1. Ultra High-speed Explosion Suppression Systems and Ultra High-speed Water Spray Systems
Chapter 7
Page 209

2. Objectives
List and explain the difference in performance objective between an explosion suppression system and an ultra high-speed water spray system, and identify the NFPA standard applicable to each performance objective
Discuss the difference between a deflagration and a detonation 2

3. Objectives (con’t.)
List and discuss methods other than an explosion suppression system that may reduce the likelihood of an explosion
List applications for explosion suppression systems
Identify the extinguishment methodologies for explosion suppression systems 3

4. Objectives (con’t.)
Evaluate an explosion pressure profile for a commodity, comparing a suppressed profile to an unsuppressed profile. Determine whether an explosion suppression system would be valuable for a vessel of a given yield strength
Describe the sequence of a suppressed explosion 4

5. Detonations and Deflagrations
Detonation: a reaction in which the flame front expands at a rate greater than the speed of sound
Deflagration: a reaction in which the flame front moves into the unburned material at less than the speed of sound 5

6. Design Approaches
Point protection: application of suppressant directly onto an expected point of hazard
Area protection: application of suppressant over the entire floor surface area of a room or enclosure 6

7. Explosion Suppression Systems
First explosion suppression systems were introduced by the British in the late 1940s to protect aircraft engines and extended to industrial use in the early 1950s
Cylinder filled with a suppressing agent, a detection system, and a system of control circuitry
Designed to protect enclosed vessels or containers in which over pressurization is the primary concern

8. Explosion Suppression Systems
Alternatives or Enhancements to Explosion Suppression Systems
How Explosion Suppression System Agents Work
Explosion Suppression System Components
Explosion Suppression System Agent Storage Container 8

9. Deflagration Pressure Containment
NFPA 69 formula to calculate an explosion protection design pressure for a vessel 9

10. Explosion Suppression Systems (con’t.)
Figure 7-6 Explosion pressure profile for a combustible undergoing deflagration in an enclosed vessel

11. Explosion Suppression Systems (con’t.)
Figure 7-7 Explosion system schematic; a detection signal is sent to the control unit, and the agent initiator valves and isolator valves are actuated simultaneously

12. Explosion Suppression Systems
Detection Systems for Explosion Suppression Systems
Fire Alarm Control Units (FACU) for Explosion Suppression Systems
Applications for Explosion Suppression Systems
Aerosol Fill Rooms
Diptanks 12

13. Explosion Suppression Systems
Applications for Explosion Suppression Systems
Dust Collectors
Grain Elevators
Other Dust Hazards
Vaporous Hazards
Industrial Processes
Other Hazards 13

14. Explosion Suppression Systems
Selection of an Explosion Suppression System Agent
Personnel Protection
Effectiveness-to-Weight Ratio
Agent Compatibility
Sequence of a Suppressed Explosion by an Explosion Suppression System 14

15. Explosion Suppression Systems (con’t.)
Figure 7-8 Sequence of a suppressed explosion

16. Ultra High-Speed Water Spray Systems
Protect hazards where overpressurization is not the primary concern
Applications for Ultra High-Speed Water Spray Systems
Munitions Manufacturing and Ultra High- Speed Water Spray Systems
Agent Selection for Ultra High-Speed Water Spray Systems 16

17. Ultra High-Speed Water Spray Systems
Squib-Actuated Ultra High-Speed Water Spray Systems
Pilot-Actuated Ultra High-Speed Water Spray Systems
NFPA 15 Requirements for Ultra High- Speed Water Spray Systems 17

18. Summary
Explosion suppression systems are designed in accordance with NFPA 69 for deflagrations in vessels where overpressurization is the primary concern
For deflagrations where enhanced suppression time is required, but where overpressurization is not the primary concern NFPA 15 is used for the design of ultra high-speed water spray systems 18

19. Summary (con’t.)
An explosion suppression system consists of a suppression container with agent initiator, a control unit, and a detection system
The suppressed explosion pressure profile must be below the vessel yield strength
Suppression agents work by absorbing the energy of the expanding flame front, by inhibiting combustion chain reactions, or by reducing the concentration of the combustible in an enclosed space