Topping Off SCBA Cylinders-"It's Not Full Until It's Cold And Full"

[LineCapt 134]

Never heard of this practice before.

 

 

[FireMedic049 597]

Only the top half of the link posted is showing and when I click on it, it disappears altogether from the post and doesn't take me to the article.  If I go back to the main menu and re-enter the thread it reappears, but the same thing happens.  Anyone else having an issue?

[antiquefirelt 994]

"the heat build up raises the pressure"Are they talking about the bottles be "warm" post fire or do they realize the filling process generates heat? I have to wonder how fast their filling their bottles. "Hot filling" speeds the process but always results in shrinkage (never good). 700 psi seems like a significant amount that likely is the direct result of speed filling the cylinders.

[BIGRED1 71]

3 hours ago, antiquefirelt said:

"the heat build up raises the pressure"Are they talking about the bottles be "warm" post fire or do they realize the filling process generates heat? I have to wonder how fast their filling their bottles. "Hot filling" speeds the process but always results in shrinkage (never good). 700 psi seems like a significant amount that likely is the direct result of speed filling the cylinders.

 

They are probably filling it with the valve full open. 700psi drop is a lot. I have filled bottles and lost a minute amount over a week. to lose that much in hours, something is wrong in the process. Slow is the way to go. if your on scene and doing refills then that's different. You most likely will use the air before it even starts to cool off.

Edited December 20, 2016 by BIGRED1

[FireMedic049 597]

19 hours ago, BIGRED1 said:

 

They are probably filling it with the valve full open.  

Which valve, the cylinder valve or the valve on the fill station?

 

19 hours ago, BIGRED1 said:

700psi drop is a lot. I have filled bottles and lost a minute amount over a week. to lose that much in hours, something is wrong in the process. Slow is the way to go. if your on scene and doing refills then that's different. You most likely will use the air before it even starts to cool off.

But that's only if it's an incident of an extended duration in which you are using a lot of cylinders.  It's pretty common for us to only need to fill most cylinders once while on scene.  When that's the case, depending on who's doing the filling, it's not uncommon to see a drop in the pressure the next day necessitating topping them off.

[BIGRED1 71]

5 minutes ago, FireMedic049 said:

Which valve, the cylinder valve or the valve on the fill station?

 

But that's only if it's an incident of an extended duration in which you are using a lot of cylinders.  It's pretty common for us to only need to fill most cylinders once while on scene.  When that's the case, depending on who's doing the filling, it's not uncommon to see a drop in the pressure the next day necessitating topping them off.

The Fill station on full. I was taught to crack the "Fill" knock and slowly fill the bottle. The valve on the bottle is either full open or full close.

 

Well this is where checking your gear comes into play. when you get to work and go over your rig, you check air pressure. If you are filling bottles on scene you are most likely using them. Most departments don't have refill rigs so they refill back at firehouse. Either way the 700psi drop in a hour is not good. Also the bottle could have been the last one to fill so heat has been building from filling station.

[FireMedic049 597]

2 hours ago, BIGRED1 said:

The Fill station on full. I was taught to crack the "Fill" knock and slowly fill the bottle. The valve on the bottle is either full open or full close.

Thanks, just wanted to confirm we were talking about the same thing.

 

 

2 hours ago, BIGRED1 said:

Well this is where checking your gear comes into play. when you get to work and go over your rig, you check air pressure.

Right and that's what I was talking about.  While checking my equipment the day after a fire, it's not uncommon to find some cylinders that have settled and need topped off.

 

 

2 hours ago, BIGRED1 said:

If you are filling bottles on scene you are most likely using them. Most departments don't have refill rigs so they refill back at firehouse.

That may be what you are used to, but in my area it's pretty common for cylinders to be filled on scene and not just for them to be reused at that incident.  Most departments don't have air trucks either, but there are enough that one typically responds to most working fires.  Many departments around here also don't have fill stations in the firehouse, which is part of the reason an air truck is usually requested at some point, even if you won't need to reuse them right away.

 

2 hours ago, BIGRED1 said:

Either way the 700psi drop in a hour is not good. Also the bottle could have been the last one to fill so heat has been building from filling station.

I would agree a 700psi drop is not good, but there generally isn't a build up of heat on the fill station end.  At least nothing I've ever experienced.  The heat is primarily generated by the air under pressure being pushed into the cylinder.  The friction of the air passing thru the cylinder valve raises the temp of the air going in.  The faster the flow, the hotter the air gets and that heat is transferred to the cylinder body. 

 

[BIGRED1 71]

On 12/21/2016 at 1:10 AM, FireMedic049 said:

I would agree a 700psi drop is not good, but there generally isn't a build up of heat on the fill station end.  At least nothing I've ever experienced.  The heat is primarily generated by the air under pressure being pushed into the cylinder.  The friction of the air passing thru the cylinder valve raises the temp of the air going in.  The faster the flow, the hotter the air gets and that heat is transferred to the cylinder body. 

 

I was thinking that maybe the air moving from the Fill bottle, constant on and off when doing multiple refills at a scene over a period of hours. Since we don't use a refill rig, i was trying to think of ways a bottle could get hot. I think the issue was just a Fill station valve opened all the way and he got hot air. Just goes to show ALWAYS CHECK YOUR GEAR.