Fiber Optic Daylighting

The build is a bore, and a bore plan needs real depths

Almost nothing in fiber construction gets trenched anymore. It gets bored, and a bore is a committed path through ground you cannot see, launched at an angle and a depth decided in advance. That plan is only as good as the depths it was built on, and the inputs people usually hand a drill crew are 811 paint and an as-built. Paint is a horizontal projection with no depth in it at all. An as-built was accurate on the day it was drawn and has been quietly going stale ever since, through road widenings that relocated services without a redline, through lines abandoned in place with new ones laid alongside, through grade raised for a parking lot. Daylighting turns the assumptions at the crossings into measurements. A drill head that finds a duct bank at a depth nobody expected stops the job, and the meeting that follows is longer than the morning the test holes would have taken.

Small cells put the conflict at the surface

Small-cell work has a geometry problem that longhaul fiber does not. The equipment goes on a pole in a right of way that is already full, the pole foundation wants real depth in a narrow strip between a curb and a sidewalk, and the fiber and power have to reach it through that same strip. Everything that ever got buried in a right of way lives there: street lighting circuits, signal interconnect, irrigation, water services, the gas service to the building behind it. A base that has to move eighteen inches because something is in the way is a drawing revision when you find out early and a permit problem when you find out with a crew and an auger on site. Daylighting the foundation footprint and the conduit path answers that ahead of time. It also tends to be what a municipal permit reviewer is looking for on a right of way application.

Existing fiber is what you are most afraid of hitting

The awkward part of building fiber is that the corridor you want is usually the corridor somebody else already used. New routes get designed parallel to existing ones because both are chasing the same easements and the same road shoulders. So the facility most likely to be in your bore path is another carrier’s live fiber, and cutting it is the outcome with the longest tail: an outage on somebody else’s network, a claim, and a relationship with a carrier who will remember. Locating existing duct is harder than locating steel, since a plastic duct with no trace wire, or with a trace wire that broke sometime in the last decade, returns nothing to a locator. Abandoned duct sits alongside working duct with nothing to tell them apart from the surface. Opening ground is how those get separated, and every one found in a window goes into the record whether or not anyone asked about it.

Rock, water and the calendar in South Florida

A fiber route through Miami-Dade runs over limestone that starts shallower than crews from other states plan for, with a tidally influenced water table not far under it. Both matter to a bore plan, and both are visible in a daylight window before they are visible in a stuck drill string. Head west into the drained wetland ground behind Broward and Palm Beach and the ground goes soft and wet, drains through improvement district canals, and holds a wall poorly. Southwest toward Fort Myers and Naples it is sand that runs easy in both directions. Then there is the calendar. From June onward an afternoon storm is the default, hurricane season reorders everybody’s priorities for a week at a time, and permit windows in a busy corridor are often nights. Vacuum excavation copes with the wet part, since the tank lifts water and spoil together and a hole that refills is an ordinary Tuesday.

What comes back, and when it is worth having

The record is the product. Each window comes back with depth to top of every facility found in it, measured from existing surface, plus size, material, duct count where it can be read, ownership markings where they exist, condition, and direction of run. Everything gets tied to your stationing, your survey control or a hard feature like a curb line or building corner, so it drops into the drawing rather than needing translation. Photographs come with it, including a tape in the hole. The timing matters as much as the content. A conflict found during design moves a line on a drawing and costs an afternoon of drafting. The same conflict found during construction costs a stopped bore, a redesign under pressure, a change order and whatever the schedule slip is worth to whoever is paying for the build. Send the alignment and we will tell you where the windows earn their keep.

Worth knowing

The most valuable exposures on a fiber build are the ones at bore entries, exits and foreign crossings, not the ones spaced evenly down the route. Send the alignment and the bore plan rather than a hole count, and the day gets aimed at the questions that can actually stop your crew.