Working on a quick reference for CF per 100PSI

[Ulfhedinn]

LP 85’s (85/2640) X2 X100 = 6.4 FT3 per 100 PSI
LP 104 (104/2640) X2 X100=7.8 FT3 per 100 PSI
LP 72 (72/2475) X2 x100 = 7.8 FT3 per 100P PSI
LP 95 (95/2475) X2 X100 = 7.19 (2) FT3 per 100PSI "or would you round down"

Is my thinking correct?

Why do I feel the math is wrong at least as to the 72?

 

[Manatee Diver]

That is called tank factor. I don't have my chart in front of me (I have a set in my wet notes), so I only know two of them on the top of my head. The LP85 is correct, but for LP10X tanks we use 8.0 as the tank factor for all those tanks. AL80s are 2.5/5.0, another one I know off the top of my head for planning stage dives.

 

[Bob DBF]

Why do I feel the math is wrong at least as to the 72?

Because it is?

72/2640 X 100 = 2.9, and I assume doubles X2 = 5.8

 

[Gone for diving]

I just want to know how many psi to 1 cuft... I'll write it on the tank or doubles

 

[Ulfhedinn]

Because it is?

72/2640 X 100 = 2.9, and I assume doubles X2 = 5.8

for the life of me.. I must have put that calculation in my computer 10 times.. then I look at your reference and bam it work.

and TY

MATH

 

[Manatee Diver]

I just want to know how many psi to 1 cuft... I'll write it on the tank or doubles

Divide 100psi by the tank factor.

But I would find that more difficult to work with.

Which is easier dividing 2,400 by 15 psi? Or multiplying 6.4 by 24? I find multiplying easier as the numbers are smaller and easier to manage. Though the only time we use tank factors is dive planning, and just before the dive starts to do dissimilar tank matching for thirds. All the other important numbers, like mingas, are already calculated during dive planning.

 

[Ulfhedinn]

That is called tank factor. I don't have my chart in front of me (I have a set in my wet notes), so I only know two of them on the top of my head. The LP85 is correct, but for LP10X tanks we use 8.0 as the tank factor for all those tanks. AL80s are 2.5/5.0, another one I know off the top of my head for planning stage dives.

Yep working in a sheet I can cram in my wetnotes. I have some GUE notes already but sometimes for me at least I need to look at math in different ways for it to click.

 

[OrcasC205]

Because it is?

72/2640 X 100 = 2.9, and I assume doubles X2 = 5.8

Your answer is correct, but that should be 72/2475 x 100 = 2.9.

I just use a tank factor of 3 (or 6 for doubles) for LP72s, LP85s or HP100s since it is close enough for scuba math.

 

[Bob DBF]

Your answer is correct, but that should be 72/2475 x 100 = 2.9.

I did the math on the right figures on his list, but copied the wrong denominator when copying off the list.

Thanks.

 

[tbone1004]

The LP95 should be over 2640 not 2475.

Remember when you do the HP tanks that you use the Z-factor or their LP equivalents. I.e. LP95-HP119, LP104-HP130. They have the same water volumes so should have the same tank factor. Z is close enough to 1 at 2640 that it's not an issue, but at 3500psi it's a legit issue.