Why choose Farrat for Steel Frame Acoustic Isolation? (AISS)

Supporting steel structures and positioning acoustic isolators is more effective and more cost efficient when done in the form of point loads rather than line or area loads. This brings with it the challenge of varying load profiles at each support point as it is very rare to have a perfectly symmetrical structure and load distribution.

For both structural and architectural reasons, it is important for a secondary structure to deflect at a minimal, but more importantly, constant rate. This can be very difficult to achieve in structures mounted on low stiffness isolators with eccentric or variable load distribution.

Farrat’s Steel Frame Acoustic Isolation (AISS) system can overcome this problem and provides huge adaptability and flexibility for acoustically isolating auditorium raked seating structures, box-in-box frames, plant decks, bridges and staircases achieving controlled live load deflection yet low natural frequencies.

Farrat Acoustic Isolators are sized to match baseplate profile to eliminate the risk of debris bridging the cavity and they have a consistent rate of deflection under load across the whole structure despite varying load profiles.

Compatible with all steel frame and baseplate/bolt combinations (including steel-steel and steel-concrete connections) subject to isolator max load capacity.

To find out more about the Farrat products used in application, please see the following pages or download our Farrat Datasheets:

Alternately, visit our Cinema Application page or download the Farrat Technical Guide for additional information.

Steel-to-steel connection detail:

Steel-to-steel connection detail with Farrat AWTH Acoustic Washer

Steel-to-concrete connection detail:

Steel-to-concrete connection detail with Farrat AWTH Acoustic Washer

Secondary Steelwork Isolation Site Applications:

Step 1

Isolators must be placed on flat, level ground (typically, concrete with a pan-float finish, and large protrusions removed) or a steel section.

They must be uniformly supported across their whole area.

Step 1 image
Step 2

If height levelling is required, full area shim plates which match the profile of the baseplate must be used. Rotational levelling is provided by the compressibility of the isolator.

Step 2 image
Step 3

After the base plate has been seated, install the acoustic washers (with the bush facing into the baseplate hole) followed by the nut.

Step 3 image
Step 4

Once the structure has received its primary load (e.g. precast concrete), tighten the nuts to the required torque, as detailed within the AWTH Acoustic Washer datasheet. DO NOT OVERTIGHTEN!

Step 4 image

Important Note: Due to constraints on rubber colour imposed by BS 6177, isolators of different rubber grades can look identical. It is essential to carefully review the location marking on the isolators prior to installation.

Full Structure Isolation Systems:

Acoustic performance of a rubber isolator is proportional to the load applied to it, therefore it is not possible to take the worst-case load as a basis as the design for all isolators within a project. To design a full-structure isolation system, we would require all of the information as shown in the table below:

LocationDrawing refQuantityL (mm)W (mm)BoltHole sizeDL (kN)LL (kN)
Example 1AP511-BO4125025042243.516.2

Typical Lead Times

1 Week Design, 2 Weeks Fabrication

Please note that production cannot commence before we receive approved drawings, therefore lead time commences when both order and approved fabrication drawings are received.

Suggested Products:

PB016

Farrat AWTH Acoustic Washers

  • Required wherever acoustic isolators are used
  • Farrat AWTH Acoustic Washers are available to match M6, M8, M10, M12, M16, M20 and M24 bolt sizes
  • See the datasheet AVW – AWTH – 16a for further information including washer dimensions

Specification, Material & Installation

Farrats friendly and helpful team can assist clients with a variety of high performance acoustic isolation solutions and damping materials.

Our team of noise & vibration engineers can provide detailed guidance on the specification of vibration isolation and damping materials, high performance sound insulation detailing and structural vibration isolation solutions at any stage of design and see this to completion with the supply of the market-leading materials and installation guidance.

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