GB/T 8982-2025Oxygen supplies for medicine and aircraft breathing (English PDF)

5.1 Batching

The oxygen supplies products for medical and aircraft breathing continuously and stably produced on the same production line constitute a batch. The oxygen supplies for medical and aircraft breathing packaged in cylinder bundles constitute a batch based on the quantity of products from one cylinder bundle.

5.2 Sampling

It shall comply with the provisions of GB/T 43306.

5.3 Sampling Inspection

5.3.1 For oxygen supplies for medical and aircraft breathing packaged in cylinders (including welded insulated cylinders), random sampling inspection shall be conducted in accordance with the sampling quantities specified in Table 2.

5.3.2 The oxygen supplies products for medical and aircraft breathing packaged in cylinder bundles shall be individually inspected as a whole for each bundle.

5.3.3 The oxygen supplies for medical and aircraft breathing packaged in mobile pressure vessels shall be individually inspected.

5.3.4 For oxygen supplies for medical and aircraft breathing transported via pipelines, sampling inspection shall be conducted every 4 hours, or the sampling frequency shall be agreed upon by the supply-side and the demand-side.

6.1 Determination of Oxygen Content

6.1.1 Paramagnetic oxygen analysis method

6.1.1.1 Principle

Oxygen molecules will be magnetized in a magnetic field, generating an additional magnetic field that is in the same direction as the external magnetic field, exhibiting paramagnetism. A paramagnetic oxygen analyzer typically contains a pair of nitrogen-filled glass spheres (dumbbells), which are mounted between the two magnetic poles of the sensor's enclosed chamber. There is a reflecting mirror on the central axis of the dumbbells that reflects the light beam emitted by the light source onto the photoelectric sensor. Oxygen in the gas to be tested will be drawn into the magnetic field, which exerts an acting force on the spheres, causing them to rotate. This changes the angle of the reflecting mirror, resulting in a change in the light intensity received by the photoelectric sensor. To ensure that the photoelectric sensor receives a strong light signal, the control system drives the electromagnetic coil of the dumbbells with current, making them return to their original positions. The driving current is proportional to the oxygen content; the oxygen content can be determined by determining the magnitude of the driving current.

6.1.1.2 Test conditions

The following requirements shall be met:

---Temperature of operating environment: 5 °C ~ 40 °C;

---Relative humidity of operating environment: 20% ~ 85%;

---No electromagnetic fields affecting the normal operation of the instrument, no interfering gases affecting the accuracy of the determination, and no strong vibrations;

---Power supply: AC voltage (220 ± 22) V, frequency (50 ± 0.5) Hz;

---Instrument earthing requirements: reliable earthing (earthing resistance <= 4 ohm).

6.1.1.3 Reagents or materials

6.1.1.3.1 Zero-point gas

The oxygen content in the zero-point gas shall be less than 0.01% of the instrument's minimum measuring range, with the residual gas being high-purity nitrogen.

6.1.1.3.2 Gas standard samples (or standard substances)

The oxygen content shall be 80% of the measuring range, with the residual gas being high-purity nitrogen, and its expanded uncertainty shall not exceed 1%.

6.1.1.4 Instruments and equipment

6.1.1.4.1 Instrument requirements

Paramagnetic oxygen analyzer, with a measuring range of 98.00% ~ 100% (mole fraction). It shall be verified or calibrated by a metrological verification institution and within its validity period.

6.1.1.4.2 Indication error

The indication error of the analyzer shall not exceed 0.05%. […]