A Brief Histroy of Resilient Channel

History of Resilient Channel:

Resilient Channel was originally brought to the mass market decades ago by USG (United States Gypsum). The product was trademarked as RC-1, and tested extensively at Riverbank Acoustic Laboratories. Today many installers, architects and material retailers refer to any channel with one “leg” as RC-1. It’s important to note that USG hasn’t dealt with the original resilient channel design for years and years. Since then, many manufacturers have made a “resilient channel” and informally referred to previous USG test data for acoustic performance. This is entirely misleading and quite unfortunate. Resilient channel available today has many profiles, mil thicknesses and performance characteristics, so it really not possible to simply predict how any given piece of “resilient channel” will perform. Additionally any 1 or 2 legged resilient channel is not specified by the Steel Stud Manufacturers Association (SSMA). So there are no standards for its construction or use.

How Acoustic Barriers Reduce Sound

Anyone who's ever shared a wall with someone else has probably wondered if the walls were intentionally thin, or the neighbors intentionally loud. Often the assumption is that the walls between dwellings simply need to be thicker to muffle sound. The fact is that the design of the wall, not the size, can be a contributing factor in transmitting sound from one side to the other.

Consider how walls are constructed in most multi-family housing units. Basically, they are made of gypsum board firmly attached to both sides of a wood frame. When sound waves hit one side of the wall it causes the gypsum board on that side to vibrate. Since the gypsum board is rigidly connected to the frame, the vibration is transmitted right through the framing to the gypsum board on the other side. Those same vibrations travelling through the wall frame can also send sound throughout adjacent floors and ceilings. Noises will radiate through the structure because there's almost nothing there to cushion or absorb the sound waves.

In order to significantly dampen those approaching sound waves, United Plastics Corporation’s dB-3 Pro can be installed between one of the gypsum walls and the frame. The United Plastics Corporation dB-3 Pro, which is made of 100% post-industrial materials  acts as a shock absorber in this system, muffling vibrations coming from either side of the wall. United Plastics Corporation’s dB-3 Pro is an improvement over the resilient channel system’s that are routinely used to improve the sound ratings for walls and are especially effective in floor/ceiling constructions.

Resilient channels typically add 3 to 5 Sound Transmission Class (STC) points to an otherwise identical wall or ceiling, whereas United Plastics Corporation’s dB-3 Pro up’s the ante by adding between 3-5 Sound Transmissions Class (STC) points per layer. This can most often is more than enough to meet the STC and Impact Insulation Class (IIC) ratings required by the project design goals or local codes. In California, the building code specifies minimum lab tested ratings of STC 50 and IIC 50 for partitions in multi-family dwellings.

In fact, the IIC 50 rating required by the building code is easily achieve using the dB-3 Pro wall material when hung in the ceiling in a multi-family project. Unless the floors are completely carpeted (which is rare for kitchens and bathrooms), it is very difficult to achieve IIC 50 ratings without using resilient channels and batt insulation in the floor-ceiling construction

Just what is the difference between Structure-borne and Air-borne noise?

	The noise given off by a particular source can usually be categorised into one of the following forms: Structure-borne noiseThis is the sound generated from a vibrating source or impact event. The acoustic energy created by these vibrations is transmitted into the structure of a building (e.g. floors, walls, pipe-work etc,) or into mechanical elements (e.g. metal frames, panel work, supports etc.) This energy travels through solid structures and is released as air-borne noise at different locations within the building or mechanical system. Air-borne noise This is the sound that travels through the air and into the surrounding environment. In closed environments such as rooms and enclosures, air-borne sound may reverberate and increase the levels of noise both in and outside the contained space. Most forms of noise will contain contributions from both air-borne and structure-borne sound. Although measures can be taken to limit structure-borne components, such as by isolation and damping, air-borne sound can be treated with the use of absorbing materials. ArmaSound RD has an extremely high absorption performance per unit thickness, offering a solution for the most demanding applications.
	By way of example, someone who is hammering a nail into a wall (See diagram) will create structural noise, causing vibration of the surrounding structure. However, they will create a significant amount of air-borne noise, which will be clearly heard in the room where the action is taking place. As the noise travels, it may also change forms. I.e. Structure-borne noise may eventually cause sympathetic vibrations in other structures and release airborne sound. In this example, the structure borne components of the noise may travel towards the light fitting that’s in the same room causing it to shake and release audible clatter. Airborne noise may also change into structure-borne and back to air-borne. This process is often called ‘transmission’ of sound energy. Once again, in the example above, the air-borne components of the noise may travel into the far wall, and then out through the other side and into an adjoining room.