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The price tags of gas products outsourced from China are considerably lower than those imported from other countries. Even with shipping costs factored in; these products could still provide substantial profit or savings for importers. Since quality and safety are major concerns when dealing with gas products, it is important that a third party inspector in China should physically represent buyers, if they are not able to do it themselves.

In hiring a gas product inspection company in China, importers must be acquainted with the key points relating to this field. The following are some of the inspection protocols applicable to gas products:

Materials Inspection

Tank Materials Verification – Verify that materials used for the manufacture of gas tanks comply with existing standards and regulations including API 510, ASME Pressure Vessel Code Section II, and API 572. Test may use special non-destructive testing devices on existing tanks, if necessary.
Purity Testing – Check the purity levels of contained gasses by using applicable test methods such as the impurity subtraction approach. This method deducts the total measured impurity from the total product volume to determine the purity level of tested gas. Depending on type of gas, purity testing may utilize other methods such as the absorption and the oxidation methods.

Visual Inspection

Cylinder Check – Visually inspect cylinder for any sign of damage or alternations such as dents, color degradation, cracks, chips, and arc burns.
Color Coding – Verify that gas cylinders adhere to standard color coding schemes provided for in importing territories. Whenever applicable, use Pantone color chart to compare actual color with approved values.

Dimensional Inspection

Tare Weight – Verify tare weight of cylinder tanks to determine compliance to contract specifications.
Cylinder Wall Thickness – Measure thickness of cylinder wall to determine compliance to contract specifications or state regulations, whichever is necessary.
Performance Inspection

Rated Capacity – Verify that LPG cylinder content does not exceed 80% of its rated maximum capacity to allow enough room for gas expansion which usually occurs when there is an increase in unit temperature.
Cylinder Connection – Check that the connection valves comply with applicable standards such as DIN 477, BS 341, and NEN 3268.
Weld Integrity – Verify the integrity of tank welds to prevent exploding of tanks or leakage of gas. Guidelines include ASME Pressure Vessel Code IX or other equivalent standards.
Internal Corrosion – Determine the likelihood of internal corrosion specifically on medical gas cylinders by using the hammer or dead ring test. Possible corrosion is indicated by the release of a dull ring when cylinder is tapped lightly. A crisp clear ring indicates absence of internal corrosion.
Odor Test – Check cylinders intended to contain medical gases for any odorous characteristics before refilling. This simple yet effective test method is not applicable to nitrous oxide, toxic, carbon dioxide, or corrosive gases.

Specific Requirements Verification

Medical Gas – Verify that gas products intended for medical purposes adhere to FDA regulations or equivalent requirements. Container openings and regulators must be constructed in such a way that it helps prevent external contaminants from entering the cylinder.

Packaging Inspection

Labels and Markings – Check for compliance with labelling and marking standards for high purity gasses and gas fuels. These marks may include cylinder identification numbers, tare weight, net product weight, storage guidelines, and purity levels.

These are just some of the procedures pertaining to gas products. To know more about these and other inspection protocols, please provide InTouch with the necessary details about your inspection needs.

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Topics: Industrial Goods

AQF Team

This article was a collaborative effort among various members of the Asia Quality Focus team.

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