LP 95 vs. HP 100

[SteveTW]

I was told that both the LP95 and the HP100 hold 'almost the same amount of air. I understand that there's only a 5cf. difference in tank size but the pressure difference is quite a bit off.

My question is this:
For the same diver and dive, will you be able to do the same dive, time wise?
The pressure difference of 2400 psi and 3300 psi has to come into play somewhere, right?
Thanks,
Steve

 

[stairman]

I dive two 95cf tanks.My buddy dives two steel 100's.We have the same sac rate and he's not getting as far as me so he's turning the dives.If your getting a working pressure fill they would be comparable.I typically get 3600 psi or 260c.f[two bottles]If he gets 3800 psi he's still only got 216 cf.However,if your at a shop that will only fill to the working pressure then the 100 will have more gas.Even an lp95 at 3000 psi has 108 cf.The 100's are lighter and skinnier though,and I find the 7 1/4 diameter to be better than 8 inches for single setup.[Less pitch and roll].

 

[Stu S.]

Steve,

After looking at dives in the same location, I'm getting the same bottom time with a HP-100 as my former "overfilled" LP-95. (At 3500 psi, it is like a 120.) Maybe the extra air that came along with overfilling was consumed moving around with that heavy tank. The 95 was like hauling around a barrel of beer down there.

The overfills are less available in my area than a couple of years ago.

For what we do and where we go, the HP-100 is the first choice of the guys I dive with.

Good luck with all of it.

Stu.

 

[DA Aquamaster]

A set of double X7-100's are about 20 lbs lighter than a set of Faber LP 95's. PST LP 95's are not as bad weight wise - maybe 7 lbs heavier.

The LP 95 is however an object of worship and reverence in cave country and saying bad htings about one there makes some people a bit gritchy.

In a cave, the weight difference is not significant, unless you have to hike it in. But on a rolling and pitching north atlantic dive boat where you are entering with back gas, stages, lights, etc that already exceed your body weight, 20 lbs is significant. Same with exiting in rough seas on a ladder that may be moving through a 4 foot arc.

If I have a heavy tank there, its because I want the gas. Although frankly, I am more likely to add a stage bottle to my double 100's for 280 cu ft total on the rare occasions I need more gas than I am to go with double 130's all of the time.

The internal volume of the tanks are different which is why they both hold similar volumes at significantly different rated pressures. If you can get your LP 95's "cave filled" to 3600 psi, they actually hold 129.5 cu ft each, which gives you some payback for the extra weight and bulk of the LP 95 compared to the X7-100.

On the other hand, an LP 95 cannot be cave filled everywhere - which is to say you can't get a 3600 psi fill almost anywhere outside north florida, but an HP 130 can be legally filled to it's rated pressure almost everywhere and it is virtually the same size and weight as an LP 95.

So the options are:

1. If you want lighter weight and don't need the extra gas all the time, go with the X7-100, and use a stage on the rare dives where you want or need more.

2. If you want the extra gas all the time, go with an HP 130.

3. If you can find an LP 95 new or used at a killer price AND have either a strong back or access to 3600 psi fills, go with an LP 95. But if the cost is in the same ballpark as the HP 130, I'd get the 130.

 

[TSandM]

I dive 95s, HP100s, and HP130s, and DA Aquamaster has said it all.

 

[Rick Inman]

If you can get your LP 95's "cave filled" to 3600 psi, they actually hold 129.5 cu ft each, which gives you some payback for the extra weight and bulk of the LP 95 compared to the X7-100.

On the other hand, an LP 95 cannot be cave filled everywhere - which is to say you can't get a 3600 psi fill almost anywhere outside north florida...

Ain't that the truth. But I sure did enjoy those fills while on vacation in Fl!

I own a set of double 100's and a set of double 95's. It's not easy in our area to get the 100's to rated pressure cool, but the local shops seem to have no trouble with the 95's. So the 95's often end up with more CF of gas than the 100's. Especially if you don't want to drop off the tanks, but wait for the fill. A hot fill requires the shop to pump those babies to about 3900psi for them to cool to full. Fortunately, at my regular shop, I fill my own.

Still, regardless of cf, I love how the double 100's trim out, and how much easier they are to haul around out of the water, and are therefore my doubles of choice in most cases.

My buddy has a set of double 130's, and I dived them a couple of times when deeper dives required the gas, and they are a hassle out of the water for an old dude like me. Still, I found them surprisingly comfortable in the water. I guess like DA Aquamaster said, I'd rather wear the 100's and haul a stage, except that if the dive really requires that much backgas, then it's gonna take 3 deco bottles already, and at my experience level, that's about the max bottles I'm comfortable dealing with.

 

[Colliam7]

So the options are:
1. If you want lighter weight and don't need the extra gas all the time, go with the X7-100, and use a stage on the rare dives where you want or need more.
2. If you want the extra gas all the time, go with an HP 130.
3. If you can find an LP 95 new or used at a killer price AND have either a strong back or access to 3600 psi fills, go with an LP 95. But if the cost is in the same ballpark as the HP 130, I'd get the 130.

I agree with Lynne, DA has said it all, said it well, said it succinctly.

 

[crpntr133]

I just had my first experience with double LP 95 a couple weeks ago, I usually dive LP85's. I did one shore dive and was fine packing the 95's since I got to drop some lead. But when it came to the boat dive I had issues and I think the 100's would have been better.

Basically the way that I see it is to buy the biggest tank that you can carry for the money that you want to spend. And don't factor in the LP's at a higher pressure since most aren't going to give it to you.

 

[TSandM]

I'm not quite sure how we got off on doubles here . . . I don't see anything in the original post indicating that the author is thinking of doubling up his tanks. If you aren't thinking of doubling them, the weight differences among the tanks are not quite as daunting. But hauling doubled 95s with cave fills into the water in Florida made me feel like an overloaded pack mule

 

[Luis H]

I was told that both the LP95 and the HP100 hold 'almost the same amount of air. I understand that there's only a 5cf. difference in tank size but the pressure difference is quite a bit off.

My question is this:
For the same diver and dive, will you be able to do the same dive, time wise?
The pressure difference of 2400 psi and 3300 psi has to come into play somewhere, right?
Thanks,
Steve

If you have 100 cu ft of air, it doesn’t mater what container it is in. The 100 cu ft rating is the amount of gas at one atmosphere (and “standard temperature&#8221.

The pressure in itself doesn’t matter; you could have 100 cu ft in a tank that its working pressure is 3500 psi or one that is 1800 psi. The 1800 psi tank would be physically much larger to hold the same amount of air.

In reality I don’t know of any 100 cu ft at 1800 psi.

Also to add to the confusion, most lower pressure tanks (from 1800 to 2400 psi) have there designated volume capacity specified when they are filled at the 10% higher rating. That higher rating is noted by a “+” sign next to the last hydro date.

In the particular case of the LP95, I think the 95 cu ft is obtained at 2640 psi (2400 + 10%).


I hope this helps.