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Thread: 2.2 vs 4.5

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    Default 2.2 vs 4.5

    We will be upgrading our sbca's this fall and have been discussing going to the 4.5's. Not looking to create the "which is better" thread, but was hoping someone knew of any studies conducted on FF stress/injuries related to longer duration.

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    Quote Originally Posted by pvfd27 View Post
    We will be upgrading our sbca's this fall and have been discussing going to the 4.5's. Not looking to create the "which is better" thread, but was hoping someone knew of any studies conducted on FF stress/injuries related to longer duration.
    We did this over 10 years ago and it was by far the best upgrade for the firefighters we done, since motorized apparatus. They're lighter and more compact and you really don't even know they're there. Now when I've worn a 2.2 for demonstration or training in another FD I bump into things as they're unwieldy.

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    Actually, if weight is your reason for switching it is a false reason. the carbon cylinder for a 2216 Scott SCBA weigh 10.7 pounds, a carbon cylinder for a 4500 Scott SCBA weighs 9.9 pounds. This equates to a 12.8 ounce difference in weight in half hour cylinders between 2216 and 4500 psi.

    The true reason for switching to 4500 psi is versatility. You can stick with the small profile 30 minute cylinder, or go to a 45 minute cylinder that is about the same size as a 2216 cylinder and weighs 14.1 pounds, or go to an hour cylinder that weighs 17.1 pounds. Adapting the cylinder size to task is the biggest advantage of 4500 psi...not weight.

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    We'll definetly get a weight savings over the current mix of STL & AL bottles. I like the versitility of the system and compact size of the 30 min bottles.

    Since we don't do haz-mat beyond petrolium products, my concern would be if we went to 45 min or greater duration on the fire ground.

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    The big things to remember are 15 year life of bottles. You replace every bottle 15 years from now. You also have to have a booster on your cascade to boost up the pressure from cascade level to 4500. Not a cheap add to the system.

    I mention these things because you're a fellow Vermonter and things are different in the Green Mountain State when it comes to funding...

    We have 4.5's because we have one of the Decon Trailers. They are 60minute bottles. We went with the carbon 2.2 bottles for weight on the attack trucks and used the Al bottles as the spares. What is truly the cat's meow is having a composite on a wireframe. My Assistant and I fight over them if we are going in vs. the AP50's.

    Phasing the composite bottles in will make it easier to deal with now and in the future when the time to replace comes around.

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    Chief you would rather use a wire harness 2.2 over an AP-50? WHY? In my mind the AP-50 is head and shoulders above the wire frame in comfort.

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    Quote Originally Posted by ChiefDog View Post
    The big things to remember are 15 year life of bottles. You replace every bottle 15 years from now. You also have to have a booster on your cascade to boost up the pressure from cascade level to 4500. Not a cheap add to the system.
    That's gotta be the biggest drawback with the wrapped bottles. I hope to God I'm not still doing this in 15 years (blended food, Depends, etc) but I've had to throw away what appear to be good bottles because of the 15 life span (not what Vamontah's are known for, ayuh). Our current cascade system will handle the 4500 bottles, thanks to Homeland Security

    Fyredup, will not miss the wire harness at all. Sorry if I gave the wrong impression.

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    I worked on a grant for 4.5s, a 6,000 compressor, and a 4 bottle 6,000 cascade (on the rescue) about 4-5 years ago through AFG. We ended up with Scott packs. We ditched our 2.2s and never looked back.

    The bottle time we (as an average) get is about 31 minutes per man. We were lucky to get 18 minutes out of the old system...

    Something about steel bottles being heavy? Who knew?

    Anyway, we love the versitility, duration, and comfort of the newer packs. We tried a lot of systems back then... More recent packs from several manufacturers are even better now as far as comfort and fit.

    My opinion, 4.5s give you time to get in, get some work done and more importantly, get out in a timely fashion. It still boils down to fitness and solid training on HOW TO MANAGE YOUR AIR. If you don't make it a habit to watch where your air is at then your still gonna be pushing your envelope to get out without hurrying.

