2 Introduction to Ceiling systems Ceiling TypesSuspension SystemsCeiling Panel TypesSurface FinishesFire PerformanceCeilings & AcousticsAbsorption, Reflection & TransmissionSummary of acoustic performanceGreen Star requirements
3 Ceiling Types Direct Fixed Suspended Ceilings Discontinuous Tensioned Therefore the effective control of sound must take place at one or more of these locations:Reduce the Source (enclose or reselect)Increase Attenuation (distance or mass)Protect the Listener (enclose and/or absorb)
4 Direct FixedMore common in commercial applications where metal linear strips or corrugated metal sheets usedMoana Pool , Dunedin
5 Suspended CeilingsThe suspension of ceiling components below structural members (floors or roof).Not part of the structural framework of a building.Commonly used to provide space for servicesExposed or concealed Grid options
6 Discontinuous Ceilings A new trend which is modified from suspended ceilings
7 Tensioned Ceilings Fixed to channels around perimeter. Bungy and eyelets or springs
9 Exposed GridMost commonly roll formed steel grid with prefinished capping15mm Suprafine24mm Peakform15mm Silhouette tophatAluminium Options
10 Semi concealed K2C2 Modules Large format module ceilings normally in aluminium gridKerf edge 2 sides Cut edge 2 sides (K2C2)Tiles are 100% accessible
11 Concealed GridConcealed mounting systems are not visible from below the ceiling.Softer ceilings prone to damageBest suited to metal systems to reduce subcontractor damage.Can incorporate services such as chilled ceilings
13 Rigid sheet concealed Normally plasterboard or fibre cement sheets Sheets are fixed by screwing to metal furring channels which are supported by top cross rails and suspension componentsSpacings of all members to suit weights and suspension points
15 Surface Finishes A variety of finishes Typical Brands Armstrong Fine Fissured, Dune , etcEurocoustic Tonga/MinervalEurocoustic Ermes, Armstrong UltimaGibtone Gib ReadytileClimateline , FentaWater based paint finishTissue (white or coloured)Tissue and paintVinylPowdercoat or enamel
16 Fire performanceSurface finish required to verified by independant testISO5660 or ISO9705Group 1 to 4 depending on safe and protected paths , unsprinklered buildings , care facilities , public assembly
17 Ceilings and Acoustics Ceiling acoustics are measured in a number of ways:Absorption (NRC , αW )Reduction/ Transmission (CAC, DnCw)
18 Ceilings and Acoustics Three concerns with ceiling acoustics:Inter-storey or plenum noise breakoutRoom to room transmission via ceiling plenumWithin room reverberationPlenum noise breakoutRoom to room transmissionWithin room Reverberation
19 (within surface and structure) Absorption, Reflection & TransmissionRH99 Armstrong Fine FissuredTransmitted Sound1%59% Absorbed Sound(within surface and structure)Reflected Sound40%60% AbsorptionIncident Sound
23 Mineral Fibre TilesArmstrong RH99 and RH100 mineral fibre tiles have medium porosity, and relatively high density…Good sound absorption and…High sound reduction.Eurocoustic soft mineral fibre is very porous,relatively low in density, therefore have …High sound absorption but …Moderately low sound reduction.Dune Max hard mineral fibre
24 Metal & Wood Veneer Tiles Acoustic performance of metal , wood or plasterboard ceilings vary depending the perforation type, acoustic tissue and acoustic insulation abovePerforated tiles with acoustic tissue may have medium to very high sound absorption, and low sound reduction without insulation behind and high sound reduction depending on the infill.Lindner Metal Acoustic TilesBNZ Harbour Quays WellingtonBoral Echostop perforated plasterboard
25 Sound Absorption Coefficient s Absorption is frequency dependent631252505001000200040008000Frequency Hz0.20.40.60.81.01.2Sound Absorption Coefficient sPorous AbsorberCombined AbsorberPanel Absorber
26 Sound Absorption Coefficient s And the depth of void is important631252505001000200040008000Frequency Hz0.20.40.60.81.01.2Sound Absorption Coefficient sMineral Fibre on200mm cavityMineral Fibre onsolid backing
27 Predicting Acoustic performance By using measured properties of various materials we can predict the acoustic performance of a roomThe widely used method is the Sabine equation.Despite several assumptions that limit it’s accuracy, the Sabine Equation is widely used for its simplicity and as people cannot differentiate between fractions of seconds or tenths of decibels.It makes a link between the amount of absorption in and the volume of a room and the reverberation time.Reverberation Time (RT) can be predicted using various methods …T = 0.16 VAWhere… T = reverberation time in secondsV = volume of the room in m3and… A = total absorption within the room
28 Applying absorption results The Reverberation Time (RT) is the time in seconds for the reverberant sound in an enclosure to decay 60dB after the noise source is stopped…Decibel dBPeriod of reverberationMoment of abrupt stopMoment where the level arrives to a difference of 60 dBTimeBackground noiseEnd of the noise source.Average sound pressure level in the room60 dB below60 dBToTr
29 Affect of Absorbers A typical cellular office (50m3) … RT= 0.97 sec ConcreteRT= 0.97 secPlasterboardRT= 0.60 secWet Felt Mineral Fibre (RH99 Dune Max )RT= 0.44 secSoft Mineral Fibre (Eurocoustic Attrium)RT= 0.29 secNote: Different room sizes and finishes to those assumed for this example will result in different reverberation times.
30 A typical primary school classroom (100m3) … ConcreteRT= 1.20 secPlasterboardRT= 1.10 secWet Felt Mineral Fibre (RH99 Dune Max )RT= 0.52 secSoft Mineral Fibre (Eurocoustic Attrium )RT= 0.34 secNote: Different room sizes and finishes to those assumed for this example will result in different reverberation times.
31 RT Calculations for Schools • According to AS the ideal outcomemeasured as RT (Reverberation Time) isseconds.
32 Armstrong Seismic Design Guide – RX system • As a result of the Christchurch earthquakes much work has been done on seismic design.Four revisions in 2 years .
33 Armstrong Grid Seismic Design Guide • Simple calculation steps to determine bracing options and requirements