|
Feature
Article
Since the time of our review of
last year (International Fire Protection Magazine, May 2002) a
number of new developments have occurred which impact the clean
agent marketplace. These recent developments include the continuing
decommissioning of Halon 1301 systems worldwide, the introduction of
new clean agents, the withdrawal of several clean agents from the
marketplace, the introduction of new suppression system designs, and
a number of proposed changes to the national and international
standards governing the use of clean agent fire suppression
systems.
Halon Out...Clean Agents
In
For over 30 years Halon 1301 has
served as a nearly ideal fire suppression agent. However, due to its
implication in the destruction of stratospheric ozone, the Montreal
Protocol of 1987 identified Halon 1301 as one of numerous compounds
requiring limitations of use and production, and an amendment to the
original Protocol resulted in the halting of Halon 1301 production
on January 1, 1994.
Today the installation of Halon 1301
suppression systems is a rare occurrence, limited to specifically
defined "essential" uses, primarily within the aviation and military
sectors. In most cases these systems employ reclaimed and recycled
Halon 1301 due to the ban on the production of new Halon
1301.
In addition to the almost worldwide
production ban on Halon 1301, numerous countries have taken steps to
mandate the removal of Halon 1301 suppression systems. The complete
removal of Halon 1301 systems, with the exception of a small number
of systems involving essential use applications, has already been
accomplished in Germany and Australia. Canada has implemented a
Halon 1301 phase out plan, whereby starting in 2010 no refills of
fixed Halon systems will be allowed.
The current and future use of Halon
1301 within the European Community is governed by EC Regulation
2037/2000. Critical uses for Halon 1301 which will be permitted
include aircraft applications (crew compartments, engine nacelles,
cargo and dry bays), military applications (engine compartments and
occupied spaces in vehicles and vessels), and specialized inerting
applications (Channel Tunnel, facilities processing radioactive
materials, communication and command centers essential for national
security).
EC Regulation 2037/2000 also sets the
dates for the decommissioning of non-critical Halon 1301 systems.
The sale and servicing of halon systems with virgin halon within the
EC has been banned since 1 October 2000. All Halon 1301 units not
listed as critical must be decommissioned by 31 December
2003.
With the growing demise of Halon 1301,
the need for alternative systems is growing, and it is expected that
a large portion of this market will be satisfied through the use of
the clean agents.
New Kids on the
Block
In response to the ban on Halon 1301
manufacture, the fire suppression industry has developed a number of
nvironmentally-friendly alternative clean agents for total flooding
applications. In the past year, two new agents have been introduced
to the clean agent marketplace, NAF S 125® and NovecTM
1230.
NAF S 125® is the trade name for a
mixture of pentafluoroethane with D-limonene, marketed by Safety
Hi-Tech Services (SHT), a division of Safety Hi-Tech Srl.
Pentafluoroethane is a hydrofluorocarbon (HFC), commonly designated
as HFC-125. D-limonene is a naturally occurring substance, also
known by the chemical name 4-isopropenyl-1-methylcyclohexene, and is
the main component of citrus peel oil. The presence of D-limonene in
the extinguishing mixture serves to reduce the amount of acidic
compounds (hydrofluoric acid) formed during fire suppression from
the decomposition of the HFC-125 component. NAF S 125TM systems are
currently being marketed in both low pressure (360 psig
superpressurization with nitrogen) and high pressure (600 psig
superpressurization with nitrogen) versions. The ozone depletion
potential (ODP) of NAF S 125® is a zero, and its global warming
potential (GWP) is 3400 (for a 100 year time horizon).
NovecTM 1230 is the trade name for the
fluorinated ketone1,1,1,2,2,4,5,5,5-Nonafluoro
-4-(trifluoromethyl)-3-pentanone, marketed by 3M. Chemically,
NovecTM 1230 belongs to the class of perfluorinated ketones, or
totally fluorinated ketones. As a member of the ketone family, the
NovecTM 1230 molecule contains a carbonyl (C=O) group within its
molecular structure. The presence of this particular "functional
group" as it is referred to by chemists, imparts two properties to
the Novec 1230TM molecule which are absent in the hydrofluorocarbon
(HFC) type agents: chemical and photolytic (light) reactivity. Due
to its photolytic reactivity, NovecTM 1230 is rapidly removed from
the troposphere via photolysis, i.e., NovecTM 1230 is rapidly
decomposed by interaction with the ultraviolet radiation from the
sun. As a result, the atmospheric lifetime and GWP of the agent are
low: 3M has reported an atmospheric lifetime of approximately five
days, and a GWP of 1. NovecTM 1230 contains no bromine or chlorine,
and hence it has an ODP of zero.
A total of three clean agents have
been voluntarily removed from the marketplace by their manufacturers
within the last year. At the recent meeting of the ISO TC/21/SC 8
subcommittee in New Orleans in September 2002, the subcommittee
agreed to eliminate the agents octafluoropropane (CF3CF2CF3,
FC-2-1-8, 3M), n-decafluorobutane (CF3CF2CF2CF3, FC-3-1-10, 3M)) and
chloro-tetrafluoroethane (CF3CHFCl, HCFC-124, Du Pont) from the ISO
14520 standard.
