Sound Absorption
Hard surfaces reflect sound and can create noisy rooms or halls. Soft furnishings or noise absorbing systems with an NRC rating control noise by reducing sound reflections.
The Noise Reduction Coefficient (NRC) is the term used to rate a system for its ability to absorb sound.
The larger the NRC value, the better the sound absorption of the system.
Noise reduction guidelines
- Excellent sound absorption (controlling reflection)
- A unique aesthetic appearance provided by superior quality perforations
- A smooth finished surface provided by recessed edges
- Prevention of dust emission and improved sound absorption due to the protective mat fixed to the back of the plasterboard.
Together with the protective mat glued to the back of the board, the perforations in AcoustiShield are designed to absorb sound. The higher the rate of perforation, the higher the sound absorption performance and NRC value [refer to section 4.7.2 for AcoustiShield systems and installation requirements]
Source – Knauf Gypsum Division Technical Development Centre.
Mineral Fibre ceiling tile (1200x600x20mm) on ceiling grid with plenum of 25cm (NRC 0.95).
Impact Resistance
Areas subject to wear and tear need special consideration to reduce damage and maintenance costs.
High traffic and wear areas are commonly found in:
- Shopping centres
- Educational facilities
- Hotels
- Airports
- Correctional centres
- Hospitals
- Garages
- Home gyms
- Corridors
- Rumpus rooms
Testing of Impact Resistant Linings
Both soft and hard body impact tests were used to measure the performance of various wall linings. The results are displayed in the graphs below.
Soft body tests were carried out by swinging a sand filled bag into a test wall according to BCA Specification C1.8. Soft body tests simulate the kind of loads applied to a wall system by the human body.
Hard body tests were carried out by dropping a steel ball from different heights and measuring the depth of the indentation caused by the impact. Hard body tests simulate loads such as a trolley or swinging a heavy suitcase.
Two conditions were measured for each of these tests:
- The damage on the face and back of the wall lining
- The depth of indentation.
The benefits of ImpactShield include:
- High resistance to marks, scores, dents and holes
- Twice as tough and hard as standard 13mm plasterboard
- Economical and easy to repair.
13mm ImpactShield can be substituted for 13mm FireShield in any system and will maintain fire and acoustic performance.
ImpactShield is not intended to safeguard against damage from deliberate attack with heavy tools or in areas where heavy moving machinery may contact the walls (eg. unprotected forklift operating areas). Consider the following to minimise damage in high wear areas:
- Make thoroughfares as wide as practical
- Install doorstops on all door openings.
X-Ray Resistance
Medical X-Ray diagnostic rooms require the use of protective barriers to shield operators and occupants of adjacent areas against unacceptable levels of X-Ray radiation.
The level of shielding required depends on:
- X-Ray workload and frequency of use
- Direction of X-Ray beam, voltage of X-Ray tube, number of exposures and X-Ray current
- Occupancy and usage of areas adjacent to X-Ray suites
- Position of the X-Ray unit and the controls in the room
- The dimensions of the room housing the equipment.
Protection usually takes the form of X-Ray absorbing sheet material on the walls of the room in which equipment is operated, together with suitably shielded windows and doors. X-Ray shielding may also be required on the floors and ceilings of X-Ray facilities in multi-storey buildings.
X-Ray resistance energy levels
X-ray radiation is measured in kilovolts peak (kVp). Depending on the type of radiation equipment used in the room, diagnostic facilities will have different requirements for shielding:
- CT 120-140 kVp
- General radiographic rooms 60-90 kVp
- Dental 60-80 kVp
- Mammography 25-35 kVp
Other facilities such as nuclear medicine suites may use higher energy X-rays or different types of radiation and additional shielding may be necessary. The level and quality of radiation differs between applications, therefore a Health Physicist must always be involved in determining the shielding requirements for X-ray diagnostic facilities.
Every Australian State and Territory has specific requirements for radiation shielding of diagnostic medical facilities. A Health Physicist or Radiation Consultant will be involved on projects to ensure that the local requirements for radiation shielding are fulfilled, according to the regulations of the State or Commonwealth.
The advantages of using GIB X-Block Shielding systems:
- Lead free and environmentally friendly
- Easy to install and joint as standard plasterboard
- Enhances other important performance requirements such as noise control and fire ratings
- Eliminates the need for backing joints with lead strips.
Separating Walls
The BCA has specific fire and acoustic requirements for separating walls for side-by-side residential dwellings, such as duplexes and townhouses. Traditional solutions, like masonry and double stud systems are time consuming and complicated to construct. Builders require simple solutions that minimise the risk of reducing fire or acoustic performance due to construction details.
Fire protection performance:
- Fire Resistance Level (FRL) 60/60/60.
Sound insulation performance for separating walls of:
- Rw + Ctr 50 + Discontinuous Construction (All states and territories except NT)
- Rw 50 + Impact Sound (for NT only).
Sound insulation performance for soil and waste pipes of:
- Rw + Ctr 25 and Rw + Ctr 40
- RRw 30 and Rw 45.
InterHome has the following advantages due to the modular central fire barrier:
- Fast to build
- Eliminates the need for timber blocking
- Allows both wall cavities to carry services without compromising fire or acoustic performance
- Outer layers of plasterboard are installed to non-fire rated installation methods
- Penetrations in outer layers are not required to be fire rated.
InterHome can be constructed by the site carpenters at the same time as the framing is erected. It is quick, economical and importantly, designed to manage health and safety concerns with respect to ease of construction.
Superior Level 4 Finish
Modern architecture and design requires a high and consistent level of finish. Premium projects require the best finish that quality installation practices and materials can provide. The Australian standard for plasterboard installation AS/NZS 2589:2007 Gypsum linings – Application and finishing, define three Levels of Finish. The default Level of Finish is Level 4 [REFER TO CHAPTER 5.1 LEVELS OF FINISH].
A Level 4 Finish consists of a plasterboard wall or ceiling with a compound joint. This results in a number of different surfaces for the paint to cover; the paper face of the plasterboard, the compound surface, and the interface between these two zones.
As each of these surfaces present varying textures and porosity, the paint will be absorbed at different rates. These types of surface variations can result in different levels of sheen, gloss and the appearance of the paint colour.
Level+ Technology is an exclusive technology which has been developed by Knauf through intensive research at the Gypsum International Technical Development Centre. Used worldwide, the system is fully patented and unique to Knauf.
The benefits of MastaDeco with Level+ Technology:
- Design solution for flat and smooth surfaces
- A higher quality surface for painting and a superior appearance that is UV resistant and easy to clean
- No specialist equipment required for installation or jointing.
Fixing of MastaDeco plasterboard is the same as standard Level 4 Finish, as is the 3-coat jointing process with MastaDeco compounds. The complete MastaDeco system must be used to deliver the benefits of Level+ Technology [REFER TO SECTION 4.7.3 FOR MASTADECO INSTALLATION REQUIREMENTS].