From all at Validation
May we wish all of our
readers and customers a healthy and prosperous 2010.
temperature for us in the northern hemisphere continues to drop, it is important
to note that the current cost of energy is not yet conducive enough to encourage
facility engineers into validating their Air Handling Unit (AHU) settings. However it is widely anticipated that as
the economy starts to grow again, so will the cost of energy. Then it will be absolutely imperative to
ensure that AHU settings are optimised for minimum energy consumption.
used by an AHU varies with the design and capacity of the AHU. However there is an optimum balance that
all AHU’s should attain where there is just sufficient preheating; to allow,
just sufficient chilling; to condense out the excess humidity without
overcooling the air and then requiring a large energy input to reheat the air to
the required room; air entry temperature.
most troublesome sensor here is the humidity sensor. A three percent adverse error can cause
a fifteen percent increase in energy consumption. A ten percent adverse error can cause a
hundred percent increase in energy consumption. We recently dealt with a system where
the humidity sensor had ceased to operate and gave a continuous output of fifty
percent relative humidity. An
adverse error that would vary (depending on ambient humidity) between zero and
one hundred percent and cause (in the worst instance) a five hundred percent
increase in energy requirements.
southern hemisphere where the requirement is often to reduce temperature and
humidity, faulty humidity sensing often results in air that is over-dried;
having to be re-humidified prior to room entry. This results in energy consumption that
is far higher than necessary.
Calibration of Humidity
& Hygrometer Sensors.
Humidity sensors require frequent calibration and continual monitoring, they are, along
with pH sensors, the most prone
to error sensors in general facility use. They should be calibrated against a
range of Chemical mixtures that establish a specified humidity calibration level
in small atmospheric containers. These chemical mixtures are
issued with UKAS traceable humidity
calibration certification. They are supplied in a kit that
includes three certified standards covering the low mid and high sectors of the
relative humidity calibration percentage range.
The kit includes three ready to use enclosures (with certification
of their values), a range of adaptors to suit your sensors, a sample FDA compliant calibration certificate and a
complete detailed method statement on exactly what to do. All
these items are contained in a robust neat and easy to handle carrying case.
To read more or purchase your test kit please click on
Are you ready
for an inspection?
With HEPA filters, the manufacturers recommended dirty filter
change pressure differential (PD), is only correct if the filter is used at
exactly the the same air flow as the makers specify. If there is any digression
(there is often as much as 50% digression) then the makers PD must be corrected.
If this is not carried out you can compromise the integrity of your room /
machine pressure regimes. As you are no doubt aware this would be a very serious
state to be in. There are also health and safety problems that can arise, if
personnel are not getting the air flow protection that is sometimes designed
into the system. This test script is not in the standard OQ, and is only
available here as a download. Regulators ask to review your writen
justification for these filter change PD's; make certain you have
Purchase your copy of this test script now at Special Price of
Click Here - To Download Your Own Free Pharmaceutical Glossary.
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