; discharge pressure = p_actual + losses
Receiver (load/unload): V = 0.25 × FAD × p_atm ÷ (f_max × Δp), with f_max in cycles per second

Assumptions and limits

  • Catalog consumption as free air (FAD) at rated pressure, usually 90 psig per ISO 2787; the absolute-pressure correction treats the tool as a fixed orifice.
  • Usage and simultaneity factors are estimates by someone who knows the operation; measure compressor loaded time to confirm.
  • Receiver by the Atlas Copco formula with equal inlet and receiver temperatures; short peaks above capacity need the receiver calculator check.
  • Standard motor: the next size above estimated input power (NEMA hp or IEC kW).

Standards and technical documents

  • ISO 2787: Rotary and percussive pneumatic tools — Performance tests
  • ISO 1217: Displacement compressors — Acceptance tests
  • ISO 8573-1: Compressed air — Contaminants and purity classes
  • ISO 4414: Pneumatic fluid power — General rules and safety requirements for systems and their components
  • Atlas Copco: Compressed Air Manual, 8th ed.
  • U.S. DOE / Compressed Air Challenge: Improving Compressed Air System Performance — A Sourcebook for Industry

U.S. regulations

  • OSHA 29 CFR 1910.243(b): pneumatic powered tools
  • OSHA 29 CFR 1910.242(b): compressed air used for cleaning (below 30 psi)
  • OSHA 29 CFR 1910.169: air receivers
  • OSHA 29 CFR 1910.95: occupational noise exposure

Frequently asked questions

How much air does a 1/2 in impact wrench use?

Catalogs list 4 to 6 cfm at 90 psig while it runs. Because it works only 10% to 30% of the time, average demand is about 0.5 to 1.8 cfm per tool.

Why apply a simultaneity factor on top of usage factors?

Usage says how much each tool runs; simultaneity recognizes that not all tools run at the peak together. With 25 tools, 70% is common; with 3 tools, use close to 100%.

What if the system runs at 110 psig and tools are rated at 90 psig?

Consumption rises with absolute pressure: (110 + 14.7) ÷ (90 + 14.7) = 1.19, or 19% more air, plus faster wear. Fit a regulator at the point of use.

How do I pick the compressor from the cfm?

Multiply flow by specific power. For 65 cfm and 18 kW per 100 cfm, input power is about 11.7 kW (15.7 hp): a 20 hp compressor covers it with margin.