Squirter DTI Washer: Frequently Asked Questions

Key things to remember

The essentials from this document in plain words. Check the full document before you rely on a figure.

• ✓AS 4100 clause 15.2.5.3 covers tensioning with a direct tension indication device, including the pre-installation calibration requirements.
• ✓Shows correct tension by squirting bright orange silicone, and is not affected by weathering, poor lubrication or damaged threads the way torque methods are. It is the same as the old style load indicator washer, with the silicone added.
• ✓Can go at the nut end or the bolt head end, depending on clearance, appearance, consistency and access for tooling and inspection.
• ✓Bolt hole size (AS 4100 14.3.5.2): 2mm larger than the bolt for bolts up to 24mm, 3mm larger for bolts over 24mm. If the hole is 3mm or more larger than the bolt, fit a plate washer at least 4mm thick under the nut; it can be mild steel.
• ✓The pressed-out silicone powder stays on the steel for up to 3 to 4 weeks, less in heavy wind or rain. After that, inspect with a feeler gauge.
• ✓Store in the Hobson cartons, dry and protected from heat, moisture, rain and dust; don't leave cartons out in the weather on site. The silicone has a shelf life of over 5 years.

Who it helps: Steel erectors, inspectors and engineers using DTI washers on structural bolting.