PNA applied to complete projects
KEY
E
ACTIVITY TITLE
earliest time of event
(()) event reference number
L latest time of event
activity duration
critical activities emphasised thus
BRICKWORK (ground floor)
FIRST FLOOR JOISTS
BRICKWORK (first floor)
BRICKWORK [topping out)
TILING
(4)
(4)
m
(2)
Fig. 5.
NOOF CARCASE/
(3)
CARPENTERS FIRST
FIXING
(2)
PARTITIONS
GAS
CARPENTERS SECOND
FIXING
(5)
PLASTERBOARD
PIPEWORK 28 AND PLASTER 11, PLUMBERS FITTING
(6)
(3)
FLASHINGS
GLAZING
RAINWATER PLUMBING
M
M
ELECTRICAL
CARCASE
GAS
(2)
[D]
INTERNAL
39 DECORATIONS 43
(4)
(2)
ELECTRICAL FITTINGS
M
EXTERNAL PAINTING
(2)
4
4!
BRICKWORK (ground Heat) (4)
FIRST FLOOR JOISTS m
BRICKWORK (first floor) (4)
TOP OUT
M
12:
TILING (2)
CARPENTERS FIRST
CARPENTERS SECOND
FIXING
PARTITIONS
(5)
PIPEWORK (3)
ט
(4)
FIXING
(6)
KEY
critical activities and heks aru m emphasised thus
ROOF CARCASS (3)
sarliest time of start
sarkest time of finish
ES
EF
ACTIVITY TITLE
(D)
LS
LF
latest time of start
latest time of finish
duration
KAINWATER PLUMBING (1)
FLASHINGS
(1)
145
GLAZING
a
EXTERNAL PAINTING
(2)
FLOOR FINISH
CLEAN AND
4 HANDOVER 45
ELECTRICAL CARCASS (2)
PLASTER
PLUMBERS FITTING
INTERNAL DECORATIONS
FLOOR FINISH
(2)
24
ELECTRICAL FITTINGS |
(3)
45
CLEAN AND HANDOVER
(1)
Fig. 6.
presented on this chart could not have been obtained without the use of the earlier network diagrams. This linked bar chart is, in fact, an arrow diagram drawn to a time scale. It may be found more useful to present this informa- tion to the executive team in small increments, for example, a fortnightly up-dating of the next four weeks' acti- vity starts.
The type of diagram shown in Fig. 7 may be set up on framework of horizontal wires on which slide beads, representing resources, with vertical wires connecting activities which have a precedence relationship. Various solutions of resource allocation to obtain an optimum use of float time may be tried; a simple method of com- munication to the executive team is a photograph of the most acceptable solution. Fig. 8 shows part of such a solution.
PNA need not be confined to site work, as in the previous example. By explicitly presenting the inter-relation- ships of the various activities that make up a project, PNA is especially useful in the design and planning stages.
Fig. 9 shows part of the arrow dia-
Far East BUILDER, June 1971 Page 37
POSSIBLE CALENDAR DATES WITH A 5-DAY WORKING WEEK
November
December
January
3 4 5 6 7 10|11| 12 | 13 | 14 | 17 | 18|19|20|21|24|25|28|27|28|| 1 | 2 | 3 | 4 | 5 8 9 10 11 12 15 16 17 18 19 22 23 24 29 30 31 1
3 19 22 23 24 29 30 31 1 256
NON-CRITICAL ACTIVITIES
The hatched portion represents the activity duration It may be moved to any place within the bar without extending the total project duration
The use of float on one operation may reduce the float on another
Example:-
If the glazing is delayed until its latest possible time the float of the external painting activity is reduced from 27 to 16 days
TOP OUT
GLAZING
す
RAINWATER PLUMBING
FLASHING
F
ELECTRIC CARCASS
GAS
EXTERNAL PAINTING
CRITICAL ACTIVITIES
PROJECT DAY NUMBERS
PLUMBERS
FITTINGS
ELECTRIC FITTINGS
CARPENTERS SECOND
FIXING
DECORATION
FLOOR FINISH
HAND OVER
1234567 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
Fig. 7.
gram for the administration and design procedures of a four-class primary school.
PNA has also been applied success- fully to large-scale planning, such as town planning (see reference 5).
Recent research into the feasibility of introducing a production bias to documents used in the preparation of tenders has indicated that a diagram showing a possible sequence of site operations may, with advantage, be
27