Testing with Triax

The process started over 15 years ago. Only a year-and-a-half ago it was approved for use by the American Society for Testing Materials (ASTM). The Triax 2000 SIT (Surface Impact Tester) is the only approved, portable, free-fall surface testing system in the world.

"The computer that is attached to the accelerometer measures the G force, the Head Injury Criteria (HIC) and the velocity of the headform at the moment of impact," said Paul Hogan, creator of Triax 2000. "ASTM requires this velocity meter because it used to be easy to say that you dropped something from 5 feet, when it was really dropped from 6. Now there is no way to cheat because it gives you a measurement in feet-per-second."

Graphs of all drops can be reviewed on a small computer screen with the push of a button. Each impact test shows the time and date of each drop. The velocity, time and date cannot be altered thereby insuring honest reporting. After uploading a drop to a PC, comments can be inserted for each particular drop and graphs can be uploaded as well.

With the push of a button, a graph of all the drops can be reviewed on a computer screen. When a drop is uploaded to a PC comments can be inserted for each particular drop. Graphs can also be uploaded to the PC as well.

Other features include five "AA" batteries in an easily changeable power clip that powers Triax 2000 for approximately six months; two operating discs along with manual and all necessary connecting cables; and a shaped foam filled plastic case for both the computer and head form is provided for safe transport.

ASTM 1292-99 requires that every impact drop test be accompanied by a velocity measurement as Hogan related earlier. Velocity reporting is required in the United States, Canada, Australia and New Zealand. Because of this requirement a velocity tripod is needed and sells for approximately $3,000. In its compact form the tripod is only 5 feet long and can extend to 14 feet with a drop capability of 12 1/2 feet. The pulley system allows you to raise the head form to the required height without the need of a step ladder.

The tripod enables you to make drops onto the exact spot from the exact height with no deviation and an electro magnetic release system operated from the hand held computer eliminates any hand or body shake movement that might disturb the drop test.

“The idea of determining the HIC is like dropping a golf ball on the concrete," Hogan explained. "The ball will bounce back at 80 percent so it is a definite shock to the ball.

“But if the ball is dropped in the sand it will penetrate the sand and come slowly to a stop in terms of milliseconds. The idea is to make the stop as slowly as possible.

"I was in the paratroopers and we had a saying: ‘It's not the fall that kills you, it's the sudden stop.’”

The surveyor's rod allows the tester to set the head form at the desired height. The rod is available in American inches or European meters and can be viewed at eye level.

According to the Consumer Product Safety Commission, there are two methods that may be used to determine when such an injury may be life threatening.

One method holds that if the peak deceleration of the head during impact does not exceed 200 times the acceleration due to gravity (200 G's), a life threatening head injury is not likely to occur. The second method holds that both the deceleration of the dead during impact and the time duration over which the head decelerates to a halt are significant in assessing head impact injury. This latter method uses a mathematical formula to derive a value for HIC. Head impact injuries are not believed to be life threatening if the HIC does not exceed a value of 1,000.

Companies, public agencies, and groups outside of the United States have started using Triax 2000, and have been pleased with the results. Recently the Anchorage School District maintenance personnel learned to use the system in a two hour session, and have implemented it into their playground testing procedures. England's Royal Society for the Prevention of Accidents is now using it throughout the country.

ASTM standard 1292-99 requires that every impact drop test be accompanied by a velocity measurement. A velocity tripod will be needed for this. The tripod can extend to 14 feet with a drop capacity of 12 1/2 feet.

"This has really worked out great for us," said Mike Street of safety surface maker Sof Surfaces. "You just set everything up on the tripod and it is really easy to use."

Another piece of equipment that can be used with the Triax 2000 is a surveyor's rod. By just setting the rod at the desired height and raising the Triax to the top of the rod and the precise height is made. The rod can be viewed at eye level and is available in American inches or European meters and comes in a heavy-duty plastic case.

For more information on Triax 2000 contact Paul Hogan at: (phone) 610-935-1549; (fax) 610-935-8626; or email at pauljhogan@aol.com.