Air compressors: In industry, a “medium-capacity” air compressor typically delivers between 0.15 m^3/s and 5 m^3/s of free air at standard conditions (per unit time).

Introduction / Context:
Compressor sizing is often communicated by volumetric delivery at standard conditions. Understanding the typical bands that classify small, medium, and large compressors helps with selection and preliminary design.

Given Data / Assumptions:

• Classification is based on free air delivery per unit time at normal temperature and pressure (standard intake conditions).
• Only an order-of-magnitude selection is required; exact manufacturer ratings vary.

Concept / Approach:
Common practice divides compressors roughly into small (up to about 0.15 m^3/s), medium (about 0.15 to 5 m^3/s), and large (above 5 m^3/s). These brackets cover the typical ranges encountered in plants, construction, and process utilities.

Step-by-Step Solution:

Verification / Alternative check:
Surveying vendor datasheets shows portable and workshop units below 0.15 m^3/s; plant utility compressors often sit between 0.15 and 5 m^3/s; multi-megawatt process machines exceed 5 m^3/s.

Why Other Options Are Wrong:

• 0.1 to 1.2 m^3/s: Too narrow; excludes many medium plant units above 1.2 m^3/s.
• Above 5 m^3/s: This is large-capacity territory.
• None of these: Incorrect because 0.15 to 5 m^3/s is a recognized medium range.

Common Pitfalls:
Confusing “delivered at standard conditions” with actual discharge conditions; always normalize to compare between compressors.

Final Answer:
0.15 to 5 m^3/s