I have been asked to come up with a procedure for an ammonia that occurs during a power failure. Does anyone have any suggestions on what one might do if this occurs Thank you.
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I have been asked to come up with a procedure for an ammonia that occurs during a power failure. Does anyone have any suggestions on what one might do if this occurs Thank you.
Nanuuk,
Can you describe side, type of ammonia system, people in possible affected areas.
Are power failures common & has something happened in the past.
Each plant you may react differently, but basics like evacuation of people may be same.
Key valves should be labeled & marked up on up to date schematic drawing.
Hi nanuuk
A few more questions to add to Rangers'
Do you have any procedures for dealing with ammonia leaks at other times?
Why would you want one specifically for a power failure?
Do you have ammonia leaks when the plant stops?
Does the system run into a vacuum?
A bit more information would be handy as it will help us help you.
Paul
Also You would have to say any leak you already know of is not really acceptable as well, otherwise someone is not doing their job.Quote:
Originally Posted by PaulZ
They should be fixed or planned to fix, also potential leaks like corroded pipework, leaking shaft seals etc.
If not its an accident waiting to happen. Have had very large plants shut off for 24 hours, no problems.
We run a 2 stage refrigeration plant actually 2 of them for a 240,000 Sq Ft facility. We have an emergency evacuation plan in place and if there is an ammonia leak to which we do not have problems with other than the odd packing leak the facility shuts down automatically including both engine rooms and all evaporators. Seeing how we are just a storage facility and no production we find this is a better and safer way to go as it makes it easier to communicate and evacuate the building as some rooms are very noisy and you have a hard time hearing the sirens we do have strobes as well or someone calling. As for leaks when the plant shuts down if for a long period more that 24 hrs. we experience small leaks through packing glands at times but rarely and is so they are addressed right away. There is always the question whether it is a good idea to have the plant run in the event of an ammonia leak if it is on the low side and you are on site and know where the leak is then yes pull the plant into a vacuum and fix/isolate the problem( we run a positive pressure of 4 psi by the way) if it is on the high side we feel that it's not a very good idea to have the plant keep on running especially if no one is on site at the time. Now back to the question of a procedure for an ammonia leak during a power failure we are being asked by our local inspector to have one drawn up and the reason behind there madness is if there is a large enough leak that could potentially cause an explosion from a power source if the power is off at the time you would want to make sure it stays off until the leak concentration is below that level.
Nanuuk,
Just a few comments as each country, region have different standards.
Also we do not know what you have.
Can suggest ammonia detection in plant room with mechanical ventilation rated or designed for this duty.
It can be used for shunt trip of plant to avoid explosive atmosphere, which can be set at a very low level so you know of possible developing problem & so it's more human friendly.
Pre-alarm could be before shunt trip.
Constant ventilation fans can have detector in it's or their air stream.
Also all areas of plant can also have ammonia alarms, roof spaces which can also have ventilation, vessels & pumps etc.
Bunding around vessels that hold ammonia & water drain areas have to be addressed so the whole community & environment does not get affected.
Maybe you need to get an expert in to asses, as that's a paper trail as well.
I'm sure it's standard for you to also check relief valves, high pressure cut outs of compressors (set at least 10% below relief settings) pipework & vessel inspections etc
Relief vent lines also are important for when plant is on or off, where do they go, what & who will it affect if one relieves.
Some are put through a scrubber or water tank.
Some leaks depending where they are, can only be isolated & wait till it leaks out, like a condenser coil or similar.
Your own staff also have to have correct training & equipment up to date.
http://www.awsacanada.com/AWSA06/ASP.html see downloads
http://www.cdc.gov/niosh/docs/81-123/pdfs/0028-rev.pdf
http://www.csb.gov/file.aspx?DocumentId=682
Liquid ammonia pumps with shaft seal also to be avoided as major source of leak.
Ok I went off the track, as no power.
Could you hire or buy a generator to plug in on such occasions.
It could plug into a compressor as well as run extraction fans and ammonia detection.
It would have to be off for a number of hours or an unknown period to justify doing it.
https://www.worksafe.qld.gov.au/__da...on-systems.pdf
https://www.aibonline.org/aibOnline_...-Checklist.pdf
https://www.ashrae.org/File%20Librar...-043_jekel.pdf
hydraulic lockup in above link should be taken into consideration