Anyone ever cover fire nozzle with finger to redirect?

[EricP]

I feel funny asking this but my curiosity is winning out:

Background: my car died on the backside of MidOhio so I pulled off into the grass near a corner worker. As I sat there it somewhat became apparent something in the engine area was on fire. I briefly contemplated the many consequences of setting off the fire system. One consequence being a face full of foam even though I wasn’t on fire. So I then considered putting my gloved thumb over the cockpit nozzle in the dash and setting off the system hoping it would just do the engine. I was afraid my thumb would end up hurt and still get a face full of foam. So I didn’t do anything. Got out and corner workers put out the little fire that was there. Just an ignition wire and breather hoses. If I had successfully set off only the engine area, I think the mess would have been about the same. Dunno.

But I’m curious, anyone try to block off a nozzle and set off the system? Successfully?

[Steve Demeter]

Never thought of it. OTOH never had reason to set it off. I would not try it personally. Of course I have an "obsolete" Halon system so expense would have been high but mess would have been small

[Dan Wellington]

You should never try to stop any thing that is stored in compressed form. Reason, when the compressed things expand it tends to cools down really fast, could have given you the 2 degree burns if contacted directly to the skin.

[TimH]

You should never try to stop any thing that is stored in compressed form. Reason, when the compressed things expand it tends to cools down really fast, could have given you the 2 degree burns if contacted directly to the skin.

..and I wouldn't trust your glove to offer more than a few seconds of protection.

[Jim Edmonds]

Growing up in Oklahoma in the 50's I remember a news story about a painter in Tulsa. He put a spray gun against his arm and pulled the trigger. Filled some of his arm with paint. Dead.

Made me respect pressure.

YMMV, Have fun today.

Jim

01 Van Diemen FF
13 USF2000 MZR
95 Stohr FIA F3 prototype
17 MV Agusta track bike that I don't get to ride enough, Ha.

[R. Pare]

It can take something like only a bit over 35 PSI for compressed air to blow through your skin (it varies, of course) which is why the OSHA regs on air guns require those 2 big holes in the sides of the nozzle.

[jcolley]

When I got to my first boat (submarine), there was a story of a previous member of the aux mechanical division who thought it would be funny to make the "squealy" sound with compressed air through his finger tips using a 700psig reducer. He ended up doing making the squealy sound himself as it inflated his hand like a balloon. Between that and being on board for a 4500 psig manifold blowing off and dumping an air bank inboard, I have a great respect for compressed gasses.

[Dan Wellington]

Man these are quiet funny but sad at the same time. I don't know should I giggle or Should I take a 2 minute of silence for those people.

[EYERACE]

Darwin Award nominees

[EricP]

…I feel kinda stupid hearing these stories but I didn’t do it so I’m not that stupid I guess…

I do wish there was a ready way to extinguish an engine fire without also getting a face full.

[mikey]

What about inserting a quarter turn in line ball valve so you can close the line off manually

[DanW]

…I feel kinda stupid hearing these stories but I didn’t do it so I’m not that stupid I guess…

I do wish there was a ready way to extinguish an engine fire without also getting a face full.

Either way, it's no fun. I'd pull the handle as soon as I knew. Alternative: Get out, then pull the handle if you can. You're skin isn't worth your car.

Another alternative: Automatic activation. Great if you are unable to pull the cable if upside down or big shunt. They can build to your requirements and provide the sensors for the engine bay and drivers bay. Only the sensor that sees heat activates. These are used on aircraft too.

https://safecraft.com/motorsports/

[johnhafkenschiel]

I feel funny asking this but my curiosity is winning out:

Background: my car died on the backside of MidOhio so I pulled off into the grass near a corner worker. As I sat there it somewhat became apparent something in the engine area was on fire. I briefly contemplated the many consequences of setting off the fire system. One consequence being a face full of foam even though I wasn’t on fire. So I then considered putting my gloved thumb over the cockpit nozzle in the dash and setting off the system hoping it would just do the engine. I was afraid my thumb would end up hurt and still get a face full of foam. So I didn’t do anything. Got out and corner workers put out the little fire that was there. Just an ignition wire and breather hoses. If I had successfully set off only the engine area, I think the mess would have been about the same. Dunno.

But I’m curious, anyone try to block off a nozzle and set off the system? Successfully?

Sounds like instant frostbite maybe.

[DanW]

Sounds like instant frostbite maybe.

Not instant as long as driver is wearing his protective gear which insulates heat or cold.

[stonebridge20]

Not instant as long as driver is wearing his protective gear which insulates heat or cold.

Blue jeans do not protect against frozen balls when you accidentally set off your Halon system at 2am while sitting on an alignment pad bored out of your mind.

I no longer point discharge nozzles directly at "the boys"

[E1pix]

Blue jeans do not protect against frozen balls when you accidentally set off your Halon system at 2am while sitting on an alignment pad bored out of your mind.

So you’ve been told?

Asking for a friend, or maybe two...

[stonebridge20]

So you’ve been told?

Asking for a friend, or maybe two...

Personal experience.

1992 sitting in my Ralt 4 while my crew guy went back and forth by .001 increments of toe out at about 2am and I decided to see what the check button did on the electric halon system battery pack.
Well, it shot the drivers compartment share of halon straight at my balls.

I walked like a cowboy for a few days after that one.

[iamuwere]

Not instant as long as driver is wearing his protective gear which insulates heat or cold.

A glove might give you 1-2 seconds. I work with compressed gas daily and freeze my fingers regularly doing it. That fire nozzle? I'm staying away from that if at all possible.

[AlanVDW]

I was told by a tech inspector to point the nozzle at the lower chest or latch/cam lock, rather than toward your neck and face.

I would assume the belt system would take the brunt of the pressure and diffuse the spray.

[Rick Kirchner]

Good points, but we are making some assumptions - like what is the discharge pressure of these devices? Might not be the fill pressure due to an orifice, and of course the other nozzles. So it may be possible to hold a gloved finger over it. REmember, it's PSI, lots of P, not so much SI.

Second, the temperature at the nozzle will only drop if there is flow. If the driver is successful at keeping his finger over the nozzle (and it only has one exit) then there will be no cold.

Would make a great Mythbuster segment. Too bad these things are too damned expensive to experiment with.

[Zonker]

Many years ago I installed a halon system in a sports racer. The instructions were clear to not point the cockpit nozzle at the driver, instead point it at a side panel or the floor and let it reflect back into the drivers area. Still get a full dose of halon around the driver with out danger of frostbite.

They also suggested mounting the nozzle far to the front near the drivers feet or knees. The halon will flow back and completely fill the cockpit. If you point it at the upper torso it will escape through the cockpit opening leaving little for the driver.

Never had to try it out to see if they were right.