068 - Back to School - Interpreting Sample Results

This episode of Fuel Pulse Show focuses on interpreting fuel test results, particularly for stored fuel samples. Host Erik Bjornstad guides listeners through various testing methods, including both ASTM D975 standard tests and predictive tests.The episode covers critical measurements like distillation temperatures, API gravity, cloud point, flashpoint, and cetane index, while also addressing water content and microbial testing. Practical solutions for addressing failing test results are provided, making this a comprehensive guide for fuel maintenance professionals.

What You'll Learn:

• How to interpret D975 standard fuel test results
• Understanding the significance of distillation test parameters
• The importance of API gravity measurements
• How to interpret cloud point and cold weather indicators
• The meaning of flashpoint test results
• Understanding cetane index and its impact on engine performance
• The significance of water content testing
• How to interpret stability and microbial test results
• Solutions for addressing various types of test failures
• How to handle multiple failing test scenarios

Ideas Worth Sharing:

Here are three notable quotes from the podcast episode:

• "Many of these options are ASTM tests, like those listed in the slate known as D 975. If it passes all the different D 975 tests, there's no reason that the fuel won't work properly if you use it."

• "Microbial testing is also predictive because if you have elevated microbial counts and you don't do anything, there's a very strong probability that they're going to cause problems in your fuel at some point in the future."

• "It's also not uncommon to have multiples of these tests coming back failing at the same time because of common factors that affect multiples of them at the same time."

Resources Mentioned:

• ASTM D975 specifications
• Bell Performance testing services
• Cold Flow Improver anti-gel solution
• Supertane cetane improver
• Erik Bjornstad: LinkedIn

Show Notes:

[00:00:00] - Introduction to episode and Back to School series
[00:01:00] - Discussion of different fuel test types and D975 specifications
[00:02:00] - Introduction to distillation test requirements
[00:03:00] - Explanation of API gravity testing and implications
[00:04:00] - Discussion of cloud point and cold filter plug point temperatures
[00:05:00] - Coverage of flashpoint specifications
[00:06:00] - Explanation of cetane index and its requirements
[00:07:00] - Details on total particulate testing
[00:08:00] - Introduction to water testing methods
[00:09:00] - Coverage of stability testing procedures
[00:10:00] - Discussion of microbial testing importance
[00:11:00] - Solutions for various test failures
[00:12:00] - Addressing multiple failing test scenarios
[00:13:00] - Closing remarks and call to action

Episode Transcript

(00:00):
Welcome to the Fuel Pulse Showpodcast where we talk about all
things fuel for all kinds of people.
I'm your host Eric Burenstedt.
I'll be your guide through theever changing world of fuel.
And today it's time for another episodeof Fuel Pulse Show, Back to School,
a series where we do short, condenseddiscussions of the major important

(00:24):
topics of fuel maintenance and fuel care.
Now, earlier in the series, wedid two episodes on fuel samples.
We talked about how to fuelsample, where in the tank is the
best place to pull samples from.
And we talked about how to handle thosesamples so that you get the best and most
useful test results, For your purposesin today's back to school episode,

(00:48):
we're digging into interpreting thetest results from the testing done
on those samples that you submitted.
We want to touch today on how tointerpret the different kinds of test
results with respect to what differentkinds of results might be telling
you about the condition of the fuel
and whether or what furtheraction might need to be taken.

(01:10):
So, let's dive in.
Now there are plenty of optionsfor different tests to be
run on stored fuel samples.
Many of these options are ASTM tests.
like those listed in theslate known as D 975.
If it passes all the different D 975tests, there's no reason that the fuel
won't work properly if you use it.

(01:32):
But that doesn't speak to whatmight happen in the future.
And that's where some of theadditional non D 975 tests come in.
These predictive tests so we're goingto try today to cover all the main
bases by going through the majortests that you'd be most likely
to consider for your stored fuel.

