My estimating career started before fiber optic cable became common in the industry. All of my early communications experience included using No. 14 600V conductors, twisted-pair cables and coaxial cables. As the use of fiber increased, I learned incrementally along the way.

Every estimator should read the specification and then read it again when performing a fiber takeoff. Compared to copper, fiber is far more complex in the number of varieties, initialisms, measurements, standards and terminologies that need to be considered. That said, estimators do not need to know every technical aspect about the fiber. They do need to know enough to include all the material and labor required to create an accurate estimate. I account for the following items when doing a fiber takeoff.

Fiber optic cable

There are several fiber properties that must be identified before you start measuring. Always start by reading the specifications for important text that may not be on the drawings, such as requirements to coil 20 feet of extra fiber in all pullboxes.

A specification to check is bend radius restrictions; similar to copper, fiber can be damaged or suffer performance degradation if bent too sharply or pulled around too sharp of a bend. I check this carefully, as I have seen instances when the electrical specification did not match the actual fiber requirement. Sometimes, I see a requirement for steel armored fiber, which is heavier and requires more labor. I also check if the fiber is approved for installing in cable tray. Another specification on some projects is the ability to gauge the pulling tension during installation, as too much can damage the fiber. 

I check for installer qualifications. Sometimes, the specifications require a certain amount of experience or certification from an independent training organization. Many specs call for conformance to industry standards—mainly TIA in the United States and Canada—covering components, installation and testing. 

Innerduct

Innerduct is used to protect fiber optic cable in free air, conduit and direct burial. It is also used to divide a conduit into multiple partitions. It is manufactured in many materials and configurations. Once again, always follow the specifications when doing your takeoff. Sometimes, there will be mistakes in the specifications or contradictions that need to be worked out. For instance, on a recent project, one part of the specification said all fiber would be installed in innerduct. In another, it said innerduct is only required in conduits 3 inches and larger. Of course, that project had fiber in 2-inch conduit.

Identification

Even if the specifications do not require it, identifying fibers in every pullbox and at every termination point is a good practice. The specifications will usually tell you which type of identification material you need to use for labels, from cheap to very expensive. The specifications will also tell you what text is required on the label.

Terminations, splices and testing

Installer qualifications are often required for terminating and splicing, as this work is much more complicated compared to copper. Poorly installed splices and terminations can cause attenuation (light losses) and will have to be redone. 

Testing is always required, and can be very expensive. Here is a sample of a testing requirement: “The tests to be performed shall consist of, but not be limited to, factory tests, circuit breakdown tests, wiring verification tests, continuity tests, resistance tests, voltage and current tests, operating tests, simulation tests, integration tests, cutover tests and such other tests as may be required to prove that the Communication System meets the specification and design requirements.” 

It can get complicated and expensive. You may also find the specifications require testing to be done by an independent, third-party organization.

A project’s scope may require you to perform work related to furnishing and installing the fiber. If you are preparing an estimate for a complete building that contains fiber, then of course you will have to install the pathways for it. The fiber may need to be installed in conduit, cable tray or innerduct hung from J-hooks. For projects that are fiber only, you may be required to add racking to maintenance holes, seal the ends of conduits, provide patchcords and perform other related work. I will stress this again: It is very important that you read all of the specifications, notes, schedules and diagrams.

Finally, make sure you understand the scope clearly. Many of the requests for proposals I have read are confusing and vague. If there is something you do not understand, get assistance or education before completing your estimate.

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