co2 abort switch

[cda]

Just wondering.

I have seen co 2 systems, but never plan reviewed one, but

Why this clasue:::

4.5.4.11 Abort switches shall not be used on carbon dioxide systems.

 

[north star]

% - % - %

Which code \ standard & edition are you referencing ?

% - % - %

 

[cda]

Comes out of NFPA 12

 

[north star]

$ = $ = $

This explanation is from Scott Stookey, ...an FPE:

"Most likely because two distinct alarm signals will be initiated before the CO2 system

discharges:

1) Activation of the occupant notification devices upon operation of the initiating device

2) A separate and distinct pre-discharge alarm before CO2 is released"

$ = $ = $

 

[cda]

Don't think that is it, because same sequence on clean agent.

I am thinking along the line of depending where the abort is located, the person might not get out of the co2 area before it dumps.

 

[FM William Burns]

I would agree with Scott's analysis

 

[cda]

I would agree with Scott's analysis

But you get that with a clean agent system

 

[mark handler]

TheAbort Station is a manually activated, electric device designed to let the user suspend discharge of the fixed fire protection system. available in Deadman and Maintained

http://www.sunway-sos.com.tw/DB/a2/system/gas/CO2/Chemetron/CO2/CH %E6%9A%AB%E6%AD%A2%E9%96%8B%E9%97%9C.pdf

• UL (864) – A releasing event starts the Pre-discharge timer. If the Abort Switch is pressed, the timer counts down to 10 seconds and holds there. If the Abort Switch is released, the timer resumes the countdown from 10 seconds.

IRI (UL 864) – Int’l Risk Insurers method functions the same way as the UL type, except that the Abort Switch will not function unless it is pressed before the cross-zoned second imput device is activated

 

[Msradell]

Mark, I looked and found the same explanation you did but it doesn't explain why you don't put an abort switch on CO2 system. The explanation proposed by Scott really doesn't make any sense because the same sequence exists for Clean Agents yet they have a "Abort Switch". I really can't think of any logical reason not to have one on a CO2 system. I've never seen an actual installation of a CO2 system, I've only seen older Halon systems or newer Clean Agent installations. I wonder if it possibly has something to do with where CO2 systems are located?

 

[mark handler]

Mark, I looked and found the same explanation you did but it doesn't explain why you don't put an abort switch on CO2 system. The explanation proposed by Scott really doesn't make any sense because the same sequence exists for Clean Agents yet they have a "Abort Switch". I really can't think of any logical reason not to have one on a CO2 system. I've never seen an actual installation of a CO2 system, I've only seen older Halon systems or newer Clean Agent installations. I wonder if it possibly has something to do with where CO2 systems are located?

If you are in the room/space. the system replaces the air with co2.

OSHA limits carbon dioxide concentration in the workplace to 5,000 ppm for prolonged periods, and 35,000 ppm for 15 minutes. These higher limits are concerned with avoiding loss of consciousness (fainting), and do not address impaired cognitive performance and energy, which begin to occur at lower concentrations of carbon dioxide.