(01:52):
So let's start with the D 975 tests,which are often included in Test Slates
or Test Panels offered by testingcompanies like ALS or by companies,
service companies like Bell Performance.
If any of these test results areoff, the, whoever's doing the test
will generally note that in thetest results report so that you can

(02:17):
determine what you need to do next.
First, the distillation test.
Now, D 975 lists a 90 percentrecovery temperature, and the
specification says that the 90 percentrecovery temperature for your fuel
sample needs to be below a maximumbenchmark of 288 degrees centigrade.

(02:38):
If it falls above that, thentechnically it's out of spec because
it doesn't meet that D 975 requirement.
Now, that kind of situation could likelybe caused by either contamination with
a heavier fuel, which would, Raisethat temperature or it could be from

(02:58):
evaporation degrading in storage wherelighter fuel components over time would
evaporate out of that fuel, change itscomposition, skew that this 90 percent
distillation temperature upwards untilit exceeds the 288 degree maximum.
Now, if you were to use that fuel, yourengines going to run, but it's going

(03:20):
to have poor combustion qualities.
Peace.
Then you're not going to run asefficiently as you want it to.
Okay, API gravity.
API gravity is a basic test becauseit's simply an index of density.
Although it's actually inversely related.
If you will, the lower the APIgravity number, the heavier the fuel.
If the API gravity is.

(03:42):
too high, i.
e.
if the fuel is too light, thenthat can be caused by contamination
with a lighter fuel, like gasoline.
If the API gravity number is too low,which means the fuel is too heavy,
that too can come from contaminationwith a heavier fuel, which is gasoline.
But that can also come from that thingwe talked about before, from that

(04:03):
long term evaporation in storage.
Either way, if you try to use thefuel, it's again, it's probably
going to run, but it's going tocause engine operation problems that
aren't going to be ideal for you.
Okay, cloud point and coldfilter plug point temperatures.
Now, these are cold weather, gellingindicators, and they are listed in

(04:23):
D 975, but they don't have mandatoryspecs assigned to them because ASTM
recognizes that different parts of thecountry have different requirements
and they can't set one value.
That's going to be best for everybody.
So it is useful to know these values.
You want to note what that temperatureis for your fuel, because as you go into

(04:46):
the fall and in the winter, you're goingto be paying attention to the weather
forecast, and you're going to want toplan to put anti gel, like Cold Flow
Improver, into your stored fuel whenthe upcoming forecasted temperatures
are predicted to drop to within July.
10 degrees of your fuels cloud point,which means for most fuels is going

(05:09):
to be when the temperatures areforecast to drop below 30 to 32 degrees
flashpoint the D 975 specification.
wants it to be abovea certain temperature.
The D 975 says it has tobe a minimum of blank.
If the flashpoint is below thatminimum, it's likely because there

(05:33):
was contamination with a lighterfuel, like, let's say, gasoline.
Now, if you try to use it, you canrun into all sorts of engine and fuel
system issues cetane index, anotherone of those combustion properties.
Cetane index is actually done bya calculation from the density
and the distillation temperatures.

(05:54):
Now, D 975 wants your cetanevalue to be at least 40, right?
If it's too low You're not going tobet, get the optimal or best kind of
combustion or operation in your engine.
So you want it to be above 40.
Total particulate.
Total particulate addresses one of thetwo tests that are listed in the test.

(06:20):
a test, specific test that's actuallyin the 975 called water and sediment.
So total particulate is sometimesa test that's broken out from those
because they want to give you one testthat tells you how much particulates
in your fuel and they typically willthen pair it as we will see with

(06:40):
a test that just measures water.
Total particulate is.
The test that measures only particulatecontent and that is important because
if you have excess particulate in yourfuel it can cause all sorts of problems
in your engine and in your fuel system.
Since total particulate isn'tactually in D 975, there's not

(07:01):
an ASTM specification on this.
However, if we know that water andsediment, which does have a specification,
if we know that that specification, thatlimit, is 500 ppm, then let's say if
you have a total particulate of Three,then that would mean you would have to

(07:22):
have at the same time on that water testthat's going to go along with it, you'd
have to have close to 500 ppm just ofwater in order for both of those together
to be equivalent to a failing test.
And then the last one,water by Carl Fisher.
Water by Carl Fisher is actuallythe industry standard for measuring

