Close call (eye opener)

[Tycho]

This is something that happened to me a few years back...

Thought I'd share.

Copy of mail sent to friends abroad:

I've just had the scariest closest call I have ever had during my nine years in this job... we were to cut two pipes on a plate freezer (a plate freezer is used to freeze fish into nice 20kg blocks (44 pounds), a freezer has three pipes with various valves, non return and overflow and shut off valves, that regulates the freezing and the defrost. The chief engineer onboard said he had evacuated the freezers and sucked all the ***** back to the liquidtank (liquid tank = a tank that by law is required to hold all the ***** in the plant) and that all the freezers were empty. we had alot of work to do onboard and the pipework on the freezers were kinda inbetween work, my co worker, who were "supervising" this job said we were to change a piece of the liquid and hotgas line (he really meant to say hotgas return valve line), he was welding pipes for a oilcooler, so I went to depressurize the freezer, checked all valves needed, shut of everything in the line we were to work on and sent the last 14 psi overboard through a hose, the chief engineer said he had had shut of all valves, but sometimes they have small internal leaks and 14 psi can be justified to that.
so, the pressure was gone and my co-worker crawls behind the freezer, puts the grinder to a 2 inch pipe and goes at it, I usually make a small hole first to make really really sure the pipe is empty, but he just tore at it, when he is almost through the pipe it blows apart *BOOOOOMWHOOOOOOOOOOOOOOOOOOOOOOOOSH* the grinder disc shatters, I freeze in place like a deer caught in headlights, I want to run, cause I know this is bad bad stuff, but he was behind a freezer, it took him five minutes to get there and I aint going nowhere till I know he is on his way to safety...
He crawls over the freezer (something I thought impossible) grinder spooling down in his hand... He lands on the deck and we both make a run for fresh air, ***** gas (not liquid thank god) rushing out of the 2 inch pipe at 100 psi... We run towards the exit stairs and once close to fresh air, we have a short, 5 sec max, mental check on all the valves and I burst out "Main return valve!!" (the engineer had shut off the return valve on each freezer instead of the main return one, and we were working on pipes connected to the main line), I pull out my trusty 14"... (adjustable spanner that is you dirty dirty minds ) and run back down into the factory to the main return valve... my 14 inch is to small to get the valve cap off so I run back into the workshop, pick up a pipe wrench and back to the valve, get the cap off, out comes the spanner, I spot my co-worker as he runs up the stairs to fresh air... I'm working that valve spindle as a madman and manages maybe 5 complete turns on it when my brain kicks in again... up until this time I had been in a almost total "panic" to close the valve before it was unbreathable on the factory deck... Thinking I had plenty of time as ***** is heavier than air and I thought it would take some time to fill the whole factory with gas, I start to feel my heart beating at an extreme rate, I see "stars" and then my brain kicks back in, holy crap, hypoxia! I run through the factory towards the stairs up to fresh air, when I get up, my ears are ringing for some strage reason, all sounds are muted, my co-worker tells me that he was about to go back down to get me, I give him a weak smile and tell him I'm ok. The valve is still not closed and we confer and conclude that we should go down in turns of thirty seconds each.
So my co-worker goes back down but reemerges after ten seconds (he's a smoker and probably has less lung capacity), he huffs and puffs and tell me he managed two turns on the valve. I think to my self "f*ck this, at this rate we'll never get the damn valve closed" I tell him to get ready and I take a few deep breaths before I run back down and start working on the valve... man does it take alot of turns to close it... I'm turning and turning on that damn valve trying to close it, then I notice that my toes start tingling, a few seconds later my knees are shaking and my heart is working at an even more unbelievable rate than the first time, my hearing is close to gone again, and my vision is fading doing the scooby doo scene change effect (without the music tho ) and the air or whatever it is I'm breathing starts tasting kinda sweet...

the valve is closed

I run/stagger to the ladder and pull myself up to the deck, I meet my co worker on his way down the ladder, we both enter the sweet sweet fresh air... might not have been fresh, but it's the best thing I have ever felt, My co-worker said I looked like a robot when I stumbled out the door and he was on his way down to drag my body out of there (his words, not mine )... Luckily we both escaped without harm, but it's by far the worst and scariest episode I have ever had.

Usually I am very very bent up on double checking the valves before doing any pipe work, and I have never found anything wrong... until this time where we were short on time and had (for once) a competent chief engineer).


From now on, I will trust myself and myself alone when it comes to valves



I hope you all read through this and dont do the mistake I did... dont ever trust anyone with your life like this, if you are doing work that might affect yourself if it's not properly prepared, always double check. And last but not least, it's better to lose $50.000 in ***** then to lose your life.
we have an escape kit with 30 minutes of fresh air at our workshop, but we were to stressed out to think of driving the ten minutes to our workshop to get it... guess the boyscouts hat it right when they said "be prepared"

[chillin out]

That was a close call mate, good to hear a happy ending though.

