Example

Days

A brief architect

B architect produces plans for planning permission

C obtain planning permission

D finalize drawings

E obtain tenders

F adjudicate bids

G builder delivers materials

H strip roof

J construct dormer

K lay floor

L tile dormer walls

M felt dormer roof

N fit window

P move CW tank

Q fit doors

R fit shelves and cupboards

S fit internal lining and insulation 4

T Lay electric cables 2

U cut hole in existing ceiling 1

V fit stairs 2 W plaster walls 2 X paint 2

Y fit carpets 1

Rather than draw out all these activities in a single long string, let us make a preliminary analysis on which activities can be carried out in parallel. The following immediately spring to mind.

1 Final drawings can be prepared while planning permission is obtained.

2 It may even be possible to obtain tenders during the planning permission period, which is often extended.

3 The floor can be laid while the dormer is being tiled.

The preliminary network would, therefore, be as shown in Figure 26.5

If all the activities were carried out in series, the project would take 156 days. As drawn in Figure 26.5 the duration of the project is 114 days. This shows already a considerable saving by utilizing the planning permission period for finalizing drawings and obtaining tenders.

However, we wish to reduce the overall time even further, so we call the builder in before we start work and go through the job with him. The first question we ask is how many men will he employ. He says between two and four. We then make the following suggestions:

1 Let the electrician lay the cables while the joiners fit the stairs.

2 Let the plumber move the tank while the roof of the dormer is being constructed.

3 Let the glazier fit the windows while the joiner fits the shelves.

4 Let the roofer felt the dormer while the walls are being tiled.

5 Fit the doors while the cupboards are being built.

The builder may object that this requires too many men, but you tell him that his overall time will be reduced and he will probably gain in the end. The revised network is, therefore, shown in Figure 26.6. The total project duration is now reduced to 108 days. The same network in precedence format (AoN) is shown in Figure 26.7

If we now wish to reduce the period even further we may have to pay the builder a little extra. However, let us assume that time is of the essence since our rich old uncle will be coming to stay and an uncomfortable night on the sofa in the sitting room might prejudice our chances in his will. It is financially viable, therefore, to ensure that the room will be complete.

Supposing we have to cut the whole job to take no longer than 96 days. Somehow we have to save another 12 days. First, let us look at those activities which have float. N and Q together take two days while R takes four. N and Q have, therefore, two days float. We can utilize this by splitting the operation S (fit internal lining) and doing two days' work while the shelves and cupboards are being built. The network of this section would, therefore, appear as in Figure 26.8. We have saved two days provided that labour can be made available to start insulating the rafters.

If we adjudicate the bids (F) before waiting for planning permission, we can save another two days. This section of the network will, therefore, appear as in Figure 26.9.

Total saving to this stage is 2 + 2 = 4 days. We have to find another eight days, so let us look at the activities which take longest: C (obtaining planning permission) cannot be reduced

o-KJ

Figure 26.6

A

B

i

7

C 60

D

E

ic

30

G

H

15

2

Figure 26.7 Precedence network

N

Q

S

U

V

W

X

Y

1

1

r*

4

1

-,

2

r>

2

2

1

Figure 26.9

since it is outside our control. It is very difficult to hurry a local authority. G (builder delivers materials) is difficult to reduce since the builders will require a reasonable mobilization period to buy materials and allocate resources. However, if we select the builder before planning permission has been received, and we do, after all, have 18 days float in loop D-E-F, we may be able to get him to place preliminary orders for the materials required first, and thus enable work to be started a little earlier. We may have to guarantee to pay the cost for this material if planning permission is not granted, but as time is of the essence we are prepared to take the risk. The saving could well be anything from one to 15 days.

Let us assume we can realistically save five days. We have now reduced the programme by 2 + 2 + 5 = 9 days. The remaining days can now only be saved by reducing the actual durations of some of the activities. This means more resources and hence more money. However, the rich uncle cannot be put off, so we offer to increase the contract sum if the builder can manage to reduce V, T, W and X by one day each, thus saving three days altogether. It should be noted that we only save three days although we have reduced the time of four activities by one day each. This is, of course, because V and T are carried out in parallel, but our overall period -for very little extra cost - is now 96 days, a saving of 60 days or 38%.

Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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