Final answer:
For lines 7/8 inches OD or larger, spacing should be up to 8 diameters side-to-side and 15 diameters deep, as expanded spacing can contribute to efficiency and safety.
Step-by-step explanation:
When considering bulb position for pipe installation, particularly for lines with an outside diameter (OD) of 7/8 inches and larger, it's important to follow current industry recommendations for spacing. The older 'rule of thumb' was 5 diameters side-to-side and 7-8 diameters deep for pipe placement. However, new recommendations suggest that a spacing of as much as 8 diameters side-to-side and 15 diameters deep may be necessary for optimal performance and safety. This reflects economies of scale, as seen in the chemical industry where larger pipes, such as 8-inch and 16-inch pipes, are compared in terms of costs and efficiency in Table 7.15