What is Discharge Time in a Fire Extinguishing System?

A fire suppression system is a system designed to detect and extinguish fires automatically or manually in various types of environments, such as commercial, industrial, or critical facilities. One important element in the operation of these systems is the discharge time. So, what is discharge time and why is it important?

Definition of Discharge Time

Release time is the duration of time taken by the extinguishing medium (such as gas, liquid, or other chemical) to be fully released from the fire extinguishing system to the intended area. This duration is usually measured from system activation until all the extinguishing media is discharged from nozzles or other distribution devices.

Factors Affecting Release Time

1. Types of Extinguishing Media
   • Media such as carbon dioxide (CO2), FM-200 gas, or water-based liquids have different physical characteristics and release mechanisms.
   • Gas-based media typically have a faster discharge time than liquid-based media.
     
2. System Pressure
   • High-pressure systems allow the media to be released more quickly.
   • Insufficient pressure can extend the discharge time and reduce the effectiveness of the system.
     
3. Size and Design of Protected Area
   • Larger or complex areas take longer to distribute the media evenly.
   • An optimal system design can minimize discharge time.
     
4. System Configuration
   • Pipe length and diameter, number of nozzles, and distribution orientation affect the flow of the extinguishing medium.
     

Importance of Release Time

1. Outage Effectiveness
   • Excessively slow discharge times can increase the risk of fire spreading before the extinguishing agent reaches the entire area.
   • Standardized extinguishing times ensure that the fire can be extinguished quickly before causing further damage.
     
2. Compliance with Standards
   • Many international standards such as NFPA (National Fire Protection Association) set maximum extinguishing times.
   • Compliance with these standards is part of ensuring occupant safety and asset protection.
     
3. Effects on Ventilation System and Environment
   • Discharging time also affects the interaction between extinguishing media and ventilation in protected areas. Emptying too soon or too late can reduce extinguishing effectiveness.

Example of Standard Discharge Time

• Definition and Factors Affecting Discharge Time: Discharge time is the duration of the release of the extinguishing medium. Several factors affect it, including the type of medium (gas vs. liquid), system pressure, size and design of the area, and system configuration (pipes, nozzles).
• The Importance of Discharge Time: Proper discharge timing is crucial for rapid fire suppression effectiveness, ensuring compliance with safety standards such as NFPA, and influencing the interaction between extinguishing media and ventilation systems.
• Example of Standard Discharge Time: Standard discharge times vary depending on the type of system, for example, inert gas systems (60-120 seconds), FM-200 systems (<10 seconds), and foam systems in mining vehicles (50 seconds with minimum release rate).