The T-DRILL System

The T-DRILL System of mechanically formed tee connection was invented in 1967 in Finland by a plumber/engineer named Leo Larikka.
Mechanical formation of tee connections had been around for many years, but Larikka developed a more sophisticated method that became the most widely adapted system of its kind in the world. In fact, in Scandinavia they do not put in tees- they put in "Larikkas," just as we use "Kleenex" tissues and "Xerox" documents. Patents were not pursued until the early 1970s, though the second- and third-generation T-DRILLS have since been patented.
As plumbing wholesalers are few and far between in Finland, Larikka developed his invention out of necessity. Lacking the right size tee fitting, he came up with a way to create what he needed out of the tube itself.
Before this method of installation could be widely used in North America, national, state and local codes had to be rewritten after suitable testing. Now, 15 years after introduction here, most plumbing codes are complied with and the method is in compliance with ANSI B 31.5 (ASME code for pressure piping) and being used by over 5,000 plumbing, mechanical and sprinkler firms.
The fast-track installation afforded also necessitated special inclusion in labor calculator manuals. According to the company, three out of the four major plumbing and mechanical cost data books now reference the Mechanically Formed Tee Connection.

Wirsbo PEX Tubing

In 1968, Thomas Engel invented a process for producing chemically cross-linked polyethylene (PEX) tubing. Considered impossible by many heating industry experts, Wirsbo Co. used Engle’s technology to develop a practical manufacturing process for PEX tubing. The cross-linked tubing was introduced to the European floor heating market in 1972 and potable water market in 1973.
PEX tubing solved a number of problems that occurred with metal pipes and some other types of plastic tubing. PEX will not corrode or erode, and is immune to the many problems associated with poor water quality that can damage metal pipes. The tubing is rated at 180 degrees F., 100 psi. Wirsbo tubing also has the highest polymer oxygen diffusion barrier of any tubing in the world, according to the company.
The growth of cross-linked polyethylene tubing has been dramatic in the European market. Today about 10 percent of all plumbing installations are made with PEX tubing, and in some countries over 50 percent. In Europe, where radiant floor heating is installed in over 50 percent of all new construction, PEX tubing goes into approximately 70 percent of all jobs.
Wirsbo-PEX was introduced to the U.S. plumbing market in 1985 by Tomas Lenman. Now director of technology at Wirsbo Co. in Apple Valley, Minn., Lenman was a leading member of the engineering team that developed the product in the early 1970s. Today, PEX tubing products are used for floor heating and other heating applications.