How do TurnaSure DTIs compare with the squirt-type available on the market?
We believe that TurnaSure DTIs are vastly superior to the squirt-type load indicator being touted by our competitor. For a more detailed side-by-side comparison, please click here.
Direct Tension Indicators (DTI) TurnaSure and ASTM F959 DTIs compared to squirt-type |
|
| TurnaSure | squirt-type |
|---|---|
| Meets or exceeds the requirements of ASTM F959 | Regarding squirt-type washers, ASTM F959 has no explicit provision or allowances for channels on the underside, or for inclusion of silicone in pockets, whose appearance would indicate the min/max compression loads. TurnaSure believes that reference to squirt-type washers meeting ASTM F959 can give users the impression that the ASTM has recognized squirt- type washers. This is not correct. |
| Fully flattened DTI provides absolute assurance bolt load has exceeded minimum. | Tests witnessed in independent laboratory show orange paste appearing before proper tension is achieved (see illustration #1 below). |
| Additional feeler gauge inspection to confirm installed gaps are smaller than ASTM specified test gap proves bolts have been tensioned properly and remains permanent evidence. | We believe temporary appearance of paste around washer circumference is neither a tool nor a substitute for inspection. |
| Unaffected by joint surface condition or cold or hot weather conditions. | We believe that the appearance of colored paste would be made more irregular by rougher surface conditions of structural plates, or if weather conditions are freezing or hot. |
| Provides solid clamped connection. | We believe any silicone type substance trapped under washer might preclude retention of clamping forces over time. (Commentary in AISC manual precludes gaskets, insulation or compressible materials in grip of connection). |
| Unique curved protrusion geometry with cylindrical pockets keeps hardness that insures against long termed stress corrosion cracking. Tests show gaps below .005" prevents ingress of moisture over time. | In our view channels are a likely long term stress crack raiser and could allow a channel for moisture ingress. (See illustrations #2A and #2B) |
Illustration #1
Picture taken at Laboratory Testing Inc 05/16/01 of squirt-type showing appearance of silicone before bolt has reached proper tension under laboratory conditions.
Illustration #2a/2b
Illustrations show a channel on squirt-type (left) compared to unique cylindrical TurnaSure geometrical protrusion designs. Red shading is where stresses would likely be the greatest after installation.
