The Mysteries of Ammonia!

[Grizzly]

Wow that is kind of miss directed. 20PPM of ammonia and most will not enter a room cause it is to harsh. a ***** plant that size with a big leak you can just go clean up the bodies when the leak is done. Because the human body can not tell how much ***** is in the air untill you go down from suffication.

Give me a NH3 plant any day

Iceman 4000.
Hey I get what you and Josip mean. may I put my take on what you are saying.
Using the extracted data below

"Permissible levels of exposure to toxic gases are defined by time-weighted average (TWA), short-term exposure limit (STEL), and concentration at which toxic gasses are immediately dangerous to life or health (IDLH). The TWA is defined as the concentration for an 8-hour workday of a 40-hour workweek that nearly all workers can be exposed to without adverse effects. Similarly, the STEL is the concentration to which an exposure of longer than 15 minutes is potentially dangerous and may produce immediate or chronic compromise to health. Anhydrous ammonia has a TWA of 25 ppm, an STEL of 35 ppm, and an IDLH of 500 ppm."
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The impotant issue here is the fact that an exposure of up to 25ppm is allowed when deemed necessary for up to 8 hrs, Within a working week.
Useful when the Coldstore / Loading bay workers smell Ammonia. Useually from an oil purge or line purge being carried out in a nearby Plant room.
You then get all sort of protestations, like ah! I smell Ammonia and I can't work in this etc etc.
It was so bad in 1 Cold Store where I was Site Engineer that whenever there was the slightest whiff of Ammonia ( remember the human nose can smell from 0.9ppm the average being 5ppm). The site staff would "down tools" and refuse to work. What the managment did was obtain one of those clever "Gasman" Sniffers that analised the Ammonia concentration. Producing the written Union agreed data which basically said "Anything around 25ppm was acceptable for up to 8 hrs, as stated above.
The workforce were then limited as to when they could "cry wolf".
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People repeatedly exposed to ammonia may develop a tolerance (or acclimatization) to the irritating effects after a few weeks. Tolerance means that higher levels of exposure are required to produce effects earlier seen at lower concentrations.
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This just confirms all the "Old Timer Stories"
Like Old Pete never bothered with a resperator he would sit in the middle of a gas cloud smoking his pipe!
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One VERY IMPORTANT differance between Ammonia
And *****s is:-
Because Ammonia vapour is LIGHTER than air.
The use of a carbon filter resperator (type K1, K2 or K3) will aid breathing and enable safe retreat from the leak/ danger area.
Whereas HFC/ HCFC ( *****) CO2 or similar refrigerants are HEAVIER than Air.
Therefore a Fresh air or circulation Breathing mask (B.A.) MUST BE USED TO ENABLE MOVEMENT in the leak/ danger area.
So guys don't ever in panic grab your colleagues resperator and dive in to help your mate!!
Unless it is the correct type for the job.
Personally I have entered a plant room with full chemical suit and B.A. Waded through Liquid Ammonia
to the far end of a plant room. Shut off the offending
Oil pressure gauge ( the bordon tube had split internally). And yes it was a steel tube. Causing all the oil from the sump of a Grasso RC911 to spew out across the plant room floor. Followed by probably 200kg of vapour / liquid Ammonia.
It is a strange feeling in a Chemical Suit and B.A.wading through Liquid Ammonia. With very little vapour being given off because basically it freezes the surrounding areas it contacts so quickly that there is no heat to boil off the remaining liquid.
The only remaining heat source is your boots as you walk through it!
Once isolated it was just a case of carefully setting up a water curtain and letting the ammonia disolve in the water. What you do with the water then can be discussed another time.
Whilst this was going on I had an extremely nerveous young Site manager. Kitted out in full Chemical Suit and B.A. watching from the plant room door. With strict Instruction that should anything go wrong. He was to come in and get me!
Well he thought it would be clever to do the relevant B.A. Training as well as me.
Rest assured My suit became My Suit and he kept his PHEW!
SERIOUSLY THOUGH Guys. that could of been a nasty situation but with the correct training it was all dealt with safely.
God I need a drink now!
Cheers Grizzly