Classification of Instruments

1. Biopharmaceutical
Manufacturing
Instrument
Classification

2. Instrument Classification
And
Identification

3. For biopharmaceutical applications,
instruments are generally classified
as critical or non-critical, with some
organizations allowing for a third
classification, diagnostic or reference.

4. Please note: The author does
not advocate the use of the
diagnostic or reference
designations. The concept of
an instrument that is not ever
calibrated, violates any concept
of good engineering or
maintenance practices.

5. Every instrument in a facility should
be identified as one of these
classifications. Generally, instruments
classified as critical are calibrated
typically on a quarterly schedule,
those classified as non-critical are
typically calibrated annually. The
diagnostic instruments are not
calibrated regularly.

6. The definitions of the various
classifications are not totally objective.
They usually have to allow for some
judgment in assigning the criticality of
the device. For example, following are
typical definitions used to distinguish
between critical and non-critical
instruments.

7. Critical Instrument: A process
instrument, the failure or
incorrect calibration of which
can create an immediate
negative impact on product
quality.

8. Non-Critical Instrument: A
process instrument, the failure or
incorrect calibration of which
may impact a secondary
processing system or a
non-quality related parameter of
the process.

9. Note that there is a lot of room for
maneuvering.
Since these definitions have to
apply to many different systems,
they cannot be exact. Judgment is
required, and wisdom to err on the
conservative side.

10. Examples of critical instruments
would be temperature recorders
on hot Water-For-Injection (WFI)
or steam sanitized USP Purified
Water systems.

11. Examples of non-critical
instruments could be a
pressure gauge on a
compressed air line for a line
supplying air to a pressure
reducer.

12. Identification means each
instrument must have a unique
identifying designation. This
identification will remain with the
instrument throughout its life and
allow for proper scheduling and
repair record. The designation
system is usually defined in the
Standard Operating Procedure
(SOP) for the Calibration System.