HVAC VALIDATION IN A
NUTSHELL
In the series as I promised this is new article on HVAC validation for
pharma foxes. It should be noted that my articles are especially for those
peoples who are very ambitious and searching new opportunities on upper levels.
In HVAC Heating (from boiler), Ventilation (To provide fresh air for
breathing) and Air conditioning unit
zones are covered and now need a well optimized validation strategy to
accomplish the mandatory requirements of national and International regulations.
The validation programme is conducted through a protocol. Following 10
parameters are validated.
1. Air flow pattern: This parameter is validated by burning Titanium tetra chloride stick
and keeping the burning stick in front of air handling unit. Make the chart
diagram of smoke movement.
2.1 Air Velocity: Divide the HEPA filter into four hypothetical grid and record the air
velocity at the center of each grid by Velometer. Calculate the average velocity.
For class 100 zone limit is 90 feet/minute.
2.2 Changes per hour: Changes per hour is calculated using following frormulae
Changes per hour: Total
air change
Total volume of the room
For class 100 limit is 100 cycle/hour.
3. HEPA/ULPA filter leak test: Check the velocity of air by placing Velometer at all
corners of air handling unit. If speed of air is not crossing the prefixed air speed limit at any point then
there is no leakage in HEPA filter.
4. Particle count: Check the particle count of room “at rest” and “in operation” ( after at
least one hour routine work) position.
5. Viable monitoring: Place the petrisish in the air sampler and operate the sampler as per
corresponding sop and observe the microbial load. For class 100 limit is <
1.
6. Filter integrity test (DOP/PAO test): DOP (Di octyl phthalate) aerosol was previously used
but due to the carcinogenic nature it was replaced by PAO (Poly alpha olefin)
in 2001. Generate the aerosol by aerosol generator at 20 psi at supply duct in
the AHU. Stabilize for 5 minute and ensure that 100% upstream concentration is
achieved at the all terminals of HEPA.
7. Pressure difference: This parameter is validated by checking pressure difference with the
help of Manometer in the room and from one room to another room.
8. Recovery (temperature and humidity): This parameter is validated when humidity/temperature
of the zone is within limit. First shut down the AHU then increase the humidity
upto a suitable level (usually 75%) by spraying hot water in the zone. Now
operate the HVAC system and count the time taken to reduce humidity within the
acceptance criteria. For the Temperature recovery shut down the AHU and
increase the temperature (usually 40ºC) of the specified zone with the help of
blower. Start the AHU and record the time taken by AHU to reduce the
temperature within acceptance criteria.
9. Temperature and humidity uniformity test: This parameter is validated with the help of
calibrated Thermometer and calibrated Hygrometer by putting them in different
locations and observing the temperature and humidity in running AHU position as
specified in protocol.
10. Fresh air determination test: Calculate the fresh air intake by Dumper in the room
and total air change per pour.
% Fresh air intake = The intake fresh air
Total air change
Clean room zones as per different Regulations: There are mainly 4 guidelines on clean room zones, FED std 209(E),
ISO 14644, EU GMP and British std. It should be noted that particles of size
≥0.5µ and ≥5µ are considered in pharma industry.
Class
|
≥ 0.5µ/feet3
|
≥ 5µ/ feet3
|
Air changes/hour
|
Microbes
|
100
|
100
|
0.7
|
100
|
< 1
|
1000
|
1000
|
7
|
100
|
<10
|
10000
|
10000
|
70
|
50
|
<100
|
100000
|
100000
|
700
|
20
|
<200
|
ISO 14644: This is globally accepted and came into effect after Federal standard
expiration. All zones are segregated from class 1 to class 9.Class 5 to 8 for
Pharmaceutical industry and remaining for Electronics and other industries.
Class
|
≥ 0.5µ/meter3
|
≥ 5µ/meter3
|
5
|
3520
|
29
|
6
|
35200
|
293
|
7
|
352000
|
2930
|
8
|
3520000
|
29300
|
EU GMP: EU GMP
is very popular in pharma industry. It should be noted that all the
aforementioned/below zones are equivalent to each other.
Class
|
At rest (per meter3)
|
In
operation (per meter3)
| ||
≥0.5µ
|
≥ 5µ
|
≥0.5µ
|
≥ 5µ
| |
A
|
3520
|
20
|
3520
|
20
|
B
|
3520
|
29
|
352000
|
2900
|
C
|
352000
|
2900
|
3520000
|
29000
|
D
|
3520000
|
29000
|
N/A
|
N/A
|