June_1971 — Page 38

KEY

antical path

ACTIVITY TITLE (0)

Av. latest, tume of event

sarkest time of event

activity dur artic

viatutory period for

public notice (13)

Schools Smaşı and

Bulding Committee recommend expenditure

“Grapare bret (1)

cost advice

sketch plans 1 (3)

sketch plane 2 (1)

Education Commitee

recommend mpondrtura (2)

Council approves

expenditure (3)

sketch plans)

complete

APPERRIENADE quantities (2)

Schools Bites and

Building Committee approve sketch plane (18)

wirte specification for electrical syriam {4}

write specification: fer heating system (4)

1

advance order for lang delivery (tama (3)

statutory period for

public netice (13)

in n

M of E approve sketch

plans and negotiation

of sendar (4)

working drawings 1 (8)

širuchung versmonni (1)

annend work ang drawings and

of if necessary (1)

working drawings 2 (3)

cost advice

agres price level (2)

cost check {2}

co-operation in design

Start of 0 {2}

prepare drawings (3)

cheese heating sức (2))

cheese electrical wie (2)

| approach Cheating s « (1)

prepare drawings (3)

Project duration

58 weeks

Fig. 9.

Schools Sries and Building Committee serovės negotiation and nomination. of sub-contractors (3)

produced at the advanced design and quantity measurement stage. It has been found convenient to set up this diagram in flow-chart form, using magnetic tiles, so that changes can be made easily in order to accommodate any differences of approach by the successful tenderer, or to allow for variations in design or materials.

Conclusions

The basis of PNA is simple to understand and its use for small pro- jects requires no apparatus more com- plex or costly than pencil and paper.

For the architect, it has an impor- tant role to play because the entire sequence of operations has its origin in the design stage. The method has a further attraction to the architect: normal drawingboard practice should enable him to appreciate readily the

6

i %

approach madeť contractor {1}

report proposed contract procedure to Finance Committee (2)

22 13

proach electrical a c (1)

order furniture (1)

diagrammatic presentation of the pro- ject plan which is central to PNA.

PNA can be used easily for con- trolling the actual construction pro- cess; the level of control can range from that provided by the linked bar chart of a dozen or so activities, to the most detailed time and resource sche- duled control system based on a net- work involving hundreds or even thou- sands of separately recorded and con- trollable activities.

The success of any control system depends on the accuracy and speed of the information feed-back from the site, the ease with which the control document can be updated and the cost of management relative to the cost of of management relative to the cost of the project. The extra cost of PNA is negligible, but many small building projects are carried out with so little project management that any control

101.

"

12 | 13 | 14 | 15

BRICK WORK

BOUNDARY

3.

ONS

ERECT FRAME

Fig. 8

ROOF STRUCTURE

BRICKWORK

30 mm

ROOF FINISH

1.

KCLADDING FRAMES,

GLAZING

EXTERNAL PAINTING

tool, even one so simple as a small net- work, seems out of place.

However, larger projects, having full-time supervision will always bene- fit from the discipline which periodic updating imposes and from the im- mediately recognisable graphical pre- sentation of up-to-date information of network and bar chart.

References

(a) Available free from the Building Research Station, Watford, UK:

1. NUTTALL J.F., JEANES R.E.; The Critical Path Method: Current Papers Construction Series No 3.

2. JEANES R.E.; Critical Path Method applied to the overall process of building: Current Papers Design Series No 11.

3. NUTTALL J.F., AMOS E.E.; CPM applied to building site control: Current Papers Construction Series No 12.

4. BRITTEN J.R.; The advantage of time-scaled networks and planning frames: Current Pages Construction Series No 41.

5. FINE B., BRITTEN J.R.; Safety nets for urban planners: Current Papers Design Series No 50.

(b) Other publications:

6. BS 4335:1968 Glossary of terms and symbols in project network analy- sis: British Standards Institution.

7. BATTERSBY A.; Network analysis for planning and scheduling: Macmillan.

8. LOCKYER K.G.; An introduc- tion to critical path analysis: Pitman.

Far East BUILDER, June 1971

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