How bad is flash filling for HPA tanks?

[Koosh]

Just wondering... The local feild here just got push button HPA, he was bragging how any tank of any size could be filled in 2-3 seconds... I asked if that was bad for the Nitro tanks to be filled that fast, and this was his reply (on their forums)...

"Yeah...thats what I think to but......that system has been in use by the PSP and NPPL for 2 years with no incident and insurance companys have rated it as safe....that is a good question koosh...one I have wondered about for a while."

Any definitive info on this?

[SlipknotX556]

Yeah, we had one at my field, never hurt my tank. Its so much better, then waiting for someone else to fill your tank.

[Steelrat]

I have the local scuba shop fill my tank occasionally. When i mentioned how fast the fields fill the tanks, they looked horrified. Thank god the tank manufacturers do such a good job, or someone would have died by now.

[Beemer]

Don't ask us. Ask a professional.

But, look at page 15 of this:http://hazmat.dot.gov/exemptions/E13105.pdf

Discoloration may be a sign of heat damage meaning the cylinder is now unserviceable/dangerous.

DON'T FLASH FILL!!
One filling procedure:http://www.survivair.com/techbulletins/TB103.pdf

This document and others all warn to fill at a maximum of 500 psi per minute. There are numerous warnings against fast/flash filling.

From this thread...../



http://www.automags.org/forums/showthread.php?t=144617

[Won Hunglo]

Flash filling can stretch & over heat a tank. It can fail the elasticity portion of the hydro test if damage has occurred. It is hard on the reg & fill nipple o-ring too. Always fill slowly if you can.

[Torbo]

if it were to over pressure, wouldnt the high pressure burst disk blow, thus saving you and the tank?

[jewie27]

Here's my input, since I've worked in a SCUBA shop for 2 years. ALWAYS fill slow if possible. The best fill rate for paintball HPA tanks is 100 PSI per second. The only problem is that the self-serve push button stations fill fast which are more risky than SCUBA tanks. The safer way is to use SCUBA TANKS or compressors that allow you to control the flow rate.

Here's why fast fills aren't good: by laws of science, air moving quickly through small spaces (regulators, fill ports) cause friction and friction causes HEAT to build up. Heat can cause bad things to happen to a tank. (possible explosion or tank stretching) The most common problem is that hot fills never give you a complete fill. Tanks that are filled fast heat up a lot, then when they cool down to room temp (72 farenheit) you lose pressure. So your 4500 psi tank filled quickly may only give you 4000 or maybe less depending on how fast you fill it.

Quick tips:

Fill at a rate of 100 psi per second when possible.

Remove tank cover when filling to reduce the amount of insulation around the tank, so it will stay cooler.

[TDonovan]

I really only have the pushbutton setups around here...

What should I do then? Last time it was filled, the fill nipple indeed started leaking right after and I still haven't gotten it fixed.

Should I just fill the tank with the push button like 500 psi at a time and let it sit or something?

[jewie27]

that might be a good solution, though it's a slower. I want to suggest to these companies that make these self-serve fillers that the stations be regulated to 100 psi/second. Will somone help me get the word out?

[Setzer]

100psi/second is over 10 times the recommended fill rate, and is considered fast. Yeah, no one likes waiting in line, but saftey is worth a couple minutes, isn't it?

[Chojin Man]

wouldn't that burden be up to the fields and not the manufactures? i mean don't the fill stations allow you to set the max fill rate?

[Setzer]

wouldn't that burden be up to the fields and not the manufactures? i mean don't the fill stations allow you to set the max fill rate?

Yes, it shold be up to the fields, but until the insurance companies mandate it, they won't change. And an insurance company won't do anything until some tank blows and kills someone. So while the fields could do somthing about it, they won't because their insurance companies consider flash filling safe.

