Labor Hours

[Little Bill]

Let's say a job calls for 30 man hours per a labor unit estimate. Assuming it would take 30 hours for one man. Now if there were to be three men, two of them with same capabilities and one slightly less. Slightly less meaning lifting, climbing, etc.
Would the hours to complete the job with three men be 1/3 of the hours vs one man?

Or would it be somewhere between 1/3 and 1/2?

Edit: The last question would also assume the two could do it in half the time. Would that be correct or would that be slightly more than half?

 

[fmtjfw]

somewhat informed GUESSES:

somewhat informed GUESSES:

Let's say a job calls for 30 man hours per a labor unit estimate. Assuming it would take 30 hours for one man. Now if there were to be three men, two of them with same capabilities and one slightly less. Slightly less meaning lifting, climbing, etc.
Would the hours to complete the job with three men be 1/3 of the hours vs one man?

Or would it be somewhere between 1/3 and 1/2?

Edit: The last question would also assume the two could do it in half the time. Would that be correct or would that be slightly more than half?

It depends on what they are doing. If the job is to finish out receptacles (wire device, stuff in box, put on cover), there and you have N people do it, the total person hours are likely to be the same no matter what N is. So clock time is 30/N.

If you are replacing ballasts in luminaires mounted 10 feet from the ground using step ladders, have a ground person will speed the job and lessen the wear and tear on the ladder people, so 3N is likely to be better that N, provided the ground person can keep up with the two ladder persons. Clock time might be (guessing) 30/2.3 or better.

If your are hanging 4in. RMC and pulling big copper once again off ladders. Clock time: two people can probably hang 4" more than twice as fast as one. Having a third person getting the parts while you leapfrog a ladder will cut the time even more. Clock time might be 30/2.7.

If I were going to estimate a lot of this, I'd time some of it. (All assumes motivated workers, not ones dogging the job).

 

[Little Bill]

It depends on what they are doing. If the job is to finish out receptacles (wire device, stuff in box, put on cover), there and you have N people do it, the total person hours are likely to be the same no matter what N is. So clock time is 30/N.

If you are replacing ballasts in luminaires mounted 10 feet from the ground using step ladders, have a ground person will speed the job and lessen the wear and tear on the ladder people, so 3N is likely to be better that N, provided the ground person can keep up with the two ladder persons. Clock time might be (guessing) 30/2.3 or better.

If your are hanging 4in. RMC and pulling big copper once again off ladders. Clock time: two people can probably hang 4" more than twice as fast as one. Having a third person getting the parts while you leapfrog a ladder will cut the time even more. Clock time might be 30/2.7.

If I were going to estimate a lot of this, I'd time some of it. (All assumes motivated workers, not ones dogging the job).

A great deal of the job will be hanging conduit off of ladders. Which I know two will be better than one. I just don't know that a 3rd person could be kept busy enough to make a great deal of difference in the total hours.

Just so I'm clear, I understand what man hours are. I'm just trying to figure total job time for estimating purposes involving more than one man.

 

[kwired]

I agree that it depends on the tasks to be performed.

Sending out 4 guys to replace one receptacle isn't going to be done in 1/4 the time it takes one to do it, and may even take longer then if just one did it.

Sending out 4 guys to hand dig a trench is likely going to go nearly four times faster then just one person doing it though.

 

[J.P.]

Two guys on ladder hanging pipe?

Having a guy on the ground would help a lot. Handing stuff up, re-handing it after you drop it

I will have a ground guy when I am on a lift, he can keep bust in the area usually, but it sure is handy when I need something.


Is there anyway you could hang the pipe from a lift or even a baker scaffold with wheels.

Ladders are the slowest thing I can think of to work from.

 

[keith gigabyte]

I used to run small industrial jobs
.4 guys one month and smaller jobs. I was never able to say 1 guy 8 hrs same as 8 guys 1. Hour. Remember can't do this till that is finished.. No wire till raceway is done..etc. Yes jobs go faster with more guys but my experience shows its never a one for one trade off

 

[Little Bill]

Two guys on ladder hanging pipe?

Having a guy on the ground would help a lot. Handing stuff up, re-handing it after you drop it

I will have a ground guy when I am on a lift, he can keep bust in the area usually, but it sure is handy when I need something.


Is there anyway you could hang the pipe from a lift or even a baker scaffold with wheels.

Ladders are the slowest thing I can think of to work from.

No, there are too many obstacles in the way to use a lift or rolling scaffold. Some things can be moved, but most can't.