Sound Transmission Control Walls and Ceiling Systems
Noise control plays an important role in the modern working and living environments by providing comfort, productivity and privacy/confidentiality. Studies show that a positive environment has a positive effect on business and living . Attention needs to be given to noise control and better room acoustics.
Areas that Require attention
 Where separate occupancies adjoin, noise is a fundamental consideration. Designers need to select an acoustic comfort level aligned with occupant expectations. Besides impacting the sense of quality, noise control reduces annoyance from neighbors and improves the sense of privacy.- Noise disturbance can come from neighbouring rooms (adjacent, above or below) in the form of airborne sound from TV and voices, impacts from footsteps along corridors and stairs, or services like showers and toilets.
- Noise from impacts travels horizontally along floors as well as up and down; impact through walls can be a concern where there are no buffers.
- Noise from lobbies, entertainment and conference rooms require special attention.
- Protection from external noise is important near main roads and airports.
- Hotel Room acoustic treatment around receptions in large foyers can aid intelligibility.
- Interior Partitions between rooms need to protect the amenity value of users.
- Senior Managers expect more noise control and require it for confidentiality.
- Seminar and Meeting Rooms, and walls between rooms need to protect the amenity value of users.
- Open Plan Offices require a degree of privacy which is achieved by masking sounds.
- Healthcare Facilities need special attention for control external noises.
- Educational Facilities need special attention for better room acoustics.
- Entertainment Facilities need special attention for noise control and sound isolation.
Noise Control Systems have been specially designed and developed with extensively independently testing and evaluation to suit every required level of STC and IIC performance ratings.
State of the Art Technology in Noise Control Systems has High Performance Ratings and Cost Effective Designs for Sound Transmission Control - Walls & Ceilings. Individually designed for every required level of STC (Sound Transmission Class) and IIC (Impact Insulation Class) ratings.
Important Elements for Building Noise Control Walls & Ceilings
- Mechanical Resilient Mounts that Controls Sound and Protects Fire (UL Classified)
- Modern Technology ACOUSTIC LININGS for WALLS and CEILING that Controls Sound Transmission.
- High Quality Sound Attenuation friction fit in-fills - Sound Blankets.
- High Performance Acoustic Sealant to prevent Sound leaks.
- Joint Compounds (Acoustic).
- System Test Standards: ASTM C 840 / ASTM E1332-90 / ASTM E90 / ASTM E90-04 and ASTM E413-87 (NZ and AUST) AS1530 Part 3
- DOOR Perimeter Sound Seals
- Motorized (Automatic & Semi Automatic) Bottoms for Sound Rated Doors.
- Intumescent Strips - Smoke Seals for Fire Protection
Special Features
Any interior hard or soft finish, paints or textures can be easily installed to match your interior decor themes.
“HEALTH WISE” and Environmental friendly / fire-rated sound attenuation blankets installed as friction fit sound control in-fills for sound absorption.
 GIB Noiseline®
Noiseline® is a high performance plasterboard designed specifically for reducing the level of sound transmission between rooms. Apart from its higher density core Noiseline® also features a smoother whiter face paper making the integration of Noise Control® for homes and other Interior Solutions much easier. Other benefits of this product are its 30 minute fire rating that it can be substituted for a equivalent bracing systems, and its increased strength and stiffness give more solid walls and ceilings.
Sound Transmission Class (STC)
Sound transmission Class (STC) is a single number quantifier used to rate partitions, doors and windows for their effectiveness in blocking sound. The number assigned to a particular partition design as a result of STC testing represents a best fit type of approach to a set of curves which define that sound transmission class. The test is conducted in such a way to make it independent of the test environment, and yields a number for the partition only. The reverberance and size of the room are factored out.
Transmission Loss data is measured in a laboratory by means of a standardized procedure defined in ASTM E90 for laboratories and E336 for field tests in actual buildings, while the STC curve is defined in ASTM E413. The STC, is heavily weighted in favor of the speech frequency range above 125 Hz and correlating with human hearing acuity. For the determination of the final STC number, the values between 400 Hz and 1250Hz are somewhat discounted, the values below 400Hz are increasingly discounted. The STC number is determined from Transmission Loss values using an algebraic formula for maximum or sum of deficiencies. The standard test method also requires minimum room volumes for the test to be correct at low frequencies.
Due to the definition of the rating, STC is only applicable to air-borne sound, and is a poor guideline for construction to contain HVAC or other mechanical equipment noise, music, transportation noise, or any other noise source which is more heavily weighted in the low frequencies than speech. The standard thus only considers frequencies above 125 Hz. Composite partitions composed of elements such as doors and windows as well as walls will tend to have an STC close to the value of the lowest STC of any component.
In practice, the STC of the laboratory sample represents the optimum condition, and is rarely achieved in actual construction. The difference between the actual or Field STC (FSTC) and the laboratory STC is a result of leaks and flanking paths, in other words, sound entering a wall in a common assembly is also entering the floor, traveling through the floor and breaking out in the adjoining space, by-passing the wall. A similar effect is found if sound is allowed to enter air return plenum spaces above or below walls. The degree to which these flanking paths are disconnected will determine how closely the field test results approach the laboratory results.
STC -Lab |
Field STC |
Subjective description of effectiveness |
26-30 |
20-22 |
Most sentences clearly understood. |
30-35 |
25-27 |
Many phrases and some sentences understood without straining to hear. |
35-40 |
30-32 |
Individual words and occasional phrases clearly heard and understood. |
42-45 |
35-37 |
Medium loud speech clearly audible, occasional words understood. |
47-50 |
40-42 |
Loud speech audible, music easily heard. |
52-55 |
45-47 |
Loud speech audible by straining to hear; music normally can be heard and may be disturbing. |
57-60 |
50-52 |
Loud speech essentially inaudible; music can be heard faintly but bass notes disturbing. |
62-65 |
55 |
Music heard faintly, bass notes "thump"; power woodworking equipment clearly audible. |
70 |
60 |
Music still heard very faintly if played loud. |
75+ |
65+ |
Effectively blocks most air-borne noise sources. |
Table 1: Subjective interpretation of effects of STC as measured (assumes normal/quiet background level - NC 35)
Note: The actual effect perceived effect of STC depends on the background noise levels, room volumes, surface areas, sound absorption values and spectral content of the sound source.
What is STC?
The actual behavior of two partitions with the same STC rating can be dramatically different, as the STC is weighted in favor of the part of the sound spectrum that represents the human voice. In practice, one of the most annoying transmitted sounds between dwelling units tends to be the bass in music, a part of the sound spectrum far removed from the voice range. So, an eight inch concrete block wall rated at STC 50, that can block 20 dB more sound in some bass frequencies would be a better choice than an STC 50 drywall partition for an application where music or mechanical noise will be a problem.
The higher the target STC, the more critical are the sealing and structural isolation requirements. The builder's best options for getting a satisfactory STC result are to specify partitions with a laboratory rating of STC 54 or better. If in doubt at an early stage in the construction, testing can be done to rate the construction and upgrades recommended before costly finishing is in place.
An STC test is conducted on partitions by placing a noise source on one side, a measuring microphone on the other side, and a spectrum analyzer connecting the two. The drop in decibels through the wall (Transmission Loss or TL), background sound level and reverberation time RT60 is measured and the resulting information compared to the standard STC definitions to arrive at the STC rating of the wall or floor. In order to be applicable, the test must be carried out according to defined test procedures from ASTM E336. |
