DESIGN OF SEMINAR HALL PROJECT DOCUMENT

Bhausaheb Vartak Polytechnic Year 2013-14 Page 1
A
Project Report
On
DESIGN OF SEMINAR HALL
Submitted as per Requirement of
Maharashtra state board of technical education
Towards partial fulfilment of
Sixth Semester in Diploma in Construction Technology
Submitted by
RUSHABH H SHAH
Under the guidance of
PROF. SALIL P. DESHPANDE
Department of CONSTRUCTION TECHNOLOGY
Vidyavardhini’s Bhausaheb Vartak Polytechnic, Vasai Road
Academic Year 2013-2014

Index
SR NO TOPIC PAGE NO
1 INTRODUCTION
1.1Objectives
1.2 Seminar hall: Seminar hall
1.3 Auditoriums
1.4 Entrances
3
2 LITERATURE REVIEW
2.1 Seminar hall rooms
2.2 The seminar hall interior
2.3 Seats
2.4 Projectionscreen(s)
2.5 Walls and ceiling
2.6 Doors
2.7 Electrical, telecommunications and audiovisual services
2.8 Fire prevention
8
3 ACOUSTICS
3.1 General
3.2 Velocity of sound
3.3 Frequency and intensity of sound
3.4 Timbre
3.5 Influence of environment
3.6 Defects due to reflectedsound
3.7 Factors affecting the acoustic design of the seminar hall
3.8 defects in a seminar hall and their remedies
51
4 CASE STUDY 76
5 CONCLUSION 87
6 FUTURE SCOPE 89
7 REFERENCES 91

LIST OF TABLES
TABLE 1 – SOUND VELOCITIES IN DIFFERENT MEDIUMS
TABLE 2- SOME TYPICAL SOUND LEVELS
TABLE 3- MATRIX TYPES OF SEATING IN DIFFERENT ROOMS
TABLE 4- TEACHING STATION
TABLE 5 – ROOM CAPACITY
LIST OF FIGURES
FIGURE 2.1 - INSTRUCTOR WORKSTATION
FIGURE 4.1 – SEMINAR HALL
4.2- MODIFIED SEMINAR HALL

DESIGN OFSEMINARHALL
1 INTRODUCTION
Seminar hall rooms are designed to facilitate interaction and face-to-face discussion
amongstudents and instructor in small classes, usually fewer than 20 students. These
rooms sometimesare used also as for departmental meetings or conferences.
Design guidelines for specific considerations such as doorway entrances, hallways,
acoustics, finishes, and air ventilation and circulation, etc. are similar to the measures
outlined in
This guidance for the design of learning environments was developed by a multi-
disciplinary team. The team included campus planners, architects, anaudio-visual
system expert, and a senior faculty member who have extensive experience inthe
design of many different kinds of rooms where learning takes place. The team
solicitedinputs from faculty, staff, and students in all of the departments of the college,
mechanical andelectrical engineers, and consultants involved with design of hundreds
of seminar hall.
Our primary reason for asking you to read this guidance is to convey the lessons
learned andhelp you avoid “reinventing the wheel” as design of future projects
proceeds. We areconfident this will expedite the design process and create better
learning environments.
Objectives
Our program to upgrade learning environments has the following objectives:
 Encourage interactive learning
 Provide comfortable seating with larger work surfaces
 Add multi-media audio-visual systems with good sight lines
 Provide a link to the Internet from every learning room
 Improve access for all persons
 Improve functional relationships
 Increase flexibility to respond to future needs
 Increase seminar hall use rates

Seminar hall: Collaborative/ Seminar halls with movable tables and chairs which
provide the instructor flexibility to arrangethe class in small discussion teams or meet
with the class as a whole.
Pedagogy and the Learning Environment
Technological advancement and accessibility of mediation at a lower cost, and
subsequent changes in pedagogy allplace demands on the physical space. There is still
a need for lecture type rooms where seat count can bemaximized by the nature of the
learning method (instructor in front with presentation area, rows of seats). Yet there is
also an increasing need for rooms that can accommodate a variety of teaching
methods, quickreconfiguration, and technology. These changes in teaching
preferences and technological advancements have notbeen reflected.
Recent programming exercises for new buildings and subsequent feedback on the use
of the current seminar hallshave rendered the following valuable information:
 Faculty demand for flexible space in seminar halls
 Faculty and student demand for collaborative work spaces
 Faculty and student demand for mediated seminar halls
 Ever increasing demand for special needs student furnishings.
The quest to prepare students for the corporate world with experimental skills and the
increase in graduatepopulation require older facilities to perform differently than
originally designed. The non‐castered tablet‐arm chairs once essential in seminar halls
design are no longer viewed as appropriate. The increased use of laptops creates
aneedfor larger flat work surface to accommodate the technology and books. The
changes in teaching methodsrequire team/collaborative work

1.2 Seminar hall: Seminar hall
Seminar hall rooms generally accommodate smaller numbers of students seated in any
number of seatingconfigurations.
 Seminar hall rooms contain 19 ‐ 25 seats.
 A face‐to‐face seating arrangement is possible.
 The instructor sometimes sits with students.
 25 ‐ 30 square feet per student accommodates this type of pedagogy.
Fig 1.3 seminar hall Fig 1.4 seminar hall
1.3 Auditoriums
 Auditoriums contain more than 150 seats
 Aisles may be sloped but all seating areas must be tiered
 Theatre‐style seating with attached tablets are allowed
 A curved configuration is optimum
 18 square feet per student overall, but at least 6.5 square feet per student in the
seating area, allows for ample circulation amongst the seats.
 The square feet per student ratio is proportionate to the space associated with
thepodium/front of room, and amount of circulation space required. If the
function of the roomrequires a large stage area or specific circulation pattern,
the overall square feet per studentmay be over guideline.

1.4 ENTRANCES
At-grade access should be provided to the front area of large lecture halls which have
slopedor tiered floors to accommodate equipment being moved into and out of the
room and toaccommodate people who use wheelchairs. In lecture halls where there is
a sloped or tiered floor, the floor must remain flat at least five feet from the entrance
into the room.
Primary entries for large lecture halls should be in the rear section of the room, with
doorsplaced in the side walls rather than the rear wall whenever possible. This reduces
the amount oflight reaching the projection screen when the doors are opened during
class. Another solution isto use light traps, two sets of doorways that trap light from
entering into the lecture hall when thedoors are opened.
There should be double doors at each entrance, with each door being a minimum of
three feetwide. If it is necessary to have a centre post between the doors, it should be
removable tofacilitate the passage of large pieces of equipment.
It is important that the doors swing open into the lobby area in a way that does not
obstructthe efficient flow of traffic to and from the lecture hall. When possible, doors
should be recessedinto the room.
The movement of students and the noise they generate should be a major
consideration indetermining the width of corridors and the location, number, and size
of entrance/exit doors incorridors, stairwells, and learning rooms. Building codes are
not the only criteria to consider.
Corridors should not be designed only for pedestrian circulation.Provide comfortable
placesfor students to sit while waiting for class, with lights above the seats and data
outlets nearbyfor laptop use. Alcoves along corridors that facilitate casual social
encounters, study, andprovide visual interest or space to wait for elevators are strongly
encouraged.

CH 2
LITERATURE REVIEW

2.1 Seats
The acoustical property of the seats should be essentially the same whether they are
vacant oroccupied.
2.1.1 Seating
Seating should be selected that will meet minimum comfort standards and still satisfy
the requirementsof Uniform Building/Fire Codes, cost, durability, functional comfort,
appearance/finish, and performanceover time. Chairs should be comfortable for use by
people ranging in size from the 5th percentile (4’‐11”tall, approximately 113 lbs) to
the 95th percentile male (6’‐2” tall, approximately 246 lbs).
Fig 2.1 fixed seating Fig 2.2 movable seating
DesignStandard
When selecting seating in order to achieve minimum standards of comfort, aspects
such aswidth of seat, type of lumbar support, appearance, versatility of seating,
replacementavailability/ease of maintenance and cost should be considered.
Seating Width
 Seat width comfort will range from 20 to 22 inches for loose seating such as
stackers, sled base chairs & chairs with casters (4‐leg or star‐base).
 Auditorium fixed seat width to be at 24 inches unless restrictedby row curve.

 The selection of seating width should be based upon the criteria set forth for the
type ofseating utilized.
Seating Back Support
 All seating shall have proper lumbar support.
 The back should have a slope ranging from 12 to 30 degrees for seminar hall
seating.
 The height of the back should not exceed 34 inch from the floor level.
2.1.2 Appearance
 The appearance shall be coordinated with the interior of the seminar hall and
meet theacoustical requirements for the space. Light colors are discouraged.
 Upholstered seating shall be used in large auditoriums or lecture halls only
wherereverberation of sound is a problem. All other rooms to have
non‐upholstered seating.
 The construction and materials should be selected so that their color and
surface areconsistent with the other furnishing within the seminar hall.
Replacement Availability/Ease of Maintenance/Warranty
 Chairs shall be procured from "name brand" manufacturers that demonstrate
proventrack records in the marketplace, and maintain stock levels that insure
replacement canbe made without timely backorder delays.
 Chairs shall be selected that facilitate cleaning of the floor surface, and
requireminimum maintenance of the seat covering (if applicable).
 Provide written warranty for all proposed furniture. ASU prefers 10 year or
longerwarranty on all furniture items.
 When casters are specified on seating, insure that the casters are the correct
type of thefloor finish (carpet, VCT, etc)

2.1.3 Quality
High quality seating shall be purchased to minimize the long term life cycle costs
since fundingfor equipment replacement, repair, and maintenance are becoming
increasingly difficult toobtain versatility
 Fixed seating shall be provided in all large lecture halls, and shall be
constructed of cast iron or steel frames. Auditorium seating shall have
retractable tablet arms.
 Non‐theatre lecture seating requires free‐standing, chairs with casters.
 In lecture rooms where programs will typically exceed 2 hours, padded seats
and backsshould be selected.
 Fixed auditorium seating may require electrical/data outlets, based on
programmingneeds.
2.1.4 Student Seating Area
Fixed Seating
There may be special circumstances when a small lecture hall, 75-100 students, would
best beserved by the use of movable seating, but in general it is recommended that
rooms seating morethan 75 have fixed seating. The seating plan should support the
anticipated function.
Continuous fixed tables with attached swing-away chairs are the preferred seating in
lecturehalls. This provides the student with the maximum work area and makes it easy
to provideelectrical and data connections at each seat. In addition, by removing the
swing-away seats inappropriate locations, easy access can be provided for wheelchair
users or for larger studentsusing straight chairs. It should be noted, however, that it is
necessary to allow more square feetper student station when installing this type of
furniture as compared to other types of fixedchairs. Other options include tables with
task chairs on casters and auditorium seating with tabletarms. In some cases, it may be
advisable to provide a mix of furniture types (I.e. fixed tables inthe front plus a back
row or two of tablet arm chairs). This allows for comfortable seating for themajority
of classes and enough extra seats for some larger groups.