    Be smart; get the most RIT friendly system you can. A life is worth the extra cash.

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    A coward stands by and watches wrongs committed without saying a word...Any opinions expressed are purely my own and not necessarily reflective of the views of my former departments

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    Quote Originally Posted by FyredUp View Post
    Chief you would rather use a wire harness 2.2 over an AP-50? WHY? In my mind the AP-50 is head and shoulders above the wire frame in comfort.

    My bad...thot u wuz tawkin at me

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    Quote Originally Posted by FyredUp View Post
    Chief you would rather use a wire harness 2.2 over an AP-50? WHY? In my mind the AP-50 is head and shoulders above the wire frame in comfort.
    I'm with Chiefdog on this one. I'd take a wire frame 4.5 any day. I hate the new AP 50 straps, the older narrower straps on the 4.5 wire frame are much more comfortable too me. I also find the AP50 straps loosen easier accidentally than the older style. Evidentially one size doesn't fit all! I'd say our guys are split abut 50/50 on the wire frame vs. AP50's but we run about 75/25 with more wire than new age!

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    Quote Originally Posted by pvfd27 View Post
    We will be upgrading our sbca's this fall and have been discussing going to the 4.5's. Not looking to create the "which is better" thread, but was hoping someone knew of any studies conducted on FF stress/injuries related to longer duration.
    Before I go any further, does your department want to stick to Scott specifically or are you open to any new brand?

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    Quote Originally Posted by KevinFFVFD View Post
    Before I go any further, does your department want to stick to Scott specifically or are you open to any new brand?
    Not married to Scotts. Scott and MSA are the most popular in the area and have the closest service reps. The salesman that we are purchasing extrication tools from has started selling Survive-air. May give them a look.

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    I have a question that comes to mind. We have Scott 45 min ap-50's with theh 30 min bottle. If i am reading the info correct, if we wanted to switch to 45 min bottles. all we would have to do is get the 45 min bottles, correct?

    Just curious about this, thanks.

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    While it's not so much a pressure thing rather than a time thing, it's information that's not particularly "well-known." Due to the fact that SCBA air is dried when it's compressed, our bodies hydrate the air when we breath it. A firefighter can lose up to a liter of fluid through this process for every 1 hour's worth of air.

    So, if you're using the "two bottle" method for rehab, or using 45- or 60-minute bottles, keep in mind the guys need to be hydrated beforehand and need to rehydrate afterward.

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    Quote Originally Posted by Catch22 View Post
    While it's not so much a pressure thing rather than a time thing, it's information that's not particularly "well-known." Due to the fact that SCBA air is dried when it's compressed, our bodies hydrate the air when we breath it. A firefighter can lose up to a liter of fluid through this process for every 1 hour's worth of air.

    So, if you're using the "two bottle" method for rehab, or using 45- or 60-minute bottles, keep in mind the guys need to be hydrated beforehand and need to rehydrate afterward.
    Thanks Catch! Just the kind of info I'm looking for.

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    Quote Originally Posted by cctrtlt2 View Post
    I have a question that comes to mind. We have Scott 45 min ap-50's with theh 30 min bottle. If i am reading the info correct, if we wanted to switch to 45 min bottles. all we would have to do is get the 45 min bottles, correct?

    Just curious about this, thanks.
    Technically, there is not a "45min" Scott AP50. AP50s come in either 2216psi or 4500psi models. The 2216 only accepts 30 minute 2216psi cylinders. The 4500 accepts 30, 45, and 60 minute 4500psi cylinders. It is the cylinders that receive the "time rating", not the pack. The only thing you must do to make the pack accept the different cylinder is adjust the retention strap.

    To the original poster, I feel that going with 4500 psi packs are worth it. It gives you the lower profile if you go with 30 minute cylinders. Or, it will give you the added time (especially if you run into trouble) with the 45 min or 60 min cylinders if you go that route.
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    Quote Originally Posted by pvfd27 View Post
    Thanks Catch! Just the kind of info I'm looking for.
    No problem.

