| Author | Message | Stephen Perrera 
Posts: 823
Since: 5/27/2008
|  6/18/2008 1:33:33 PM 
I can see that happening Stephen........ WOW>..... if you did not get shot before leaving the house, you would never work again.
Yes but there is a formula for finding psi of a radius. Lee just called me and told me how to do it.
I heard it is used in reports if the manufacture has limits designated. How else would you do it?
Would you tell them no I cannot figure it out?
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| Selva Lee Tucker
Posts: 634
Since: 5/25/2008
| 6/18/2008 4:25:34 PM
No Ray, we do not do PSI tests in the field, but, this is a tool just
like calculating MC/milling using the formula in the Wood
Handbook.
It is a tool to demonstrate what has happen and how.
Now, have you or anyone here ever used the PSI of a woman in
high heel shoes in a report to describe the small round indents
in a wood floor or vinyl floor to explain how they happen?
Come now, an honest answer. I am sure all inspectors on this
site has, if not in a report, then in a verbal explanation, use this
example.
It is also why they teach it at the Memphis class to show and
understand how and why indents happen in wood.
You can, measure the diameter of a circular indent,,,,now, also,
there are formulas that can calculate more, but, I will stay away
from that,,,,it will measure how much a wood will recover from
stress on wood. So, wood will recover some, but not completely
if enough force is applied,,,,and that, is another discussion from
this.
So, am I saying do PSI tests in the field? no, but, you can
measure the bottom of a chair leg, and do some "examples of"
to explain how it happen if you are called upon to explain how
the wood/cork/vinyl will indent in their home.
so, if Ray is sitting in a chair, it indents the floor. He says, how
did this happen with my flooring? so, Ray is about 180 lbs. / 4
(4 chair legs 1/8" diameter) /area = psi. so, is that about 110
pounds of pressure? ok, now, people tend to sit more at the
back of a chair, so, there is more weight there, ever notice how
the indents tend to be more from the rear legs? I have, start to
take notice and you will see this. Also look to the shape at the
rear indents, and you will see how they are shaped at a slant or
angle where the edge was dug into the product at an angle. This
will increase the pressure exponentially and that will require a
very very smart person to calculate. People like to lean back in
their chairs which decreases the area pressing into the flooring
increasing the pressure.
Last Edited 6/18/2008
5:04:16 PM
| |
| Ray Darrah
Posts: 1411
Since: 2/18/2008
| 6/18/2008 7:28:18 PM
Are you saying you perform PSI testing in the field?
| |
| David Kern
Posts: 518
Since: 2/20/2008
| 6/18/2008 7:47:34 PM
quote:
Are you saying you perform PSI testing in the field?
'So, am I saying do PSI tests in the field? no, but, you can measure the bottom of a chair leg, and do some "examples of" to explain how it happen if you are called upon to explain how the wood/cork/vinyl will indent in their home.'
| |
| Ray Darrah
Posts: 1411
Since: 2/18/2008
| 6/18/2008 9:07:50 PM
thank you for clarification.
| |
| Selva Lee Tucker
Posts: 634
Since: 5/25/2008
| 6/18/2008 11:10:54 PM
Thank you David,
the idea is to understand! what is happening, how it happens,
and
be able to explain it to others.
Inspections should be more than just reporting observations if
we
are to be considered the "experts"... and we should be able to
help
to further education to help people, not just report, "installer
error
or manufacturing defect or site conditions". That does nothing
to
advance our industry and help the least among us.
Dang, here I am preaching again. sorry, time to go...
by the way,,,,did you guys see Boston Kick big time on LA last
night!
congrats to Boston! NBA Best
| |
| Ray Darrah
Posts: 1411
Since: 2/18/2008
| 6/19/2008 2:50:52 PM
Most manufacturers require felt or state "plastic buttons will dent" and void warranty.
Stephen: we don't do psi testing and in 20 years; it has NEVER been an issue.
I have sent in materials for j. testing to see if they meet minimum standards. Lots of bamboo sent in for testing and it was TOOOOOOO soft.
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| Stephen Perrera
Posts: 823
Since: 5/27/2008
| 6/19/2008 3:45:06 PM
Ray, I think your confusing "testing" the flooring itself and "calculating" the psi.
| |
| Selva Lee Tucker
Posts: 634
Since: 5/25/2008
| 6/19/2008 6:08:00 PM
he is Stephen,
but, what he really wants to know is how to do it,
pounds/Pi*r2
Ray,
I know you know the difference, everyone in the industry uses
this,
example, remember the lit Mannington used to put out how
much
PSI a woman with high heels would exert upon they vinyl?
120 pound woman = 1200 plus or 1250 or so PSI???? Now Ray, I
know you remember that from the Mannington inspection
school way back in 1994,,,you and I both were there,,,,so, I
know you know!  Don't make me have to call Karen on
you,,,,she is tougher than you and I both, and we both know
that also....
the tech department of one carpet mill that use to be in the
small town below Macon,GA use to have me measure the size of
whatever object was indenting their carpet that would not
recover and "estimate" or "estiguess!" the weight so they could
have an idea how their carpet performed....
so, if the lady is wearing 1/4 wide heels, what is the radius? and
what is the PSI she is exerting upon the flooring?
is it 1250 PSI?