When fixed chairs with tablet arms are used, the tablet arm should have a minimum of
150square inches of writing surface. The arm also should fold to facilitate passage of
studentsthrough the rows of seats. If fixed chairs are attached directly to the floor,
exposed bolt headsshould be covered.
Since the number of seats in each row and the relationship of this number to the aisles
are oftencovered by code requirements, these should be consulted in determining the
layout of a room. Toprotect the wall surfaces from damage, fixed seating should not
be located adjacent to walls, especially walls having acoustic panels.
It is recommended that all components of seating carry a minimum five year
manufacturer’s warranty. Further, the manufacturer should warrant the availability of
replacement parts for aminimum of ten years.
Seating for Left-Handed Persons
When installing fixed seating other than tables, a minimum of ten percent left-handed
tabletarms is needed. These left-handed seats should be installed on the left side of the
aisle whenviewed from the instructor area.
Seating for Persons withMobilityImpairments
Seating for mobility-impaired students should be provided in all lecture halls in
accordancewith federal and state accessibility codes relative to the capacity of the
room. Wheelchair stationsshould be available in a variety of locations within the
seating area. In addition, one percent andat least one of all the fixed seats should be
aisle seats with no armrests on the aisle side. To
36accommodate students in wheelchairs, a table 19 inches deep, 31 inches high (with
29 inchesclearance), and 36 inches wide is recommended. Provisions may be
necessary to accommodate companions who assist studentswith hearing, sight and
mobility impairments.

2.2. The Seminar hall Interiors
2.2.1 Design
Seminar halls should be developed and designed from the “inside out”. The following
items should beconsidered when creating a new seminar hall:
 The optimum orientation and shape of the seminar hall should be determined
by the primaryexpected teaching style, the capacity of the room, and the level
of mediation.
 Designing for the flexibility of room use is strongly encouraged. The more
square footageallotted to each student, the greater the opportunity for
flexibility.
 The total square footage of each room is to be based on the type of seminar
hall, the specificcapacity and the type of seating, as specified in Section 3,
Room Definitions.
 Seminar halls with a capacity of 49 or less are to be as square as possible to
allow for greaterflexibility in furniture arrangement, and better sight lines.
 Generally, seminar halls should be sized in a 2:3 or 3:4 widths to length ratio.
Long, narrow, “railcar”
 Style rooms are not acceptable.
 Lecture halls with capacities above 60 require tiered seating. A curved
configuration improvesvisibility and student/instructor connectivity.
 Every seat must have an unobstructed view of the teaching wall. No columns
or other visualobstructions are allowed in Arizona State Collegeseminar halls.
 Inseminar halls where the instructor’s workstation is movable, adequate space
must be provided to allow the workstation to be positioned at least 3 feet away
from the teaching wall. Inseminar halls with fixed tables and/or fixed seating,
the front edge of the instructor’s workstationmust be at least six feet from the
front row.

Fig 2.3-INTERIORS Fig 2.4 – SEMINAR HALL INTERIORS
2.2.2 DIMENSIONS
The room dimensions should be similar to those of general purpose seminar halls
butbecauseseminar hall rooms typically have tables and chairs, the total room area
should allow 20square feet per student station. Long narrow rooms limit eye contact
and reduce personalinteraction among participants in a class. Ceiling height should be
ten feet minimum.
The projection screen or chalkboard/markerboard defines the front of the room.
Ifachieving maximum capacity is an objective, a single entrance at the front of the
room will allowthe incorporation of the entry space into the instructor area. A single
rear entrance reducesinterruptions from late-arriving students but will require more
space.
Although many seminar hall rooms have the same installed technology as general
purposeseminar halls that may not always be the case. In rooms without installed
technology, the front ofthe room should be large enough to accommodate at least
basic AV equipment, such as acomputer and LCD projector. It is recommended that a
projector used in a seminar hall room mayneed to be equipped with a short focal
length lens to reduce the distance from the projector to thescreen. Faculty also should
be aware that placing the projector on the table where students sitmay create
distracting noise and heat.
As the size of the space increases, the complexity of design for that space
increasesgeometrically. It is not a linear process. Design mistakes that may go

unnoticed in a smallseminar hall room will be magnified many times in large lecture
halls to the point where the spacemay become dysfunctional.
To provide good sight lines and acoustics, a modified fan-shaped design is often best.
In thisconfiguration, student seating can be arranged to provide good viewing angles
from all seats.
Rooms that are wider will require a much deeper instructor area in order to maintain
goodviewing angles.
Larger rooms must be sloped or tiered to provide good sight lines. The slope of the
floorin a large room or lecture hall should be no more than 1:12
If there is a rise of four inches or less from one row to the next, then the seating ineach
row should be offset to permit clear visibility to the front of the room. The slope of the
floor32in a lecture hall should maximize sight lines. An accessible route within the
lecture hall and achoice of wheelchair seating locations are required (see Furnishings).
Some small lecture halls (under 100-student capacity) may have a sloped or tiered
floor whilesome may have a flat floor.
The aisles in a lecture hall should be arranged to provide the maximum prime
viewinglocations for the audience. Generally, this will mean no centre aisle. Building
codes must beconsulted to determine the number of seats in a continuous row and the
distance between rowsallowed in the jurisdiction.
There must be no posts or other obstructions anywhere inside a lecture hall that would
blockthe view of the teaching area from any seat.
Ceiling heights will vary, depending upon a variety of factors. The following
arerecommended optimum ceiling heights, based on the number of student stations
within the lecturehall and the appropriate projection viewing guidelines. These
guidelines include:
• The screenhaving an aspect ratio of 4:3
• The bottom of the screen being at the top of the chalkboard
• The distance from screen to farthest viewer being no more than 4 times the screen
width
• The distance from screen to first row of seats being no less than 1.5 - 2 times the
screen width

2.2.3 WINDOW AND WALL TREATMENTS
Fenestration should be kept to a minimum. All windows must be equipped with
windowcoverings (shades, drapes, venetian blinds) that are opaque and mounted to
prevent ambient lightleakage around the edges
To protect the wall surfaces, wainscot chair railing is often installed in seminar hall
rooms toprevent the backs of chairs from rubbing and scarring the walls.
WINDOWS
Daylight is an important part of most learning environments. Windows should be
included inseminar halls whenever possible. Lecture halls require excellent light
control. This can be accomplished by eliminatingwindows (except for the vision
panels in the doors) or by having shades that completely block thelight. If windows
must be preserved as an exterior architectural element, glass panes can bereplaced
with mirrors or other opaque material or the entire window opening can be covered
onthe inside with some type of decorative/acoustic panel.
Windows must comply with the “Glass and Glazing”.
 If easily accessible, window coverings can be manually operable; otherwise,
coverings must bemotorized with controls located at the instructor’s
workstation on the AV touch panel. Whereapplicable, the depth of the window
should be designed to allow for the installation ofmotorized shade tracks.
 Vertical blinds and drapes are not desired. If necessary, they are to have non
plastic, heavy dutyoperating components.
 Use of a light diffusing roller shade in conjunction with a room darkening
roller shade is requiredsuch as Draper Dual Roller Flex shade. Percentages of
light diffusion will be determined for eachwindow by evaluating the individual
window’s orientation and the intensity of the exposure.
 All window treatments are required to have a non reflective matte finish and
unless otherwisespecified, the color selection should match or blend with the
window frame.

2.2.4 FURNISHING AND EQUIPMENTS
Movable tables and chairs are the primary furnishings for seminar hall rooms. The
collegehas a standard table and chair for use in seminar hall rooms.A portable lectern
should be placed in the room.
Instructor Area
As the use of media in instruction increases, particularly in large group instruction, a
tableand lectern are no longer considered adequate furniture for the teaching station in
a large lecturehall. Media needs may dictate the installation of a teaching station or
podium at the front of the room that serves as the master control centre for the room.
Instructors in wheelchairs should beable to access any controls provided.
The teaching station should provide access to a variety of communication and
controlcapabilities, including electrical outlets; voice, video, and data outlets; controls
for the lights andthe projection screen(s); controls for the voice amplification system,
including a microphone; andcontrols for all equipment built into the room, projection
booth, or equipment closet.
The dimensions of the teaching station for a lecture hall should be large enough
toaccommodate all equipment and controls to be housed there as well as provide space
for layingout papers and notes. Ideally, the podium should be adjustable in height or
be a tabletop model.
The size and placement of the teaching station are critical. Neither the station nor the
faculty member standing behind it should block student’s view of the projection
screen(s) or the chalkboard/marker board. If an overhead projector is to be used, it
should be able to be positioned close to the teaching station and at a sufficient distance
from the screento provide an acceptable image size.
2.2.5 Chalkboards/Marker boards
Special attention should be given to the amount of space available at the instructor
area for chalkboard/marker board and for other visual presentations. The emphasis,
particularly in largelecture halls, is usually on the use of projection tools in the place
of the chalkboard/marker-boardin order to provide for maximum visibility to students

throughout the lecture hall. Despite theincreased use of projected media, a
chalkboard/marker board is still essential to effective use ofthe room and should be
permanently mounted in the lecture hall.
Seminar hall rooms typically provide a large amount of chalkboard or marker board
space.
The boards should be four feet high and mounted to the wall so the bottom edge is
three feetabove the finished floor. A two-inch tack strip with movable mounting/map
hooks should beabove the writing surface. Tack boards are not standard and should be
placed in the room only if required by the users.
If the teaching station is to contain equipment that is permanently housed in the room,
then it should be constructed of materials and using methods that provide the
maximum security for theequipment housed within it.
The chair or stool for the instructor should be of adjustable height in order to make
itconvenient for the instructor to use all types of teaching devices.
A telephone or voice communications device, connected to the service unit on
campusassigned to provide emergency support to the seminar halls, should be located
either in the podiumor in the immediate vicinity of the teaching station.
Tables/Work Surfaces
Typical work surfaces found in most teaching seminar halls are inadequate for today's
college student.
The tablet‐arm chairs used do not allow students to take notes while referencing
textbooks or othersmaterials. Also, without specially configured chairs, a left‐handed
student must contort themselves to utilize the tablet. Therefore, a much larger surface
area must be provided to comfortably accommodate basic needs of left or
right‐handed students.

