I'm going to give a quick answer to your quick question: No, there's not.
There are, however, some magic numbers pulled off the air that some piping engineers or piping foremen like to use, as, for example, that there must be three piping diameters between two welds. There are also numbers set forth on General Piping Specifications issued by engineering firms. Some companies also have their own numbers that their contractors should follow.
All of these numbers, of course, are valid WHEN POSSIBLE, because there are circumstances when they simply can not be followed. In those cases, well, consider the maximum possible length between the two welds.
Giovanni S. Crisi
Sao Paulo - Brazil