How to Calculate Your Nitrogen Requirements

Whether you're in manufacturing, food processing, laser cutting, or another industry that relies on nitrogen, knowing how much nitrogen you need is essential for optimizing operations and selecting the right nitrogen generator. Overestimating your requirement can lead to wasted capital and energy, while underestimating it can cause production delays and quality issues.

In this post, we'll walk you through a straightforward way to calculate your nitrogen requirement—and explain why it's a critical step in transitioning to on-site nitrogen generation.

Why You Need to Calculate Nitrogen Demand

Before investing in a nitrogen generator, it’s important to understand:

• Flow rate (how much nitrogen you use over time)

• Pressure (how much pressure your application requires)

• Purity (what percentage of nitrogen is needed)

These factors determine the size, type, and configuration of the generator you’ll need.

Step 1: Identify All Nitrogen Usage Points

Start by listing every piece of equipment or process that consumes nitrogen. This may include:

• Packaging machines (in food and beverage)

• Laser cutters (in metal fabrication)

• Blanketing systems (in chemical or oil & gas)

• Inerting or purging systems

For each point of use, note the manufacturer’s specs for flow (usually in SCFM or Nm³/hr), pressure, and operating time.

Step 2: Determine Flow Rate (Total Demand)

Add the flow requirements from each usage point. Be sure to consider whether they operate simultaneously or intermittently.

Example:

Equipment	Flow Rate (Nm³/hr)	Operating Time	Simultaneous Use?
Packaging machine	5	8 hrs/day	Yes
Laser cutter	10	4 hrs/day	Yes
Inerting tank	3	6 hrs/day	No

Peak demand is your most important number—it’s the total flow rate when everything runs at once. In this example, peak would be:

5 (packaging) + 10 (laser) = 15 Nm³/hr

You may also want to calculate your average daily usage, which helps estimate operating costs.

Step 3: Determine Required Pressure

Each application has a minimum operating pressure. For example:

• Laser cutting may require 20–30 bar

• Food packaging may work at 4–7 bar

The generator must meet the highest pressure requirement unless you use a booster system for selective processes.

Step 4: Define Nitrogen Purity Requirements

Purity levels vary depending on the application:

• Food & Beverage: 99%–99.5%

• Electronics: 99.999%

• General Industry: 95%–99.9%

Higher purity = lower flow and higher generator cost. Be sure you're not over-specifying purity unnecessarily—it could lead to overspending.

Step 5: Add a Safety Margin

Add a 10–20% buffer to your total calculated flow. This ensures:

• Coverage during unexpected demand spikes

• Room for future expansion

• Generator isn’t running at full capacity all the time (improves longevity)

Step 6: Consult with a Specialist

While these steps give you a solid estimate, every facility is different. A nitrogen generation expert can:

• Conduct a site audit

• Analyse your historical gas usage

• Recommend an optimized generator size and type (PSA or membrane)

Sample Calculation Summary

Let’s assume the following:

• Packaging (5 Nm³/hr) + Laser (10 Nm³/hr) = 15 Nm³/hr

• Required pressure = 8 bar

• Required purity = 99.5%

• Add 15% safety margin: 15 × 1.15 = 17.25 Nm³/hr

You’d need a nitrogen generator rated for:

• Flow: 17.25 Nm³/hr

• Pressure: ≥ 8 bar

• Purity: 99.5%

Final Thoughts

Calculating your nitrogen requirement is the first and most crucial step toward cutting operational costs, boosting efficiency, and gaining independence from bulk gas deliveries. With the right data—and expert help—you can select a nitrogen generator that fits your needs exactly.

Want help calculating your nitrogen needs? Contact us today for a free consultation and site evaluation.