Design Standard
 Tables can be for 1, 2, or 3 students allowing a minimum of 30” per student.
The number of students per table is flexible and is determined by the type of
seminar hall and theconfiguration of the seminar hall.
 To allow for note taking and reference materials the minimum work surface
area shouldbe 3.75 square feet per occupant.
 Depths of table vary from 18”‐24” based on room layout.
 Modesty panels are allowed.
 Fixed tables with cantilevered pivot arm seats are not allowed. If fixed tables
are installed, provide loose seating with casters.
 Furniture must be able to interface with technology (i.e. pathway for
power/data)
 Tablet arms should be considered only related with theatre seating.
‐ Provided tablet size should be equal to or larger than 12 inch x 15 inch (1.25
squarefeet).
‐ 10% ‐ 15% of the tablet work surfaces should have a left‐handed orientation.
Matrix of types of seating in seminar halls
Tiered Fixed seat Fixed
table
Moveable
seat
Moveable
table
Tablet
Seminar N/A N/A N/A X X N/A
Classroom O N/A O X X N/A
Lecture X N/A X X N/A N/A
Auditorium X X N/A N/A N/A O
X preferred O Accepted N/A Not Accepted
TABLE 3- MATRIX TYPES OF SEATING IN SEMINAR ROOMS
Construction/Fabrication
 Laminated work surfaces shall be constructed of high‐pressure plastic laminate
applied tosolid wood or hardwood plywood. Tops shall have a non‐glare.
Medium tone surface toreduce eye strain.
 The legs of fixed tables should not block the student’s knee space within the
30‐inch workspace allotment. Table legs should not impede configurations that
allow additionalstudents to work collaboratively.

 Table edge to be a heavy‐duty extremely durable material. Edge banding can
be T‐moldor glued into place as long as the application is sufficient to prevent
removal by a knife orother sharp object a student may have.
 Tables to withstand loading of 300 lbs of superimposed load (people sitting on
table) perlinear foot.
2.2.6 Furnishings Types and Layouts
Successful learning rooms require careful study of:
 The type, size, and location of furnishings planned for each type of room
 Aisle widths and seat spacing
 Flexibility to accommodate people of different sizes and needs
 How computers and audio-visual components will be accommodated
The type, size, and arrangement of furnishings determines how large each learning
room mustbe to accommodate the number of students programmed and where
different types of lights,diffusers, and power/data outlets need to be located.
Furnishings layouts drawn to scale must therefore be included beginning with the
earliestschematicdesign submission
They will be carefully reviewed. Architects will adjustroom floor areas after
furnishings layouts are developed to insure seating capacities:
 Meet programmed capacities in rooms with 48 seats or less
 Are within 10% of programmed capacities in rooms with more than 48 seats
This iterative approach contrasts sharply with the design process used by some
architects andinterior designers, who design rooms to meet estimated space targets in
the program, and thenadjust seating capacities to fit.
Designs where seating capacities are reduced because rooms are too small, have
inefficientshapes, have obstructions or narrow aisles, have work surfaces that are too
small, or haveseats spaced too close together for comfort will not be accepted.
Seminar halls seating more than 48 students and auditoriums with 200-399 seats shall
bedesigned with continuous fixed work surfaces, tiered floors, and upholstered

movablechairs with adjustable-height seats and backs. Comfortable auditorium-style
seats withtablet-arms can be used in larger auditoriums to reduce room depth and
costs
The following seating types do not meet this guidance and should not be considered:
 Movable chairs with tablet-arms
 Pivot-arm seats without adjustable-height seats and backs
 Pivot-arm seats that do not comfortably accommodate large/small students
 Pedestal seats bolted to the floor
 Movable student desks with seats attached
 Custom-designs that cannot be used by all students, such as:
 Oversize tables and chairs
 Adjustable-height tables
Large auditoriums with tablet-arm seats:
 Seats spaced minimum 24 inches on centre
 Minimum 21 inches clearance between tablet-arm supports
 Minimum 12 inches clearance between tablet-arms in use and seat backs (with
seatsfully reclined).
MULTIPLE USE CONSIDERATIONS
General purpose seminar hall rooms that also will be used as meeting or conference
roomsmay need to have built-in counter space, with lockable
2.3. PROJECTION SCREEN(S)
Because many seminar hall rooms are rather small, they may have a single screen. If
usersneed a second screen and space permits, it is always preferable to mount two
screens. Thescreen(s) should be matte white and mounted so that board space is
available when one screen isdown.
These should be mounted above thechalkboard if the design of the lecture hall
permits, with the bottom of the screens being levelwith the top of the chalkboard. The

exact mounting height must take into account a variety of factors (ceiling height, how
steeply the seats are tiered, etc.) to insure appropriate viewing angles.
Fig 2.5 Folding Screen Fig 2.6 Fixed screen
 The number of screens required is based on the seating capacity, the
configuration ofthe room, and the primary instruction style.
 Where possible, angling the screen in the corner of the seminar hall toboth
maximize the viewing angle to the audience and increase free whiteboard
writingspace. Angle‐mounting the screen must typically addressed in building
planning stages since it usually requires detailing reflected ceiling plan to
address ceiling grid andlighting. If angle‐mounting the screen is unfeasible,
screen placement should stillremain opposite from the teaching station area on
the teaching wall to maintainwhiteboard surface ceiling height is also critical
whenplanning the layout of a Seminar hall.
 The higher the ceiling, the larger the screen and image size it can
accommodate.
Screens should drop no lower than 48 inches from the floor.
Overhead (Transparency) Projectors and Carts
Show the location of overhead projectors in all rooms. Projector lens shall be located:

 Minimum 6 feet from the screen (seminar hall rooms/seminar halls seating 21-
48-students)
 Minimum 10 feet from the screen (larger seminar halls and auditoriums)
 Provide a power outlet nearby (in the floor, on a riser, or in a built-in work
surface). Ifprojectors will be located on seminar hall tables, provide a floor
power outlet under the table.
 In seminar halls and auditoriums, provide overhead projector carts that have:
 Work surface height about 34 inches above the floor
 Space for transparencies on both sides of the projector’s glass surface
 A recess so the glass surface is at the same height as the work surface
 Nominal dimensions: 18 inches deep, 36 inches width
2.3.1 ProjectionBooth
Many larger lecture halls have a projection booth constructed in the rear of the room.
At thistime, slide projection is still used in seminar halls, and a projection booth
provides sound separationbetween noise of the machine and the audience. In addition,
projection booths may serve otherneeds.
For example, projectors with long-throw lenses may be installed there or in
roomsequipped for distance learning, the booth is often used as a control room for
operating therecording system.
The dimensions of the projection booth are critical and to a great extent will dictate
the size.
The booth and its projection window must be wide enough that projectors can be lined
upperpendicular to the centre line of all screens and it must be deep enough for easy
passage ofpeople and carts behind the projection shelf where the projectors sit. In
addition, allowance mustbe made for door swings. That means that for projection
booths that are used to house distancelearning consoles and other functions, the space
required may exceed 200 sq. ft. while a booththat houses only a couple of slide
projectors, may be smaller.

The wall between the projection booth and the lecture hall should have a window
whoselower edge is a minimum of 48 inches above the floor, so that images will be
projected above theheads of those seated in the last row of seats next to the window.
This window should be angledapproximately five percent off vertical to reduce
reflections, with the bottom being the extendedsection.
A shelf should be mounted directly beneath the window and should be just below the
bottomedge of the glass. The shelf should be hinged so that it can be folded down and
should be dividedinto two sections so that each section can be folded independently of
the other. Severalconveniently located electrical outlets are needed near the shelf.
The projection booth should have a speaker to monitor the house audio and
voiceamplificationsystems. The booth should contain a work light designed so as not
to shine into thelecture hall. The booth also may include controls for audio, lights,
screens, and other built-inprojection equipment.
The booth should have adequate ventilation, including temperature and humidity
control. Theexhaust system should not have a direct connection to the lecture hall.
Security is a major concern, given the amount of equipment installed in some
projectionbooths. All doors should have locks and consideration should be given to
additional measures, such as alarm systems or lockable storage cabinets.
The booth should have two doors. A door from the hallway is needed to move
equipment inland out of the booth or to allow technicians to enter without disrupting
the class. The doorshould be a minimum of 36 inches wide with no obstruction on the
floor. A door from the lecturehall into the booth is needed so the instructor or teaching
assistant can enter the booth directlyfrom the lecture hall.
2.3.2 AUDIOVISUAL EQUIPMENT AND CONTROLS
Audio-visual systems in learning environments shall be designed for the most
commonly usedconventional and electronic media, to include marker boards, display
boards, transparencies,slides, videotapes, DVDs, compact disks, document cameras,
and computer-generated media.

