Bendability

When it comes to the structure of a building, rigidity is an important trait. After all, a strong skeleton is the basis of a strong body. But as in the case of a willow, flexibility is a good thing, especially for one building system in particular—plumbing. Suppleness is becoming not only more prominent, but also more desired. The reasons and appropriateness for it vary depending on the particular plumbing application.

Sprinkler system connection is one area where flexible piping can prove beneficial. Difficult angles and re-cutting can be eliminated in the connection between a water main and sprinkler head by using a braided-steel, bendable pipe as opposed to a rigid one. The technology is still fairly new, though. "It's coming, but it hasn't arrived, you might say," says Alex Tanalski, senior associate with Flack + Kurtz, Inc.'s San Francisco office.

Tanalski notes that while the benefits of flexible sprinkler plumbing are gaining more recognition, the technology's main obstacle is the fact that it simply hasn't become "bona fide." In other words, it hasn't received the necessary approvals from the appropriate code-making agencies, and therefore, hasn't been taken into account by current codes and standards. "Nobody is really going to go out on a limb [with this technology] unless all of the approvals are secured and the administrative codes get modified to incorporate it," he explains.

However, he feels that the desire for the technology is definitely there, as it is a practical and cost-effective alternative to rigid piping in certain applications such as sprinkler systems. A negative result of this efficiency, he notes, is that it might not be embraced by labor unions. While unions like to keep their members busy, technologies like flexible piping, which allow for sprinkler hoses to be installed much quicker than rigid piping, can potentially put installers out of work.

A flexible plumbing application that has been around much longer is that of spanning expansion joints, especially in earthquake-conscious buildings. The idea is that if different sections of a building shift in the event of a tremor, a flexible connection between two sections of piping on different sides of the joint will act as a shock absorber, allowing the pipes to move independently of each other while they remain connected.

Tanalski gives the example of a baseball stadium that's been built as five sections—all part of the same structure—with independent movement from the ground level to the top level. This means five joints that various types of piping—potable water, fire protection, sanitary, storm, etc.—will need to cross.

These are just two areas where flexibility in plumbing can be beneficial to a building. Others are applications where vibration and thermal expansion are issues. Again, good, strong bones are necessary to support the body. But the importance of cartilage should not be overlooked.

For more on flexible piping in sprinkler systems, see "Unusual Sprinkler Hose Lends Unexpected Flexibility", CSE 03/03 p. 61.