SafeSet™ Technology and Adhesive Anchors

Why do clean drilled holes matter?

Improper hole cleaning is the largest variable affecting performance of adhesive anchors

What is the proper way to clean a drilled hole?

Hilti standard hole cleaning method

To properly clean a drilled hole for a Hilti adhesive anchor, the installer must follow the Instructions for Use (IFU) provided with the product. The most common procedure is the 2 Blow x 2 Brush x 2 Blow method using a 90 psi minimum air compressor and matched diameter steel wire brush.

traditional standard hole cleaning method
properly cleaned hole

Following this procedure helps to ensure the drill hole is free of dust and debris, giving the adhesive anchor a clean surface to bond to and penetrate the concrete.

improperly cleaned hole

Not following the hole cleaning procedure leaves a significant amount of dust and debris in the hole, preventing the adhesive from bonding to the base concrete.

Each manufacturer has its own cleaning method

competitor hole cleaning methods

Other adhesive anchor manufacturers have different cleaning methods, so it is imperative to check the Instructions for Use included with all adhesive anchors.

Installers may not consistently clean drilled holes properly

field study of adhesive anchor installations
  • 23 jobsites throughout US
  • 26 different applications observed
  • 31 installer surveys completed

Key Takeaways

  1. 77% of drilled holes were not cleaned per IFU
  2. Majority of sites did not have the proper cleaning tools available
  3. 74% of installers interviewed believe hole cleaning has a direct effect on performance
  4. Only 27% of installers were using the blow/brush/blow cleaning method
  5. Only 33% of installers knew compressed air was required for proper hole cleaning

Read the full article

Concrete International, V33, No 1, pp. 57-63 01/ 2011

Grosser, P; Fuschs, W.; Eligehausen, R.; University of Stuttgart

How do improperly cleaned holes affect the performance of your design?

improperly cleaned hole and design performance

Improperly cleaned drilled holes can have a significant effect on the performance of adhesive anchors.

Introducing Hilti SafeSet™ Technology for adhesive anchors

Hilti SafeSet™ Technology

safeset technology for adhesive anchors

Hilti SafeSet™ Technology is a proven methodology developed by Hilti concrete construction experts to provide new ways for engineers and contractors to reduce installation errors. Hilti offers two SafeSet™ solutions for adhesive anchors. The Hilti HIT-Z, a torque controlled adhesive anchor that does NOT require hole cleaning and Hilti's Hollow Drill Bits combined with Hilti's VC 20/40/150/300 vacuums clean the holes as they are being drilled.


1 / 5

The HIT-Z Rod, when used with HIT-HY200, eliminates the need for hole cleaning by relying not only on bond but also expansion forces. Due to the special design of the helix and the expansion forces generated by torqueing the anchor the need for drill hole cleaning is NOT required.

coating on helix of HIT-Z rod
2 / 5

A Hilti proprietary coating on the helix prevents bonding between the HIT-HY 200 and the HIT-Z Rod.

friction and expansion forces of HIT-Z rod
3 / 5

Applying the installation torque to the nut forces the HIT-Z Rod up, which in turn pushes the HIT-HY 200 into the sides of the drilled hole, creating friction and expansion forces.

Please enter alternative text here (optional)
4 / 5

Even without cleaning the drill hole, the HIT-Z Rod performs just as well as the standard cleaning method.

ESR 3187 for HY 200
5 / 5

For the non-hole cleaning method, the HIT-Z Rod will only work with with HIT-HY 200. The HIT-Z rod is included in the ICC-ES ESR for HIT-HY 200.

Hilti Hollow Drill Bit

Hilti hollow drill bit
1 / 5

The Hilti Hollow Drill Bit is a hammer drill bit that removes dust and debris as it drills when attached to a Hilti VC 20/40/150/300 vacuum.

Hilti hollow drill bit end detail
2 / 5

Each hollow drill bit has four openings at the tip of the drill bit. The dust is sucked up into the holes and up through the center of the drill bit.

VC 20/40/150/300 vacuums
3 / 5

Hilti Hollow Drill Bits must be used with Hilti's VC 20/40/150/300 vacuums. These vacuums have a minimum suction capacity of 129 ft3/min and a self-cleaning air filter that helps prevent loss of suction.

hollow drill bits and vacuum cleaning method performance
4 / 5

With the hollow drill bits and vacuum cleaning the hole as its drilled there is no need to use the blow/brush/blow method after drilling is completed and there is no reduction in load performance.

ESR 3187, ESR 3814
5 / 5

The Hilti Hollow Drill Bits are an approved installation method listed in the ICC-ES ESRs for both HIT-HY 200 and HIT-RE 500 V3.

Resources for Specifying Hilti SafeSet™

PROFIS Engineering Design Software

PROFIS Engineering

Hilti PROFIS Engineering allows designers and specifiers to quickly, easily evaluate Hilti anchor products and systems—and then choose the best solution for any conditions.

Learn more about PROFIS Engineering
Specifications, details, general notes

Specifications, General Notes and CAD Details

Incorporate Hilti anchor products into your designs.

Learn more