Download a study on ventilation requirements in a standard university lecture

9/1/2011
ARC 810
A STUDY ON VENTILATION
REQUIREMENTS IN A STANDARD
UNIVERSITY LECTURE THEATRE
A CASE STUDY OF BIG LECTURE THEATRE
FEDERAL UNIVERSITY OF TECHNOLOGY AKURE
WRITTEN BY
OGUNRUKU O.A
(ARC/05/5626)
SUBMITTED TO
PROF OLA OGUNSOTE
DEPARTMENT OF ARCHITECTURE,
FEDERRAL UNIVERSITY OF TECHNOLOGY, AKURE
IN PARTIAL FUFILMENT OF THE REQUIREMENT OF ARC 810
FOR THE AWARD OF M.TECH IN ARCHITECTURE
INTRODUCTION
In the evaluation of a Lecture halls in relation to the environment in the
past the past decades, the importance of providing good ventilation has
become a predominating issue in the search for a model architectural
environment. The issue of air flow, its sources and methods of control has
been subjected to intense study. Ventilation is fundamentally important
to the success of any building especially those meant for listening. With
an increased awareness of the cost and environmental impacts of energy
use, natural ventilation has become an increasingly attractive method for
reducing energy use and cost and for providing acceptable indoor
environmental quality and maintaining a healthy, comfortable, and
productive indoor climate rather than the more prevailing approach of
using mechanical ventilation. In favourable climates and buildings types,
natural ventilation can be used as an alternative to air-conditioning
plants, saving 10%-30% of total energy consumption.
Modern lecture theatre design is based on the hard facts that it is a
rarely new form of invention to the previous existing form. Designing a
lecture theatre is a complex elaborate but constrained exercise. As with all
buildings, structural needs can limit freedom and architectural style is the
balance between respect for precedents and the current fashions. The
lecture theatre is an example of a single performance space or a form of
auditorium with a single function (speech). Due to hearing and visual
complications arising from both the physiological and psychological
peculiarities of individuals, it is necessary to incorporate environmental
control factors like ventilation in theatre designs. In analyzing and
designing a theatre, there are the additional constrains : in planning for
good visual conditions and sightlines of meeting the functional demands
of the space in regards to layout of seating and most importantly the
provision of a good ventilation conditions.
In Nigeria today, it is common to find auditoriums that are hastily
put together, where no consideration is given to environmental control
factors like proper ventilation in design until after construction, when it is
discovered that the comfort level of the building are unacceptable. This
often makes it necessary for various mechanical ways of ventilation to be
put in place. This is not cost effective. Therefore, it has become imperative
for the architect to understand the negative impacts of insufficient
ventilation planning.
This report is a study of the BIG LECTURE THEATRE, located in
the Federal University of Technology Akure. The study described in this
report examines the building’s ventilation with emphasis on the effects of
building size, shape, window positions and window sizes on its general
thermal comfort condition. It studies the behavior of air in spaces and the
optimization of its flow to meet the specific needs of the users.
ANALYSIS OF VENTILATION IN CASE STUDY AUDITORIUMS
(Dublin’s Science Complex)
University College Dublin’s Science Complex opened in 1964, and was the
first purpose-built academic structure to be built at the Belfield campus.
The complex consists of a central lecture theatre building, which is
connected by link bridge to the Biology, Chemistry and Physics buildings.
The “Lecture” building is 8,000 m2 in size. It contains six lecture theatres,
with capacities ranging from 200 to 400 occupants. Most theatres have
their original heating and ventilation plant.
The theatre is heated using heat recovered by the thermal wheel and a
supply air heating battery. The BMS compares actual air temperature with
a temperature set point and adjusts heating accordingly. The set-up could
lead to an occupant experiencing cold temperatures on entering the
space. To address this, temperature is maintained at 17ºC when the
theatre is not occupied, but is scheduled to be occupied.
UCD has three control strategies for heating and lighting regulation:
(1) Occupied control - the optimum temperature of the theatre when
occupied: Time schedule and occupancy detectors are in.
Temperature set point is 20ºC. Main lights are on, access lights are off.
(2) Unoccupied control - the minimum temperature of the theatre when
unoccupied: Time schedule is out (building closed).Temperature setpoint
is 10ºC (for fabric protection). Access lights are on, main lights are off.
(3) Non-occupied control - the minimum temperature of the theatre when
occupied but not scheduled for use: Time schedule is in, occupancy
detector is out. Temperature set point is 17ºC.
VENTILATION CONDITIONS IN SELECTED BUILDING
(THE BIG LECTURE THEATRE)
The BIG LECTURE THEATRE is one of the lecture theatre located in
the Federal University of Technology Akure campus. It is a centre
designated for lecture/ speech function only. It is located in Obanla
campus area and sited in between the academic buildings. It is bounded
by the small lecture theatre, the ETF lecture theatre, school of engineering
and engineering technology and a well landscaped environment. The
major factors that affect the ventilation of this lecture theatre include its
size, shape nature of materials and finishes, acoustic zoning etc. in
attempting to analyse the acoustic performance of a building all these
must be considered.
Building size
This can greatly influence ventilation condition. This is mainly
because the size of the hall will have to be proportional to the number
and sizes of the windows so as to allow proper exchange of indoor and
outdoor air. The BIG LT (as it is popularly called) has an area of
approximately 402.3sq m. With a ceiling height of 5100mm at the lowest
floor level and 3600mm at the highest floor level. It is rectangular with
chamfers at the rear corners and at the stage.
Number of window openings and their sizes
The big lecture theatre has 18 number window units on each side of the
theatre making 36 windows servicing the whole theatre, providing both
ventilation and illumination and the set of windows with different sizes.
The size of opening are 24 number 1500 x 1800mm which are the
regular sized windows in the theatre. The rest of the windows are
arranged in a ascending order
AIR INLET
AIR OUTLET
Arrangement and size of windows
Discussion
The openings of the lecture hall are directly opposite which adequately
allows for cross ventilation in the building. The orientation of the theatre
is in such a way that the adjoining buildings cannot disrupts the air flow
into the building because they are at a considerable distance away from
each other.
The choice of window in the building provides a good ventilation
compare to the number of user intended for the building. There is
a provision of electric fan to complement the natural ventilation
but this is not adequate compare to the number of intending user.
CONCLUSION
The treatment of ventilation is an important issue to be considered in an
interior space of every building. From preliminary design to detailed
design stage, ventilation should be considered while planning the
building layout. Idiosyncrasy of the area as pertaining to ventilation
should also be put into consideration. The facilities in the building should
also be maintained and replaced when needed to curb the present
challenge in the LT. This report has clearly stated the present situation at
the big LT could be transformed to meet up with its present challenges, so
as to create an ideal environment for learning.
REFERENCES
Perera, E. “Natural ventilation for offices.” BRECSU, Building Research
establishment, Watford, UK, 1999.
Allard, F. “Natural ventilation in buildings.” James and James (Science
Publishers), London, UK, 1998.
Rassmussen, S. E. “Experiencing Architecture.” Chapter 10, ‘Hearing
Architecture.’MIT Press, 1962