    Something we took into account on our packs (recently went from 2.2's to 4.5, even though everyone around us is 2216's) is the amount of time in a bottle. With a 2216 system you're limited to 30 min. bottles. You're talking maybe 20 minutes if you're doing much work at all. If you're dealing with a large area, you've got 10 minutes before you need to start thinking on how to get out. When the low air alarm goes off (approx. 25% of the bottle, not "5 minutes" like some like to think), you're behind the 8 ball if you're deep in and have a ways to travel to get out.

    Now, keep in mind that 25% (not a minute rating!). If your 2216 bottle sounds low-air, you're looking at 500-600 psi left in the bottle. Depending on how fast you breath it, it could be a couple of minutes or it could be 5. With a 4500 bottle, you're looking at 1100-1200 psi, no matter the time rating on the bottle. That's twice what you have with the 2216's and twice the air if the excrement hits the oscillating device and you get trapped.

    We hold to the theory that the bottom 1/4 of the bottle is for emergency use only (and most SCBA manufacturers should tell you they are designed and intended to be used that way). If we're in overhaul mode, there's a bit of flexibility. However, if we're actively fighting fire and a low air alarm goes off, I'm usually chewing someone's butt... er, kindly reminding them. When we do our PAR's (every 10 mins), my guys are to check their bottle pressure. If they're below the 2,000 mark, they start their way out and head to rehab.

    Just a note on the 15-year life span. I've heard a lot of scuttlebutt, including speculation from a manfacturer rep that taught my repair tech class, that there's a push for the carbon bottles to be good for as long as they'll pass the hydrostatic testing. From my understanding, when the carbon's were new, there was some concerns about how long they'd last, hence the 15-year lifespan. They're not showing any issues if properly cared for, so they're expecting that lifespan limit to be lifted in the near future. Now, I don't know that I'll believe until I see it, but that's the word on the street. Take it for what it's worth.
    Last edited by Catch22; 03-20-2009 at 10:11 PM.

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    I am seriously considering the 4.5's, mostly for the flexibility.

    The fact that our current 2216 bottles will work means not having to obsolete 30 or so spares, plus the packs will work in the MA system. We can take experiment with the 45 minute bottles.

    I've also heard the rumors about the 15 year life span.

    Has anyone heard of catastrophic failures with the carbon wrapped (under "normal" use)?

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    Quote Originally Posted by pvfd27 View Post
    The fact that our current 2216 bottles will work means not having to obsolete 30 or so spares, plus the packs will work in the MA system. We can take experiment with the 45 minute bottles.
    The problem here is that the low pressure alarm (Vibralert) will not function at the proper time. Basically the Vibralert activates at 25% of the system PSI (4500) so when you put a 2216 bottle one the pack the Vibralert will activate around at half a tank vs. a quarter. The fact you can use the 2216's is really only for "in a pinch". Relying on this as a basic operating procedure like spare bottles or M/A replacement bottles is not a good idea. Also, remember that the bottles will not go the other way,that is you cannot put the 4500 psi bottles in a 2216 SCBA.
    Quote Originally Posted by pvfd27 View Post
    I've also heard the rumors about the 15 year life span.
    They've been rumoring this for as long as Carbon Fiber bottles have been around, yet we still haven't see it. It would be nice, but given the NFPA, manufacturers and how close we could have come to all being forced to use baby blue bottles, I wouldn't bank on this happening.

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    Quote Originally Posted by RFDACM02 View Post
    The problem here is that the low pressure alarm (Vibralert) will not function at the proper time. Basically the Vibralert activates at 25% of the system PSI (4500) so when you put a 2216 bottle one the pack the Vibralert will activate around at half a tank vs. a quarter. The fact you can use the 2216's is really only for "in a pinch". Relying on this as a basic operating procedure like spare bottles or M/A replacement bottles is not a good idea. Also, remember that the bottles will not go the other way,that is you cannot put the 4500 psi bottles in a 2216 SCBA.
    They've been rumoring this for as long as Carbon Fiber bottles have been around, yet we still haven't see it. It would be nice, but given the NFPA, manufacturers and how close we could have come to all being forced to use baby blue bottles, I wouldn't bank on this happening.
    Being able to use the 2216's at all will lessen the financial burden of replacing everything a once. It will also spread out the replacement date for the wrapped tanks.

