carla posted on January 12, 2012 08:57
The NFPA 2001 Standard on Clean Agent Fire Extinguishing Systems 2012 edition has been released. One of the major changes in the standard is the design concentration levels for both halocarbon agents and inert gas agents.
Essentially, the 2008 edition of the standard stated that for Class A and Class C fires the Miniumum Design Concentration (MDC) is equal to 1.2 x the Minimum Extinguishing Concentration (MEC).
The 2012 edition states that the Class A MDC is equal to 1.2 x the MEC OR equal to the MDC for Heptane, whichever is greater. This results in a Class A extinguishing concentration increase of approximately 7-8% for the halocarbon agents with no change to the inert gas agent concentrations.
For Class C fires, the 2012 edition states the MDC is equal to 1.35 x the MEC. If the Class C hazard contains electronics energized at greater than 480 volts the extinguishing concentration shall be determined by further analysis. (NOTE: If all electronic equipment is shutdown prior to discharge of a suppression agent the hazard can be considered Class A). This results in a Class C extinguishing concentration increase of approximately 12-13% for both halocarbon and inert agents.
Below is a table of commonly used suppression agents and their minimum design concentrations.
|
|
HFC-227ea
|
FK-5-1-12
|
HFC-125
|
IG-55 |
IG-541 |
IG-100 |
|
Class A/C (2008 edition)
|
6.25
|
4.2
|
8
|
37.9 |
34.2 |
36
|
|
|
|
|
|
|
|
|
Class A (2012 edition)
|
6.7
|
4.5
|
8.7
|
37.9
|
34.2 |
36 |
|
|
|
|
|
|
|
|
Class C (2012 edition)
|
7
|
4.7
|
9
|
42.7 |
38.5
|
40.5
|
|
|
|
|
|
|
|
Concentrations are minimum requirements per the NFPA 2001 Standard (Edition as noted).
Flooding factors are based on 70-degrees F min. temp and are provided for estimating purposes.
It's important to realize that these changes come about due to the diligent ongoing testing of agents and the rapid changes that take place in the data center arena. All of the existing systems that have been installed over the past 20 years are considered safe and effective in design, the margin of safety is what has increased in this edition of the standard.
Advanced Safety Systems is here to answer your questions regarding new hazards that need fire protection as well as existing fire suppression systems. For over 45 years we have been at the forefront of suppression technology and will keep on top of the changes in the marketplace.