Last Edited 6/19/2008
6:08:31 PM
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| David Kern
Posts: 518
Since: 2/20/2008
| 6/19/2008 6:21:17 PM
My educated guess is 2400 PSI...
The smaller the heel the greater PSI, so a 3/16 heel exerts some 4286 PSI.
Last Edited 6/19/2008
6:24:07 PM
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| David Kern
Posts: 518
Since: 2/20/2008
| 6/19/2008 6:34:01 PM
How to do the math:
convert 1/4 inch to decimal = .25
divide this by 2 = .125
multiply by itself = .016
multiply by 3.14 = .050
divide into 1 (for 1 square inch) = 20
multiply by 120 lb woman = 2400 PSI
Of course I could be wrong 
Last Edited 6/19/2008
6:37:45 PM
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| Ray Darrah
Posts: 1411
Since: 2/18/2008
| 6/19/2008 7:06:11 PM
Stephen,
I am not confusing the "so called" test with testing the material.
We don't do psi testing.
We send in the material for J. Testing.
Selva is describing a manufacturer of commercial carpet that is the claims department for Mohawk. Mohawk tech services out of Dalton sends the claims to the inspectors, not the claims department. And that claims department was moved (if memory serves).
Mannington taught psi as an example only, not the procedure. They never asked us to perform psi field testing.
I'll not perform psi field tests.
Question:
If you have a plastic button on the bottom of a chair, How much of the plastic button is touching, or in contact with the floor?
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| Stephen Perrera
Posts: 823
Since: 5/27/2008
| 6/19/2008 7:46:19 PM
Question:
If you have a plastic button on the bottom of a chair, How much of the plastic button is touching, or in contact with the floor?
Don't tell him Lee!
Here's a question for ya: Whats the max psi for a hardwood floor? Is it different for an engineered wood floor? For vinyl or carpet?
Someone said the manufacture testing product and found too much psi was applied to it? How do they come about these figures? Are the secret?
Does the janka ball test reflect on max psi on a hardwood floor?
Just rattling.
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| Ray Darrah
Posts: 1411
Since: 2/18/2008
| 6/19/2008 8:31:09 PM
The Janka hardness test for hardwood flooring measures the force required to embed a .444 inch steel ball to half its diameter in the hardwood meant for flooring. The hardness is expressed numerically as the pounds per square inch of pressure required to sink the ball into the species of hardwood meant for flooring; the higher the number the harder the hardwood for flooring. Janka hardness scale is the industry standard for judging the ability of various hardwood flooring species to withstand denting and wear. It also indicates the effort required to either nail or saw the particular wood and therefore, also helps determine whether the hardwood is suitable for flooring or not. Red Oak hardwood flooring, which has a Janka rating of 1290, is the flooring industry benchmark for comparing the relative hardness of different wood species.
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| Selva Lee Tucker
Posts: 634
Since: 5/25/2008
| 6/19/2008 10:25:37 PM
Ray,
once again, no one is testing. To do the test, I would have
someone, as you said, apply the weight to the material to see
the results,
all I am doing, is calculating PSI for a measured area and known
weight.....that is not a lab test,,,,
did you see anywhere I stated anything about hardness?
or softness?
No, this is used for vinyl, carpet, wood, all surfaces, if you have
the size and weight, you can calculate PSI,,,,
knowing how hardheaded you can be, call up either one of our
two engineering friends, and find out.
I know you will never listen to me, but I know you will listen to
one of them.
At this point, further discussion in useless.
Ok
pi is 3.14...
if the radius is 1/8 = .125(2)= .0156 X 3.14 = .0490
60 pounds/ .0490 = 1224.
here is a funny thing, seems each calculator gives a slightly
different number??? I wonder why that is?
so, you guys can calculate the PSI if two facts are known, the
radius and the weight....
there you go Ray, if you had only asked, I would have told you,,,
Ray, M.M. and Dr. Cr. Dew. taught this a few years ago at the
NOFMA class,,,and they taught it to show us a way to
understand indents,,,such I posted here so guys can have an
understanding of the amount of pressure they may be seeing in
the field....understanding what we see, is important.
Now, I just deleted a big bunch of preaching at you,,,,I figure
you done been preached at enough lately,,,,
so, go back to NOFMA this year, and ask them to go over that
again, each year is a little different and each year, new stuff is
added but because new material is added, sometimes, they do
not go over some stuff from years before. That is why it is good
to go back each year,,,,learning is fun,,,,I enjoy it,,,
If I send in a sample, and ask them to test the hardness, they
will do the test you describe and state the results. But, that is
not what I am saying or doing,,,,
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Don't make me have to call Karen on 