A compressible steel washer manufactured with protrusions on one side, known as a direct tension indicator washer (DTI). When used with structural bolts the DTI is designed to compress to correlate to bolt tension.
The Squirter® DTI is the same as other DTI washer except for the orange silicone that has been added to the welds under each bump. As the bolt is tighten the bump compress pushing the silicone to edge of the washer indicating to the installer the correct tension has been achieved. Squirter® DTIs are made and certified to ASTM F959.
The silicone has a shelf life of 5 years. When installed the silicone becomes fully cured omitting a powdered textured, this powered remains visible on the steel structure for a period of 3-4 weeks. This normally allows enough time for inspection of each bolt assembly pending weather conditions as wind and rain may affect visibility.
Squirter® DTIs are used by more and more engineers, contractors, and project owners like Alstom https://www.alstom.com/, Babcock & Wilcox https://www.babcock.com/, Bechtel Corporation https://www.bechtel.com/, Amec Foster Wheeler Energy www.amecfw.com, Jacob Constructors https://www.jacobs.com/ and many others.