ANSI/TPI 1 – 2014: National Design Standard for Metal Plate Connected Wood Truss Construction

by Ryan VanArsdale

What does ANSI/TPI 1 do?

ANSI/TPI 1 not only provides technical information and specifications for metal plate connected wood truss design, but establishes minimum requirements for the design and construction of the trusses. It also sets out the methods for evaluating the metal connector plates, as well as laying out the quality standard for manufacturing processes of metal plate connected wood trusses that need to be in place along with a quality assurance program. Even the manufacturer of the metal connector plates must have a QAP (Quality Assurance Program) in place.

Trusses are engineered to exacting specifications by a computer, is all this really necessary?

Yes! ANSI/TPI 1 provides information on everything from the steel used in the metal connector plates to the overall construction of the truss for one reason: building safety. Trusses are an integral piece of the structural strength of the building. Once installed, trusses are very strong, and they distribute the weight of what is above them to their exterior edges. This means that when a structure is built with trusses, it allows the interior of the home to have fewer “load-bearing” walls and still remain strong.

This type of strength is why trusses are often used in structures that will be going into hurricane or snow load zones. If a home is built using a truss that was not built correctly (perhaps they used metal that does not conform to codes for the metal connector plates, or maybe they used the wrong type of fasteners when connecting one piece of the truss to another), there is a risk of massive truss failure resulting in property damage, injuries and possibly even the loss of life.  By having a Quality System in place to watch over your manufacturing processes, you ensuring that your trusses are all built to the same exacting standards and according to the design specifications, greatly reducing the risk to life and property.

How do I make sure my Quality System is doing its job? What about manufacturers who don’t even have one, how do they get started?

NTA has highly experienced and efficient inspectors, auditors and test engineers with decades of combined experience in setting up and maintaining (or improving upon) a Quality Assurance Program (QAP). In fact, when a truss manufacturer participates in one of our truss certification programs, they receive our nationally recognized label as evidence of their commitment to building safety and quality. It’s easy to reach us, all you need is our simple contact us form.