So let's talk about underground conduit and I said underground pipe underground conduit is not the same as water pipe. This is the type of pipe that is used in the U.S. You can see on the picture on your right one of the pipes has a bell housing and the other pipe doesn't. They just slide together, you just glue them together. Some regions we see a lot of use of roll pipe and roll pipe is used definitely here in the United States particularly in very long-haul applications where a telephone provider or internet service provider is building a large network but roll pipe is indeed used in the U.S. This is what I see most common across Asia and Africa. Here we're looking at the difference between water pipe and this pipe that's specifically built for mostly it's built for electrical conductors but fiber optic cable handles a lot like a electrical conductor. You can see the white one on the left, that is what is used to transport water here in the United States. Water flows just fine around a really, really tight 90-degree like that you can see if I was trying to pull a cable around that, that would be kind of difficult. The black one on the left, that is for waste water here in the U.S., so drains out of sinks, showers and even toilets are in this other type. Now since there is matter in the waste water you can see the pipe does have a more gradual bend but it still would be very difficult to pull a fiber optic cable through there. The three on the right hand side that are large circumference those are all appropriate for fiber optic cable. That's what you would want to do. And by the way all of these pipes are 50 millimeter pipes so they're pipes about thisbig. You can see the gray pipe on the very right and top is going to be much easier to pull in than the gray pipe, kind of on the bottom, simply because of the bend radius. So if you're using roll pipe think about the bend radius as well because when you make a 90 degree turn make sure you do that in a gradual fashion so that it's easier to pull fiber through there. And again, roll pipe has the same rules, just keep in mind that roll pipe doesn't lay flat in the trench and it will kind of have a few degrees of bend just the way it's not laying flat. But as long as you follow these rules you're going to be fine getting conduit in and out of a building. So getting pipe in and out of the building. These are correctly done. It's important that you enter a building in such a way that you don't allow rodents to get in and you don't allow water to getin. These are weatherproof boxes that are placed on the side of the building and then a hole is drilled out the back to have the the cable enter that and this also counts as a pull point. You can remove the lid, you can pull on the conductor and then put put it inside the side of the building. I have not seen this in the uh outside of the U.S. so I have not seen this in emerging regions but the picture on the left, there's a shiny little thing called that says no pointing at it that's called a "condulet" and it's just a 90 degree in the pipe. And the reason that that's not okay is fiber can be damaged if you bend it too tight. And the one on the right bends it too tight so the one on the left is okay. And then trenching buried conduits. Here's some photos of conduit being trenched and laid. This actually looks like it might be in India or in South Asia somewhere. I see a tuk-tuk there in that lower picture and then on the left-hand side you can see i've kind of done a cross-section of the trench. You want to dig the trench, the trench ought to be 1-meter deep. If there's a lot of rocks you'll want to put some kind of bedding material down. Then you want to put your pipes and then you want to put dirt over that without big rocks init. And then you can backfill with the native materials which might include some big rocks. And conduit fill, keep in mind that you can't fill a a pipe totally full. The U.S. National Electric Code recommends only 40% of the volume of a pipe be filled and that's typically about all you want to put in even if you're not governed by the National ElectricCode simply because it becomes very difficult to pull cable into a pipe that has a lot of other cables. And you risk damaging those cables. Labeling here, you can see on the cable itself, there's a yellow tag on that cable you know that says what that cable is where it goes from and where it goes to. I also think we ought to have labeled in written on the side of this vault where those pipes come from and where those pipes go to. We want to seal conduits so there are conduit plugs that are shown on the left hand side there. Those you just stick at the end of the pipe, you turn the the little knob on them, it'll waterproof it and it'll also not allow rats to use those conduits as a path. The picture on your right shows some existing, some pipes with existing stuff in it. What you do is you use grout which is the same kind of stuff you put between bricks to seal the pipes so that water won't come and the rodents won't get inside your buildings.
© Produced by Philip Smith and the Network Startup Resource Center, through the University of Oregon.
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