How is the compressed air demand of a factory determined? Equipment air consumption, simultaneity factor, and expansion margin.

I. Accurately measure equipment gas consumption

The first step in determining a plant’s compressed‑air demand is to comprehensively inventory the air consumption of all pneumatic equipment. This includes cylinders, pneumatic valves, blow‑off devices, and auxiliary tools on the production line. During this process, consult the equipment nameplates or technical manuals to obtain the rated air consumption of each unit under standard operating conditions. If a nameplate is missing, estimate the consumption based on actual measurements or by referencing average data from similar equipment. Ensuring the accuracy of these figures is essential for subsequent calculations.

II. Reasonable Introduction of the Simultaneous Coefficient

In actual production, not all pneumatic equipment operates at full load simultaneously. Consequently, simply summing the rated air consumption of all devices can lead to an oversized compressor selection, resulting in energy waste. In such cases, it is necessary to introduce…Simultaneous coefficientMeanwhile, the simultaneity factor is the ratio of the total gas consumption of equipment actually in operation during a given time period to the sum of the rated gas consumptions of all equipment. Depending on the plant’s production process, equipment operating patterns, and level of automation, the simultaneity factor typically ranges from 0.6 to 0.9. For production lines that operate continuously at full load, the factor is higher; for groups of equipment that operate intermittently, the factor is lower.

III. Scientifically Reserve Capacity Expansion Margins

The factory’s production scale and product mix may change over time; therefore, when calculating total demand, a certain margin must be allowed for.Capacity expansion marginThis is intended not only to meet the demand for additional equipment in the future, but also to compensate for pipeline leakage, filter pressure drop, and efficiency losses caused by equipment aging. As a general rule, it is recommended to reserve 10% to 20% of the total calculated demand as expansion capacity. If the plant has a clear plan for future capacity expansion, this additional requirement should be calculated separately based on the specific expansion schedule and then added accordingly.

IV. Comprehensive Calculation and System Evaluation

Once the equipment’s air consumption, simultaneity factor, and expansion margin have been determined, a comprehensive calculation can be performed. The formula for calculating the total demand is typically:Total demand = (Sum of the rated gas consumption of all equipment × Demand simultaneity factor) × (1 + Expansion margin ratio)After calculating the theoretical total demand, a systematic assessment must also be conducted, taking into account the plant’s actual pipeline network layout, gas pressure levels, and peak‑off‑peak consumption patterns. For operating conditions with significant fluctuations in gas consumption, it is recommended to install gas storage tanks to buffer peak demand, thereby ensuring the stable and efficient operation of the entire compressed air system.