Table 1 lists the clean agent fire
extinguishants which are currently commercially available. The clean
agent marketplace is currently dominated by two agents: FM-200® and
Inergen®; FM-200® has an estimated 100,000 installations in more
than 70 countries worldwide. Clean agents are employed in a myriad
of applications, including pleasure boats, marine and military
vessels, flight simulators, medical facilities, cellular sites,
internet service provider (ISP) centers, TV and radio control rooms,
microwave relay towers, anechoic rest chambers, clean rooms,
flammable liquid storage areas, art galleries, libraries and
museums. Worldwide, numerous high value items are protected by clean
agent systems. FM-200® suppression systems protect the electrical
systems of the Eiffel Tower, the first draft of the Declaration of
Independence, and protected the Star Spangled Banner during its
recent restoration. FE-125 suppression systems protect the engine
nacelles of the U.S. Navy F/A-18E/C and V-22 aircraft. FE-13 systems
are employed in inerting applications on the North slope, and
Inergen® systems protect a copy of the Gettysburg
address.
Table 1. Commercially Available Clean
Agents
| Tradename |
Manufacturer |
Chemical Formula |
Contact Information |
| FM-200 |
Great Lakes Chemical |
CF3CHFCF3 |
www.fm-200.com |
| FE-227 |
Du Pont |
CF3CHFCF3 |
www.dupont.com/fire |
| FE-125 |
Du Pont |
CF3CF2H |
www.dupont.com/fire |
| FE-13 |
Du Pont |
CF3H |
www.dupont.com/fire |
| FE-36 |
Du Pont |
CF3CH2CF3 |
www.dupont.com/fire |
| Triodide |
Ajay North America |
CF3I |
www.CF3I.com |
| NAF S 125 |
Safety Hi-Tech, Srl |
CF3CF2H
0.1% D-limonene |
www.safetyhitech.com |
| NAF S III |
Safety Hi-Tech |
4.75% CF3CHCl2
82% CF2HCl
9.5% CF3CHFCl
3.75%
D-limonene |
www.safetyhitech.com |
| Novec 1230 |
3M |
CF3CF2C(O)CF(CF3)2 |
www.3m.com |
| Argotec |
Minimax GmbH |
Ar |
www.minimax.com |
| N100 |
Koatsu |
N2 |
www.koatsu.co.jp |
| Argonite |
Ginge-Kerr |
50% N2
50% Ar |
www.ginge-kerr.com |
| Inergen |
Ansul |
52% N2
40% Ar
8% CO2 |
www.ansul.com |
New Clean Agent System
Designs
In addition to the introduction of new
agents, the past year has also seen the introduction of new
suppression system designs into the clean agent
marketplace.
Kidde-Fenwal has recently introduced
its Advanced Delivery System (ADS), which employs FM-200® as the
fire suppression agent. The ADS system utilizes a "piston-flow"
design in which nitrogen gas is used to "push" liquid FM-200®
through a pipe network. Nitrogen and FM-200® are stored in separate
cylinders, connected through the appropriate hoses and control
hardware. Upon activation of the system, nitrogen flows into the
headspace of the FM-200 cylinder, "pushing" the FM-200® through the
cylinder dip tube and through the system piping network.
The ADS system offers several
advantages compared to "traditional" FM-200® systems, which employ
liquid FM-200® superpressurized with nitrogen (i.e., nitrogen and
FM-200® are in the same cylinder). The ADS system enables greatly
improved mass flow rates to be obtained, and also results in higher
sustained average cylinder pressures. This allows the use of longer
and more complex pipe distributions, as well as the use of smaller
diameter pipework. According to Kidde-Fenwal, the use of the ADS
system allows pipe distances of up to three times the normal pipe
length for an FM-200® system to be easily achieved. The ability to
use smaller diameter piping and longer pipe runs is essential when
retrofitting existing Halon 1301 systems, and the ADS systems can be
an effective retrofit solution for existing Halon 1301 systems. The
ADS systems are both UL listed and FM approved.
Fike Corporation has recently
introduced its ECARO-25TM clean agent fire suppression systems in
Europe as well as in the United States. "ECARO" stands for
Extinguishing Clean Agent Retrofit Option, and the Fike ECARO-25TM
systems employ Du Pont FE-25 fire extinguishing agent. The
ECARO-25TM systems are also marketed as retrofit solutions for
existing Halon 1301 systems. ECARO-25TM systems are FM
approved.
The inert gas clean agent
manufacturers have also introduced system changes within the past
year, and both lower and higher pressure systems have entered into
the clean agent marketplace. The use of lower pressure systems is
aimed at the retrofit market to allow utilization of existing Halon
1301 pipework where appropriate. The use of higher pressure systems
increases cylinder capacity and hence reduces cylinder storage
requirements.
