# Thread: The Brush-Monkey Needs Help

1. ## The Brush-Monkey Needs Help

Alright GentleMen Need some Opinions,

Background: Small Local VFD Is looking to set-up a Compressor System, Needs to Be Mobile, Self-contained, and Space is a bit of a Issue.
We are Running 4500psi cylinder, Same with Our surrounding Company's,

I have stumbled across this little guy.
http://www.edarley.com/finditem/22358
I need you to break down as to how Fast It can Re-fill, capabilities, what would be a Good Set-up For it. And just kind of give me the low down.

2. It says the fill rate of the compressor is 4.9 standard cubic feet per minute (scfm) the 4500 psi 30 minute air pak has a capacity of 45 scf so you are looking at about a 10 minute fill time per cylinder. The 45 minute cylinder is about 68.5 cubic feet and the hour bottle is 91 cubic feet. So doing the math it will take 14 minutes to fill the 45 minute cylinder and 19 minutes to fill the hour cylinder.

While the compressor is good as an inexhaustable source of filling cylinders it will take time. Better bet might be a 4 cylinder 6000 psi cascade system to couple with the compressor to give you a volume of air to fill from the compressor is just there to refill while you are waiting for cylinders. Just a thought though.

3. Alright in the Notes there, It says Able to work with a Maximum Of 2 Cylinder Cascade system. What Kind Of a Refill Time would We Be looking at If We incorporated 2 6000psi bottles into the system?

4. Originally Posted by Bushwhacker
Alright in the Notes there, It says Able to work with a Maximum Of 2 Cylinder Cascade system. What Kind Of a Refill Time would We Be looking at If We incorporated 2 6000psi bottles into the system?
The limit may be do to the "Duty Cycle" of the compressor. The compressor needs to rest after running for a period of time. I can not say for sure since I am not familiar with that unit.
Example: If the duty cycle is 60%, then in an hour the compressor run 36 minutes and need to rest 24 minutes. This is common in non-breathing air compressors, like found in mechanic shop.
Contact the manufacture directly for exact details.
Bauer Corp.

5. Why do you need it to be portable?

We don't usually fill on scene unless a m/a air truck was requested. Even then, it's just to save us time when we get back to the firehouse.

We have quite a few spares.

6. The capacity of a 6000 psi cascade cylinder is 509 cf. So 2 would be 1018 cf at 6000 psi. If you were to get the 5000 psi cylinders the capacity goes down to 474 cf. You can fill the scba cylinders in about 4-5 minutes depending on how warm it is outside. The key is to not do it too quickly and heat the cylinder up causing it to delaminate or crack. Rapid filling will shorten the life of the carbon fiber cylinders.

I would agree that the better solution would be to get the in station compressor with a remote fill port and hose. You can fill the cylinders in station or if need be fill a cascade using the remote fill set up and take some extra air with you if you have limited spare cylinders. We have a Bauer Unicus 3 cylinder compressor with 2 ASTM 6000 psi cylinders on the back of it and it can fill all of our 2216 psi cylinders (25) off of the volume of the tanks on the back. The compressor runs when the pressure gets to a certain point and automatically shuts off. We have a 4 cylinder cascade system that we keep full for the times when we need to bring some air to the scene for refills. We also have via M/A an air trailer available.

7. Originally Posted by ChiefKN
Why do you need it to be portable?

We don't usually fill on scene unless a m/a air truck was requested. Even then, it's just to save us time when we get back to the firehouse.

We have quite a few spares.
That's just the thing Chief, six Packs one Spare bottle a piece, for a total of 12, cylinders. With the Abundance of H2S in our Area, And the Distance of District, Spending 2-3 hours in a IDLH atmosphere is not completely out of the realm of possibilities.

The other Deciding Factor IS that there is only 1 Compressor system within 20 Miles of us That is 4500psi. There is not a mobile Cascade capable of Filling us for the better part of 80 miles. So If I Play the cards Right and swing this as a Benefit to More than My Dept. It ups the funding options. translated to my VFD Terms- IF we Don't have to pay for it hell-ya buy that!

I would Love to Have our own in House Compressor. But, The Mindless Bureaucracy attached to us, has already shot it down twice.

