Table 3 Activities for fabricating the three sample spools

 A₁

Fit 2″ elbow and 2″ flange

2 Fitters

30

 B₁

Weld 2″ elbow and 2″ flange (sub1_1)

1 Welder

30

 C₁

Fit the sub1_1 with 2″ pipe

2 Fitters

11

 D₁

Weld the subassembly with 2″ pipe (sub1_2)

1 Welder

30

 E₁

Fit sub1_2 with olet

2 Fitters

13

 F₁

Weld sub1_2 with olet (sub1_3)

1 Welder

17

 G₁

Fit two 6″ pipes together

2 Fitters

36

 H₁

Weld two 6″ pipes together (sub1_4)

1 Welder

44

 I₁

Fit sub1_3 and sub1_ 4

2 Fitters

24

 J₁

Weld sub1_3 and sub1_4

1 Welder

57

 A₂

Fit 6″ elbow with 6″ pipe

2 Fitters

41

 B₂

Weld 6″ elbow with 6″ pipe (sub2_1)

1 Welder

68

 C₂

Fit sub2_1 with 6″ pipe

2 Fitters

39

 D₂

Weld sub2_1 with 6″ pipe

1 Welder

69

 A₃

Fit 6″ hydro pipe and 6″ elbow

2 Fitters

12

 B₃

Weld 6″ hydro pipe and 6″ elbow (sub3_1)

1 Welder

42

 C₃

Fit 6″ elbow and 6″ pipe

2 Fitters

15

 D₃

Weld 6″ elbow and 6″ pipe (sub3_2)

1 Welder

14

 E₃

Fit sub3_1 and sub3_2

2 Fitters

18

 F₃

Weld sub3_1 and sub3_2 (sub3_3)

1 Welder

12

 G₃

Fit 6″ pipe and tee

2 Fitters

31

 H₃

Weld 6″ pipe and tee (sub3_4)

1 Welder

56

 I₃

Fit sub3_4 and reducer

2 Fitters

37

 J₃

Weld sub3_4 and reducer (sub3_5)

1 Welder

46

 K₃

Fit sub3_5 and 3″ pipe

2 Fitters

19

 L₃

Weld sub3_5 and 3″ pipe (sub3_6)

1 Welder

15

 M₃

Fit sub3_6 and 3″ Flange

2 Fitters

11

 N₃

Weld sub3_6 and 3″ Flange (sub3_7)

1 Welder

130

 O₃

Fit sub3_3 and 6″ pipe

2 Fitters

27

 P₃

Weld sub3_3 and 6″ pipe (sub3_8)

1 Welder

52

 Q₃

Fit sub3_7 and sub3_8

2 Fitters

29

 R₃

Weld sub3_7 and sub3_8

1 Welder

80