HVAC systems are an integral part of environmental control and include air handling units. AHU are large metal boxes that condition and circulate air, containing components like blowers, filters, and controls for temperature and humidity. Proper filtration is important for pharmaceutical facilities, utilizing filters like HEPA that can remove 99.97% of particles over 0.3 microns through mechanisms like impingement, diffusion, and interception. Dust collectors are also used to control air pollution and maintain clean environments through various collection methods. Regular inspection and maintenance of air handling systems is crucial to ensure quality pharmaceutical production.

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.

5. Air Handling Unit

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.

22. Mono disperse
particles
Poly disperse
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.

27. Dust collectors
Types of dust collectors
1) Dry mechanical collectors
2) Wet collectors & scrubbers
3) Fabric collectors
4) ESP

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

30. ESP

31. Dust collectors
2.Fabric collectors
Collection mechanism:
 Impaction
 Interception
 Diffusion
Advantages:
 can handle varying exhaust gas flow rates
& particle loading

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

33. Fabric collectors

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

35. Wet collectors
Types:
 Spray dryer
 Packed towers
 Wet centrifugal collectors
 Wet dynamic precipitator
 Venturi type
 Orifice type

36. Dust collectors
4. Dry centrifugal collectors
Collection efficiency is influenced by
 size, shape, weight of the particles
 Conc. Of dust & inlet velocity
Types
 Gravity seperators
 Inertial seperators
 Cyclone collectors
 High efficiency centrifugals

37. Cyclone filter

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.