Adhesive Anchors Need Caution

Adhesive Anchors Need Caution

The International Building Code (IBC) allows several methods for anchoring in hardened concrete, but for construction specifiers the choice of one method—adhesive anchors—can result in damaging project delays. The IBC, referencing an American Concrete Institute (ACI) provision in its 2012 edition, requires that such anchors only be installed by personnel who have received certification to do so. The catch is that a lack of training opportunities is making it extremely difficult for installers to get this certification. Nowhere has this problem loomed larger than in New York City, where contractors are scrambling to find certified installers in time to meet an October deadline.

The requirement itself is not unreasonable. ACI developed it in response to the anchor failures that caused the collapse of several ceiling panels in the Boston Tunnel of Big Dig infamy. The construction community’s concern lies in the fact that the code restricts who is allowed to conduct certification training and testing. By limiting training opportunities for installers who want to get certified, ACI has put many contractors in an impossible position: They cannot install adhesive anchors without maintaining certified installers on their workforce, and if they install without certification they risk a violation or stop work order.



To understand how the shortage of certified installers came about, it helps to review ACI 318’s requirement in more detail. In order to become certified, an anchor installer needs to enroll in the ACI-Concrete Reinforcing Steel Institute (CRSI) Adhesive Anchor Installation Certification Program. Certification is awarded upon completing the two-day program, which costs anywhere from $500 to $900 per person depending upon location plus any travel expenses. Anchor installers must demonstrate an ability to read, comprehend, and execute instructions for properly installing adhesive anchors in concrete. To demonstrate this ability they have to possess knowledge and ability in several areas that include:

•    Understanding relevant jobsite conditions for correct selection of installation procedures in accordance with adhesive anchor manufacturer’s instructions
•    Understanding the manufacturer’s instructions and using proper procedures, sequence, and tools to clean the holes that receive anchors
•    Properly selecting and assembling adhesive injection equipment
•    Injecting adhesives to the proper depth in holes at various orientations
•    Recognizing time limits for installing and positioning anchor elements
•    Knowing how to protect anchor threads from contamination by the
•    Securing anchor elements from loading or movement during the adhesive cure

They also have to pass a 90-minute, closed-book, written examination composed of 75 multiple-choice questions; and pass a two-part performance examination by successfully installing adhesive anchors in a vertical down and vertical up position. In addition, installers must successfully complete both the written and performance examinations every five years in order to retain their certification.

Few certification courses available

For installers, the challenge isn’t completing the program or even recertifying; it is securing a spot in one of the few training courses available. The root of the problem is that, according to ACI 318-2011, certification can only be awarded when the training program is given by ACI-CRSI or one of its sponsoring groups, typically a local chapter of ACI.

In New York City, ACI designated the Concrete Industry Board (CIB) to provide this training, one of only three sponsoring groups chosen throughout the state. As of this writing, the CIB is only training and certifying 15 adhesive anchor installers a month, similar to the output of programs in other smaller states. Given the number of building trades that install adhesive anchors, this will produce just a small percentage of the certified installers needed in the city for projects getting underway in October.

Sending installers to a program out of the city for certification adds significantly to the already high cost of the training, ruling this out as a remedy. Given the number of installers seeking certification, it is not clear whether this would even help satisfy the need.

Impact on the industry

In New York City, the shortage of training opportunities has created a bottleneck with the potential to interrupt construction schedules citywide. President Gary LaBarbera of the Building and Construction Trades Council of Greater New York, representing 100,000 working men and women, warns, “at least 30,000 tradespersons must be certified by the October deadline if we are to avoid stalling major public and private projects in the city.”

Not specifying adhesive anchors might seem like a reasonable solution. However, in many applications they may be the preferred—or only—anchorage method because of their superior holding power in tension in cracked or damaged concrete.

At this point, it is important to note that not all adhesive anchor installations fall under this requirement. Only anchors installed in a horizontal or overhead orientation and under a sustained tension load are affected.

Since they are installed in these orientations, the anchors become subject to special inspection. This leads to a host of additional responsibilities—and costs—for the project team. The architect and engineer must identify on plans filed with a building department those adhesive anchors for which special inspection is required. In addition, the owner must engage an independent testing laboratory to perform the inspection, which ACI 318-11 requires to be continuous, meaning no drilling and installing of adhesive anchors should occur unless an inspector is observing the installers’ procedures.

The special inspector is required to furnish a report to both the engineer of record and the building official stating whether the installation procedures and materials covered by the report conform to the approved contract documents and the manufacturers printed installation instructions.

Finally, before any installation is performed, the inspector must verify the certification of the installer, which brings us back to the original problem—shortage of training opportunities. While the provision entails responsibilities and costs for both the designer and the owner, only the contractor has the responsibility for maintaining certified personnel on his or her workforce to perform the installations. For construction activity to move forward without large delays, these contractors must be able to find certified installers, meaning opportunities for installers to obtain certification must grow sharply.

Concerned groups have proposed alternatives to address this potential bottleneck, including moratoriums on enforcement and permitting qualified training entities outside the ACI-CRSI to develop and conduct a certification testing and training program. Until any proposal becomes reality, the best course of action for construction specifiers might be to avoid the use of adhesive anchors for horizontal or overhead installations under sustained tension load unless absolutely necessary.