Chemical Engineering March 2019 - 30

Facts At Your Fingertips
Hygienic Process Equipment Fabrication
Department Editor: Scott Jenkins
n hygienic process operations,
proper system construction and
fabrication has the greatest influence
on end-product quality and the
success of process validation. Even
well-designed hygienic systems can
be compromised by leaching, poor
internal finishes and mishandled material
sourcing and other fabrication
issues. All can lead to contamination
and bacterial growth in the system.
This one-page reference provides
information on key quality-assurance
procedures for the fabrication and assembly
of hygienic systems that will
help prevent contamination and bacteria
growth during operation.
Contamination can come from unlikely
sources, such as process media
reacting with rubber over time,
causing carbon to be extracted from
rubber parts. Pipes can have improper
finishes or poor welds, creating
safe harbors for bacteria to grow.
Following proper procedures can
minimize potential issues.
I
Setup considerations
The following are considerations for
each stage of the hygienic process
build, from sourcing to assembly.
Parts and materials purchasing.
From raw metal suppliers to shop
welders, materials must be handled
properly, and procedures should create
individual responsibilities for verifying
proper handling at every step.
Important information includes the
source of the metal materials and
what requirements those materials
need to meet. Determine what
documentation (for example, proof
of chemical composition) is needed
from each supplier and conduct a review
of the orders to verify that they
meet the requirements for materials
of construction.
Material handling. During sourcing
of process components, it is
important to know how equipment
parts and materials are handled and
shipped from the supplier. For example,
what do parts touch during
shipping and how are they handled
during receiving? Once the parts
arrive, there should also be an or30
TABLE
1. EXAMPLE HYGIENIC FABRICATION QUALITY AUDIT
Activity / inspection and test required
Verify that all tubing, piping, fittings and valves are capped, except when being used
in fabrication
Storage area is clean and free of contaminants
Pipe and fittings are segregated by material type, size, surface finish and so on
Stainless-steel, aluminum and high-alloy piping is covered and off the ground
Material and parts are staged and stored with protection in assigned area
Verify forklift forks, hooks and straps are protected against cross-contamination
Verify fabricators, welders, welding operators or inspection personnel are wearing
clean, white cotton, lint-free or latex gloves when around interior product surfaces or
unwelded joints on impact piping
Verify gas certifications received and displayed on stainless dewar cylinders
Weld sample board made and kept in fabrication area
Verify lint-free wipes are of desired brand
Verify marking pens are " white low-chloride marker " for use on stainless steel
Verify that tables used in fabrication are protected agaist cross-contamination
Verify that high-purity argon (99.999%) is available for shielding and purge, and is
stored in stainless-steel dewars with test report attached from supplier
Verify argon hoses for welding equipment and purging are plastic (not rubber)
Verify tools are color coded for hygenic stainless steel use only
Verify material and parts are being cleaned with denatured alcohol and lint-free wipes
Verify project work area is clean and orderly. Ensure that tools are put away and fabrication
area is cleaned at the end of each day
Verify that post-weld shielding and purge gas is greater than 30 seconds
ganized way to identify parts at the
facility. Also, a procedure is needed
to verify the mill test report (MTR) review,
logging and tracking. What are
the conditions under which parts are
stored and who is responsible?
Fabrication and assembly. A procedure
should be in place to approve
parts and materials for use, as well as
to ensure that parts are fabricated,
welded and tested correctly. A thirdparty
Level-2 certified welding inspector
(CWI) should inspecting welds in
the process equipment.
Fabrication quality audit
Conducting a fabrication quality audit
can help ensure that necessary quality
assurance activities are completed
according to the correct procedures.
An example audit list, showing activities,
inspections and tests, is presented
in Table 1. Proper storage methods
are included for verification. Also, the
standards (not shown here) against
which the activities should be verified
are listed next to each item with a personal
sign-off to verify proper procedures
have been followed throughout.
Validation sheets matching each procedure
ensures the process was followed
and documented. The followResponsible
department
Quality
control (QC)
Engineering / QC
Receiving/Eng./ QC
Rec./Eng./ QC
Rec./Eng./ QC
QC
QC
QC
Eng./QC
Eng./QC
Eng./QC
Eng./QC
Eng./QC
Eng./QC
QC
QC
SF/ QC
QC
Source: EPIC Quality Assurance team
ing are areas that would be covered
by hygienic quality assurance audit:
Weld documentation. This includes
the welder's name, when the weld
was performed, and what materials
were used. Also included is which
weld procedure was performed and
whether it was the proper procedure.
Other questions include: how much
oxygen was used during the welding?
Who inspected the weld and when?
Assembly documentation. This includes,
for example, the type of gaskets
used, documentation showing
where they were used and the date installed,
as well as an audit of all joints,
verifying that the correct gaskets are
present and correctly installed.
Proper fabrication validation. As
an example, hygienic systems are
designed to eliminate dead legs
during fabrication. Questions that
should be asked include the following:
is everything on the assembled
system properly sloped? Were pockets
created during fabrication? Did all
piping get processed to the correct
internal finish? Which requirement
are you verifying against?
n
Editor's note: Content for this column was provided by Jeff
Koenigs, principal project manager and professional engineer,
EPIC Process Systems (www.epicmodularprocess.com)
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
MARCH 2019

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Chemical Engineering March 2019

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