Chemical Engineering September 2014 - 44

Department Editor: Scott Jenkins
Safe Sampling of
Heat-Transfer
Fluids
ollecting representative samples of heattransfer
fluid for routine quality checks falls
short of the goal if safety or the environment
is compromised. While users should
consider their systems' unique design features
in consultation with their safety and health
experts, incorporating the tips below can help
to avoid common potential safety concerns associated
with sampling these fluids, which may
be at extreme temperatures. Understanding
these safety issues is the first step in planning a
safely conducted task.
C
Ergonomics
Safe access to heat-transfer-fluid sample ports
is a key part of an ergonomically designed
station. Important aspects of a well-designed
sampling station include the following:
* Clear standing area with unobstructed path
of egress
* Height of sample port below chest-high, to
avoid upper body splash
* Limited extent of reach required to avoid
body strain
* Space beneath sample port to allow handsfree
placement of a properly labelled flush
bucket
* Non-slip, solid floor surfaces to prevent drips
to a lower level
* Globe valves in sample port are preferred
for the best control of flowrate
Extreme temperatures
Representative samples are best collected
during operation, when the fluid is uniformly
mixed throughout the system. Heat-transfer
fluids routinely reach temperatures that can
present thermal burn hazards. The following
tips are for sampling hot streams:
* Review safety data sheets (SDS) for the
personal protective equipment (PPE) that is
required for the fluid being sampled, as well
as its physical and chemical properties, and
hazard information
* Use a sample cooler to reduce fluid temperature
to below 93ºC (200ºF) to protect sample
composition integrity
* Wear gloves that provide chemical and thermal
protection, as well as a splash apron,
eye goggles and a face shield
* Inspect the port area for uninsulated contact
points to avoid
* Avoid drips which may occur before, during
or after collection
* Do not remove PPE until the port and sample
bottle are secured
Splashes and spray
Even with the proper PPE in use, initiating flow
from the sample port is a transient operation
that can result in splatter or spray, and efforts
should be made to limit the splash potential.
Since the fluid may be hot, it is important to
take precautions against accidental hot-fluid
contact to avoid thermal burns. Thermal burns
are the single greatest safety concern to
personnel working with high-temperature fluids
and equipment. Use of a globe valve can
provide better flow control when opening the
sample port.
Think ahead to plan what actions will be
taken in the event of an unexpected spray.
Anticipate pressure on the line when opening
the port valve, and open the valve gradually.
Stand to the side so that any spray will
be directed away from potential physical
contact. One technique to better control the
sample stream is to install a short length
of small-diameter tubing on the sample
valve outlet, which steadies the stream and
also permits easy insertion into the neck of
sample bottles.
When flushing the sample port prior to
collecting the " good " sample, direct the stream
into a dry bucket. Any moisture in the flush
bucket can result in violent splatter of the hot
heat-transfer fluid into the vicinity, if the sample
stream is above the boiling point of water.
Take the time needed to sample the fluid
safely. Rushing to perform this task can pose
unnecessary safety risks for those collecting the
fluid samples.
Spills
By expecting the unexpected, we can prepare
adequately to avoid potential spills and their
consequences, or minimize their extent and
impact. A well-placed sample port will be at
ground level with little exposure to sewers or
floor drains. A small, curbed area can help
keep small releases contained. Above all, efforts
should be taken to keep potential releases
of organic heat-transfer fluids from drains and
waterways. If a storm drain is in the area, it
should be adequately covered or otherwise
blocked during sample collection.
High-temperature heat-transfer fluids are
commonly organic liquids, and suitable dry,
absorbent media should be available in the
area for response to stabilize and aid in cleanup.
These fluids are also likely to be combustible,
and clean-up should be performed
promptly.
Some heat-transfer fluids may have unique
spill clean-up and disposal methods that are
directed by their manufacturers, so refer to the
product SDS for specific guidance.
Finally, any fluid residues will also create a
hazard by making walking surfaces, handrails,
or coated structures slippery. To avoid slips
and falls, and to avoid fueling a fire, these
residues should also be cleaned. Oil-absorbent
cloths and socks can also be used to help keep
the areas clean. Additional clean-up may be
done with appropriate detergents or chemical
cleaners.
Inhalation
Each heat-transfer fluid chemistry can be different,
so learn about the unique requirements
of each one from the supplier's literature. Key
concepts to avoid unnecessary exposure to
fluid vapors are the following:
* Cooler fluid has lower vapor pressure, and
provides less exposure
* Stand upwind of the sample port during
flushing and sampling
* Place a lid over the sample port flush bucket
when finished
* Promptly cap and seal the sample bottle
once filled
For products containing components that have
established airborne-exposure limits, consult
with an industrial hygiene technician about the
need for respiratory protection. In many cases,
proper job planning and sample cooling may
eliminate the need for respiratory protection.
Finishing the job well
Now that the sample has been collected, it
is ready for packaging and shipment to the
laboratory for analysis. While most organic
heat-transfer fluids are not regulated for
transport by the U.S. Dept. of Transportation
(Washington, D.C.; www.dot.gov) for sample
quantities, the bottle should be packed properly
so that it remains leak- and damage-free
until it arrives at its destination.
Bottles should be protected against breakage.
Metal containers offer the greatest
resistance, and glass containers will require
adequate packing materials. Precautions
against container leakage can include the
following actions:
* Ensure all seals are properly in place in the
neck and mouth of the bottle
* Do not use substitute parts for liquid seals
* Apply tape to the outside of the tightly-sealed
container cap
* Place the bottle within a chemically compatible
bag, which is then closed to prevent
liquid escape into the outer package
* Foam packing (pre-formed, or " peanuts " )
can be placed around the sample container
to protect it against sharp blows
* Properly dispose of fluid collected in the
sample-port flush bucket
References
1. " Therminol Information Bulletin #2: In-Use
Testing of Therminol Heat Transfer Fluids. Pub.
#7239112C, Solutia Inc., a subsidiary of Eastman
Chemical Co.
2. " Liquid Phase Design Guide " Pub. #TF-04,
5/14, Eastman Chemical Co.
Editor's note: The content for this column was provided
by Eastman Chemical Co. (Kingsport, Tenn.;
www.eastman.com).
Eastman and Therminol are trademarks of Eastman
Chemical Co. or its subsidiaries.
DISCLAIMER: Although the information and recommendations set forth herein are presented in good faith, Eastman Chemical
Co. and its subsidiaries make no representations or warranties as to the completeness or accuracy thereof. You must
make your own determination of suitability and completeness for your own use, for the protection of the environment and
for the health and safety of your employees and purchasers of your products. Nothing contained herein is to be construed
as a recommendation to use any product, process, equipment or formulation in conflict with any patent, and we make no
representations or warranties, express or implied, that the use thereof will not infringe any patent. NO REPRESENTATIONS
OR WARRANTIES, EITHER EXPRESS OR IMPLIED, OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
OF ANY OTHER NATURE ARE MADE HEREUNDER WITH RESPECT TO INFORMATION OR THE PRODUCT TO WHICH
INFORMATION REFERS AND NOTHING HEREIN WAIVES ANY OF THE SELLER'S CONDITIONS OF SALE. Safety Data
Sheets providing safety precautions that should be observed when handling and storing our products are available online
or by request. You should obtain and review available material safety information before handling our products. If any
materials mentioned are not our products, appropriate industrial hygiene and other safety precautions recommended by
their manufacturers should be observed.

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Chemical Engineering September 2014

Table of Contents for the Digital Edition of Chemical Engineering September 2014