1. Mallareddy college of Pharmacy
AIR HANDLING SYSTEMS
guided by: Presented By
Dr. Satyabrata Bhanja Aslesha.E
M.Pharmacy 1st yr
2. AIR HANDLING SYSTEMS
CONTENTS
HVAC systems
Air handling units
Air filteration systems
Dust collectors
Humidity and temperature control
3. HVAC systems
Heating Ventilation and Air Conditioning
systems are the integral part of
environmental control system design.
Basic components of HVAC:
1. Air Handling Unit
2. Air distribution
Dust network
Insulator
Dampers/valves
Return lower & grills.
3. Air filters
4. Air Handling Unit
AHU is a device used to condition and
circulate air as part of a heating ventilating
and air-conditioning (HVAC) system.
It is a large metal box containing a blower,
heating or cooling elements, filter racks or
chambers, humidity & temperature control
loops.
6. Temperature and humidity control
Temperatures in the 68-74 F (19-23 C)
range is comfortable for working
environment.
Temperature control is important in the
areas where autoclaves, ovens, dry heat
strerilization tunnels are present.
Humidity comfort levels are in the 45-55%
RH range.
Air dryers can be used to maintain lower
than normal humidity levels.
7. AIR FILTERATION SYSTEMS
CONTENTS
Introduction
Types of filteration
Mechanisms of filteration
Types of air filters
8. Introduction
Filteration is an important aspect of
environmental control in Pharmaceutical
industry.
The main aim of filteration is to produce
dust free atmosphere.
It is required in areas like spray drying,
coating, granulating, milling, packaging etc.
Filters are selected based on the required
environment.
9. Mechanisms of air filteration
Air filteration involves the removal of
unwanted particles due to collision of
particles with the filter.
Such removal of particles due to collisions
are governed by forces called as
a) Impingement
b) Diffusion
c) Interception
10. Mechanisms of air filteration
Impingement
It is also called as Inertial impaction.
Particle inertia causes it to leave the flow
streamlines and impact on the fiber. This is
called as spraining effect.
This is not suitable for particles of size <5
microns.
11. Mechanisms of air filteration
Diffusion
This is also known as Brownian Movement
resulting in the movement of particles from
molecular collisions.
Efficient method for particles of size <1
microns.
12. Mechanisms of air filteration
Interception
The particle/droplet collides to the one of the
filter’s fibre after coming close enough to it.
Oil metal plates/mesh are used.
Affects the particles above 4 microns.
13. Air filter efficiency
Air filter efficiency is
Maximum – impingement in low velocity
diffusion at high velocities
Minimum – impingement in high velocity
diffusion at low velocities
14. Air filters
Air filters are made up of fibre glass, sinter glass,
charcoal, glass wool, dry fabric, oil wetting fabric.
Arrangement: sandwich
flat
disk
pleated
box
Purpose: final filter
post filter
fine filter
intermediate filter
15. Types of air filters
1. Ultra low penetration and high
efficiency particulate air filters
(ULPA & HEPA)
2. Packed towers
3. Membrane filter catridges
4. Hydrophobic filters
16. HEPA FILTER
HEPA is an acronym
for “High Efficiency
Particulate Air”
This type of air filter
can remove at least
99.97% of dust,
pollen, mold, bacteria
and any airborne
particles with a size of
0.3 micrometres (μm)
17. HEPA FILTER
Media is the filtering material.
Eg: glass fiber, synthetic fiber, non-woven fiber
Sealant is the adhesive material that creates a
leak-proof seal between the filter media and the
frame.
Frame is where the filter media is inserted.
Eg: aluminum, stainless steel, plastic or wood.
Faceguard is a screen attached to the filter to
protect the filter media during handling and
installation.
Gasket is a rubber or sponge like material used
to prevent air leaks between the filter and its
housing by compressing the two together.
18. HEPA FILTER
Construction:
HEPA filter is constructed of borosilicate
microfibres in the form of pleated sheet
Sheet is pleated to increase the overall
filtration surface area.
The pleats are separated by serrated
aluminum baffles or stitched fabric ribbons,
which direct airflow through the filter
This combination of pleated sheets and
baffles acts as filtration medium.
19. HEPA FILTER
It is installed into
an outer frame made
of fire-rated particle
board, aluminum, or
stainless steel
The frame-media
junctions are
permanently glued or
‘‘pot-sealed’’ to
ensure a leak proof
20. HEPA FILTER
HEPA filter performance is dependent upon th
following characteristics:
Air flow
Temperature
Pollutant loading
Dust holding capacity
Filter media
Contruction of HEPA
Operating conditions etc.
21. Testing of HEPA filters
There are 2 separate tests for HEPA and ULPA
filter collection efficies.
HEPA efficeincy is rated using a thermal di octyl
phthalate (DOP) test. The test dust for HEPA filters
is mono-sized, DOP particles, generated by
vapourization and condensation. Photometer
measures particle penetration by sensing the
scattered light.
ULPA efficiency is tested using a particle counter
upstream & downstream of filter. Automizer
injects DOP,alcohol & mineral oil in hexane to
generate particles.
23. Types of air filters
2.Packed towers
Packed towers are
custom designed to
provide removal
efficiencies in the
range of 95% to
99% for acid and
toxic gases with a
low pressure drop
24. Types of air filters
3. Membrane filter
catridges
oThese are compact,
easily handled and can be
manufactured as fully
disposal form.
oThese are available as
either pre filter
(particulate and liquid
aerosal) or sterilizing
filter (bacterial
contaminents).
25. Types of air filters
4. Hydrophobic filters
These are generally used as vent filters.
They protect the contents of the containers
against contamination in the air which
enters or leaves them.
26. Dust collectors
Dust collectors are used for equipment
maintanance.
Air pollution is controlled.
Main features
Low cost & maintainance
Most commonly used for all type of medium
from coarse to fine except <5 microns
particles.
Collection efficiency of 10 to 100 microns
with multiclones.
28. Types of dust collectors
1.Electrostatic precipitators(ESP)
Mechanism:
Ionizing the gas
Charging the dust particles
Transporting the particles to the collecting
tube
Neutralizing the dust particles
Removing the dust from the collecting
surface
29. ESP
TYPES
i. Cottrell or single stage – combines
ionization and collection in a single stage
ii. Penny or Two stage – ionization and
collection in different stages
Advantages:
Large gas volumes & high collection
efficiency for small particles.
Disadvantages:
This is a costly method
32. Fabric collectors
The amount of filter area depends on:
Release characteristics of dust
Porosity of dust cake
Conc. Of dust in carrier gas stream
Type of fabric & surface
Airflow patternn within the collector
Temperature & humidity within the gas
stream
34. Dust collectors
3. Wet collectors
Collection mechanism:
Collect the droplets
Contact particles with water or another
liquid
Advantages:
Can handle high temperature & moisture
Dust which represent explosion or fire
hazards in the dry form can be wetted and
collected
38. Inspecting the air handling plant
1. Verification of design documentation, including
description of installation and functions
specification of the requirements
2. Operating procedures
3. Maintenance instructions
4. Maintenance records
5. Training logs
6. Environmental records
7. Walking around the plant
39. Conclusion
Air handling systems:
Play a major role in the quality of
pharmaceuticals
Must be designed properly, by professionals
Must be treated as a critical system
40. References
L.Lachman, The theory and practice
of industrial pharmacy
Bentleys textbook of pharmaceutics
Dust collectors – learning guide for
dust collectors [Internet]
Handbook of heating, ventilation &
air-conditioning.