(07:44):
total water content in fuel.
That means it measures all forms of water.
Every kind of water that's in the test,every kind of water that is in the fuel
is measured by water by Carl Fischer.
That means free water,suspended or emulsified water,
and also dissolved water.
D 975 does not give a waterlimit since D 975 leans on that

(08:09):
combo water and sediment test.
But many engine manufacturersdo have their own standards
or their own thresholds.
And generally speaking, they like it tobe below 200 parts per million water.
Okay, so you've got those tests.
And so we go from those to nowtalking about some of the important

(08:30):
non D975 tests that we wouldclassify as predictive tests.
So with that, we have the stability tests,oxidative and accelerated stability.
These are two versions of the same test.
They're accelerated test methods,where the method forces exposure
of a fuel sample to massive amountsof oxygen at any given time.

(08:52):
elevated temperatures to tryand speed up degradation.
The stability tests are predictivetests because they're giving you a
window into what's likely to happento the fuel over a period of time.
They just use a specialized testmethod to try and compress the time.
And so the lab report that youget is going to tell you if the

(09:16):
stability result is too high.
Now, if it is, one thing you do haveto keep in mind is a high stability
result does not mean that the fuelhas elevated particulate in it.
What it does mean is that the fuelcontains enough molecular precursors that

(09:37):
if they're left to their own devices overtime, they are going to be more likely to
form sediments and more likely to degradethe condition of the fuel in the future.
More likely than a fuel thathas a better stability score.
Okay, then the last oneis the microbial testing.
Now, in a way, microbial testing isdescriptive because it's trying to tell

(10:00):
you the level of microbial contaminationthat's in your fuel right now.
That's the definitionof a descriptive test.
But microbial testing is also predictivebecause if you have elevated microbial
counts and you don't do anything,there's a very strong probability that
they're going to cause problems inyour fuel at some point in the future.

(10:24):
So you definitely don't want to have anelevated microbial contamination reading.
Okay, so those are some of the tests.
Last thing to consider, what should youdo if you have elevated results on these?
Okay, so for certain of them thatwe started off with, flashpoint,
distillation, API gravity.

(10:45):
There's no simple chemical fix, if youwill, to make those go back in line.
You can try diluting the fuel withfresh fuel, fresh high quality fuel
to try and bring those back in line.
But if those don't work and if the problemis serious enough, then it's possible
you may need to get rid of the fuel.
You're just going to have to makea business judgment call on whether

(11:07):
it's worth it for you to do that.
Okay.
What about cloud point orcold filter plug point?
Well, those aren't.
things really that you can fix interms of changing the temperature
property of the fuel, but what youwill do is use that information to
tell you when you need to add antigen.

(11:27):
Okay, what about cetane value?
Well, if your cetane is toolow, you can add a chemical
cetane improver like supertane.
Now, how much you're going to needto add in order to raise it, how many
numbers, that depends on your fuel.
Stability testing.
If your stability testing comesback poor, that is a sign for you

(11:48):
to add stabilizer to the fuel.
Easy fix.
If the microbial test comesback with indications of high
contamination, then you need touse biocide to kill those microbes.
If the water and sediment or CarlFisher or total particulate tests
come back failing, that is a sure signthat you need to do fuel polishing.

(12:13):
It's also not uncommon to have multiplesof these tests coming back failing at the
same time because of common factors thataffect multiples of them at the same time.
So let's say you have botha failing microbe test and
a failing particulate test.
Your solution for both of those atthe same time would be to do fuel

(12:34):
polishing and you would want to addboth biocide and chemical stabilizer
during your polishing process toknock out those problems together.
And so that's going to do it fortoday's Fuel Pulse Show back to school
review of things to consider wheninterpreting test results that you

(12:54):
get back for your stored fuel samples.
If you liked what you heard andyou haven't done so already, feel
free to subscribe at your podcastplatform of choice and leave us
a review if you can because thatreally helps other people find us.
So until next time, I'm EricBierenstadt thanking you for joining
us and I'll see you next timeat the Fuel Pulse Show podcast.