PLB Duct Pipes
HDPE Permanently Lubricated Ducts for Utility Networks
Every digital and utility connection, from fibre internet and telecom to power and smart city networks, depends on protected underground cabling. NATRAJ PLB Permanently Lubricated Duct Pipes create a safe, durable pathway for OFC and other utility cables, enabling faster, smoother and more reliable installation.
Co extruded from virgin HDPE, the duct combines a silicone enriched low friction inner layer with a UV stabilised outer sheath to support long pulls across varied ground conditions. Tight OD and ID control, low ovality and uniform wall thickness deliver a smooth, consistent bore, while colour coding, tracer stripes, continuous print line and metre marking support on site identification and traceability.
Designed for blowing, jetting and controlled hauling, the round snag free bore helps protect cable sheath integrity and supports long continuous runs with fewer joints. Permanent lubrication is created through a silicone enhanced lubricity package locked into the inner layer during co extrusion, delivering predictably low drag and retaining performance after ageing and moisture exposure. Typical dynamic coefficient of friction can be ≤ 0.06 with standard optical fibre cables. Actual values depend on cable design, installation method and site conditions.
Natraj PLB Duct Pipes are available in standard sizes suitable for OFC and other underground utility cabling, with options for project specific customisation.
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Standard Sizes: 32/26 mm, 40/33 mm, 50/42 mm (other sizes on request)
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Coil Lengths: 1000 m, 500 m, 200 m (custom coil lengths on request)
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Colours and Coding: Green, orange, red, yellow, grey, with single or double tracer stripes as per client coding scheme
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Construction: Co extruded duct with permanently lubricated low friction inner layer and UV stabilised outer sheath
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Material Grade: Virgin HDPE conforming to IS 4984 classification, PE grades such as PE63, PE80, PE100 as specified in the order
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Compliance Reference: Produced to relevant Indian requirements and TEC and GR specifications for PLB ducts, with test methods referenced to IS, ASTM and ISO as applicable
OFC Backbone Networks
Protects optical fibre cables in long distance telecom routes with smoother cable pulling and buried duct safety.
FTTx Broadband Lines
Used for last mile fibre rollout to homes, offices and distribution points with faster, cleaner cable installation.
Smart City Networks
Supports fibre routes for CCTV, traffic signals, public Wi Fi and connected urban utility infrastructure.
Road & Highway Crossings
Provides protected cable pathways under roads, highways and medians where open cable laying is not practical.
Railway Fibre Routes
Used along railway corridors to protect communication cables for signalling, surveillance and control networks.
Utility Cable Ducting
Creates dedicated underground pathways for fibre and low voltage utility cables across campuses and townships.
Permanently Lubricated Inner Layer
The inner lubricated layer reduces friction during cable blowing or pulling, helping optical fibre cables move smoothly through long underground duct routes.
Strong Optical Fibre Protection
HDPE duct construction protects optical fibre cables from soil pressure, moisture, handling stress and underground utility exposure.
Smooth Cable Pulling Performance
The smooth inner surface helps cables travel with lower resistance, reducing installation effort and supporting cleaner cable routing.
Flexible Underground Installation
Duct flexibility helps follow trench routes, bends and site conditions, making it suitable for telecom, broadband and utility networks.
Moisture And Corrosion Resistance
HDPE resists moisture, corrosion and many soil related effects, helping maintain long term duct performance in buried installations.
Easy Identification And Handling
Colour coded ducts and lightweight lengths make telecom routes easier to identify, handle, lay and manage during installation.
| Parameter | Details |
| Size range | 32/26 mm, 40/33 mm, 50/42 mm (other sizes on request) |
| Colours and coding | Green, orange, red, yellow, grey; customer colour schemes with single or double tracer stripes |
| Coil lengths | 1000 m, 500 m, 200 m (custom coil lengths on request) |
| Material grade (base resin) | Virgin HDPE conforming to IS 4984:1995 classification (PE grades such as PE63 / PE80 / PE100 as specified in the order) |
| Compliance and references | Produced to relevant Indian requirements and TEC/GR for PLB ducts; test methods referenced to IS, ASTM, ISO as applicable |
PLB DUCT 40/33 MM
| Parameter / Test | Method / Standard | Requirement |
|---|---|---|
| Density | ASTM F2160 | 0.940–0.955 g/cc |
| Melt flow index | ASTM F2160 | < 0.55 g / 10 min |
| Workmanship and finish | ASTM F2160 | Co extruded layers to be homogeneous and uniform in colour opacity density; inner and outer surfaces free from visible defects such as cracks, blisters, holes, voids, inclusions |
| Dimensions and tolerances | Drawing / QAP | OD 40.0 ± 0.4 mm; wall thickness 3.3–3.7 mm |
| Silicone inner layer thickness | GR No. GR/CDS/08/02 | 0.28–0.42 mm |
| Identification stripes | ASTM F2160 | Tracer stripe(s) provided as per customer coding scheme |
| End roundness at cut (toe in) | ASTM F2160 | OD at cut end ≤ 1.5% lower than OD measured 300 mm from the end |
| Lubrication system compatibility | ASTM F2160 | Lubricant compatible with conduit material and common cable jackets |
| Crush resistance | ASTM F2412 | After 15% deflection, duct recovers ≥ 95% within 2.5 min |
| ESCR | ASTM D1693 | No cracking after 96 h in 10% Igepal at 50 ± 1 °C |
| Ovality on coil | ASTM F2160 | < 7% |
| Tensile strength | ASTM F2160 (Specimen Type IV per ASTM D638) | ≥ 20 N/mm² |
| Elongation at break | ASTM F2160 | ≥ 400% |
| Impact performance | ASTM F2160 (per ASTM D2444, Type B tup 9.1 kg) | No failure when impacted at centre from 1.5 m after conditioning at −20 °C for ≥ 1 h |
| Hydrostatic strength | ISO 1167 | No swelling, leakage or burst for 165 h at 3.5 MPa, 80 °C |
| Carbon black content (outer sheath) | ISO 4427-2 | 2.5% ± 0.5% |
| Carbon black dispersion | ISO 4427-2 | Uniform dispersion as per standard |
| Thermal reversion | As per specification | ≤ 3% |
| Internal coefficient of friction | As per specification | < 0.6 |
| Identification marking | As per approved print line | Ink jet high contrast print with brand, size 40/33, colour stripe, lot date; metre marks at 1 m intervals |
To support safe storage, quicker laying and cleaner installations, Natraj PLB Duct Pipes can be supplied with essential accessories as per project requirement.
Push Fit Couplers
Precision couplers designed to align the duct bore accurately and ensure a secure joint. Provided with sealing O ring and locking ring for reliable connection. Typically supplied with coils unless specified otherwise.
End Caps / Sealing Plugs
Used to seal duct ends before and after installation to prevent entry of dust, water, mud and debris, helping maintain a clean bore for smooth cable pulling, blowing or jetting.
Warning Tape
Used in backfill to identify the duct route and alert excavation teams during future digging, reducing the risk of accidental damage.
Pulling Rope / Jetting Leader
Helps in cable hauling setups and blowing or jetting preparation, supporting faster installation and better site handling.
- Socket and Spigot Jointing
- Push Fit Couplers
- Mechanical Couplings