Image ‐ Maximum vertical viewing angle
15.2. Projection Surfaces
Projection should ideally be directly onto a flat wall. All new buildings should be constructed with a flat display wall suitable for projection. The wall should be clean and painted flat (matt) white and be uniformly flat and perpendicular to the projector and the audience.
For existing installation refurbishments where there is not a suitable wall for projection in the room, a motorised drop‐down projection screen is permitted.
Whiteboards are generally not suitable to use as a projection screen as the shiny surface causes unacceptable glare and hot‐spotting. Where whiteboard surfaces are used for projection (for example in an interactive whiteboard installation with an ultra‐short throw projector), the whiteboard needs to be non‐gloss type suitable for projection.
15.3. Lectern and Presenter Desks
The University has developed standard lectern designs, intended for use in all lecture theatres and classrooms. The lectern design is standardised in a spatial sense, however the outer skin can be modified to match the architectural design and aesthetic of individual spaces.
Liaise directly with LTU ICT/AV for the current standard lectern designs.
15.4. Room Acoustics
Room acoustics that support intelligible communication with all participants is of critical importance in all teaching spaces. Special consideration must be given to the design of teaching spaces with regards to acoustic performance. The choice of room size, shape, layout, construction, materials and finishes should be chosen carefully to provide spaces with the required acoustic performance for the intended use.
Ambient Sound Levels and Reverberation Times
The design sound levels and reverberation times for all rooms and spaces should be in accordance with the Noise Rating & RT60 defined in Australian Standard AS 2107.
Speech Intelligibility
Speech intelligibility as quantified by the Speech Intelligibility Index (STI) that measures in the
“excellent” range 0.75‐1.0 should be achieved at the listening position for all teaching spaces. In large lecture theatres or open teaching spaces an STI that measures in the “good” range 0.60‐0.75 is acceptable.
Mechanical Services and Air Conditioning
The level of ambient noise from air‐conditioning, ventilation and other mechanical equipment can pose significant challenges to acoustic performance. High capacity air handling systems should typically operate at low velocity to minimise noise. Air handling systems with Fan Coil Units (FCUs)
15.5. Room Lighting
Careful lighting design (selection, arrangement and control of light fittings) is critical for a successful presentation and teaching venue so that presentation materials can be easily read and the presenter clearly seen by the audience and the camera.
It is important that the lighting design addresses the following objectives:
Control of ambient light so that the image is not washed out
Provide task lighting for students
Illuminate the presenter and presentation areaLighting fittings should be selected that provide a high degree of direction control and avoid glare.
Lighting should be divided into zones so that front lights that spill directly onto the screen can be dimmed (or separately switched) to prevent the image from becoming washed out and difficult to read. Task lighting and spot lights should be used to properly illuminate the presenter and presentation area.
Generally a lighting control system should be provided for flexible and easy‐to‐use control of the room lighting from the presenter position. This often involves integration of the lighting control with the AV control system.
Actual lighting levels must meet the requirements of Australian Standards AS 1680 and the Building Code of Australia.
15.6. Motorised Blinds
For teaching spaces with projection systems, special consideration should be given to the control of natural ambient light by limiting the use of windows and glazing. Where windows and glazing is present, the use of curtains and blinds will be required for control of ambient and spilled light falling on the projection screen is essential in all spaces with projection so that the image will not be washed out or difficult to read.
For spaces with video conference systems complete control of ambient light is needed and black out blinds are recommended.
Control of the motorised blinds or curtains from the presenter position often involves integration of the blinds control with the AV control system.
15.7. Emergency Evacuation
Emergency evacuation systems may require the room sound system to be muted in the event of a building fire alarm. Advice should be sought from the Fire Engineer as to what is required of the sound system in relation to evacuation alarms/announcements.
16. EQUIPMENT RACKS 16.1. Equipment Racks
All audio visual equipment should be installed into purpose built, lockable and ventilated equipment racks.
16.2. Joinery
All audio visual equipment needs to be accessible for routine maintenance as well as repairs for equipment failure.
Where equipment racks are installed inside joinery, front and rear access doors should be provided to allow removal of the rack without disassembly. Where rear access cannot be provided, the rack should be installed with castor wheels to allow removal for service.
Adequate clearance must be provided inside joinery for equipment racks, access, audio visual cable looms, power and data distribution and ventilation. Provide minimum 150mm clear space behind the equipment racks inside joinery.
16.3. Ventilation
Where equipment racks are installed inside joinery, adequate cooling and ventilation must be provided to ensure that all equipment operates within the recommended operating temperature band.
For small equipment racks with minimum equipment natural convection is often adequate. To facilitate natural convection must be ventilated with provision to draw air in at the bottom and release air at the top.
For large equipment racks with critical equipment installed, a cooling system should be considered.
17. CABLING STANDARDS 17.1. Cabling and Connections
All cabling materials and workmanship shall comply with the relevant Australian Standards, the Building Code of Australia and any other governing authority forming part of the installation.
All audio visual cabling shall be segregated from all other cables by minimum 300mm to ensure there is no induced current flow on the audio visual cable.
All cabling should be installed in accordance with the manufacturers guidelines for segregation and minimum bend radius.
All cables should be cut to length.
Where cables cross they shall do so at an angle of 90 degrees.
All connections and cable terminations shall be covered by a connector hood or shall have crimp ferrules which securely grasp the cable outer jacket to provide protection to the connector and provide strain relief for the cable. All connectors shall have mechanical attaching connectors so that connections cannot fall off.
Cable runs should be continuous, and without joins, unless approved by LTU ICT/AV.
All use of twisted pair data cabling for network data or AV signal transmission must comply with the La Trobe University Cabling Standards. Provide test results and manufacturers certification and warranty for the installation.
All cabling shall be neatly laced, dressed and adequately supported. All exposed cabling shall be neatly bundled and dressed within black nylon woven mesh fabric.
17.2. Labelling
All connectors, patch leads, cabling, equipment and equipment racks shall be permanently typed labels (handwritten labels are not acceptable).