A Confined Space Rig: Anchors, Pulleys And The Haul Field in Rope Rigging Systems

Written By: Pat Rhodes

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Let’s continue with our pulley discussion. We have here a confined space rig, what I like to call it. It’s unique in that we have a tripod, and anybody who’s been around these things know they’re susceptible to tipping over, so it’s important, if you’re going to do something like this, that you have equal forces on either side of it. That’s what we have here. On my left, we’re rigged for lowering on this line right here. You can see that there’s a 2:1 in the middle that would go down into a hypothetical confined space.

On this side, it’s pre-rigged with a 3:1. On one side, we’re lowering. On the other side, we’re raising. Now, the 3:1 is right here, but the 3:1 is acting on original 2:1, so what do we have? We have a 6:1. Lowering with a 2:1 straight down into the hole, lifting with a 6:1 coming out of the hole. Our rope bag is over here, so the bulk of the rope is here. We just have enough on this side to build the 3:1.

On this side, it’s pre-rigged with a 3:1. On one side, we’re lowering. On the other side, we’re raising. Now, the 3:1 is right here, but the 3:1 is acting on original 2:1, so what do we have? We have a 6:1. Lowering with a 2:1 straight down into the hole, lifting with a 6:1 coming out of the hole. Our rope bag is over here, so the bulk of the rope is here. We just have enough on this side to build the 3:1.

Let’s move over to the lowering system and lower our sandbag down a little bit and see how that works. Let’s look at our confined space rig right now. I’m on the lowering side. The other side is locked off and it’s rigged for a raise, so we can put this into operation. You’ll probably notice that we don’t have a belay line on this right now. Just for this little pulley practice and demonstration, we’re leaving that out for clarity. Okay. Now, we’re down into the confined space. We can quickly, without anything to do, lock off our I’D, move to the other side for the raising system.

Okay. Now, we’re on the haul side of our confined space rig. The Petzl I’D on the other side is locked off, and it’s now the anchor and the opposition to our haul team on this side, which is going to keep the tripod from tipping over. Let’s untie this, and we can start hauling back up. It’s a really quick operation as far as either lowering or operating. What do we have here as far as the mechanical advantage? Well, we have this 3:1 acting on the 2:1 going down into the haul. What is it? The 6:1. Three times two, six. This is really good for those straight up and down especially deep manhole type of operations. It works quite well with that.

Let’s move over to the lowering system and lower our sandbag down a little bit and see how that works. Let’s look at our confined space rig right now. I’m on the lowering side. The other side is locked off and it’s rigged for a raise, so we can put this into operation. You’ll probably notice that we don’t have a belay line on this right now. Just for this little pulley practice and demonstration, we’re leaving that out for clarity. Okay. Now, we’re down into the confined space. We can quickly, without anything to do, lock off our I’D, move to the other side for the raising system.

Okay. Now, we’re on the haul side of our confined space rig. The I’D on the other side is locked off, and it’s now the anchor and the opposition to our haul team on this side, which is going to keep the tripod from tipping over. Let’s untie this, and we can start hauling back up. It’s a really quick operation as far as either lowering or operating. What do we have here as far as the mechanical advantage? Well, we have this 3:1 acting on the 2:1 going down into the haul. What is it? The 6:1. Three times two, six. This is really good for those straight up and down especially deep manhole type of operations. It works quite well with that.

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