I heard a similar story once but is was with ammonia and both guys died.

Chillin

[US Iceman]

One afternoon we were working on an ammonia system used to cool calcium chloride for soil freezing. The screw compressor was shut off and the oil filter housings were depressurized to change the oil filters.

Everything was going fine until my co-worker came into the trailer. Oh, I forgot to mention this system was inside of an enclosed 40 ft. semi-trailer.

There was about 12 inches of clearance between anything in this trailer. The motor starter, control system, receiver, condenser, chiller, and screw compressor were all inside. Not much room to work.

Back to the story...

Someones shirt got caught on a 1/4 turn ball valve. Anyone want to guess which valve it was?

The valve happened to be the one I closed to isolate the oil filter housing. Within seconds I found myself trapped in this trailer with 100 psig ammonia vapor hitting me in the chest. The guy who opened the valve accidentally froze in surprise.

I had to hit him to get him to move and then we both tried to work our way through the 12" clearances until out of the trailer.

Lesson of the story... Always lockout valves during service. And never let anyone stand in your way to safety!

Sometime I'll tell you the story about the 4" hose that burst with -20F calcium chloride in it.

If I was a cat I would be down to 7 lives. The first one was my mistake not for locking out the valve. The second was pure accident. Wrong place at the wrong time.

Want to guess how hard calcium chloride will make your clothes?

[Andy]

Hi Tyco/Iceman.
I so far have lived a charmed life, the only near one was whilst changing a single relief valve that had been fitted to a receiver (r22) pumped it out, and recovered all but 4 psig of the gas. I started to screw off the relief, after protests from my co-worker, it will be fine a said, as the relief valve came to the end of it's treads, blew out of my hand and went straight over the top of the evaporative condenser beside me.

Had I been bending over the valve, it would have killed me. The receiver had some liquid in it, the pressure was rising all the time I was un-screwing the valve, it blew the valve in the air like a rocket.

Should have pulled the pressure down into a vacumn and bored a vent hole in one on the nozzles on the receiver.

Won't be doing that one again

Also remember the burning pain in my nuts after going in to isolate an ammonia leak on a high level gantry, no BA on site, just a mask
Half way up the 30' ladder the ammonia started to come thru the mask, options were to go down into the cloud of ammonia below me or to hold my breath and keep going, reached the top of the ladder and ran down the gantry, pulled of the mask, lucky for me there was breathable air up there.

Won't be doing that again, no BA set no Chemical suit and no back up.

Probably only saved a few bottles of gas anyway as I had to add 3000kg to make up the loss, 1/4" hot gas pilot line to the suction solinoide had been leaking all weekend.

Kind Regards. Andy

[chillin out]

Want to guess how hard calcium chloride will make your clothes?

Hope you didn`t spray it anywhere else!!!!! LOL

Theres pills you can take for that at your time of life...

Chillin

[phil68]

Was the stopping the escape of the ***** really worth risking your life for? OK, if it was going to endanger other poeple's lives then maybe the heroism was called for. But to stop the escape of ***** for purely monetary reasons I would've let it escape & let the engineer who made the mistake take the rap. This may sound harsh but hopefully then he wouldn't make the same mistake again.

[US Iceman]

Also remember the burning pain in my nuts after going in to isolate an ammonia leak

Hi Andy. One form of first aid I found that works very well for this problem is the same ointment that is used for diaper rash on babies.

It is rather humbling, but it is much better than spending days in agony.

Hope you didn`t spray it anywhere else!!!!!

We were absolutely soaked. The spray went about 40 feet sideways. Of course, this happened to be where we were at!

There's pills you can take for that at your time of life...

I suspected someone would have some comments like this. This should also give you some time to think about this yourself.

[aawood1]

Hi Andy/ US Iceman. I was called back to work one night for an Ammonia leak in a 4" Hot gas defrost pipe line to a Gryo freezer. It turned out that the shift engineer on at the time had found the leak as he had been sitting on the pipe line at the time. He spent the next 20 min. washing his nuts in the sump of a old Halls cooling tower. He did get me one day on a RS mag valve change on the coldstore, He said he had pumped it down and shut all the valves, It was at -15" vac. untill some switched the defrost on and the hot gas started to come from the poilot line made it a bit hot around the nuts and eyes. So from that day on I do all my own pump downs and check any thing that any engineer tells me he has done.

[US Iceman]

...check any thing that any engineer tells me he has done.

Very good advice. Never believe anyone who say they took care of it. If you are working on it, check it yourself.

Had a similar problem on a 600 volt system. Someone says the breaker is turned off. It wasn't. I have not believed anyone since. I think the water behind my ears and beginning experience made this a very important lesson.