    I would be pretty damned suprised if the industry would approve of extending tank life.
    Last edited by pvfd27; 03-21-2009 at 03:40 PM.

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    The question of tank life actually has some good info behind it.

    For steel or Al bottles, the hydrostatic test measures the bottles expansion and permanent deformation. So long as its within a specific percentage, it passes and the metal is still good. Its basically working in a well understood and easily tested property of the metal to give a go/no go test.

    For composite bottles, the failure mode is different. It is believed over time, individual fibers of the composite material will break. This is due to both sustained load and fill cycles. Each fiber breakage represents a loss of strength. The problem is how to test this 'strength' without damaging the bottle in the process. Once someone comes up with a mechanism to do a good go/no go test that is reliable, I think you'll see the service life increase. Until that point, the 15 year timeframe is a compromise to predict the longest safe usage period for a well maintained bottle. Is it perfect - nope. I am sure quite a few still good bottles get pitched each year. With that, I am sure some bad ones go too.

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    Quote Originally Posted by pvfd27 View Post
    Being able to use the 2216's at all will lessen the financial burden of replacing everything a once. It will also spread out the replacement date for the wrapped tanks.
    I feel your pain, we too had some financial constraints during the conversion. We found we could buy used bottles with 5 or more years left for less than 1/3 the cost of new, making them a better deal than new and giving us a the ability to cycle in new ones over the 5 years. We still have some of the "used" hoop wounds while everything bought new has been CF.

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    From a user standpoint... Survive Air: Poor reg useability, great buddy system. MSA:Horrible design IMHO. Poor usability overall. Not comfy, Poor visability. Scott 4.5: Great mask comfort, great buddy system, light wire frame that is comfy for extended periods 2+ hours, love the vibralert, hate the HUD for remaining air. Easy bottle change, multiple bottle options, great PASS.
    Don't know about price or maint. concerns, because our logistics dept. takes care of all that. I would guess we have over 300 bottles, but who knows. I do know that they had to take them all down for testing this winter. Don't think any failed. They get used and abused by us.

    I've used steel, ALM, and composite bottles. Please make the switch to composite. Your guys will thank you. Again my disclaimer: I don't know what the cost is for any of this stuff.

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    From a conditioning standpoint, if you're pretty much done by the time the alarm goes off on a 30 min. pack, you're going to really be dragging with a 45.

    Another thing to consider when switching to larger bottles is the amount of room required on the apparatus. Eight 45 min. bottles take up less space than twelve 30 min. bottles but provide the same amount of air.

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    Two things to consider:

    #1. Although many people are voicing their opinions about the versatility of 4500 psi bottles and the fact that you can use 30, 45, or 60 minutes bottles, this is really most likely NOT the case. Yes, you have that option when you initially order, but that will be about the extent of it. There is not an SCBA on the market that I am aware of that allows you to easily interchange different rated bottles onto the same backplate and harness. The strap, linkage, or whatever is used to hold the bottle to the backplate will vary in length due to the difference in circumference of the different bottles and will not work for all 3 different sizes. Additionally, you will have the same problem carrying them on your apparatus due to the same reasons. They will not all fit in the same bracket.

    #2. Seriously consider what is gained when increasing the amount of air that you give your firefighters. IMO, to many departments (including my own) jumped into the more air is better theory without considering anything else.

    More air is only better in worst case scenario - You are alive, trapped, and inaccessible for an undetermined amount of time. However, how much more harm are you placing firefighters in by giving them more air and therefore more working time by giving them the larger bottles? More air does not mean less fatigue. I do not like 45 or 60 minute bottles for firefighting. I would go with the lighter, smaller high pressure 30 minute bottle and reduce the amount of stress involved in firefighting, not a heavier 45 or 60 minute bottle which will increase the stress and workload along with the "benefit" of more air to do it longer.
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