8. Originally Posted by Lewiston2Capt
We also have via M/A an air trailer available.
Our county got a grant for a county air truck. It's really nice and every department donated a few cylinders so that the whole county can be well served by a dedicated air truck with a bunch of extra cylinders for the various types of packs (mostly msa and scott around here).

http://www.1strespondernews.com/webp...5-dda1d4114565

9. Originally Posted by ChiefKN
Our county got a grant for a county air truck. It's really nice and every department donated a few cylinders so that the whole county can be well served by a dedicated air truck with a bunch of extra cylinders for the various types of packs (mostly msa and scott around here).

http://www.1strespondernews.com/webp...5-dda1d4114565
Our M/A is a cascade trailer so it doesnt matter what SCBA you are using they can fill em. Its actually the air force base in the area and they have Interspiro, we also have Scott and MSA in use in the area so a truck with spare cylinders on it is going to be a challange.

10. Originally Posted by Lewiston2Capt
Our M/A is a cascade trailer so it doesnt matter what SCBA you are using they can fill em. Its actually the air force base in the area and they have Interspiro, we also have Scott and MSA in use in the area so a truck with spare cylinders on it is going to be a challange.
This vehicle can fill them also.

The spares are "just in case".

11. Ah makes sense. We carry 2 spares per pack on the engines so grab a spare drop the empty at the air trailer/cascade and back in to fight. Makes sleeping alot easier on those days. Often we dont even call for the air trailer because of the spares, but the long duration incidents are where it really comes in handy. We offer to refill their cascade for them but they usually refuse as they have a compressor at their station. It just seems like the nice thing to do. We used the air we should offer to refill it.

12. My vol dept was able to obtain a Scott Liberty Mobile compressor thanks to an AFG grant last year (or was it the year before??).

Anyways, it's a nice system, and the plus side is that we can operate air tools off of it, and it has generator that runs a 4 light tower.

With my area being one of those rural areas that what you see is what you have and that's it except maybe a straggler or two beyond the initial call, it's nice to not have to worry about who's left that can go back to the station and fill bottles (in my case the neighbors have the fixed system, we have the mobile).

13. The Scott unit is a GREAT tool. Be CAREFUL about mobile filling using the compressor. You need to be in a "clean"air area even with the "snorkel" so you don't get CO in the system and ruin the filters.The Scott unit has several 6000# cylinders PLUS the light and generator so it's self contained. NOT cheap but they work GREAT,we have one about 1.5 hrs away from us. T.C.

14. Originally Posted by Bushwhacker
That's just the thing Chief, six Packs one Spare bottle a piece, for a total of 12, cylinders. With the Abundance of H2S in our Area, And the Distance of District, Spending 2-3 hours in a IDLH atmosphere is not completely out of the realm of possibilities.

The other Deciding Factor IS that there is only 1 Compressor system within 20 Miles of us That is 4500psi. There is not a mobile Cascade capable of Filling us for the better part of 80 miles. So If I Play the cards Right and swing this as a Benefit to More than My Dept. It ups the funding options. translated to my VFD Terms- IF we Don't have to pay for it hell-ya buy that!

I would Love to Have our own in House Compressor. But, The Mindless Bureaucracy attached to us, has already shot it down twice.
Have you looked at all the options out there before settling on a small, mobile compressor? The one thing that jumps out to me is a nearby department that has an air unit that consists of a pick-up with a topper and a cascade in the back. They respond it automatically to any fire in their county to provide air support. With a four, or even eight-bottle 6,000 psi cascade you could fill a TON of bottles. When you're done, drive it to the nearest compressor to fill it up.

I've also seen cascades on trailers. Enclosed trailers are nice as you can use them for rehab or command. I've seen a department that took a utility bed off a pick-up and made a trailer out of it for their cascade, plus they could hall some equipment in the compartments. The sky's the limit when you get to thinking about it.

Of course, you've got the grant angle to try to boost what money you have to spend on this set-up. While you might only be able to afford something like that unit you posted, you might be able to afford the matching funds on a much larger set-up that might work better for you.