[Tycho]

Phil68: Nope, wasnt worth it but, I didnt think it would get that bad that fast, and when it indeed did, adrenaline did all the thinking I guess...


will never do it again to, and as aawood1 said, from now on I always check and double check the valves, even if I was the one who closed them



ah, ammonia... dontcha just love it

was changing a refrig pump on one of our plants (spray cooler, RSW http://www.pbase.com/kimmo98/image/49607773.jpg )
if you look at the picture, you can barely see the pump, under the cooler to the left.

No pressure, all valves closed.

I was standing with a leg on each side of the pumps suction line and tilted the pump away from me needless to say, the small amount of gas still left in the pump and pipes rose straight up to the place where it was most painfull...

tangled up between pipes there was nothing to do but get the pump out, then me, then a short run to wash the equipment in the nearest sink

[wambat]

Speaking of close calls, I was changing out a defective seal on a 5H60 Carrier compresor which was connected to a 100 HP double ended motor with a 5H 40 Carrier on the other end. This unit was close to a cement wall which was about 1/2 meter away. I was alone in the room, in the pent house whan another mechanic walked in to see if I needed any help. I said no, and I was just in the process of turning the coupling and shaft over to tighten the other bolts on this Thomas coupling, I picked up my socket wrenches and was starting to tighten the bolts when.... Yes you guessed it! the motor started and both wrenches flew out of my hands. Would you believe that both mised me
As I am one who believes in God, I believe the force was with me at that moment. If any of you are familier with a Thomas coupling you know that they can be quity large and they have many disks and bolts to provide flexibility so whan you turn the motor shaft over you usually put your fingers in between the spaces and turn the shaft over that way. What happened was the other mechanic went in the motor control panel room and decided he was going to protect me by turning off the the main circuit breaker ...instead he turned in on. Needless to say he didn't come out of that room until I went to see what the hell he did that for
He was shaking and had tears in his eyes, actually he was in more shock then I was. I NEVER GOT MAD AT HIM as I knew it was my bad because I didn't lock out or tag the breaker. I was just glad to be alive with both hands and arms intact. I believe I learned a lesson that day and always tagged and locked out the equipment. I do have other close but that was the worse.

[US Iceman]

Hi wambat,

As your story points out this is a very good reason for not wearing neck ties in an engine room. I have seen this too many times.

As anyone who has had a close call can attest to, you do things differently the second time.

[US Iceman]

...then a short run to wash the equipment in the nearest sink

Do you have to have personnel safety showers in the engine rooms in Norway?

[Tycho]

Do you have to have personnel safety showers in the engine rooms in Norway?

yup, safety showers outside every door leading in to the refrigeration machinery room, if it's ammonia... most ships throw in a sink with warm and cold water taps at one of the entrypoints

[nh3wizard]

Glad to hear everyone was safe, I never trust anyone, always double check it myself.

[Andy]

ah, ammonia... dontcha just love it

was changing a refrig pump on one of our plants (spray cooler, RSW http://www.pbase.com/kimmo98/image/49607773.jpg )
if you look at the picture, you can barely see the pump, under the cooler to the left.

Tyco,
nice piece of kit you have there. What type of compressor, it looks familar, but I can't put a name on it.


Kind Regards. Andy

[Andy]

Hi

It seems that the industrial refrigeration industry has more potential to kill and injure that other branches of the family.

All those who have posted are competent experienced engineers and yet all have a story of danger to tell.

I suppose we could all change to A/C or Commercial refrigeration, health and safety might be a bit better, but it would be a bit of a no brainer

Kind Regards. Andy

[Tycho]

Tyco,
nice piece of kit you have there. What type of compressor, it looks familar, but I can't put a name on it.


Kind Regards. Andy

It's a Howden XRW 204

and just noticed I said the pump was on the left, my bad, the pump is to the right

nice units indeed this one is a 950Kw unit charged with ammonia...

Wanna make a quess on the size of the ammonia charge?

[Mark C]

ah, ammonia... dontcha just love it

Yes, At least I know its in the atmosphere!

[Frosty]

Gent's some people say UK health and safety laws are strangling business - I say, I would rather work to procedures, method statements etc than have to face the awefullness of telling one of my workers wifes/children that there father has been killed in a tragic accident! We've all been there, I took a risk many years ago, I decided to shim down a cold room, high-level ceiling onto a lower level, I used the suction line and a purling to navigate my way down. The purling gave way and I landed back first across a horizontal suction line!! All around me were 12mm cooler support rods - I could have been well and truly 'speared' Think about it...risk assessments and method statements are there for a reason!! PS, I still suffered cracked vertabrae and broken ribs...but I live to tell the story. Be careful, it's a dangerous industry.