Sourcing glass sight gauge tubes from China

Duty and classification

Heading 7020 covers other articles of glass not covered elsewhere. This guide concerns glass sight gauge tubes for viewing liquid levels, rather than complete gauge assemblies. The table shows material-based candidates, subject to classification confirmation; plain and graduated low-expansion tubes share a line. See the wider glass articles guide.

Read from the UK Trade Tariff on 20 October 2026, all relevant lines carried 0% duty for goods from China. The supplied tariff record lists no anti-dumping or countervailing duties and no suspensions. It attaches cat and dog fur import and export controls: imports and exports of such fur and products made from it are banned. Check any accompanying materials with your customs broker.

Confirm the glass composition, expansion properties, processing and supplied form before choosing a code. Send drawings and material evidence to your customs broker; use finding your commodity code to prepare the classification enquiry.

Specify the tube and its gauge assembly

Specify the glass grade, outside and inside diameters, wall thickness, length, straightness, ovality and end finish. Show the seal contact surfaces on the drawing and agree tolerances against the actual gauge fittings. For graduated tubes, agree the scale position, units, visibility and resistance to the intended cleaning process.

State the liquid, operating temperature, pressure and cleaning conditions. Ask for material certificates and service-relevant thermal shock evidence. Pressure-equipment rules regulate the design, manufacture and conformity assessment of pressure equipment and assemblies with maximum allowable pressure greater than 0.5 bar. Ask a competent adviser to assess the intended supply; the appropriate conformity procedure depends on equipment or assembly classification.

For tubes contacting food or drink, obtain food-contact evidence, as explained in the site's wider glass guide. Agree individual protection, carton partitions and packed-carton drop tests before production.

Worked duty example

Illustrative example, not a quote: Illustrative order: 20,000 borosilicate glass sight gauge tubes under 7020 00 30 00, invoiced at £15,000 free on board, with £1,200 of freight and insurance to the UK. The customs value is £16,200. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £16,200, so it is £3,240. With no duty, the only import tax is the VAT, which a VAT-registered importer can usually reclaim. The import duty and VAT guide explains each step.

Inspection checklist

Material: compare the batch certificate and expansion properties with the ordered glass grade; inspect bubbles and inclusions against the agreed sample.

Dimensions and seals: measure diameters, wall thickness, length and straightness; inspect end squareness and chips, then trial-fit samples in the intended fittings.

Stress and service tests: examine residual stress with a polariscope and perform agreed thermal shock and assembly tests under controlled conditions matching the intended service.

Arrival and traceability: inspect protective packing, cracks and scale alignment; match carton and batch records to the certificates. Agree the sampling and rejection process through quality inspection.

What goes wrong

A tube can match the nominal diameter yet leak because ovality, end damage or the seal contact surface differs from the drawing. Glass supplied as borosilicate may have the wrong expansion properties; residual stress and chipped ends can cause later cracking. Approve samples in the actual fittings and retain the agreed drawing and material certificate.

A supplier's pressure claim may describe a different tube length, wall thickness, seal arrangement or test temperature. Ask for the test configuration and results for your assembly. On arrival, segregate chipped or cracked tubes and record the affected batch before installation.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For own-brand ranges, see sourcing for brands.