The ASFF Series are adjustable spring floor isolators that provide a solution for low frequency vibration and impact attenuation by isolating disturbing frequencies. The ASFF Series use the spring elements within a cast housing that are positioned within the floating slab while still accessible from above for adjusting the slab to a specified height.                     

Spring supported concrete bases have long been used to isolate individual pieces of equipment. The ASFF adjustable spring jacks have expanded on that concept - from the support of an individual piece of equipment, to supporting an entire room. The design consists of two reinforced concrete slabs - the floating or isolated wearing slab and the structural floor slab.

The floating floor slab is designed with a minimum thickness of 4" between the structural and the floating slabs. The ASFF Series serve as a permanent load bearing resilient material that connects the two slabs while isolating the floating floor form the base floor. ASFF mountings offer permanent, safe support for both the floating slab and the imposed live load over the life of the building.

Features & Benefits

  • Adjustable system and easy access after installation allows for future changes in the use of the room or space
  • Isolator deflections from 1”-3” over a wide range of low frequency attenuation
  • Large outer diameter springs deliver increased lateral stability
  • Interchange capability offers the versatility of spring, neoprene and seismic applications
  • Unit accommodates floors from 3” to 12” thick and air spaces from ¼” to 4” – providing excellent flexibility in a wide range of building applications
  • Precision concentric threads provide easier lifting of the floating floor


  • Commercial utility and HVAC space
  • Performing arts centers
  • Computer operation rooms
  • Entertainment, social event spaces and health clubs
  • Transportation depots
  • Hospitals and research facilities
  • Office and residential complexes


Spec Sheets

No downloads for this item at this time.



The engineers we employ hold the highest industry-recognized credentials in structural analysis, elastomer development and system dynamics.


We are the first ISO accredited PCA ISO-17065, third-party certification body for special seismic certification of non-structural building components and their mounting configurations by the ICC’s International Accreditation Service.

Test & Measurement

We are the only ISO 17025:2005 Accredited Seismic Simulation Test Laboratory with a triaxial shake table owned and operated by California licensed Structural engineers.

Testing Services Update
DCL now offers Nuclear Qualification and Testing services.

In partnership with Greenberry Industrial, we now offer testing services that meet the requirements of ASME NQA-1.

Call for more information.