Views: 500 Author: Curry Publish Time: 2026-04-09 Origin: https://www.microductcoupler.com/
For an effective blown fiber optic cable installation, selecting the correct blowing sponge is essential for both cleaning the duct and applying lubricant. The sponge diameter should typically be slightly larger than the microduct's inner diameter (ID) to ensure a snug fit that creates a sufficient seal for air pressure to propel it through.
Why Sizing Matters
Too Small: The sponge will bypass air, lose pressure, and fail to push out debris or water.
Too Large: Excessive friction may cause the sponge to get stuck in tight bends or microduct connectors.
For highly restricted or suspected blocked ducts, some technicians use a proofing ball (approximately 10% smaller than the ID) to verify a clear pathway before the final sponge and lubricant pass.
Recommended Sponge-to-Microduct Sizing
Different application scenarios, working air pressures, and power ratings of fiber blowing machines will all affect their applicable scope. Drawing on years of air-blowing experience, FCST has compiled the following size references for your selection.
FTTH Scenario
Sponges Diameter | Inner Duct Dimension |
4mm | 2.1~3.5mm |
5mm | 2.5~4.0mm |
8mm | 4.0~6.0mm |
12mm | 6.0~9.0mm |
*Blowing Sponge Density:70mm
Backbone Network Scenario
Sponges Diameter | Inner Duct Dimension |
5mm | 4.0~6.0mm |
12mm | 6.0~9.0mm |
18mm | 9.0~14.0mm |
25mm | 14.0~21.0mm |
45mm | 21.0~35.0mm |
50mm | 25.0~45.0mm |
60mm | 30.0~50.0mm |
*Blowing Sponge Density:70mm
Construction Guidance
Place the next blowing sponge 5 cm from the duct's end.
Adjust the inlet pressure to approximately 4 - 5 bar to propel the blowing sponge, ensuring proper setup to capture the sponge at the other end.
PIG1-Blowing Sponge Actual Usage Diagram
Record and take note of the blowing sponge's travel time. In a clean and unobstructed duct route, the approximate travel times per 1 km are the
following:
5 mm ID microduct → 4 – 8 minutes
6 mm ID microduct ID → 2 – 4 minutes
If the specified time elapses, increase the pressure to 6 – 8 bar, and wait for the indicated duration. If it still hasn't reached the destination, an obstacle may be present. Remove the obstacle and then proceed.
Product Advantages
1.The cylindrical design provides greater stability within the microtubes, preventing rolling.
2.Made of high-density PU sponge, it absorbs a suitable amount of air-blown lubricant without breaking.
3.A variety of sizes are available to meet the needs of cleaning and lubricating microtubes.
4.The white exterior makes it easier to spot when the sponge is dirty or depleted.
PIG2-Blowing Sponge Ordering Information
FCST - Better FTTx, Better Life.
At FCST, we manufacture top-quality microduct connector, microduct closure, telecom manhole chambers, Warning Nets and Locators and fiber splice boxes since 2003. Our products boast superior resistance to failure, corrosion, and deposits, and are designed for high performance in extreme temperatures. We prioritize sustainability with mechanical couplers and long-lasting durability.
FCST, aspires to a more connected world, believing everyone deserves access to high-speed broadband. We're dedicated to expanding globally, evolving our products, and tackling modern challenges with innovative solutions. As technology advances and connects billions more devices, FCST helps developing regions leapfrog outdated technologies with sustainable solutions, evolving from a small company to a global leader in future fiber cable needs.
