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# Conversion of Manhours into Durations

4 replies [Last post]
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Joined: 9 Apr 2015
Posts: 14
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Dear Sirs / Fellows,

Please let me know that how Manhours will be transformed into duration of activities?

I have set of activities having manhours per unit basis. e.g.

For Example:

Armoured Cable #14, 2 Conductor, Solid Copper

Unit of Time: "Hours";

Unit of Qty "Meter";

Manhour Factor: 0.09

If BOQ Quantity of Cable is 3000 Meter, So using this Manhour Factor, How could i Calculate the Estimated Duration of Cable Laying?

Responses are awaited.

## Replies

Anoon Iimos
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Joined: 22 Sep 2006
Posts: 1422
Again, I'm not a mathematician, but obviously option number 1 (one) is the best answer. You always multiply the standard factor to the given quantity. I supposed there is an explanation in the reference book that you were using? Otherwise, I guess you'll still find the answers when you try to divide whole numbers with decimals as you will get unreasonable results. The factors I believe include the use of some tools and or equipment plus the condition of how the installation is supposed to be (supposed to be clearly explained in the reference book).
Johannes Vandenberg
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Joined: 21 Jan 2010
Posts: 232

The tools & techniques to calculate the duration of each activity is very well explained on this website. The link is displayed below.

Here you learn the different techniques such as analog, parametric and bottom-up estimating to find the quantitative assessment, effort, and duration.

Regards Johannes

http://www.planningplanet.com/guild/gpccar/calculate-the-duration-of-eac...

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Joined: 9 Apr 2015
Posts: 14
Groups: None

Anoon Thanks for your reply, exactly what i want the answer. but the confusion is that, 0.09 manhour would be hours/unit or unit/hours? means we have to multiply it with the total quantity as you did or have to divide with it?

if 0.09 manhour is Unit/Hour productivity then have to divide to get the duration...

Similarly, another example is

Buried Steel Duct 100x600 (4"x 24")

Unit of Time: "Hours";

Unit of Qty "Meter";

Manhour Factor: 2.16

If BOQ Quantity of Steel Duct is 800 Meter, So what would be the correct Answer? Number 1 or Number 2 ???

Number 1:

800 x 2.16 = 1728 Hours = 1728/10 (Working Hours) = 172.8 Days further Divided by Size of Crew to get the estimated duration.

Number 2:

800 / 2.16 = 370.3 Hours = 370.3/10 (Working Hours) = 37 Days further Divided by Size of Crew to get the estimated duration.

Kindly, Help me out to understand how can i use standard manhours (Productivity) to calculate the activity durations?

Anoon Iimos
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Joined: 22 Sep 2006
Posts: 1422
I'm not sure about this but let me try: 3000 x 0.09 = 270 man-hours; 270 m/h divided by 8 (regular work hours per day) = 33.75 man/day; Say you will allocate 10 men for cable laying: 33.75 man/day divided by 10 = 3.375 Days. This means that it will take around 3 days for 10 men to do the 3 kilometer cable laying. But it doesn't define if the cable is buried underground or on a cable tray, plus what are the tools and equipment necessary for the cable laying.