An engineer poster here tom.k ran tests that revealed gauging was usually inconsequential regarding psi EXCEPT when done carelessly. Way too much opportunity for someone with an agenda to "accidentally" let several tenths of a psi out to allow such gauging.
Correct.
Just by doing the tests, I learned several things, that I hadn't previously realized, about something as simple as sticking a needle into a football.
1) mach 1 spit works just fine as a lubricant for the needle. Use it every time.
2) clean out the top of the valve & the outside of the needle before measuring. Any grit or dirt can be pushed into the valve, causing an immediate leak, or a long term leak after the needle is removed.
3) The easiest way to let air out unintentionally, is to put any side pressure on the needle. This causes the valve to "ovalize", & an oval valve won't seal on a cylindrical needle. This DID happen to me a couple of times before I got my technique down.
4) With bad technique (producing a momentary hiss), you could lose 0.05 - 0.1 psi per measurement.
With horrible technique (producing a long hiss), you could lose nearly 0.2 psi per measurement.
5) because of 3) above, the best technique is to quickly sink the needle ALL THE WAY into the valve in one fast stroke, bottoming out on the needle housing. This allows you to support the body of the pressure gauge against the surface of the football. Pushing the needle in half-way, then trying to hold the gauge in the right position such that the needle stays straight while you take a reading, is a good way to bleed air out of the ball.
I knew that I was going to be doing a lot of pressure measurements, & I wanted to know exactly how much those measurements were going to change the pressure. So I ran a check of about 30 sequential measurements per ball, without any other change to their condition.
Using the above techniques, I found that it took a fairly consistent 9-12 measurements to drop the pressure in the ball by 0.1 psi. Or around 0.01 psi per measurement. So this is inconsequential.
I assume that anyone who checks pressure often (such as the ball boys & refs) will stumble onto these tricks.
I don't believe that the typical NFL player, coach or team official (e.g., GM) will inflate balls very often.
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With regard to the Colts' measuring the intercepted ball:
Assuming the Colts were NOT attempting to "rig" the results with lots of air-releasing measurements, it seems clear to me that they would have had to have done at least 4 measurements, most likely 6 to 8, on one ball only.
The first time by whoever had suspicion that something was "wrong". (Grigson? Who actually did the measurement? Grigson or a ball boy?)
A 2nd check by the same person, just to make sure.
A 3rd check, to show other Colts' officials/coaches, to decide whether to protest.
A 4th time to show a referee.
Then perhaps a 5th time for the ref to do the measurement himself, to convince himself that the pressure was low.
(Note that, when taking measurements and something comes up "unexpected", there is always a tendency to repeat the measurement, looking for consistency.)
Then the ref would have become suspicious & asked for the Pats balls, down on the field.
Likely he would have checked 2 to 4 of those balls, perhaps once each.
And then, when the ref was convinced the readings were low, he gathered up all the Pats balls & brings them to the locker room, that one ball gets a 6th check.
In this scenario, one ball gets checked about 5-8 times.
2 to 4 balls get checked twice.
The remaining balls get checked once.
But even with 7 measurements, the pressure drop in that one ball should have been only about 0.07 psi.
As long as they were checked with good technique.
That minimal error is inconsequential to the discussion.
And lost in the noise of the resolution & accuracy of the gauges.
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I don't believe that it is illegal to check the pressure of any ball, according to the rules, unless they attempted to re-introduce that ball into play.
I don't think that there is any way to do that, or any intention to do that, because the Pats' balls are kept on the Pats' side of the field. And handled by the Pats' ball boys. None of the Pats' players or ball boys are going to take a ball from a Colt player & introduce it into the mix. If they had, it would have come out already.
As to whether or not it was legal for the refs to re-inflate the Pats' balls, I believe that it was not legal. But I'm inclined to give the refs the benefit of the doubt. Even tho they were wrong to do so, I believe it is likely that they viewed it as "correcting a faulty condition."
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Finally, I believe that the whole question of "did the Colts let air out of the one ball they intercepted" is a fair misdirection (that can only be responsible for about 0.1 psi drop of one ball), because the cold wet conditions will clearly, unequivocally, be responsible for a 1.5 psi pressure loss in the Pats' balls.
