In the field of specialty gases, a clear understanding of different types of errors is essential—not only for proper equipment operation but also to ensure the legal integrity of analytical results. What are the differences between these types of tolerances;
Preparation Tolerance
This represents the maximum allowable deviation between the Target Concentration (requested by the customer) and the Actual Filled Concentration. This helps customers determine if the gas cylinder falls within the measuring range and the calibration capability of the on-site analytical instruments
Preparation Tolerance serves the purpose of production control. When performing instrument calibration, customers must not use the target concentration; instead, the certified actual concentration stated on the CoA must be utilized
Typical Preparation Tolerance values ± 1% rel; ±2%rel; ±3% rel; ±10%rel,
Measurement Uncertainty
Measurement Uncertainty is a parameter associated with the result of a measurement that characterizes the dispersion of the values that could reasonably be attributed to the measurand. It represents the reliability of the actual concentration value recorded on the gas cylinder. Measurement Uncertainty is rigorously calculated based on a combination of factors: the sensitivity of the high-precision electronic scales, the purity of the raw gases, and the chemical stability of the gas mixture over time.
This is the definitive figure to be entered into calibration software to establish the accuracy and legal validity of all subsequent analytical results.
Typical Measurement Uncertainty values: ± 0.05% rel; 0.1% rel; ± 0.2% rel; ±0.5% rel
%Rel (Relative): The error calculated as a percentage of the value itself.
Preparation Tolerance
Customer Order: Oxygen concentration 10,0000% mole (Nominal Value).
Actual Factory Fill: 9,9955% mole (Actual Value).
Analysis: The preparation tolerance here is extremely low (a deviation of only $0.045\%$ from the target), proving the factory’s exceptionally precise filling process.
Measurement Uncertainty
Absolute Uncertainty for Oxygen: 9,9955* 0,0005 = 0,00499…
Commitment: The manufacturer guarantees with high confidence that the true Oxygen concentration in the cylinder lies within the range of 9,9955 ± 0,0050 %mol.
Vina Industrial Gas is proud to be a specialized provider of calibration gas cylinders, fully certified with CoAs from the world-renowned manufacturer, Air Products. Our products ensure high accuracy and long-term stability, providing optimal performance for analytical instruments and continuous emission monitoring systems (CEMS).
Our Products and Services Include:
- Specialty Gases: High Purity Gases and Calibration Gas Mixtures.
- Helium lỏng(Liquid Helium) và Khí Helium (Helium gas)
Contact us today for professional consultation and to request a quotation:
Hotline: 028 3636 4195
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Address: Lot B5-14, N6 Street, Tan Phu Trung Industrial Park, Cu Chi Commune, Ho Chi Minh City, Vietnam.