Read a Basflex size as a pair of dimensions, rather than choosing from the largest number in the row. Basflex is a basalt-fiber sleeve formed by intertwining multiple basalt filaments into a closed radial structure. Its tubular braid surrounds the line being protected; the installed line shape and the geometry encountered during assembly both belong in the size review.
The Basflex dimension table pairs nominal inner diameters from 6 mm to 20 mm with maximum diameters from 10 mm to 30 mm across seven sizes. These two columns give a starting point for comparing named BSF sizes. Maximum diameter is not, by itself, a recommendation to operate the sleeve at that diameter.
Understand the basalt braid before choosing a size
Basflex protects wire bundles, tubes, pipes and conduits against heat, flame, chemical agents and mechanical stresses. The practical starting point is the surrounding basalt-fiber structure: the product forms a textile covering around the selected line, rather than a flat strip placed on only one face.
That form helps a buyer relate the material to a real cross-section. A circular tube, an uneven wire bundle and a conduit transition can present different shapes even when one measured dimension is similar. The sleeve should be evaluated around the shape it will actually cover.
Use the intended protective task to guide that evaluation. A mechanical-protection application and a chemical-exposure application may involve the same sleeve family, but their acceptance conditions differ. Identify the particular contact, movement or exposure relevant to the line; do not treat a material name as universal chemical compatibility.
Read the two diameter columns together
Keep the size designation attached to both values when passing information between design and purchasing.
| Basflex size | Nominal inner diameter | Maximum diameter |
|---|---|---|
| BSF-6 | 6 mm | 10 mm |
| BSF-8 | 8 mm | 12 mm |
| BSF-10 | 10 mm | 15 mm |
| BSF-12 | 12 mm | 18 mm |
| BSF-14 | 14 mm | 20 mm |
| BSF-18 | 18 mm | 25 mm |
| BSF-20 | 20 mm | 30 mm |
For example, BSF-6 pairs a nominal inner diameter of 6 mm with a maximum diameter of 10 mm. That is a named size row, not an instruction to select BSF-6 for every 10 mm line. The installed geometry and desired covering condition still need to be evaluated together.
Likewise, do not create an unlisted size by interpolating between two rows. Shortlist the relevant named sizes and take the actual cross-section into a fit discussion. This keeps the quotation tied to an identifiable product configuration.
Product and dimension reference: Basflex basalt-fiber sleeve; Bonsing public product-detail page, reviewed October 2026. The table reproduces that page’s seven nominal/max diameter pairs. Confirm the requested size, installed shape and application conditions during technical review; the maximum-diameter column is not an operating-limit or fit guarantee.
A flattened width is a different measurement
A loose tubular sleeve can appear flat in a photograph or on a work surface. Its visible width in that state is not the table’s nominal inner diameter. A product photograph also has no reliable scale unless a dimension is explicitly established.
Keep the measurement description with the number. “Flat width,” “line outside diameter” and “sleeve nominal inner diameter” identify different things. Replacing those descriptions with the single word “size” can make two teams appear to agree while they are comparing unlike measurements.
For an irregular bundle, provide a cross-section or drawing instead of reducing the shape to an unexplained width. This gives the reviewer more useful information than a picture with an approximate dimension alone.
Preserve a tubular covering around the actual shape
The open end shows the sleeve’s surrounding wall and inner passage. That passage is where the protected line sits. The fit review should therefore consider how the braid covers the line along the required length, including transitions or local changes in section.
Assess a representative sleeve on the actual line shape. Note whether the selected row offers the intended covering arrangement and how the material lies at changes in section. An acceptable entry condition does not automatically establish the desired condition along the rest of the route.
If the line shape or duty differs from the initial candidate, discuss a customised configuration using the drawing and protective task. The useful outcome is a defined size and construction for review, rather than a universal expansion allowance.
Match the supply form to the assembly
Basflex can be delivered in spools, festooned lengths or cut pieces. After identifying candidate sizes, match the receiving format to how the buyer prepares and installs the covering.
A spool-based process requires local length preparation; a cut-piece request needs an agreed piece length and quantity. Specify those items alongside the BSF size so that the supply request does not lose the configuration selected by engineering.
FAQ
Is maximum diameter the recommended installed diameter?
No. It is a separate field paired with nominal inner diameter in the Basflex size table. Evaluate the intended installed shape and covering condition before choosing the size.
Can I use a flattened sleeve width as nominal inner diameter?
No. Flattened width and nominal inner diameter are different measurements. Label the measurement and use the named size row for the product request.
Which Basflex supply forms are available for discussion?
Basflex can be delivered in spools, festooned lengths or cut pieces. Include the selected size, required length and quantity in the discussion.
Request a Basflex Size Review
Share the line cross-section, installed and entry dimensions, required coverage length, candidate BSF size, exposure and preferred supply form. Request a Basflex size review with Bonsing using the Basflex product details as the starting reference.
Post time: Oct-21-2026