Some rooms shall also be designed to project cable or satellite television images.
Thefollowing sections provide applicable guidance for each of these media.
Often, portable audiovisual equipment is used in seminar hall rooms so that it can be
shared among several locations. The use of technology in instruction has increased,
however, to thepoint that it is desirable to install equipment similar to what is done in
other general purposeseminar halls. Typically, some type of locking rack/storage
cabinet/projection station is provided tosecurely house equipment.
Seminar hall Storage
There is often a need for a small storage room for seminar hall supplies that is separate
from theaudio/visual storage. It should be approximately 100 square feet to store
board supplies, movablelecterns and additional chairs. This space requires lighting, a
lockable door, conditioned air, power, anda few shelving units for small supplies. It
should have no window and needs to be equipped with astoreroom function lock.
Seminar hall storage should be accessible from outside the seminar hall.
Voice amplification should be installed in all lecture halls. Where technically feasible,
awireless microphone should be installed with the voice amplification system to allow
theinstructor the maximum flexibility of movement throughout the lecture hall.
A stereo sound system separate from the voice amplification system should be
installed tohandle other sound sources. The system should be capable of amplifying
the soundtrack ofvideotapes, films, audiotapes, compact discs, videotape, DVD’s, etc.
Distribution from thesystem can be fed into speakers properly mounted on either side
of the instructor area.
If the instructor’s teaching station or podium is movable, then floor box connections
shouldbe provided at the right, left, and centre of the instructor area. The boxes and
conduits should besized to accommodate all the necessary cabling (including spare
capacity and pull wires).

Although the specific location of conduits or cable trays will vary depending on the
design ofthe lecture hall, in general, connections are needed: 1) from the instructor
area to the projectionbooth and AV equipment closet, and 2) from the AV equipment
closet to the video projector(s), speakers, screens, projection booth, camera locations,
mic locations, wireless mic antenna, assistive listening transmitter, instructor area, and
lighting control system. Any conduit or cabletray that is installed should have spare
capacity and contain pull wires.
For video recording or distance learning capabilities, consideration must be given to
cameraplacements, monitor locations, microphones for student-instructor interaction,
etc.
2.3.3 Ceiling-MountedProjectors
All learning rooms shall have ceiling-mounted projectors, regardless of room size. To
keeppace with current technology, audio-visual consultants shall specify projectors
that meetcurrent criteria established by UC audio-visual technology specialists
responsible for eachcampus: Central Campus West and the College of Applied
Science, Central Campus East, Raymond Walters College and Clermont College.
Consider projector performance and costin relation to room size. Performance goals
include:
 Low noise level
 Uniformly bright, clear images with good resolution and excellent color
rendition
 Compatibility with other audio-visual components
 Reliability; availability and cost of replacement parts
 Compact size to avoid blocking views of screens and marker boards

Fig 2.7 projector details Fig 2.8 projector
Slide Projectors
Provide slide-viewing capability in all seminar halls with more than 49 seats and in
smallerrooms where conventional slides remain an important teaching resource.
Conventional slide projectors will be used in seminar hall rooms and seminar halls
with movablefurnishings. Refer to page 37 for guidance on carts and enclosures.
Projectors shall have:
 Low-noise fans
 Ability to accommodate carousel slide trays
 Automatic focusing and a wireless remote control system
 A lens with focal length appropriate for the screen size and room depth
 Ability to illuminate the image with a minimum brightness level of 45 foot-
candles
 A simple way to adjust image height and remove jammed slides
 A storage compartment for a spare bulb and an easy way to change them
 In rooms with three projection screens (75 seats or more), provide dual-screen
slide projectioncapability via ceiling-mounted data projectors using real-time
electronic slide to XGA (orbetter) converters that use standard carousel slide
trays. Install them in the instructorworkstation for convenient access. Control
them via the audio-visual “smart” control system.

 A tamper loop that sounds an alarm if a ceiling projector is removed from its
brackets
 Low-voltage wiring that connects the workstation alarms to the
communications room
 Radio transmitters in the communications room linked to the campus security
system
 A keypad inside the workstation to disarm the system for maintenance
2.3.4 Equipment Closets
Increasingly, users find it more convenient to have equipment at the front of the
lecture hallwhere it is more convenient to the instructor. AV equipment closets often
house equipment inracks as well as carts for equipment that isn’t permanently
installed in the room but is used on aregular basis.
Adequate and secure storage for all types of instructional equipment must be provided
insidethe lecture hall. In most cases, this means at least one AV equipment closet at
the front of theseminar hall and in some cases, a projection booth at the rear.
Equipment not needed on a regularbasis may be stored in a nearby secure equipment
room. This storage should be accessible fromthe hallway and not require entering
another seminar hall for accessibility.
2.3.5 Security for Audio-Visual System Components
Provide a security alarm system on the instructor workstation to prevent theft of
audio-visual system components. The typical system includes Locks and alarms for
components located on the instructor workstation
2.4 ELECTRICAL, TELECOMMUNICATION, & AUDIOVISUAL SERVICES
Seminar hall rooms are similar to small general purpose seminar halls and should have
at least asingle duplex outlet in each side wall of the room, one fourplex outlet in the
centre of the rearwall of the room, and three outlets in the front of the room (one
fourplex outlet located in thecentre of the front wall and one duplex outlet near each

corner). A duplex outlet, data jack, andcable TV jack are needed adjacent to every AV
rack. In addition to the basic requirements outlined in the section on Electrical and
Telecommunications Services, lecture halls often have additional needs.
Fig 2.9 Telecommunication Fig 2.10Telecommunication
2.4.1 Electrical
The front of the lecture hall should be equipped with a minimum of four duplex
outletsdistributed evenly across the instructor area. Depending on the design of the
room, floor boxes(located right, centre, and left) with at least 1 duplex outlet may be
needed. If the room has abuilt-in instructor station, it should contain a quadruple
outlet.
Duplex outlets should be located every 6-8’ on each of the other walls. If the fixed
furniturewill be wired for power and/or data, appropriate service connections to the
furniture shall beprovided.
In the projection booth, at least two fourplex outlets should be mounted near the shelf
whereequipment will be projecting into the room. In addition, two duplex outlets
should be located onthe wall opposite the projection window.
2.4.2 Wall Outlets
 Place outlets on walls of the seminar halls at 6’ intervals or as necessary to
allow for 30%student utilization.
 Wall outlet intervals in the lecture halls are not as critical. Follow code to
determine theappropriate number.
 Install one phone jack, one data port, and one electrical outlet adjacent to
theinstructor’s workstation (Figure 1).

 Install one 2‐gang AV wall box (min 2 ½” D) at least 18 inches above the
finished floor.
Install two 1 ¼” conduit stub outs above the ceiling (if the existing wall is hollow,
conduit may not be necessary).
. Ceiling Outlets
 Install one AC power quad outlet attached by flexible conduit to a J‐box
located abovethe suspended ceiling to allow for the future installation of a data
projector. This quadshould be sited 12’15’ from the screen.
 Install one single gang data outlet above the ceiling 12’15’ from the screen.
 Provide 120V power capped at a J box located above the suspended ceiling to
allow forthe future installation of a low voltage motorized screen controller.
 Floor Outlets
 Provide floor outlets for every seminar hall to ensure optimum flexibility.
 Floor boxes are to accommodate AV, AC power, data.
 The number of floor outlets is determined by the size of the room, the capacity,
and thefunction.
2.4.3Telecommunications
If the design of the room includes floor boxes in the instructor area, each floor box
shouldcontain a data outlet.
Provide an analogue wall-mounted telephone near the instructor workstation in all
learningrooms. Phones are used to obtain technical support and enhance security.
Insure phone cordis long enough to reach all areas of the instructor workstation.
Contact UCit for specifications.
Project Administrators shall make arrangements to activate phone and data service.
2.4.4LIGHTING SYSTEMS
Lighting in large lecture halls is a particularly critical element, not only because of
theincrease in the use of technology in teaching, but also because of the lack of natural

lighttypically available in these facilities. See the Lighting section in Chapter 2 for a
discussion ofbasic lighting requirements.
Because lecture halls often have high ceilings, the design of the ceiling lighting
shouldrecognize the need to regularly change lamps. Lamp-changing is often difficult
in a facilitywhich may be heavily used and which may require special equipment to
reach the high ceilings.
Lighting and electrical power systems shall:
 Be energy-efficient
 Be easy to maintain and modify
 Provide appropriate lighting levels for all room activities that are easy to
control
Consider using low-voltage (analogue and digital) and RF control systems for lighting
andscreens or window shades operated by electric motors. Rationale: Low voltage and
RFcontrols are generally easier to interface to “Smart” control systems used for audio-
visualsystems and energy management. This is especially true when the “Smart”
controls are notinstalled originally and are added later.
Most lighting and electrical power systems lack flexibility and can only be modified at
highcost. Systems with conventional outlets, conduit, and hard-wired connections are
simply notas easy to modify as systems with accessible raceways and quick-
disconnect wiring.
Provide natural lighting and window coverings as follows:
 Natural light is available (not excessive) in all learning rooms except distance
learning
 Locate windows away from projected images; avoid skylights and clerestory
windows
 Window coverings that reduce light intensity and glare when full darkening is
not required
 Opaque window coverings that reduce light levels to 2 foot-candles
 Window coverings that are easy to open and close and do not jam:
 Provide electrically-operated shades when budgets permit
 Provide manually-operated shades in rooms with only one or two windows

