Odorant Dosing Calculator

Calculator Inputs

Example Data Table

Numbers are illustrative. Use site specifications and odorant data sheets.

Formula Used

1) Convert target to mg/m³

• If target is already in mg/m³, use it directly.
• If target is g/m³, then mg/m³ = g/m³ × 1000.
• If target is ppmv, approximate: mg/m³ ≈ (ppmv × MW) / 24.45 (assumes 25°C and 1 atm).

2) Base mass dosing rate

Mass (mg/h) = Flow (Nm³/h) × Target (mg/m³)
Mass (g/h) = Mass (mg/h) ÷ 1000

3) Adjust for purity and safety

Adjusted mass (g/h) = Base mass (g/h) × (100 / Purity%) × (1 + Safety%/100)

4) Convert mass rate to pump volume rate

Volume (mL/h) = Adjusted mass (g/h) ÷ Density (g/mL)

How to Use This Calculator

1. Enter the expected gas flow during the activity.
2. Set the target odorant concentration from your spec.
3. Enter odorant density from the product data sheet.
4. Apply purity and a safety factor, if required.
5. Click Calculate to get pump setpoints and usage.
6. Download CSV or PDF for shift logs and QA records.

Odorant Dosing Guide for Field Work

1) Why odorant dosing matters on site

Odorants provide a detectable warning in fuel-gas and distribution lines. During tie-ins, purging, or recommissioning, a temporary flow condition can dilute odorant and create uneven mixing. This calculator translates your flow and target specification into practical pump settings so supervisors can document dosing actions and maintain consistent safety practices.

2) Turning a concentration target into an hourly rate

The core step is converting the target concentration into a mass-per-volume basis, then multiplying by the gas flow. For example, at 2,000 Nm³/h and 10 mg/m³, the base requirement is 20,000 mg/h (20 g/h). The tool then adjusts for purity and a safety factor to account for mixing losses and operational uncertainty.

3) Using density to set the pump accurately

Metering pumps usually operate in volume terms, so the adjusted mass rate is divided by liquid density. With density 0.83 g/mL and the example above, a 99% purity and 10% safety factor yields roughly 0.267 mL/h. Low rates like this often require calibration checks, stable suction, and clean injection quills to avoid drift.

4) Planning storage and consumption for shifts

Estimating daily usage supports logistics and avoids running the odorizer dry mid-task. Using the same scenario, 0.267 mL/h equals about 0.0064 L/day, and for an 8-hour activity the expected usage is about 0.0021 L. Record these values in the shift log and compare with tank level changes to validate the injection system.

5) Practical inputs and common checks

Confirm whether your flow is normalized and use the correct target units from the project specification. Set purity from the odorant certificate of analysis, and apply a safety factor aligned with your company procedure. After calculation, verify the pump range, line pressure, and injection point turbulence. Use the CSV or PDF outputs for QA, commissioning records, and handover documentation.

FAQs

1) What flow rate should I enter for purging?

Use the expected average flow during the purge step. If flow varies, calculate with a conservative upper value, or run separate calculations for each stage and document the settings for the crew.

2) Should I use Nm³/h or m³/h?

Prefer normalized flow when available because target specifications are commonly referenced to standard conditions. If you only have actual m³/h, confirm the basis and keep units consistent with your specification.

3) How do I choose a safety factor?

Select a percentage that matches your procedure and risk tolerance. Higher factors are common when mixing is uncertain, injection points are poorly turbulent, or commissioning conditions are changing frequently.

4) Why does purity change the dosing rate?

If the odorant product is not 100% active ingredient, you must inject more liquid to deliver the same effective mass. The calculator scales the dosing rate using the entered purity percentage.

5) My result is very small. Is that realistic?

Yes, odorants can be effective at low concentrations. Verify the pump’s minimum stable output, confirm density and units, and consider a calibration run to ensure the injector can deliver the required micro-flow.

6) When should I use ppmv input?

Use ppmv only when your project specifies ppmv and you know the odorant molecular weight basis. The conversion assumes 25°C and 1 atm, so treat it as an estimate unless your standard states otherwise.

7) What should I include in commissioning records?

Log flow, target concentration, density, purity, safety factor, calculated pump setpoint, runtime, and observed tank level changes. Attach the exported CSV or PDF for traceable QA documentation.