[xXHavokXx]

500 psi per minute is 9 minutes for a full fill at 4500psi, or 6 minutes for 3000psi. Imagine being at a tournament of 25 teams of five guys. 125x 6 = 750 minutes for one fill total or over 2 hours with one fill station, 4 hours with three, 2 hours with 6 , then yu have to account for multiple games ending quickly and other factors including everyone will want a fill before their first games. Huge events like NPPL, PSP and IAO would come to a grinding halt as getting air would be the new comperative sport.

[Steelrat]

500 psi per minute is 9 minutes for a full fill at 4500psi, or 6 minutes for 3000psi. Imagine being at a tournament of 25 teams of five guys. 125x 6 = 750 minutes for one fill total or over 2 hours with one fill station, 4 hours with three, 2 hours with 6 , then yu have to account for multiple games ending quickly and other factors including everyone will want a fill before their first games. Huge events like NPPL, PSP and IAO would come to a grinding halt as getting air would be the new comperative sport.

This must be a common feeling, that increased speed in filling is worth the corresponding trade-off in safety. However, if there is ever a serious injury or fatality caused by improper filling, watch how quickly things will change. We'd probably better off finding out a workable solution before one is forced on us.

[Setzer]

500 psi per minute is 9 minutes for a full fill at 4500psi, or 6 minutes for 3000psi. Imagine being at a tournament of 25 teams of five guys. 125x 6 = 750 minutes for one fill total or over 2 hours with one fill station, 4 hours with three, 2 hours with 6 , then yu have to account for multiple games ending quickly and other factors including everyone will want a fill before their first games. Huge events like NPPL, PSP and IAO would come to a grinding halt as getting air would be the new comperative sport.

That just doesn't fly with me. Its okay to disreguard saftey because there are games to be played? Now if someone gets killed, will you still feel the same way? I hope it doesn't have to come to that, because then it will be too late.

[xXHavokXx]

That just doesn't fly with me. Its okay to disreguard saftey because there are games to be played? Now if someone gets killed, will you still feel the same way? I hope it doesn't have to come to that, because then it will be too late.




It's not so much that I want to disreguard safety, I'm merely pointing out the inherent problem in the safe speed. Yes I agree there needs to be a safer way to do this but until safety meets speed people are going to err on the side of getting things done.

Like today for instance. We got about 9 kids in at the same time all who wanted 3000 fills because they play in a private field behind a house so they take breaks and get fills as we are 15 min away. 9 kids X 6 minutes is only 45 minutes but do I really want to sit there holding down the fil station button for 45 minutes while the ravenous hordes of people who aren't having their tanks filled pick on the one other guy working. Then we'd have to have another employee come in to fill CO2 because we keep the co2 tanks in the back away from customers for safety reasons, so we'd need another guy to run the register and help people out creating a pay problem. We'd need three people instead of 2.

[Setzer]

It's not so much that I want to disreguard safety, I'm merely pointing out the inherent problem in the safe speed. Yes I agree there needs to be a safer way to do this but until safety meets speed people are going to err on the side of getting things done.

Good, we seem to agree on somthing :)


Like today for instance. We got about 9 kids in at the same time all who wanted 3000 fills because they play in a private field behind a house so they take breaks and get fills as we are 15 min away. 9 kids X 6 minutes is only 45 minutes but do I really want to sit there holding down the fil station button for 45 minutes while the ravenous hordes of people who aren't having their tanks filled pick on the one other guy working. Then we'd have to have another employee come in to fill CO2 because we keep the co2 tanks in the back away from customers for safety reasons, so we'd need another guy to run the register and help people out creating a pay problem. We'd need three people instead of 2.

And herein lies the other part of the issue. Not only does saftey take too long, but it costs too much money. There needs to be a way of being safe, without sending the fields, including the small ones, under. Unfortunatly, there is no way to increase saftey while keeping costs the same. If there was, many fields would of already done it. Costs for more fill stations, people to operate them, ect. Well, once someone dies, or is seriously injured, not only are you going to have to go through those costs, but chances are pretty good that insurance costs will go up too...now that they know for a fact how dangerous it can be.