 Avoid use of mini-blinds
Rationale: Instructors and students have consistently expressed a strong preference
forwindows to be included in all learning rooms. Mini-blinds are difficult to clean
andmaintain, frequently jam, and allow too much light into rooms.
Avoid light that creates glare or reflections on computer screens:
 Use indirect natural and artificial lighting in computer instruction and study
labs
 Use indirect or parabolic fluorescent lights in other learning rooms
 Avoid placing lights behind instructor workstations
Increase energy efficiency and the ability to see projected images by using:
 Lighting controls that automatically turn off lights in vacant rooms
 Energy-efficient dimmable lighting for seating areas
 Light fixtures that don’t block views of:
 Screens, marker boards, or instructors
 Light paths from projectors
 Lighting zones and levels appropriate for each area of the room (see diagram):
 70 foot-candles over seating areas only, dimmable to 5 to 10 foot-candles
 In rooms were very dark images such as x-rays are projected, provide
lightingdimmable to 2 foot-candles and full blackout capability
 Avoid lights in front of projection screens
 Lower light levels in corridors and instructor areas, and on ramps and tiered
floors
 Task light for instructor work stations that avoid light spill over to
screens/monitors
 Lights focused on markerboards that do not wash out screen images
 Safety lights that remain on when other lights are off, but do not illuminate
screens

Provide lighting and audio-visual system controls that are easy to use:
 Pre-set light levels on the audio-visual control system menu
 Wall-mounted switch for seating area lights near each entrance door
 Wall switches in one area near the instructor workstation, mounted 48” above
the floor:
 Dimmer switches that allow lights to be turned fully on, dimmed, or off.
 On-off switches for marker board lights
 Up-off-down switches for projection screens and electrically-operated shades
 Switches shall not have to be held in the up or down position to make screens
orshades move, and can stop them at any point.
 Brushed stainless steel faceplates with engraved black letters that identify
functions.
 Arrange switches as illustrated in the diagram on the next page.
 The wall-mounted switch set and audio-visual “smart” control system must be
coordinatedduring design so that they remain operable at all times. Leaving
either one in any positionor condition must not prevent the other from
functioning normally and fully.
Avoid wall-mounted signs or faceplates that vary in color, style, size, and mounting
height.
Rationale: Some instructors find pre-set light levels on the audio-visual system
remotecontroller easy to use. Other instructors prefer simple switches and dimmer
controls mountedon the wall. Complex wall switches with pre-set levels and too many
choices are hard foranyone to understand, especially if switch functions are not clearly
identified.
2.4.5 Lighting Zones
As a rule, all seminar hall spaces will have lighting organized into a number of zones.
These zones can becombined and dimmed to create any number of different lighting
scenarios. Seminar hall lighting should include day lighting, multi modal lighting,
controllability, and optimize energy performance. A room canbe zoned based on the

amount of day lighting available, with each fixture responding to the amount oflight at
any time and location.
The zones described below are functional zones. There are five functional lighting
zones in mostseminar halls:
Zone 1 – Main seminar hall lighting (student seating area) this zone services students
and allows them toread and take notes in class. Use multi directional recessed (lay in)
fixtures that cast a modestamount of light downward (35%) and a larger amount of
light toward the ceiling (65%), provides a comfortable overall lighting with relatively
high efficiency. Avoid pendant mountfixtures.
Zone 2 – Instruction area (front of seminar hall and lectern area). Design whiteboard
and demonstrationtable lighting to provide visibility when the room lights are at full
intensity. The foot candles isthis area should be consistent with the overall lighting of
the room.
Zone 3 – Non projection white board (board that is not obscured by a lowered
projection screen).
Lighting of white boards during concurrent AV presentations allows instructor to
write on theboard while in projection, without light bleeding over onto the projected
image.
Zone 4 – Projection white board (board that is obscured by a lowered projection
screen) Use the samerequirements as Zone 3 during non projection mode.
Zone 5 – Instructor workstation. The instructor should be able to read notes and use
board AV equipment with low light conditions of projectionmode
Emergency Lights
Isolate emergency light radiation away from the projectionscreen.
Color Temperature
The color temperature for all light fixtures should be the same. The color temperature
goal is3200 degree Kelvin.Color temperature range of 3000‐3500 degree Kelvin is
acceptable as longas all of the fixtures are the same.
Motion Sensors:

Motion sensors are preferred in all rooms. When installing motion sensors, be sure to
set timerto maximum to avoid light shut off during low‐motion activities such as test
taking.
2.5 Walls and Ceiling
Walls should be constructed of a durable material that is easy to maintain and should
bebasically acoustically non-absorbent except in those areas of the lecture halls where
acousticaltreatment is prescribed. The ceiling in a large lecture hall is an important
factor in the overallroom acoustics. For more details, see the Acoustics sectionbelow.
The ceiling should be a neutral factor in the lighting scheme of the room, projecting a
lightcolor from nonreflective material.
It is recommended that both the floor treatment and the wall treatment be in light
colors withtextures and designs used to add visual interest to the room.
Fig 2.11 ceiling of seminar hall Fig 2.12 walls of seminar hall
For acoustical value, walls in the lecture hall should be non-parallel, and should have
a roughor textured surface. Side walls should be angled away from the instructor area
in a fan-shapedpattern to focus sound toward the audience and the back of the room.
The rear wall surface should not be parallel to the front wall and should be tilted,
textured, or faceted to prevent "slapback"noise that bounces directly toward the
instructor. All walls should have a Sound
Transmission Coefficient (STC) rating of no less than 50, and should extend to the
floor above orto the roof construction. Most rooms have suspended ceilings which
hide mechanical systems,cabling, etc. so walls that stop at the ceiling may allow sound
to travel from room to room as wellas create security problems.

The front wall that contains the teaching station should utilize hard surface materials.
Sounddampeningmaterials should be applied to the rear and side walls as needed. In
many instances,the back wall may need to be 50-100% covered with acoustical
absorption materials.
2.5.1 Ceiling
The ceiling is the most critical element in insuring that the sound in the lecture hall
isdistributed evenly and at appropriate loudness to all portions of the seating area. The
ceilingshould act as a sound mirror, reflecting sound downward to blend with the
sound from thespeaker system. To achieve this ceiling should be sloped or stepped
and the majority of theceiling should be primarily of a hard surface. If the ceiling has
too much sound absorbentmaterial, the loudness will diminish at the back of the room.
If some acoustical treatment is needed as part of the ceiling, it should be installed
around thesides and rear in a horse-shoe shape, with the front and middle sections of
hard-surfaced, sound39reluctant materials. If needed, acoustical treatment normally
will not exceed 40-50 percent ofthe total ceiling surface.
To enhance the instructor's voice projection, the ceiling should be hard surfaced
nearest theinstructor, and tilted at an angle from the ceiling to the front wall, similar to
the ceiling of anorchestra shell.
Seats in some lecture hall may not be able to receive sounds that are reflected from
theceiling, which is often the case for seats beneath a balcony. In these situations, the
soundreinforcement system should include speakers with appropriate sound delay to
eliminate the echoeffect often experienced in these seats.
2.5.2 OPTIMUM CEILING HEIGHTS
Distance to Last Row Rear of the Lecture Hall Front of the Lecture Hall
50 feet 10 feet 17 feet
For acoustical purposes, walls in lecture halls should not be parallel and should have a
roughor textured surface.

 Internalseminar hall walls shall run deck‐to‐deck, with a Sound Transmission
Coefficient (STC) rating of 50 minimum.
 Folding or moveable walls must meet the STC rating of 50 and should be
specified forunique use only.
 Walls in lecture halls should be designed to provide the optimum acoustical
environment.
(See Acoustical Section 9)
 Walls to be painted in an eggshell finish. No wall coverings should be used. No
VOC paintshould be used to improve Indoor Air Quality (IAQ).
. Wall Protection
 Apply chair rail on the rear and side walls of CollegeSeminar halls that are non
masonrycontaining movable student furniture.
 Chair rail material should be wide enough to work with tables and chairs of
varying proportions and must be mounted at a height that will prevent damage
to wall surfaces.
Typically, the chair rail will be 6” – 10” wide and the bottom edge will start
approximately twenty five inches above the finished floor. Approved rails include
Inpro Corp #1800Silhouette 8” wall guard or approved equal. Rails shall match the
design of the room.
 Outside wall corners (such as entry recesses) shall receive corner guards 4’0”
A.F.F.applied so that students cannot work them loose.
Ceilings
 To accommodate seminar hall lighting and technology requirements, the
ceiling height of allseminar halls should be no less than twelve feet above the
finished floor.
 In large sloped or tiered seminar halls, the ceiling height is directly related to
the distancefrom the front of the room to the last row of seats. Ceilings
inlecture halls should be at least 9 feet high at the rear, and the ceiling height at
the front of the room mustaccommodate the appropriate screen size.

 The surface of the ceiling must be designed to accommodate the required
acousticalproperties of the room. Ceiling panels shall have a Noise Reducing
Coefficient (NRC) between .65 and .85, and a STC of 50.
 The ceiling should act as a sound mirror, reflecting sound downward to blend
with directsound.
 Ceiling material to be non sagging (humidity resistant) lay‐in acoustical tile for
most ceilingareas. Nominal size 24” x 24” or 24” x 48”.
 Access for the maintenance of technology, power, etc. must be included where
applicable.
 A high fired, ceramic covered steel, dry marker writing surface shall be
provided in eachseminar hall.
 Fixed height whiteboards should be mounted with the bottom edge at 36 inches
abovethe floor.
 Each whiteboard should have a continuous marker tray below each marker
board. Do notmount marker holder to wall due to marker bleed ruining wall
finish.
 At the top of the whiteboard, a tack board strip and clips for display materials
arerequired.
 The whiteboard should have an attached flag holder to accommodate a 2’ x 3’
flag.
 Multiple boards may be required depending on programming.
 Boards should be located on at least two different walls. A board must always
be installedon the front teaching wall; the other wall/walls should be selected as
appropriate to thelayout of the room.

