Carbon Dioxide Systems

Frequently Asked Questions (FAQs)

How do I design a CO2 system for an industrial Fryer?

When protecting a subfloor only with CO2, are there any guidelines to follow for Design, Installation, Recharge and Maintenance Manual?

1. How do I design a CO2 system for an Industrial Fryer?

2. When protecting a subfloor only with CO2, are there any guidelines to follow for design to help reduce CO2 lost through the subfloor?

Subfloor hazards involving dry electrical wiring are protected as deep-seated fires requiring a 50% design concentration of CO2. For deep-seated fires, the design concentration shall be achieved within 7 minutes, but the rate shall be not less than that required to develop a concentration of 30 percent in 2 minutes.

Wiring and the minimal height of subfloors can cause the CO2 to be deflected upon discharge. This deflection, if in the direction of the floor tiles, can cause the CO2 to flow up through any openings into the room or space above. Because the total CO2 flow rate required to reach 30% concentration in 2 minutes is constant for a volume, increasing the number of nozzles reduces the flow requirement per nozzle (lbs. Of CO2 per minute), which reduces the velocity of the CO2 discharge per nozzle. Therefore, Ansul recommends reducing nozzle spacing from 20 ft. to 15 ft. between nozzles and using more nozzles when protecting subfloors.

The type of nozzle utilized also will make a difference in velocity. A “D” nozzle will have a softer velocity than a “Baffle” nozzle. With the “D” nozzle, the CO2 makes a directional change out of the nozzle orifice insert and is forced up against the deflector in the back of the nozzle. The CO2 is then forced past the deflector tabs and out against the sides of the discharge horn. The turbulence created inside the nozzle creates a soft cone shaped discharge pattern.

However, the only way to verify that proper concentration will be achieved is to run a discharge test.