Flame-retardant Sheathed Duct Type Optical Cable
Built for the Conduit, Rated for the Flame Code
Every cable that enters a building passes through a duct - a riser, a floor conduit, a corridor tray - and every such duct sits inside a fire code. This cable answers both demands at once: a jacket system built for the abuse of duct pulling, wrapped around a core that meets the flame ratings inspectors actually check. Drag it through a 90-degree bend, then hand it to the inspector with confidence.
Jacket Engineering, Layer by Layer
The defining feature is a sheathing stack built in layers, not a single compromise material.
Outer jacket - abrasion and drag performance. The exterior layer is compounded for toughness: it shrugs off scraping against duct ribs and pull-rope friction, and stays flexible from −40 °C to +70 °C. A smoother skin also lowers friction against conduit, cutting winch time.
Flame-rated inner sheath. Beneath the tough skin sits the material that satisfies the flame specification - self-extinguishing, resistant to flame propagation, and low-smoke. Splitting the mechanical and safety layers lets each be optimized instead of one material doing both jobs poorly.
Water-blocking and strength beneath the sheath. Dry swellable yarn and FRP strength members sit inside the flame-rated layer, so a cable that is pulled, crushed, or submerged still protects its fibers.
Installation Realities Inside the Duct
Side-wall pressure. Every bend multiplies the force between cable and duct wall; the outer jacket's crush resistance keeps the flame layer from pressing into the fiber tubes at tight radii.
Friction management. A pre-lubricated option cuts pulling tension by up to 30 percent, enabling 300–500 meter pulls through congested conduit with a single winch set.
Bend and crush margins. With a 10–15× diameter minimum bend radius and crush resistance above 2200 N/100 mm, it tolerates the misaligned joints and stacked conduit layers crews meet daily.
Re-pull capability. A scuff-resistant outer jacket lets a cable be withdrawn and re-pulled without shedding fragments that jam the duct - a failure mode common with soft single-layer sheaths.
Where This Specification Makes a Difference
Building risers and floor conduits: Fire-rated duct runs in towers, hospitals, and hotels, sharing the riser with power circuits.
Metro and tunnel utilities: Rail corridor ducts must meet transit flame rules while surviving vibration and maintenance access.
Data center under-floor conduit: Raised-floor pathways combining fire codes with dense, hard-to-reach pulls.
Industrial plant cable ways: Conduit runs through zones with ignition sources and strict inspections.
Mixed outdoor-to-indoor routes: One reel that leaves an outdoor pit, enters through a wall duct, and terminates at the equipment room.
Advantages at a Glance
Dual-purpose jacket: mechanical toughness and flame compliance in one cable, no double-buying
Faster, safer pulls: friction-optimized surface and pre-lubrication cut winch time
Inspection-ready: meets the flame propagation and smoke limits commissioning engineers verify on site
Rugged enough for re-pulls: no jacket shedding, no duct jams, no crushed-sheath damage
Full accessory fit: works with standard duct, conduit, closures, and glanded wall entries
Key attributes
|
Brand Name |
Sheng Tang |
Model Number |
Stranded Loose Tube Fiber Optic Cable GYFTY |
|
Type |
Outdoor Fiber Optic Cable |
Place of Origin |
Guangdong, China |
|
Number of Conductors |
≥ 10 | Core | 2 to 144 |
| Jacket Material | HDPE | Fiber Type | SM/MM |
| Strength member | FRP | Temperature range | -40~+60℃ |
| MOQ | 2Kilometer | Application | outdoor/aerial/duct |
| Port | GUANGZHOU | Place of Origin | Guangdong, China (Mainland) |
Packaging and delivery
| Packaging Details | Wooden Drum,70X70X55 cm | Port of dispatch | GUANGZHOU,SHENZHEN |
| Selling Units | Single item | Single package size | 70X70X55 cm |
| Single gross weight | 0.070 kg | Packaging examples |  |
Supply capacity
| Supply Ability | 1000000 meters per Day |
Lead time
| Quantity (meters) | 1 - 1000 | 1001 - 50000 | 50001 - 300000 | > 300000 |
| Lead time (days) | 7 | 12 | 25 | To be negotiated |
Customization options
| Option | Min. order: | Customization fee |
|
Customized logo As requested |
1000 meters | -- |
|
Customized packaging As requested |
1000 meters | -- |
|
Graphic customization As requested |
1000 meters | -- |
Packaging & Shipping
FAQ
Q1: Why does a duct-type cable need a flame-retardant rating at all?
Ducts inside buildings are escape corridors in the eyes of building codes. Any cable routed through a riser or floor conduit must limit flame spread and smoke so it does not become a chimney. The rating is a legal requirement, not an option.
Q2: What is the practical pulling distance in a single duct run?
With a pre-lubricated jacket and proper winch setup, crews routinely pull 300–500 meters per section. Beyond that, intermediate pull boxes are recommended, mainly to manage side-wall pressure at bends rather than cable strength.
Q3: Is the flame-rated jacket softer and more damage-prone than a standard PE sheath?
Not in this design. The two-layer construction keeps a tough outer skin for abrasion while the flame-rated material sits protected beneath it - fire performance without sacrificing the durability duct pulls demand.
Q4: How does this cable behave in sub-zero outdoor duct sections?
The outer jacket stays flexible down to −40 °C, so winter pulls do not stiffen the cable into cracking at duct mouths. The inner flame layer retains its rating across the same range.
Q5: Can the same reel transition from an outdoor underground duct into a building riser?
Yes - that is the intended use case. With the whole sheath flame-rated, there is no need to splice to a second indoor cable at the boundary, saving a closure and a splice point.
Available in 2 to 144 fibers, with pre-lubricated, rodent-resistant, or armoured variants. Contact our engineers for a pull-plan review matched to your duct profile.