2.5.3 Floor
The amount of tile and/or carpet used will have an impact on the acoustics of the room
andshould be given careful consideration during the design phase of the project.
Generally, carpet isused in the front, rear, and aisles of lecture halls and tile under the
seating area.
Resilient, nonskid vinyl or rubber tile is a good choice of floor covering for lecture
halls. Ifcarpeting is used, it should be installed only in the aisles, entry, and instructor
area, not in thestudent seating area. In lecture halls where science demonstrations
occur, tile should be used inthe instructor area. Because it is difficult to prohibit
students and faculty from bringing food anddrink into seminar halls, only industrial
grade, stain resistant carpet should be installed since it iseasier to maintain and clean.
If carpet is used, its effect on the acoustics of the room should beconsidered.
2.5.4 Flooring
 Specify an antistatic, high traffic, commercial grade carpet tile. No solid or
light colors arepermitted.
 All carpet must conform to the ASU Purchasing Department’s “green”
guidelines. Carpet shallhave a high recycled content. All demolished carpet to
be recycled when renovations occur.
 Contact ASU Recycling Program Manager for additional information.
 A four inch or six inch cove base must be included when carpet is specified.
 If carpet cannot be installed underneath fixed seating, all aisles and other open
areas must becarpeted.
 All aisle risers must be of contrasting color to the remaining floor to highlight
level change.
 Aisle risers’ nosings to be metal only. Vinyl and rubber nosings are not
permitted as they do nothold up in high traffic areas such as CollegeSeminar
halls.

2.6 .Doors
 Doors should be located at the back of the seminar hall to ensure that students
who areentering or exiting the space will not disrupt instruction. Exceptions
include large tieredseminar halls or auditoriums, since those kinds of spaces
can require multiple doors. Inrooms that require two or more egress points, the
doors should be located as far from thepresentation area as possible while still
meeting current building codes.
 Each door leaf to be a minimum of 36” wide, including those used in pairs at
double doors.
 No strike mullion on double doors.
 Door opening force, hardware, width, thresholds and man euvering clearances
should comply with ADA Standards.
 Occupancy within the seminar hall should be clearly (but discretely) visible
from the hallway.
Any viewing device must be positioned to meet ADA standards. Door shall be
equippedwith a vision panel made of shatterproof glass and tinted to reduce light
transmission.
The area of the glass shall not exceed 100 square inches and should be doublepaned
withacoustically rated seals. Doors without vision panels shall have either a viewer
peep holeinstalled to provide a view into the room to check activity or have a separate
sidelight.
2.6.1 Door/Room Security
Door Hardware
All seminar hall doors shall conform to Design Guidelines.
Additionally seminar hall doors should have the following:
 Concave wall bumpers installed at an appropriate height to assure wall
protection.
 Door silencers to muffle the noise of the door closing.
 Card readers

 ADA accessible doors and hardware as specified in design standards
2.6.2 Instructor Seminar hall Furniture Accessories
Teaching seminar halls should be equipped with proper lecterns, podiums, and tables.
In providing thisequipment, attempts should be made to maintain aesthetic and
functional compatibility with the overalldecor of the room.
Design Standard
 Small and medium sized rooms with less than 40 seats with seminar hall tables.
Provide atable top lecternwhich can be easily placed on the seminar hall table.
 Small and medium sized rooms with less than 100 seats. Provide a table
withdetachable lectern and a stool to be placed at the front of the room.
 Large rooms with more than 100 seats. Provide an instructor’s podium and
availabilityof a seminar hall table with lecternand stool.
Teaching Station (lecterns)
Seminar Classroom Lecture Auditorium
P P or F P or F F
P Portable table type F Floor type
Room Table top Table with
lectern
Podium Stage
Seminar X O
Classroom O X O
Lecture O X
Auditorium X O
O – Accepted X - preferred
TABLE 4- TEACHING STATION
Types of Furniture to Avoid
 Tablet arm chairs in non theatre style seating applications
 Pivot arm seats
 Pedestal seats that are bolted to the floor

2.6.3 Miscellaneous Seminar hall Items
 Clocks are required in each seminar hall. They should be large and easy to read
with a simple blackframe. It should be placed on the back or side wall in a
location visible to the instructor. Neverlocate the clock at the front of the
seminar hall. Battery clocks are required but must be “noisefree”.
 Recycling and trash receptacles are required in all rooms. See ASU Purchasing
Guidelines.
 Containers shall not encroach on circulation path.
 ASU’s Emergency Response wall mount Guide must be displayed in the front
of all seminar hallsnear the instructor’s station.
2.7. Fire Prevention
2.7.1 Diffuser Location
Diffusers should be located as to avoid any movement of the screens which would be
caused by air flow.
2.7.2 Location of Above‐Ceiling Mechanical Equipment
Access to mechanical equipment for the building should not be located within a
seminar hall.
2.7.3 Noise
Excessive background noise or reverberation in seminar halls interferes with speech
communication andthus presents an acoustical barrier to learning. In all phases of the
seminar hall design and constructionprocess, careful attention must be paid to
acoustics. Locate all mechanical equipment as far from theseminar hall as possible. If
adjacency is unavoidable, provide for sound attenuation methods at
doors,lightfixtures, and all other ceiling or wall breaches. System components (fans,
ductwork & diffusers)shall be selectedto meet sound criteriaof NC20 to NC25.

HVAC systems shall be designed to provide a comfortable environment for learning
withoutcreating too much noise or wasting energy. The following criteria applies in
addition to thecriteria in ASHRAE Standards:
Indoor air conditions:
The HVAC system shall be designed to maintain 72 degrees Fahrenheit year-round
with ahumidity range of 35-50% relative humidity.
On small renovation projects where it is not possible to maintain these conditions due
toexisting building or mechanical system design restraints, consult with the Project
Administrator to determine acceptable ranges of temperature and humidity.
Outdoor air temperatures:
The winter outdoor air temperature used to determine the heating load shall be the
ASHRAE99.6% heating design temperature.
To increase energy efficiency and reduce noise levels:
 Use equipment with a minimum 10.0 Energy Efficiency Rating (EER)
 Noise levels produced shall not exceed NC-30
 Fans, ductwork, and diffuser noise ratings shall not exceed NC-25
 Provide balancing dampers in supply ductwork to serve all diffusers. Locate
dampers farenough upstream (minimum 2.5 equivalent duct diameters) to
provide uniform airflow atthe inlet to the diffuser:
 Use opposed-blade dampers in rectangular ductwork.
 Use butterfly dampers in round ductwork.
 If there isn’t enough space to provide a long-enough straight duct into the
diffuser neck, use other means to reduce noise (equalizing grid, opposed-blade
dampers, etc.).
2.7.4 Fire Strobes
Locate fire strobes away from projection screen to prevent sightline obstructions when
screen isextended.

Fig 2.13smoke detection device Fig 2.14 fire extinguisher
2.8.Seminar hall Room
A room used primarily for scheduled classes of multiple academic disciplines with a
seatingcapacity of about 10 to 22 students. Seminar hall rooms may also serve non-
instructionalpurposes, but only to a minor or incidental extent.
Description: Rooms typically have a multi-media audio-visual system, with seats and
tablesoriented so that students and instructors can easily interact with each other. They
do not havespecial-purpose equipment for student use (such as that found in a
scheduled instructionlaboratory) that would make the room unusable for multiple
disciplines.
Limitation: Excludes conference rooms, which may have similar design features but
areprimarily used for faculty and staff meetings.
2.8.1 Room Location
Learning rooms shall be located as close to building entrance levels as possible to
improveaccess and reduce noise levels in other parts of the building. Large learning
rooms shall belocated close to primary building entrances and circulation spaces that
are large enough toaccommodate students waiting for the next class.
Where existing learning spaces do not meet these goals, rehabilitation projects should
relocatethem, add entrances, or create more spacious circulation elements with places
for students tosit while waiting for the next class.
The location of learning rooms in relation to natural light should also be considered.
Roomswith windows facing north can be more easily designed to provide adequate

blackoutcapability and energy-efficiency than rooms with windows facing other
directions. Passivesolar design features should be considered for rooms where
windows face the sun.
2.8.2 Room Size and Proportion
Learning spaces need to be large enough to comfortably accommodate the number of
studentsplanned for each type of room using the types and sizes of furnishings
anticipated forinstructors, students, and audio-visual components. Campus Planning
shall be involved in anydiscussions that arise in design that could potentially change
functions or seating capacities. Seminar hall rooms with rectangular shapes and long,
narrow tables make it hard for studentsand instructors to see each other, projected
images, or writing on markerboards. Wheninstructors sit at the head of the table to
improve eye contact, this makes it more difficultfor them to encourage students to
actively participate in the discussion.
To encourage interactive discussion while providing good sight lines, rooms that are
nearlysquare or have a shape based on “viewing angles” from projection screens
almost alwayswork out best.
To develop learning rooms with good sight lines and efficient seating layouts,
designprofessionals should design from the “inside out”, not from the “outside in”
2.8.3 Instructor Workstations
Learning rooms will include instructor workstations designed to accommodate:
 Computer-based audio-visual systems and other commonly-used audio-visual
components
 Instructors who are standing, seated, or using a wheelchair
 Most “off-the-shelf” lectern and podium designs and computer workstations
designed foroffices do not meet these goals. The College has developed custom
designs that do andseeks to standardize workstation designs for each campus to
simplify instructor training.
Refinements to the College’s custom-designed instructor workstations are
madeperiodically. Consultants should obtain electronic copies of drawings for the

appropriatecurrent design(s) from the Department of Renovations in the College
Architect’s office.
AutoCAD copies are normally filed in the s:shareallDesign GuidanceSeminar halls
directory.
Floor plans and cross sections that show the workstation drawn toscale shall be
included in design submissions.
Key workstation design features and location considerations are as follows:
 Workstations shall be oriented to allow instructors to maintain eye contact with
studentswhile using keyboards and allow students to see projected media:
 In rooms with one screen, an instructor workstation on the left side of the
instructorarea, marker boards in the center, and a screen in the right corner
usually works well.
 In large rooms with multiple screens, a workstation located on the left side of
theinstructor area, near the markerboard and overhead projectors, usually
works well, buta more central location may be preferable in some rooms.
Tables used for paneldiscussions or references are also needed.
 Work surfaces and audio-visual components shall not block views of screens
andmarkerboards:
 34 inches above floor–maximum height of work surfaces
 41 inches above floor–maximum height of monitors/task lights/other
components
 Work stations shall accommodate instructors who stand, sit, or use a
wheelchair:
 Provide accessible route to workstations (flat floor or ramps < 30 feet and 8%
slope)
 Minimum knee clearance: 27 inches high, 18 inches wide (avoid keyboard
trays)
 PC keyboard/mouse/controls within easy reach of instructors
 Control panel for A/V system in easy reach of instructors
 Height of instructor’s seat easily adjusted - 19 to 27 inches above floor

