situation. Rather than going through the calculations involved, just

remember this rule of thumb: To find the travel for a 45° straight offset,

simply multiply the amount of offset by 1.414. In the example given in

Fig. 1-11, for instance, the offset is 12 in. The travel, therefore, is 12

1.414, or 16.968 in.

1.41

The pipes in Fig. 1-11 are 2 in. in diameter, connected by two

250 lb, 45° elbows. The center-to-face dimension of the elbows is 2 in.

(Table 1-4). Subtract twice this amount—4 in.—from the travel, leaving

12.968 in. Thread length for 2 in. pipe is

in. (Table 1-5). Add twice

that, or 1.50 in., for an end-to-end pipe length of 14.468 in.

Rolling Offsets

1.42

rolling offset

is similar to a straight

offset except that the two lines are not in the

same vertical or horizontal plane. Figure 1-12

illustrates a rolling offset.

1.43

To find the travel, you must develop the

triangle, 1-2-3, which lies in the plane of the

travel distance. From the figure you know that

the 1 in. pipe is offset 10 in., the roll is 12 in.,

and the fittings are 125 lb, threaded, 45° elbows.

Given these dimensions, you can calculate the

distance S. Then, combining this with the travel

and fitting angle, you can define the triangle

needed to determine the length of the travel.

2-in. pipe

right angle

12-in. offset

Travel

Offset

elbow

250 lb

Fig. 1-11.

Straight offset

10-in. offset

12-in.

roll

Travel

elbow

125 lb

threaded

Fig. 1-12.

Rolling offset