A suitable figure for the rate of contaminant release, Carbon Monoxide, in commercial kitchens?

[MrDoodaa]

Hi all,
I'm trying to calculate if my fresh air supply rates are sufficient to ensure CO levels don't exceed 300 ppm over ten minutes, but I am unable to find a suitable value for q = the rate of contaminant release in L/s. Would any of you nice people be able to help me out.
Also excuse me if this sounds like a stupid question, I'm a first year building services engineering student.

 

[miningman]

Well in my world , we get a bit concerned when the CO levels exceed 50ppm, and I personally would have evacuated the entire facility as soon as I got an instantaneous value of 200ppm. Dont know if thats relevant for you or not, but again from memory I think 300ppm corresponds to the the onset of nausea, and other serious symptoms on the way to collapse and death.

 

[MrDoodaa]

I know what you're saying, the figure I got was from the Control of Substances Hazardous to Health (COSHH) as a maximum allowable over 10 mins. As I said before I'm only a first year student designing a ventilation system for a college project, so my understanding of things is probably a bit wrong. I was just trying to find out a flow rate in Litres/sec for the release rate of CO in a commercial kitchen to use in Q = (q(10^6-Ci))/(Ci-Co) to see if my supply ventilation rate was satisfactory, what I did in the end was let q be the unknown and therefore saw what release rate my system could handle, and then provided provisions by way of a sensor that would increase extract and supply rates if that release rate was exceeded. Still trying to find my feet with it all. It's good fun though.
Thanks very much for your reply, much appreciated.

 

[miningman]

Well, as a bit of general advice, first off, the rules of eng-tips specifically forbid student postings of homework type questions. However you demonstrate sufficient humility that perhaps you deserve a bit more help. If I were you, as you complete this assignment, I would make reference the idea that designing a system to allow even 10 minute exposure to 300ppm would not be a smart bit of design engineering. The fact is, even with sophisticated controls, things go wrong. I suspect that if this commercial kitchen of yours ever reached 100 ppm, there is something seriously wrong and without dramatic intervention, things will only get worse. Again, I suspect that in the real world, a facility like this would not tolerate more than 25 ppm ( hence my reference to 50ppm in my underground mines). I have had my miners on their hands and knees puking their guts up because of excess CO.... things had gone wrong despite normally adequate ventilation. If I were your prof , I would give you extra marks for recognising these facts, but I might also ask you how you came by this knowledge.

 

[MrDoodaa]

Thanks very much for your knowledge and time.