 Instructor’s chair has integral footrest and can be easily moved
FIGURE 1 - INSTRUCTOR WORKSTATION
Instructor workstations shall provide space for the following:
 Instructor’s references and handouts (also see “Tables for References”)
 Personal computer/monitor and power/data outlets for laptops
 Audio-visual components installed in standard 19-inch slide-out rack
 Task lights focused on usable work surfaces, with shades to avoid light spill
over
 Lockable access to computer and audio-visual components for maintenance
 Electronic security system to prevent theft of components

2.8.4 Computer Workstations
Computer workstations are used for teaching methods which require Collegeprocured
computers/laptops. Computer workstations should accommodate computer equipment,
plus thenecessary space for student materials.
Design Standard
 Allow for a minimum surface area of six and one quarter (6.25) square feet to
beprovided.
 Furniture selection for computer workstations shall have provisions for
securing theequipment and the furniture in the room.
 Computer workstation seminar halls shall have provisions for increased
ventilation andconditioned air supply due to the increased heat load produced
by the computers.
 Provisions for electrical fires should be considered for computer workstation
equippedseminar halls.
 Furniture may be arranged in a row or in collaborative pods.
 ADA tables must be provided according to ASU Accessibility Standards.
 Computer seminar hall furniture is an extension of the programming
requirement andshould conform to Seminar hall Specifications.
2.8.5 Storage and Preparation Areas
Consideration should be given to providing secure storage in the immediate vicinity of
alecture hall where instructors can keep materials needed on a repeated basis as well
as providespace for the preparation of lecture materials.
2.8.6 Auxiliary Input Panels
Faculty often want to bring in equipment that may not be used frequently enough to
warrant its being permanently installed in a room. An auxiliary input panel is needed
(with clearly labelled connectors) which makes it easy for faculty to interface
additional equipment with theother systems in the room

2.8.7DesignFlexibilityand Computers
Movable tables and chairs (or student desks) give instructors the flexibility to
rearrangeseating into smaller groups during class. This level of flexibility is much
harder to achieve incomputer instruction labs or other rooms with equipment that
requires power, data, and utilityconnections. If an academic program requires this
level of flexibility, consider:
 Use of wireless components
 Raised floor systems with flush floor outlets and quick-disconnect power/data
wiring
Avoid the following:
 Power poles or other features that block views of instructors, markerboards,
screens
 Plastic floor outlets/covers that break easily
 Raised floor outlets that present a trip hazard
 Plastic raised floor systems that present fire/smoke hazards
2.8.8Tables for References and Guest Speakers
In seminar halls and instruction labs seating up to 48 students, provide a table near the
instructorworkstation for the instructor’s references or handouts:
 Work surface 18 inches deep and 36 inches wide
 Colors and style compatible with other seminar hall furnishings
 Larger seminar halls and auditoriums are often used for panel discussions or
other events wheremore than one person makes a presentation.
 Provide tables and comfortable upholsteredchairs to accommodate the
instructor’s references, handouts, and other speakers as follows:

Room capacity No. of table No. of chairs Table dimension
50-79 seats 1 2 24”deep,60”wide
80-119 seats 2 4 24”deep,60”wide
120seats or more 3 6 24”deep,60”wide
TABLE 5 – ROOM CAPACITY
2.8.9Special Equipment for Music Instruction
Music Instruction labs shall have high-quality stereo components in addition to the
audiovisualcomponents typically provided in seminar halls. Contact UC audio-visual
technologyspecialist for specifications. Components shall:
 Be designed to play vinyl records, audiocassette tapes, and compact disks
 Be installed on standard racks to facilitate updates as recording technology
changes
 Be located on portable carts or in wall-mounted racks
 Have a security alarm system linked to the central control panel

CH 3 ACOUSTICS

3 .ACOUSTICS
3.1 GENERAL
The word acoustics is originally derived from a Greek word meaning to hear.
Hence, the acoustics is defined as the science of sound and as such, it discusses the
origin, propagation and auditory sensation of sound.
A sound is produced when part of the atmosphere is compressed suddenly. This
compression would have remained stationary at the place only in the case the air was
not elastic. But due to elasticity of air, the particles originally disturbed in turn disturb
the neighbouring particles. Ultimately the compression is propagated or spread away
from the source. The sound thus travels in the form of waves and when these waves
come near our ear-drums, we feel a sensation of hearing.
Following important facts in connection with the sound are to be noted:
 The sounding body which throws the sound waves is in a state of
vibration. If vibrations of the sounding body die out, the sound emitted
by the sounding body will also die out.
 It is absolutely necessary that for a sound to be heard by our ears, the
sound body and ear must be connected by an uninterrupted series of
portions of elastic matter. The physical state of the matter, namely,
solid, liquid or gaseous, is of no importance.
 The presence of some matter is required for the transmission of sound.
The sound cannot travel in vacuum.
 The sound waves are longitudinal waves and hence, each particle of the
medium through which sound waves is proceeding, moves backwards
and forwards along a line in the direction in which the sound wave is
travelling
 The relation of sound with the human being is so common that we
rarely appreciate its functions in our daily life. It permits us enjoyable
experiences like listening to the musical programme, singing of birds,
etc. It also permits the spoken communication with our family members

and friends. It also warns us or alerts us e.g. singing of telephone, knock
at door, etc.
 The modern society, many sounds are unpleasant or unwanted and we
call them noise. However, how much a noise annoys depends not only
on its quality but also our altitude to it. The sound need not be loud to
develop noise. For instance, a scratch in a record or a dripping faucet
may annoy us much more than aloud thunder.
 The worst effect of sound is that it can damage and destroy. A sonic
boom may shatter windows and can cause damage to the plaster of
walls. But the most unfortunate case is when the sound damages the
delicate organ to receive it, namely, the human ear.
3.2 VELOCITY OF SOUND
The speed at which the sound waves travel or pass through any medium is
termed as the sound velocity and it depends on the nature and temperature of
medium through which the sound travels. Table gives the sound velocities in
different mediums.

SOUND VELOCITIES IN DIFFERENT MEDIUMS
Medium Sound velocity at 20 * C in m/sec
Atmospheric air 340
Hydrogen 1305
Nitrogen 338
Pure water 1450
Granite 6400
Glass 5000 to 6000
Aluminum 5100
Brick 4300
Concrete 4000
Iron 4700 to 5100
Copper 3900
Brass 3500
Silver 2600
Lead 1320
Cork 450 to 530
Rubber 40 to 150
TABLE 1 – SOUND VELOCITIES IN DIFFERENT MEDIUMS
The important fact to be remembered in connection with the velocity of
sound is as follows:
 The time required by sound waves to travel from one place to another is
quite appreciable.
 The velocity of sound in air is affected by the amount of moisture in the
air, the temperature of the air and the intensity of wind.
 The velocity of the sound is independent of the frequency or pitch of
sound.
 It can be seen from the table that sound travels much faster in solids and
liquid than it does in air.

 dB METER
Fig 3.1 dB Meter Fig 3.2 Reading of dB meter
 A sound level meter or sound meter is an instrument that
measures sound pressure level, commonly used in noise
pollution studies for the quantification of different kinds of noise,
especially for industrial, environmental and aircraft noise. However, the
reading from a sound level meter does not correlate well to human-
perceived loudness, which is better measured by a loudness meter. The
current international standard that specifies sound level meter
functionality and performance. It is generally used to calculate the
intensity of sound at any distance we want itis very useful instrument
when learning about itensity of sound and basic unit of measurement is
in decibels
3.3 FREQUENCY AND INTENSITY OF SOUND
The frequency or the pitch is defined as the number of pressure variations
which a sounding body makes in each unit of time. The greater the number of
variations, the higher will be the pitch. The intensity of sound is defined as the flow of
sound energy per unit of time through unit area.

Thus, the frequency or the pitch is a measure of the quality of sound while
intensity is a measure of the quality of the sound energy. The difference between the
two terms intensity of sound and loudness should also be noted. The intensity of
sound is purely a physical quantity which can be accurately measured and it is
independent of ear of listener. On the other hand, the loudness is the degree of
sensation which is not wholly physical, but partly subjective and it does depend upon
the ear of listener.
The frequency is measured in cycles per second or Hertz (Hz) as it is now
called by the international agreement. The range of human hearing is very wide
extending from 20 Hz to 20000 Hz ( or 20 KHz ). It may be noted that the range from
the lowest to the highest note of piano is about 27.5 Hz to 4186 Hz.
The lower limit indicates the frequency which is required for an average human
ear to perceive the sound. If the frequency of sound is below the lower limit, the effect
of sound is lost and distinct pulses are experienced. The upper limit of frequency
depends on the age of the person and his physical fitness to receive the sound.
The wave length of sound i.e. the physical distance in air from one wave top to
the next can be found out by knowing its speed and frequency with the help of the
following equation:
𝑤𝑎𝑣𝑒𝑙𝑒𝑛𝑔𝑡ℎ =
speed
frequency
For acoustics and sound measurement purposes, the speed of sound is
taken as 340 m/sec. Thus, the wavelength at 20 Hz will be 17 m while at 20
KHz, it will be only 17 mm.
The intensity of sound is measured on a logarithmic scale due to a wide range
of variation of the intensity of sound. The two sounds of the same character and
of intensities I and I (energy units) are said to differ by n bells when
𝑛 = log10
I
I
The unit of bel is named after Alexander Graham Bell (1847 -
1922), U.S. inventor of the telephone, born in Scotland.

