3M Support

The Benefits of Using 3M™ Adhesives in SAFE-T-PROOF™ Earthquake Fasteners

Securing equipment with flexible fastening that incorporates 3M™ VHB™ Tape (VHB) has showed remarkable results in shake table testing, with limited damage to the equipment anchored compared to equipment anchored using a traditional, mechanical anchorage method. This tape forms a strong adhesive bond, secures multiple types of substrates together, and continues to perform in wide temperature and humidity variations. Additionally, aging tests show an increase in the holding capacity of the bond as time passes, and various pull tests at different strain rates show the adhesive exhibits greater strength in sudden tugging motion (i.e., fast strain rates) common to actual earthquakes.

VHB tapes are acrylic foam pressure sensitive adhesive (PSA) tapes that adhere to the substrates via electrostatic adhesion and viscous flow. They do not damage substrates during attachment as with mechanical fastening (e.g., screws and bolts). Additionally, there is no heat involved and no chemical reactions taking place which allow for a smoother aesthetic when compared to positive attachment methods.

VHB tapes are characterized by having a viscoelastic conformable acrylic foam core with acrylic SA skins. The acrylic foam provides energy absorption and stress relaxation properties that are beneficial for absorbing energy and reducing fatigue during stress loading. Viscoelastic materials like VHB tape have a modulus and ultimate strength that is strain rate or time dependent. Fast strain rates will exhibit increased modulus and ultimate strength values when compared to slower strain rates. Seismic induced movement is representative of a fast strain rate and therefore, this type of stress loading is where VHB tapes show increased strength values.

The advantages to utilizing adhesive fasteners are many-fold and include eliminating the need to drill into the sides of equipment (thus often voiding the warranty) and allowing for maximum flexibility to move and clean equipment and furniture. As these fastening systems are further developed, it is likely that they will become increasingly common options for the seismic anchorage of heavier and larger pieces of equipment. The factor that limits the weight of equipment that can be secured in this manner will no longer be the adhesive fasteners themselves, but the structure to which these systems are connected.