15. Originally Posted by Catch22
Have you looked at all the options out there before settling on a small, mobile compressor? The one thing that jumps out to me is a nearby department that has an air unit that consists of a pick-up with a topper and a cascade in the back. They respond it automatically to any fire in their county to provide air support. With a four, or even eight-bottle 6,000 psi cascade you could fill a TON of bottles. When you're done, drive it to the nearest compressor to fill it up.

I've also seen cascades on trailers. Enclosed trailers are nice as you can use them for rehab or command. I've seen a department that took a utility bed off a pick-up and made a trailer out of it for their cascade, plus they could hall some equipment in the compartments. The sky's the limit when you get to thinking about it.

Of course, you've got the grant angle to try to boost what money you have to spend on this set-up. While you might only be able to afford something like that unit you posted, you might be able to afford the matching funds on a much larger set-up that might work better for you.
The Deeper I get Dug into this the more and more it is looking like a Enclosed trailer with a 4-6 5000PSI mobile Cascade, That little compressor maybe a after thought for filling them. I talked to the Bauer Rep yesterday And he Said it would average a 60/40 Duty cycle. He figured 2 5000psi Cascade cylinder then about a 40 min break.
I was looking to keep the Cost down on it but. If I skimp here I am gonna be ****ed at myself farther down the road when we actually need it

16. Originally Posted by Bushwhacker
The Deeper I get Dug into this the more and more it is looking like a Enclosed trailer with a 4-6 5000PSI mobile Cascade, That little compressor maybe a after thought for filling them. I talked to the Bauer Rep yesterday And he Said it would average a 60/40 Duty cycle. He figured 2 5000psi Cascade cylinder then about a 40 min break.
I was looking to keep the Cost down on it but. If I skimp here I am gonna be ****ed at myself farther down the road when we actually need it
You might be able to get an enclosed trailer lined out to where you can upgrade it later. If the money comes available, add a compressor. I'm sure you're already going to be looking at the option of having a generator on it, just make sure you get one that would power a compressor if you might add it later.

Personally, I kind of like the enclosed trailer idea for mobile filling. The Scott Liberty trailers are nice, don't get me wrong, but they're only good for filling SCBA. An enclosed box trailer you can multi-function. Put a heater/AC unit on top and use it for rehab, put some counters in it and you've got a command area. The list can go on and on.

17. Originally Posted by Lewiston2Capt
It says the fill rate of the compressor is 4.9 standard cubic feet per minute (scfm) the 4500 psi 30 minute air pak has a capacity of 45 scf so you are looking at about a 10 minute fill time per cylinder. The 45 minute cylinder is about 68.5 cubic feet and the hour bottle is 91 cubic feet. So doing the math it will take 14 minutes to fill the 45 minute cylinder and 19 minutes to fill the hour cylinder.
Okay so Correct Me if I am Worng here,

1-30 min Cylinder Holds 45scf and 1-5000PSI Cascade Cylinder holds 486scf. So In Theroy You Could Get 10 reFills From one Cascade Cylinder Correct?

So then the Number of Cascade Cylinders Corrolates Directly to the Number of Refills, 4 Cylinder Cascade 40 Fills....Right?

18. Originally Posted by Bushwhacker
Okay so Correct Me if I am Worng here,

1-30 min Cylinder Holds 45scf and 1-5000PSI Cascade Cylinder holds 486scf. So In Theroy You Could Get 10 reFills From one Cascade Cylinder Correct?

So then the Number of Cascade Cylinders Corrolates Directly to the Number of Refills, 4 Cylinder Cascade 40 Fills....Right?
You also have to take into account the equalization of the cylinders. The 486scf is the total capacity of the cascade cylinder. You wont be able to fill cylinders beyond the equalization point. You need a difference in pressure to make the air flow from one cylinder to the next. The advantage to the cascade system is on an empty scba cylinder you fill from the lowest pressure cascade cylinder to maximize the number of cylinders you can fill. Since you have 4500 psi paks it will diminish the number of cylinders you can fill from your cascade. If you were to get a 6000 psi cascade system it would allow you to fill more SCBAs.