The unit of bel is comparatively large and hence, in practise, a shorter practical
unit of decibel (abbreviated to db) equal to 1/10 of a bel is used. Thus, the two
sounds as mentioned in the previous case are said to differ by m decibels
when 𝑚 = 10log10
I
I
. The difference in loudness m of the two sounds is
technically known as the intensity level.
If m = 1 db
1 = 10log10
𝐼1
𝐼2
Or log10
𝐼1
𝐼2 =
1
10
𝐼1
𝐼2
= 1.26
Thus, he change in intensity by 26 per cent alters the level by one db.
This is practically the smallest change in intensity level that the human ear can
ordinarily detect or appreciate. Also,
When I1 =I2
We get, m= 10 log10 100 = 10 log10 102 = 20 db;
And when I1 = 1000 I2
We get , m = 10 log10 10 1000
= 10 log10 103 = 30 db.
It is thus seen that when two sounds differ by 20 db, the louder of them
is100 times more intense and when they differ by 30 db, the louder one is 1000
times more intense.
The range of audible sound of painful noise varies from 1 to 10. But this
wide range is covered on logarithmic scale between 1 to 130 db units. One db
unit is approximately the smallest change of sound intensity which the human
ear is able to appreciate.
It is quite clear that intensity of sound is affected by the frequency of
sound and as this scale does not take into account this factor, the more
representative unit of phon is used. The phon indicates the level of sounds

equal loudness at all frequencies. For convenience, the phons and decibels
differ so slightly that they may be treated as synonymous.
Table gives a scale of loudness. The threshold of hearing is the zero on
this scale while 130 db is the threshold of painful hearing.
SOME TYPICAL SOUND LEVELS
Sources or location Sound level in db
Threshold of audibility (inaudible) Zero
Rustling of leaves due to a gentle wind 20
Quiet whispering 30
Conversation at a distance of 1 meter 40
Quiet speech 50
Average office 55
Small shop 60
City traffic in busy street 70
Printing press 80
Large factory 90
Boiler factory 110
Loud noise accompanying lightning 120
Aeroplane noise at a distance of 3 meter (painful) 130
TABLE 2- SOME TYPICAL SOUND LEVELS
It should be noted that the intensity of sound in db and frequency of sound in
cycles per second are physical quantities which are defined arbitrarily. These
quantities are measured with the help of mechanical or electrical equipments. There is
no compulsion on the ear of the human being to interpret these physical quantities
according to the same rules.

3.4 TIMBRE
One of the important characteristic of sound is its timbre or quality. The notes given
by two different musical instruments like piano and cornet, although they may be of
the same pitch and intensity, are clearly distinguishable by the human ear. This
quality of a musical note is called its timbre.
Fig 3.3 Timber at ceiling of seminar hall Fig 3.4 Timber at walls of seminar hall
A tone is a sound of distinct pitch that may be put into harmonic relation with
other such sounds. In general, the musical notes are composed of tones, the pitch of
the note being that corresponding to the lowest tone it contains. The tone having the
frequency n is called the fundamental tone. The additional tones of frequency 2n, 3n,
4n, etc. are called the overtones or upper partials of the fundamental.
The quality or timbre of a note is determined by its complex structure and it
depends on the overtones which accompany the fundamental. In general, the notes in
which the fundamental is relatively strong and the overtones are few and feeble are of
soft and sweet character. On the other hand, the notes in which the overtones are
numerous and strong, are harsher and have a so-called metallic sound. It is to be
noted that the memory of this tonal quality assists us in recognising a large number of
different sounds such as cries of animals, voices of friends and relatives, sounds of
familiar musical instruments, etc.
MEASUREMENT OF SOUND
Objects: Following are the objects or purposes of measuring the sound:
 It helps in improvising building acoustics and loudspeakers and thus
enhances our enjoyment of music, both in the concert hall and home.

 It indicates when a sound may cause hearing damage and thus helps in
taking corrective measures to be taken, for avoiding the same.
 It permits evaluation of the hearing sensitivity of a individual.
 It permits precise and scientific analysis of the annoying sounds and as
such, gives us an objective means of comparing annoying sounds under
different conditions.
 It permits the improvement of the quality of our lives.
 It serves as a powerful diagnostic tool in the noise reduction programmes.
Sound level meter: A sound level meter is an instrument which responds to the
sound in approximately the same way as the human ear and which gives objective
reproducible measurements of the sound level.
The sound level is converted to an identical electrical signal by a high quality
microphone and since the signal is quite small, it must be amplified before it can
be read on a meter.
The quality of the measuring microphone must meet many high standards. It
must have uniform frequency response i.e. it must be equally sensitive at all
frequencies. The microphone should be equally sensitive to the sounds coming
from all angels or in other words, it must possess an Omni directional
characteristic.
The sound level meter is a precise instrument and hence provision is made to
calibrate it for accurate results. It is best done be placing a portable acoustic
calibrator directly over the microphone. This calibrator is basically a miniature
loudspeaker giving a precisely defined sound pressure level to which the sound
level meter can be adjusted.
3.5 INFLUENCE OF ENVIRONMENT
The environmental factors which affect the measurement of sound are as
follows:
 Ambient pressure: The variations in the atmospheric pressure will have a
negligible influence on the microphone sensitivity. For extremely high altitudes

and other unusual conditions, the microphone instruction manual should be
referred.
 Humidity : The sound level meter and microphone will not be Influenced by
relative humidity levels up to 90%. It is however necessary to shield the
instrument from rain, snow, etc.
 Magnetic fields : The influence of the electrostatic and magnetic fields On the
sound level meter is quite negligible.
 Temperature : The sound level meters are designed to operate Accurately
over the temperature range of -10°C to + 50°C. It is necessary to avoid sudden
temperature changes which may cause condensation in the microphone.
 Vibration : The sound level meters are relatively insensitive to the Vibration.
But it is a good practice to provide foam rubber pads or similar material to
isolate them from strong vibrations and shock.
 Wind : The wind blowing across the microphone disturbs the readings and to
minimize the effects of wind while working outdoors, a special wind screen
consisting of a ball of porous polyurethane sponge should always be used over
the microphone. It will also give protection to the microphone from dust, dirt
and precipitation.
MEASUREMENT REPORT
It is necessary to have a good measurement report containing the following
information:
 Background noise level;
 Data on object being measured like machine type load, speed, etc.;
 Meteorological data and date;
 Method of calibration;
 Sketch showing measuring site, location of microphone and object being
measured;
 Type and serial number of instrument;

 Type of sound signal;
 Weighing networks and meters responses used; etc.
With a careful written report, the future comparisons can be made more
Accurately and treated as reliable.
SOUND IN ENCLOSURES
When the sound waves strike the surfaces of an enclosure in the form of a room with
walls, the following three things happen:
 Some of the sound is reflectedback in the room.
 Some of the sound energy is absorbed by the surfaces and listeners or persons
present in the room.
 Some of the sound waves are transmitted outside the room through the
vibration of walls, floors and ceiling.
The amount of sound reflected or absorbed depends upon the surfaces while the third
category of transmitted sound depends upon the sound insulation properties f the
surfaces.
REFLECTION OF SOUND
When a free sound wave travelling through air strikes a uniform, large, solid, plane
surface, it is reflected in the same manner as that of a light ray. Thus the angle which
the incident wave makes with plane surface is equal to the angle which the reflected
wave makes with the plane surface.
 Following facts in connection with the reflectionof sound are to be noted:
 The analysis of reflection from the curved surfaces may be deprived by
applying the laws of reflectionof light.
 A concave surface leads to the concentration of reflected sound waves at
certain points and they are considerably smaller in magnitude as shown in.
They are most condensed and hence, they are amplified in nature. Hence, the
concave surfaces may be provided to work as the reflectors.

 A convex surface ends to spread the reflected sound waves which are
magnified and are considerable bigger in magnitude. Hence, the convex
surfaces may be used with advantage to spread the sound waves throughout the
room.
 The study of law of the reflection of sound helps in selecting the proper shape
of the room with regard to distribution of sound in that room.
 The assumption that the sound is reflected in the same manner as light is true
only for limited circumstances and hence, great caution should be exercised
while applying the law of reflectionof sound.
3.6DEFECTS DUE TO REFLECTED SOUND
The acoustical design of an enclosed space is primarily governed by the behaviour of
the reflected sound. Following are the two main defects developed due to the
reflectionof sound:
 Echoes
 Reverberation
Each of the above defects due to the reflected sound will now be briefly
described.
 Echoes:
When the reflected sound wave reaches the ear just when the original sound
from the same source has been already reached, an echo is produced and it
thus indicates the repetition of a sound by reflection of sound waves from a
surface.
The sensation of sound persists for one-tenth of a second after the
source has ceased. Hence in order that an echo may be distinguished as
separate, the sound must reach the ear one-teeth of a second after the direct
sound. Taking the velocity of sound in the atmosphere air as 343 m/sec, it
means that the sound must come after traversing a distance of (0.10 x 343)

= 34.30 m i.e. the minimum distance of the obstacles from the source of
sound must be half of 34.30 m i.e. 17.5 m., say 17 m. However, if the
distance of reflecting surface if less than 17 m., the sound distorted of
modified sound will be heard. When the distance of the reflecting surface is
between 8 m. and 17 m., the echoes are formed.
When a sound is reflected from a number reflecting surfaces play
suitably, the multiple echoes are formed. The heavy rolling sound of a
thunder is due to successive reflections from a number of reflecting surfaces
like clouds, mountains, various strata of air, etc.
 Reverberation:
It is quite clear that some interval of time will be required for the sound
energy to convert in to other form of energy. This transformation is usually
brought about by friction between the sound wave and air particles as well
as the sound wave and the surfaces with which it comes in to contact.
Naturally, the more the friction, the quicker will be the transformation. This
gradual process of transformation operates over a certain interval of time
and this is known as the reverberation.
Now, m = log10
𝐼1
𝐼2
SABIN’S EQUATION
Prof. W.C. Sabine of Harvard University, U.S.A. carried out a number of experiments
in rooms of different sizes and he was able to establish the following formula which is
knows as Sabin’s equation
t=
0.16 𝑉
𝐴
Where t= reverberation time in seconds

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