I think we'e pretty much covered this. I can totally see your side of this xXHavokXx, and understand where you are coming from. Its not fun standing in line waiting for air. And fields do not make enough money to buy extra fill stations, compressors, and pay for more staff. Unfortunatly, in order to save money and time, people in general have decided to push saftey off to the side. Nothing really bad has happened so far, and hopefully it never will. I think we all can agree that there needs to be a better way, so somthing bad does not have to happen in order to have things changed.

[LeatherPants]

FYI flash fills slowly bend the piston in the fill nipples for PMI tanks. I noticed that all 3 of my tanks over time the piston actually gets crushed to the point it no longer seals. It bends so the either the Oring gets pinched or will not seat correctly..

[_tMAN]

I wish I had a real field around here.
we only have a scuba shop about 10 minutes from me, they can only fill my tank to 3200 psi. I have a 91/4500, kind o makes me mad that I can't fill it fully

[jewie27]

I wish I had a real field around here.
we only have a scuba shop about 10 minutes from me, they can only fill my tank to 3200 psi. I have a 91/4500, kind o makes me mad that I can't fill it fully

My shop's Bauer compressor does 4500 psi. :)

[_tMAN]

dang you :)

[teufelhunden]

If this was truly unsafe, I'd bet something a) would've happened already and b) something would've changed. Tanks are hydro'd every 3-5 years, so something would be caught. People filling the tanks are usually at least competent in paintball, seeing as they were smart enough to get HPA... and if their tank turns colors they'd ask somebody 'wtf?'

I just get pissed when I buy a 4500PSI fill that ends up cooling off at 3800-3900 PSI.

[logamus]

i have used several different push button systems. i havent seen one that fills in 2-3 seconds, but usually less than a minute. my beef with them is that nobody is there to check the dates on peoples tanks. now i wouldnt use a tank thats out of date, and the people i play with on a regular basis wouldnt either, but there are a lot of kids out there that dont even know their tank has a date.

[Setzer]

If this was truly unsafe, I'd bet something a) would've happened already and b) something would've changed. Tanks are hydro'd every 3-5 years, so something would be caught. People filling the tanks are usually at least competent in paintball, seeing as they were smart enough to get HPA... and if their tank turns colors they'd ask somebody 'wtf?'

I just get pissed when I buy a 4500PSI fill that ends up cooling off at 3800-3900 PSI.

Thats another side effect of flash filling. The tanks heat up, which makes the air inside expand, creating higher pressure. When it cools off, you now have 3800-3900psi inside. Also, the push button fillers don't have people there checking hydro dates. Now, 5 years is a long time between hydros. If you fill your tank up twice a week, thats 104 fills per year. 520 fills between hydros. If those were flash fills, a lot of damage can be done to the tank. Flash fills wear out the elastisity of the tank. Now, to say that "if it really was unsafe, something bad would of happened by now" is just ignorance.

[NukeGoose]

If the rate of filling is slowed down, then more people should be able to fill per station. Perhaps a slew of Y-connectors to allow 5 or 10 people (spread out, of course) to fill slowly at the same time? I'm not very familiar with air compressors, but I'm guessing that there's a large tank which is filled to over 4500 PSI, which is pressurized by the compressor, and the large chamber feeds the tanks? If so, then you should still be able to get the same flow out of the tank/line, just add multiple stations.

[Beemer]

Ya I know. Back to post more later. There is a reason. :ninja:

[t_boneshacone]

ehh my field has one and it takes about 5 seconds, the tank doesnt get any warmer than it does when filling off a scuba tank, as a matter of fact, it doesnt get as warm, well compared to my other filling place. i really dont know anything about filling tanks, i just know that push button is easy and my tank works fine with it

[ta2maki]

Is 'psi per minute' the correct way to determine how fast a tank is filled? If friction from the air is a bad thing, shouldn't larger tanks take longer to fill than a slower tank? Which would mean the 500 psi per minute would only apply to 80cu ft tanks, paintball tanks are much, much smaller and should be able to fill faster.

