1. Carbon Dioxide System Design
Chapter 9
Page 257

2. Objectives
Demonstrate understanding of the carbon dioxide phase diagram
Explain why storing carbon dioxide in its liquid form is desirable
Describe two methods for maintaining carbon dioxide in its liquid form, using the carbon dioxide phase diagram as a basis
List potential uses for a carbon dioxide fire protection system 2

3. Objectives
Detail the limitations and personnel concerns that must be considered when specifying or designing a carbon dioxide system
Compare and contrast the types of carbon dioxide systems
Calculate the carbon dioxide required for a rate-by-volume or rate-by-area local application fire protection system 3

4. Objectives
Calculate the carbon dioxide required for a total flooding application fire protection system 4

5. Carbon Dioxide Carbon dioxide: a gaseous fire protection agent
Chemical designation CO2
Phase diagram: a graph that represents the physical state of a specific substance at varying pressures and temperatures 5

6. Triple Point

7. Carbon Dioxide
Triple point: point at which carbon dioxide exists in all three states simultaneously
Critical temperature: temperature beyond which carbon dioxide can exist only in its vapor phase 7

8. Carbon Dioxide Storage
High-Pressure Cylinders
Low-Pressure Storage Containers
Determination of High Pressure Versus Low Pressure 8

10. Ex. 9-1: Calculating Carbon Dioxide Cylinder Quantity

11. Uses For Carbon Dioxide Systems
Carbon dioxide is effective extinguishant:
Ordinary combustibles—Class A commodities
Flammable liquids—Class B commodities
Electrical hazards—Class C commodities 11

12. Carbon Dioxide System Limitations
Not to be used for materials containing their own oxygen supply, for hazards involving reactive metals such as magnesium, and for metal hydrides
Personnel Hazards Related to Carbon Dioxide 12

13. Carbon Dioxide System Limitations
Actions to protect personnel
Continuous predischarge alarms
Breathing apparatus
Voice alarm systems
Exits
Signs
Training procedures 13

14. Carbon Dioxide System Limitations
Actions to protect personnel
Time delay
Manual activation
Manual override
Scented gas 14

15. Types Of Carbon Dioxide Systems
Four types of carbon dioxide systems are recognized by NFPA 12:
Total flooding carbon dioxide systems
Local application carbon dioxide systems
Hand hose line carbon dioxide systems
Standpipe systems with mobile supply 15

16. Total Flooding

17. Total Flooding

18. Local Application

19. Local Application Carbon Dioxide System Design Procedure
Design methods for local application design
Rate-by-volume method
Rate-by-area method
Each method applies carbon dioxide directly on an object without the intent of filling a volume with carbon dioxide 18

20. Rate-By-Volume Carbon Dioxide Local Application: Design Procedure
Rate-by-volume method: a method of local application of carbon dioxide where an imaginary volume larger than the hazard is created to account for the dissipation and loss of carbon dioxide during discharge 19

21. Rate-By-Volume Carbon Dioxide Local Application: Design Procedure
Local Application Imaginary Volume Calculation—Raised 2 Feet Above Solid Floor
Local Application Imaginary Volume Calculation—Raised Less Than 2 Feet Above Solid Floor
Determination of Local Application Rate- By-Area Carbon Dioxide Quantity—Walls Remote From Hazard 20

22. Rate-By-Volume Carbon Dioxide Local Application: Design Procedure
Determination of Local Application Rate- By-Area Carbon Dioxide Quantity—Walls Very Close to Hazard
Determination of Local Application Carbon Dioxide Weight 21

23. Local Application Imaginary Volume Calculation—Mounted to Solid Floor
The design volume of an object mounted to a solid floor is the product of the
length, width, and height of the imaginary volume, as shown in Figure 9-11.
V imaginary = (length + 4 ft.) x (width + 4 ft.) x (height + 2 ft.)
No deduction is permitted for any solid objects within the imaginary volume.

24. Local Application Imaginary Volume Calculation—Raised 2 Feet (0
Local Application Imaginary Volume Calculation—Raised 2 Feet (0.6 m) Above Solid Floor
The design volume of an object mounted to a solid floor is the product of the
length, width, and height of the imaginary volume, as shown in Figure 9-11.
V imaginary = (length + 4 ft.) x (width + 4 ft.) x (height + 2 ft.)
No deduction is permitted for any solid objects within the imaginary volume.

25. Local Application Imaginary Volume Calculation—Raised Less Than 2 Feet Above Solid Floor
If a hazard is raised less than 2 ft. (0.6 m) above a solid floor, the imaginary
volume is:
V imaginary = (length + 4 ft.) x (width + 4 ft.) x (height + 2 ft.)
Distance from floor to bottom of hazard
No deduction is permitted for any solid objects within the imaginary volume.

