Question

AURAK Paper Plant AURAK Paper Factory, located near downtown RAK, has long been delaying the expense of installing air pollution control equipment in its facility. The Environmental Protection Agency (EPA) has recently given the manufacturer 16 weeks to install a complex air filter system. AURAK Paper has been warned that it may be forced to close the facility unless the device is installed in the allotted time. The Plant Manager, wants to make sure that installation of the filtering system progresses smoothly and on time. Given the following information, develop a table showing activity precedence relationships. AURAK Paper has identified the eight activities that need to be performed in order for the project to be completed. When the project begins, two activities can be simultaneously started: building the internal components for the device (activity A) and the modifications necessary for the floor and roof (activity B). The construction of the collection stack (activity C) can begin when the internal components are completed. Pouring the concrete floor and installation of the frame (activity D) can be started as soon as the internal components are completed and the roof and floor have been modified. After the collection stack had been constructed, two activities can begin: building the high-temperature burner (activity E) and installing the pollution control system (activity F). The air pollution device can be installed (activity G) after the concrete floor has been built. Finally, after the control system and pollution device have been installed, the system can be inspected and tested (activity H). Activities and precedence relationships may seem rather confusing when they are presented in this descriptive form. It is therefore convenient to list all the activity information in a table first. You are required to: 1. Draw AON network diagram for AURAK Paper Plant 2. What is the critical path method of this diagram? 3. What is the impact on the sequence of activities if EPA approval is required after Inspect and Test?

Answer 1

Solution:

Activity table is shown below:

Solution 1:

AON network diagram for AURAK Paper Plant is shown below:

Solution 2:

In order to determine the critical path the exact most likely time of each activity is required. The various paths are obtained from the network diagram and their total duration is calculated. The path having the highest duration total is considered as the critical path. Following are the path in the AON diagram

1. A – C – E – H

2. A-C-F-H

3. A-D-G-H

4. B-D-G-H

Based on the duration of the activities, the total of the entire path is calculated to determine the critical path with the highest path duration.

Solution 3:

If EPA approval (let us assume it as an activity I ) is required after Inspect and Test, then one more activity would be required to be added in the precedence table of activities and in the network diagram as well.

In that situation, the table will change as follows:

And the AON diagram will change as follows:

And while determining the critical path, one more activity and its duration will get added in to the various available paths in the AON diagram as follows:

1. A – C – E – H - I

2. A-C-F-H-I

3. A-D-G-H -I

4. . B-D-G-H-I

Based on the duration of the activities, the total of the entire path is calculated to determine the critical path with the highest path duration.