[Chrishew09]

they way I understand it is like this.
if you fill a HP tank quickly then the air is heated and heated air molecules are further apart then cooler air molecules so once the air cools and the molecules reduce so does the fill.

my 2 cents..........

[Chaos_Theory!]

they way I understand it is like this.
if you fill a HP tank quickly then the air is heated and heated air molecules are further apart then cooler air molecules so once the air cools and the molecules reduce so does the fill.

my 2 cents..........

Thats obvious, but really has nothing to do with it being dangerous.

[WalkingTarget]

My local scuba shop stopped filling Paintball tanks after their tech went to play at a field in Toronto and witnessed tanks being flash-filled.

in his words "i'll fill my own tanks, but i refuse to fill a tank that has been flash-filled"

true to his words, the last time he filled my HPA before i sold it, he did it at 700PSI/minute, only because he couldn't set their booster to do such a small tank any slower.

[OneUp]

i suppose it is up to the consumers then.

tell everyone fast fills lose pressure when cooled down, that they wasted their $. They'd care unless it's all day air.

[Shane-O-Mac]

D.O.T regs require that if a cylinder gets over a certain temp it is to be destroyed. That temp is around 130F IIRC. At the last Chicago open I went to, I used a temp gun and was reading temps of the tank itself over 140F right after filling. The tanks at many times was too hot to handle. Also, heating up your tank by flash filling is harder on the tank and outside of its design boundaries. If you consistently heat up your tank with flash fills you are risking not passing hydro, and weakening the tank. Just because the tanks works fine with flash fills, doesnt mean it IS fine. If the tank that failed due to oil being put in the fill nipple, had been filled slowly, they proabably wouldnt have failed the way they did. The HEAT was a big factor in those incidences. The motor in your car operates the same way, except it use spark plugs, instead if heat to ignite. It is actually the way a diesel engine works. My point is that if the heat wasn't present, it wouldn't have happened....................

If you are faced with having to fill with a self serve station, fill it in slow bursts. Like a 1000psi at a time and let it cool for 30 seconds. Or hit the button for 30 seconds then wait 20 seconds or so.

[Chaos_Theory!]

If you are faced with having to fill with a self serve station, fill it in slow bursts. Like a 1000psi at a time and let it cool for 30 seconds. Or hit the button for 30 seconds then wait 20 seconds or so.

Thats not very realistic unless your the only person around who needs a fill. I havnt been to a field yet where it takes more than like 10 seconds to fill to 4500psi. Also, i have not gotten a really warm tank any of those times.

[OneUp]

Thats not very realistic unless your the only person around who needs a fill. I havnt been to a field yet where it takes more than like 10 seconds to fill to 4500psi. Also, i have not gotten a really warm tank any of those times.
I get warm tanks all the time. :(

i remember when i was using a steely they were indeed too hot to handle after a fill.

so i suppose asking them to fill my 45 4500 only to 3000 is a good thing since it doesn't put that much pressure and heat into it? cuz I've been doing that.

[fullofpaint]

slightly off topic here. Does anyone els have a CP tank? Everyone I know who has a cp tank, when they fill it (regardless of the fill station) the tank fills extremly slowly. Anyone know what causes this?

[Hilltop Customs]

ehh my field has one and it takes about 5 seconds, the tank doesnt get any warmer than it does when filling off a scuba tank, as a matter of fact, it doesnt get as warm, well compared to my other filling place. i really dont know anything about filling tanks, i just know that push button is easy and my tank works fine with it

I can guarantee the air inside the tank gets much much hotter when you flash fill. When you flash fill the outside of the tank doesnt have time to heat evenly with the inside air in the tank. So you have a cool outer surface and a really hot gas inside....this temp differential is what can causes microscopic stress cracks to form in the tank.(if you want I can explain that in more depth) I think everyone has to agree cracks in a tank are bad no matter how small they are. The sad thing is flash filling has been accepted by the mass majority of fields. (this isnt a knock on you, sorry if it sounds that way, i just cant think of a nicer way to put it)


slightly off topic here. Does anyone els have a CP tank? Everyone I know who has a cp tank, when they fill it (regardless of the fill station) the tank fills extremly slowly. Anyone know what causes this?