26. Determination of Local Application Rate-By-Area Carbon Dioxide Quantity—Walls Remote From Hazard
To determine the minimum rate of carbon dioxide required, multiply the imaginary volume by a factor of 1 lb/min/ft 3
NFPA 12 requires that high-pressure local application systems have quantities increased by 40%.
Low-pressure Systems: R = (V imaginary) x (1 lb/min/ft.3) x High-pressure Systems:
R = (V imaginary) x (1 lb/min/ft.3) x (1.4)

27. Rate-By-Volume Carbon Dioxide Local Application: Design Procedure

28. Calculation of Local Application Rate-

29. Calculation of Local Application Rate-By-Volume Quantity
Use the rate-by-volume local application method to determine the carbon dioxide flow rate (R) for a small newspaper printing press in a very large room, mounted to a solid floor, protected by a high-pressure carbon dioxide system.
The press is 4 ft. in width (W), 3 ft. in length (L), and 7 ft. in height (H) and is not located near any walls. Determine the total amount of carbon dioxide required (W) if the required duration (D) is 30 sec.

30. Calculation of Local Application Rate-By-Volume Quantity
Solution L is given as 3 ft., W is given as 4 ft., H is given as 7 ft., and D is given as 1⁄2 minute.
The imaginary volume (V imaginary) for an object mounted to a solid floor is computed as follows:
V imaginary = (length + 4) x (width + 4) x (height + 2)
= (3 + 4) x (4 + 4) x (7 + 2)
= (7) x (8) x (9)
= 504 ft.3

31. Calculation of Local Application Rate-By-Volume Quantity
The rate of discharge is computed as follows for a high-pressure local application system:
R = (V imaginary) x (1 lb/min/ft.3) x (1.4)
= (504 ft.3) x (1 lb/min/ft.3) x (1.4)
= 504 lb/min x (1.4)
= lb/min

32. Calculation of Local Application Rate-By-Volume Quantity
The total weight of liquid carbon dioxide required is computed as follows:
W = R x D
= (705.6 lb/min) x (1/2 min)
= pounds of carbon dioxide required

33. Rate-By-Area Local Application: Design Procedure
Rate-by-area method: a method of applying carbon dioxide to a two- dimensional surface area based on the capability of listed nozzles to discharge a given amount of carbon dioxide over a fixed area of coverage
Diptank: a vat used for dipping, coating, or stripping an object in a flammable liquid 28

35. Rate-By-Area Local Application: Design Procedure
Drainboard: an object that collects flammable liquid residue that drips from the dipped item onto an inclined surface, allowing the flammable liquid residue to drain back to the diptank
Example 9-3 follows. See Figures and 9-14 on Pages 281 and 282 30

36. Total Flooding Carbon Dioxide System Design Procedure
Total flooding systems involve analysis not only of the expected fire but also of the integrity of the enclosure
Evaluate Enclosure Integrity
Evaluate Personnel Hazards
Evaluate Fire Scenario of Expected Fire
Accurately Measure Room Volume 31

37. Room Volumetric Calculation

38. Total Flooding Carbon Dioxide System Design Procedure (con’t.)
Determine Type of Combustible
Determine Minimum Design Concentration (see Table 9-2, Page 288)
Determine Volume Factor
Volume factor: a value used to determine the amount of carbon dioxide required to be injected into a room at the minimum design concentration of 34%
Determine Basic Quantity of Carbon Dioxide 33

39. Ex. 9-5: Determination of Minimum Design Concentration for Total Flooding Carbon Dioxide Systems

40. Ex. 9-6: Determine Total Flooding Carbon Dioxide Volume Factor for a Surface Fire

41. Total Flooding Carbon Dioxide System Design Procedure
Determine the Material Conversion Factor
Material conversion factor: a dimensionless number that increases the basic quantity of carbon dioxide for hazards where the minimum design concentration exceeds 34%
Adjust Basic Quantity for Temperature
Adjust Basic Quantity for Unclosable Openings 36

42. Ex. 9-7: Determining the Basic Quantity of Total Flooding Carbon Dioxide Volume Factor for a Surface Fire

43. Ex. 9-8: Determining the Total Flooding Carbon Dioxide Material Conversion Factor for a Surface Fire

44. Ex. 9-9: Adjusting Carbon Dioxide Total Flooding Quantity to Account for Temperature

45. Total Flooding Carbon Dioxide System Design Procedure
Carbon Dioxide Total Flooding Discharge Duration
Consider Other Scenarios for Loss of Gas
Extended Rates of Total Flooding Carbon Dioxide Application 40

46. Total Flooding Carbon Dioxide System Design Procedure
Extended discharge system: system of small pipes and nozzles that provides a rate of discharge after the primary discharge system ceases operation
Calculate Pressure Relief Venting Area
Select Carbon Dioxide Containers
Determine Number of Nozzles 41

47. Total Flooding Carbon Dioxide System Design Procedure
Select Detection System
Use Carbon Dioxide System Calculation Form 42

48. Summary
Designers must consider personnel hazards when specifying a carbon dioxide system for an enclosure
Carbon dioxide
Stored in liquid form
High-pressure cylinders store it room temperature
Low-pressure containers store refrigerated liquid carbon dioxide at a low-pressure 43

49. Summary Carbon dioxide systems can be designed for Total flooding
Local application
Hand hose lines
Standpipe systems with mobile supply 44