Short version once the pressures in the Cascade cylinder and the SCBA cylinder are the same you are done flowing air. You will need to get a cascade cylinder with a higher pressure to continue filling the SCBA cylinder.

19. ^Exactly what I was thinking. Basically you can't put 4500 psi in your cylinder if your cascade only has 2000.

20. ## Yep.............

Originally Posted by CGITCH
^Exactly what I was thinking. Basically you can't put 4500 psi in your cylinder if your cascade only has 2000.

You hit the Center of the debate....... A minimum 4 Cylinder Bank would get you started, but an 8 Cylinder Setup would be a lot better. Squeezing the Max out of a Cascade System is an art, as well as a Skill. In my days of filling Bottles, It wasn't often that I'd find a really empty one, usually the wearer wouldn't breath it all the way down, rather there would be 500, 1000 psi or more left.

21. Originally Posted by hwoods
You hit the Center of the debate....... A minimum 4 Cylinder Bank would get you started, but an 8 Cylinder Setup would be a lot better. Squeezing the Max out of a Cascade System is an art, as well as a Skill. In my days of filling Bottles, It wasn't often that I'd find a really empty one, usually the wearer wouldn't breath it all the way down, rather there would be 500, 1000 psi or more left.
Whats the Formula For cascade Cylinder Pressure Drop per SCF of Air Moved?

I understand the Equalization Factor, I guesse what I was Getting at is "Whats the Average Numbers of Fills from a 4 Series Cascade?" remember I need to Make the best of Both worlds, Mobility and Supply. One that note, DOT States that I Can only Run with 5000psi Cylinders the 6's arent approved..

22. Originally Posted by Bushwhacker
Whats the Formula For cascade Cylinder Pressure Drop per SCF of Air Moved?
I don't know the formula, but just from thinking about that it would seem pretty difficult. Since the psi is exponentially dropping per scf moved. I think...

23. Originally Posted by CGITCH
I don't know the formula, but just from thinking about that it would seem pretty difficult. Since the psi is exponentially dropping per scf moved. I think...
I have looked through my FF1-2 And Can Come up with nothing even close, And I really Don't Wanna Run over to the Neighbors and Ask, "Hey Can I use Your Cascade for a Little Experiment?" But I think that I am going to have too.

24. Originally Posted by Bushwhacker
I have looked through my FF1-2 And Can Come up with nothing even close, And I really Don't Wanna Run over to the Neighbors and Ask, "Hey Can I use Your Cascade for a Little Experiment?" But I think that I am going to have too.
I just went through that course, and I know none of it is in there. It's one of those things that people could spend the time to figure the formula out. But it wouldn't really be effective since every cylinder has a little air, or a lot of air, in it. And also if you are filling them relatively quickly you may not get all 4500 psi in there maybe 4200. Just too many variables to get a steadfast formula.

Just a thought though, if you have a 5000 psi cascade cylinder that holds 500 scf of air (just to make math simple). You would be able to take 500 psi off that 5000 until you had to open another cylinder. Each SCBA cylinder, for simple math holds 50 scf of air. So 500 is 1/10 of 5000. 1/10 of 500 scf is 50. So, if I'm thinking right, you would be able to fill one bottle from the first one before having to open the second. I may be way out of the ballpark, just trying to think about this at my low educational level.

25. Originally Posted by CGITCH
I just went through that course, and I know none of it is in there. It's one of those things that people could spend the time to figure the formula out. But it wouldn't really be effective since every cylinder has a little air, or a lot of air, in it. And also if you are filling them relatively quickly you may not get all 4500 psi in there maybe 4200. Just too many variables to get a steadfast formula.

Just a thought though, if you have a 5000 psi cascade cylinder that holds 500 scf of air (just to make math simple). You would be able to take 500 psi off that 5000 until you had to open another cylinder. Each SCBA cylinder, for simple math holds 50 scf of air. So 500 is 1/10 of 5000. 1/10 of 500 scf is 50. So, if I'm thinking right, you would be able to fill one bottle from the first one before having to open the second. I may be way out of the ballpark, just trying to think about this at my low educational level.
I came up with something Similar to that also. But I am not to sure that My math was correct or even it is Relatively close to how it actually works.

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