Probably a really restrictive fill nipple, or passage from the fill nipple to the inside the tank. That could be a good or bad thing depending if its accounted for in the design of the tank.

IMO tank companies could have taken care of this problem in production....a restrictive fill port would slow filling to an acceptable level. Considering the young age group that plays paintball, that is a saftey precatuion that SHOULD have been implemented. Another saftey precatution would have been a fill nipple that couldnt be oiled......but then again what do I know. :tard:

[pyrodragon]

500 psi per minute is 9 minutes for a full fill at 4500psi, or 6 minutes for 3000psi. Imagine being at a tournament of 25 teams of five guys. 125x 6 = 750 minutes for one fill total or over 2 hours with one fill station, 4 hours with three, 2 hours with 6 , then yu have to account for multiple games ending quickly and other factors including everyone will want a fill before their first games. Huge events like NPPL, PSP and IAO would come to a grinding halt as getting air would be the new comperative sport.

don't know where u get ur 500psi per minute, because 100psi/second = 6000psi/minute. that means 4.5kpsi bottles would only take 45 seconds and a 3k psi bottle only 30 seconds. i agree that it's fast. i run scuba tanks and fill from them at our games. i'm the one that usually fills everyone's tanks and i run them very slow. safety is the number one thing at our games. if done right u can get plenty of tanks filled in time for big tounries. plus don't these tourny guys have pod monkeys filling their pods in between games? and don't they carry more than one tank to a tourny? so ur point about waiting in line? full multiple tanks at first then switch when one tank is empty. while tourny player is playing, pod monkey goes and has empty tank filled. i've never played tourny but like they say it's part of the game. be prepare for the unexpected. if it was me and i played tourny, i would show up with more than i needed. if i'm worry i wouldn't have enough air, i would make sure i had a backup plan. kids nowadays. :tard: better to be safe than sorry later.

[Shane-O-Mac]

Thats not very realistic unless your the only person around who needs a fill. I havnt been to a field yet where it takes more than like 10 seconds to fill to 4500psi. Also, i have not gotten a really warm tank any of those times.

Realistic huh?

Well, how do you want it, SLOW or DANGEROUS?

If a field owner staffed his fill station with a properly trained employee, it wouldn't take that long. My time suggestion was maybe a bit on the long side, but the point is still the same. If the air station flash fills without you being able to slow it down, then some steps are necessary for safety. And I am sorry but your tank isn't immune to physics. If you keep your tank cover on, your not gonna feel much warmth. Not sure if thats the case with yours, but a possibility. Filling a 68/4500psi tank in 10 seconds is very bad, and will heat up a tank.

Heres part of the reason for filling slow. When you fill your HPA tank, it expands slightly, when filled properly, it expands less and doesnt get expanded beyond design parameters. When flash filled the tank expands quickly and beyond design parameters, which leads to weakening of the inner liner. The inner liner is a thin aluminum shell, that is then wrapped in carbonfiber or fiberglass.

Like I said before, just because it doesn't appear to hurt your tank, it is hurting it.

[Beemer]

Realistic huh?

Well, how do you want it, SLOW or DANGEROUS?

Like I said before, just because it doesn't appear to hurt your tank, it is hurting it.

LOL thats classic, SLOw or.......

So without a real Governing Body and manufacturers not telling us and ASTM standards that arent followed what is the safe fill rate for 4500psi???? I looked around and came up with the same thing. 500psi per min. Not to mention most of the fills we get are probably real DIRTY. I want some of that Hpac air in my fills. Breathing QUALITY. A slow fill will be a FULL fill every time first time. :clap:

Hey tell the folks on the governing body we need to talk, hmm what? We dont have no stinking governing body. Really? Thats pretty stupid.

