Estimating 101

NukeWorker · #1 (**permalink**) 11-30-2007, 11:49 AM

We recently hired a Civil Engineering grad and are putting him through his paces

Sometime in the near future we have to drop an exhaust stack. So I asked him a simple question "Will it fit"
He said "I think so" (bad answer).
I asked him "What is the height?"
He said "I don't know we don't have the plans "
I said "So how do you know it's going to fit then?"

I was leading him down the path a little but if you let them get away with being sloppy early on there is no hope later.

So I taught him how to always be able to determing the height of an object. Pretty soon I was giving a lesson to 10 people then I figure out maybe more people would like to know an easy accurate method, so here it is.

1. Place a small mirror on the ground between you and the structure. Position the mirror or your self (in a straight line of course) so that you can just see the reflection of the very top of the structure in the mirror.

2. Now you have created 2 triangles where:

h = height of person
d = distance from person to mirror
D = Distance between mirror and structure
H = Height of structure

H/D = h/d so H=hD/d

Crete Buster · #2 (**permalink**) 11-30-2007, 12:28 PM

This is a new member saying thanks for the info. I'm young (in age and amount of time in this industry) and will be doing some estimating along with marketing for my company. Learning from experienced professionals that are willing to share/teach information is one of the many reasons I was excited when I came across this forum. Thanks again and please share more soon.

Kerry

Wolf · #3 (**permalink**) 12-03-2007, 10:02 AM

Hey Kerry:

Great attitude, man. With that kind of approach, you will win many supporters and go far. Good luck to you.

Crete Buster · #4 (**permalink**) 12-03-2007, 10:13 AM

Thanks Wolf.

**James** · #5 (**permalink**) 12-05-2007, 08:55 AM

That's a pretty neat trick!

NukeWorker · #6 (**permalink**) 12-05-2007, 10:16 AM

Today we have a little weather delay so we are going over how to calculate the velocity of the falling structure. It's not just good enough to measure the fall area and the height. We also have to figure out the velocity and the rotational moments because a tall structure when felled will actually launch itself as it develops speed when it falls.
For example, we felled a flare stack that was 200' tall. After it was on the ground we measured from the base of the standing structure to the top of the fallen stack and it measured 230'.

nitrox2595 · #7 (**permalink**) 12-21-2007, 07:24 PM

Do you guys think that the volume of material removed is the hardest to estimate? I usually have the labor and equipment very close, but I sometimes
mess up on debris quantity.I just did a very small house and thought i could fit it all into a 30 yd, but wound up with 2 40yds packed so tight, i couldn't believe it. I will only make a couple of $100's on the, but i'd rather lose on a small job.