Clean Agent
Standards
ISO 14520,
Gaseous Fire Extinguishing Systems: Physical Properties and System
Design, specifies requirements and gives recommendations for the
design, installation, testing, maintenance and safety of clean agent
systems. The standard is comprised of part 1 covering general
requirements, and parts 2 through 15 covering agent-specific
requirements. The current version of ISO 14520 is the first edition,
published in August of 2000.
Recent developments related to ISO
14520 result from the recent meeting of the ISO TC/21/SC 8
subcommittee in New Orleans in September 2002, where a number of
proposals were approved by the subcommittee.
The ISO TC/21/SC 8 subcommittee agreed
to the addition of two new agents to the ISO 14520 standard: NAF S
125TM and NovecTM 1230, discussed above. Three agents were
eliminated from the standard: FC-2-1-8, FC-3-1-10, and
HCFC-124.
The subcommittee agreed to allow agent
exposure limits for the HFC clean agents to be based upon the PBPK
model. The PBPK (physiologically based pharmacokinetics) model
represents an improvement over the cardiac sensitization NOAEL/LOAEL
approach previously employed to set exposure limits. The end result
of the acceptance of the PBPK model is an increase in the maximum
design concentrations allowed for HFC clean agents in normally
occupied enclosures. Under the current proposal, design
concentrations up to the cardiac LOAEL level would be allowed in
normally occupied areas.
The subcommittee also accepted new
fire test data for the clean agents. Extinguishing concentrations
were determined according to the current procedures described in ISO
14520-1, first edition, Annex C. The data were produced by third
party laboratories, and will serve as the basis for agent design
concentrations in future additions of ISO 14520. Table 2 shows the
new fire test data.
Table 2. Fire Test Data for Clean
Agents: Extinguishing Concentrations, % v/v
| Agent |
Test Laboratory |
Heptane Cup Burner |
Heptane Pan Fire |
Wood Crib Fire |
| FM-200/FE227 |
HAI |
6.7 |
6.9 |
4.9 |
| FE-125(a) |
HAI |
9.3 |
9.3 |
6.7 |
| FE-13 |
HAI |
12.6 |
12.3 |
10.5 |
| FE-36 |
HAI |
6.5 |
7.5 |
5 |
| Triodide |
HAI |
3.5 |
3.5 |
3.5 |
| NAF S 125(b) |
VdS/HAE |
9.2 |
8.7 |
7.5 |
| NAF S III |
HAE |
10 |
9.9 |
6 |
| Novec 1230 |
UL |
NA |
4.4 |
3.4 |
| Argotec |
VdS |
39.2 |
33.7 |
30.7 |
| N100 |
NMRI |
33.6 |
33.6 |
30 |
| Argonite |
DIFT/FM |
37.8 |
30.2 |
28.7 |
| Inergen |
UL |
31.7 |
29.6 |
28.2 |
(a)
360 psig system; (b) 600 psig system; HAI = Hughes Associates, Inc.;
HAE = Hughes Associates Europe; UL = Underwriters Laboratories; NMRI
= National Maritime Research Institute of Japan; DIFT = Danish
Institute of Fire Technology; FM = Factory Mutual
Additional changes to the ISO 14520
standard accepted by the subcommittee included the acceptance of a
plastics sheet fire test. The test procedure is similar to the
plastic sheet tests of UL 2166 and UL 2127 and will serve as one of
the bases for the determination of Class A design concentrations
under future ISO 14520 editions. The cup burner procedure described
in Annex B of ISO 14520 has also been altered to eliminate the
testing of heated fuels and to eliminate the determination of the
cup burner extinguishing concentration at airflows other than 40
L/minute.
NFPA 2001 Standard for Clean Agent
Fire Extinguishing Systems, also specifies the minimum requirements
for clean agent systems; the current version of NFPA 2001 is the
2000 Edition. Two items have recently been proposed for inclusion in
future editions of the NFPA 2001 Standard.
The NFPA 2001 Technical Committee has
accepted the addition of a new agent, NovecTM 1230, described
above.
In addition, the NFPA 2001 Technical
Committee has accepted a proposal to allow increases in the
allowable design concentrations of HFC agents in normally occupied
areas. Maximum allowable design concentrations would be based upon
the results of PBPK calculations. Under the current proposal, design
concentrations for HFC agents in normally occupied areas would be
allowed to exceed the cardiac LOAEL level, as long as the design
concentration is deemed safe for a 5 minute exposure by PBPK
calculations.
Conclusion
The manufacturers of clean agents and
clean agent systems continue to make available to the marketplace
innovative suppression systems which avoid the environmental
problems associated with Halon, through the introduction of both new
agents and new system designs. Despite the ban and inevitable
disappearance of Halon 1301, the availability of these clean agent
systems ensures that businesses worldwide will continue to have the
ability to protect critical equipment and assets. At the same time,
the national and international standards governing the design and
use of the clean agents are being constantly updated to ensure their
inclusion of the latest technologies. As the mandated removal of
Halon in the EC continues, and as the pressure to reduce dependency
on ozone depleting substances increases worldwide, the clean agents
will take on an increasingly important role in the solution of
global environmental problems.
IFP | 