Paintball must be stupid because that is all I ever hear. Show the scuba guys and the real fire arms folks how we do stuff and you will hear........Thats pretty stupid. :tard:

Even our employees at the CPSC and some laywers and others say the same thing about not following ASTM standards or not having any at all and no REAL governing body.

Three tanks in a year. Any one want a stako tank? Whats up with that?

http://www.p8ntballer-forums.com/vb/showthread.php?t=96946

http://www.mcarterbrown.com/forums/paintball-news/31245-stako-tank-blows-up-uk.html

[cpt]

We call them "hot fills" in the fire service. You lose about 500 psi once the tanks cool down and we started noticing we were losing seals a lot more. The tanks always passed inspection but we have quit doing it unless we are in emergency mode.

[jenarelJAM]

Some fields actually limit fill speed. My home field, Davis Paintball, fills at about 100 psi/second. This is all self-serve. They've got a table, you just go up to it and hook in, and press the lever. Now, that may be faster than said "recommended" fill speeds, but it gets the tank filled in under a minute still, and it merely warm at the end. Generally, you lose ~200 psi when it cools down.

[Corvad]

After reading this thread I got concerned about the safe fill rates for an HPA tank although the suggested maximum rates didn't quite feel right to me so I attempted to figure out the physics behind it. While I'm no engineer or physicist I have come to a satisfactory conclusion for myself and I'll attempt to share it here.

What made me pause what the large size difference in the tanks, I have an 88cui HPA tank, while an average scuba tank holds 80cf of air, its inner volume is about 678cui according to luxfer cylinders. While my tank is a 4500 I'm just going to use a basis of 3000psi as that is the pressure of a general 80cf scuba tank for comparison, still this a difference of 8 times the volume of air, and I feel this is a very important fact.

The maximum suggested fill rate for a scuba tank is about 500psi per minute and applying this directly to a tank that is 8 times smaller can't be right, so down to some wordy math now. Since this isn't really my area of expertise I may be in need of correction.

The heat generated in the tank is due to the friction of the gas moving through the fill nipple and hoses, not because of any pressure changes. The heat does increase the pressure in the tank, but once it cools back down to room temperature the pressure will go down accordingly which has been observed. It is the friction that is the problem, and with a scuba tank being 678cui you have approximately 8 times the amount of air rubbing through the fill fixtures creating heat, so in that minute of fill, I approximated about 23,000 cubic inches of air flowing into the scuba tank. (this is assuming that it takes 46cui of air to increase the pressure by 1 psi) Now compare that with an HPA tank of 88cui, at 500psi/minute its only about 2,685 cubic inches of air(assuming its approximate 5cui of air per psi in the 88cui tank), that translates into a whole lot less friction and heat generated. So this means we should be able to fill about 6-7 times faster than a scuba tank, unless I missed an important fact in there, again, I'm not engineer or physicist. This is also assuming that the smaller filling fixtures on the HPA tank generate more friction ans more of the air is in contact with a surface its moving past.

Important note, as I wrote this I found a few flaws in my math and have attempted to fix them before posting.

Now this is assuming the fixtures are the same diameter and sizes, but I know they aren't and this is where my math ends at the flow rate section.

Still, to me this means yes, we should be able to fill faster on our smaller HPA tanks, but still nowhere near the 3 second fills bragged about. Personally this means I'll shoot for about 90 - 120 second fills for my 88/4500 tank.

And yes, I did just register to post wordy math...

Notes on how I figured the amount of air per psi in each tank.
Since a scuba holds 80cubic feet of air at 3000 psi in a 678 cui tank.
And 1 cubic foot is equal to 1728 cubic inches.
80 * 1728 = 138240 cubic inches of air at 3000psi, so for 1 psi
138240 / 3000 = 46.08cubic inches per psi
similarly for an 88cubic inch HPA tank holding 14cubic feet of air at 4500 psi according to luxfer.