Fiber Optic Pulling or Blowing?
When planning an underground network, one of the first decisions is how the cable will be installed inside the duct.
The two most common methods are:
- Pulling or hauling
- Blowing or jetting
Both can benefit from lubrication, but the type of product and the method of application are different.
How does pulling work?
In pulling, a rope or tape is pre-installed inside the duct and connected to the end of the cable. Subsequently, a winch or pulling equipment pulls the cable along the route.
The force is mainly concentrated at the pulling end. As the cable passes through curves, friction increases and lateral forces can be generated against the duct wall.
For this reason, pulling requires controlling:
- Maximum allowable tension
- Lateral force on curves
- Minimum bend radius
- Installation speed
- Lubricant distribution
This method is usually used for short or moderate runs and in infrastructure where a pulling rope already exists. Technical guides distinguish it from blowing because it requires direct pulling force and can generate higher lateral loads on the cable and duct.
How does blowing work?
In blowing, a mechanical unit feeds the cable while a high-velocity airflow circulates through the duct. The air helps distribute the stress along the installation.
It can be favorable for:
- Long runs
- Routes with numerous curves
- Continuous and sealed ducts
- Light cable installations
- Microduct systems
Blown cable is not simply "pushed with air." The operation depends on the relationship between cable and duct diameter, airflow, pushing force, airtightness, cleanliness, and friction.
Which lubricant corresponds to each method?
For fiber optic pulling
A lubricant is sought that covers the outer surface of the cable and maintains its effect as the cable travels the route.
For long underground fiber optic pulls, a pourable product like Polywater F can be used, designed to adhere to the jacket and distribute itself over it during installation.
For drop cables, small cables, and jobs where spray or wipe application is desired, Polywater FTTx offers a thin-film option for communication cables.
For blowing in conventional duct
A pre-lubricant capable of spreading along the inside of the duct and forming a uniform layer is needed. Polywater Prelube 2000 is oriented towards fiber optic blowing in conventional ducts.
For blowing in microduct
The available space is smaller, so the product must work with a very thin film. Polywater Prelube 5000 is formulated for fiber optic microcables installed inside microducts.
Common mistakes when choosing a lubricant
1. Using the same product for all installations
A pulling gel can be too thick for a microduct. A blowing pre-lubricant may not have the necessary consistency to remain on the jacket during a traditional pull.
2. Not checking compatibility
It is necessary to check both the cable jacket material and the duct material. Residues, drying, and environmental conditions must also be considered.
3. Applying it only at the beginning
In long pulls, lubrication must reach the relevant contact points. In blowing, the film must be distributed along the inside of the duct.
4. Ignoring duct cleanliness
The lubricant does not remove stones, mud, water, deformations, or obstructions.
5. Using lubricant to compensate for poor planning
Before starting, the length, curves, splices, registers, equipment capacity, and mechanical limits of the cable must be checked.
Comparison table of fiber optic pulling and blowing lubricants
| Installation Type | Main Need |
Lubricant Type
|
| Long underground pull | Reduce tension and cover the jacket | Pourable lubricant for communications |
| Drop cable or small cable | Clean and controlled application | Sprayable or thin-film lubricant |
| Blowing in conventional duct | Pre-lubricate the inner wall | Lubricant for blowing |
| Microcable blowing | Ultra-thin film | Specific lubricant for microduct |
Conclusion
There is no single ideal lubricant for every fiber optic installation.
The first step is to identify whether the cable will be pulled or blown. Then, the diameter, length, curves, materials, and site conditions must be analyzed.
When the lubricant corresponds to the installation method, it ceases to be a mere consumable and becomes a tool to control friction, protect the cable, and improve project productivity.
