Significant New Alternatives Policy Program

Fire Extinguishing and Explosion Prevention Sector

Risk Screen on Substitutes for Halon 1301

Total Flooding Systems in Normally Occupied or Unoccupied Spaces

Substitute: Victaulic Vortex System®

This risk screen does not contain Clean Air Act (CAA) Confidential
Business Information (CBI) and, therefore, can be disclosed to the
public.



1. 	Introduction

Ozone-depleting substances (ODS) are being phased out of production in
response to a series of diplomatic and legislative efforts that have
taken place over the past decade, including the Montreal Protocol and
the Clean Air Act Amendments of 1990 (CAAA).  The U.S. Environmental
Protection Agency (EPA), as authorized by Section 612 of the CAAA, is
developing a program to evaluate the human health and environmental
risks posed by alternatives to ODS.  The main purpose of EPA's program,
called the Significant New Alternatives Policy (SNAP) program, is to
identify acceptable and unacceptable substitutes for ODS in specific end
uses.  

EPA’s decision on the acceptability of a substitute is based largely
on the findings of a screening assessment of potential human health and
environmental risks posed by the substitute in specific applications. 
EPA has already screened a large number of substitutes in many end uses
within all of the major ODS-using sectors, including refrigeration and
air conditioning, solvent cleaning, foam blowing, aerosols, fire
suppression, adhesives, coatings and inks, and sterilization.  The
results of these risk screens are presented in a series of Background
Documents that are available in EPA's docket.

The purpose of this report is to supplement EPA’s Background Document
on the fire suppression and explosion protection sector (hereinafter
referred to as the Background Document, EPA 1994). This risk screen
discusses potential human health and environmental risks posed by the
Victaulic Vortex System® when used as a replacement for Halon 1301 for
use as a total flooding system in normally occupied or unoccupied
spaces.

The Victaulic Vortex System® is a hybrid water mist/inert gas system,
and is designed for total flooding applications for both Class A and B
fires in normally occupied or unoccupied spaces.  Upon activation,
pressurized streams of nitrogen and water are fed into an emitter, where
they are combined and discharged in a homogenous suspension.  Nitrogen
and water enter the emitter at rates of 6.2 and 3.7 kg/minute,
respectively (Victaulic Vortex System® SNAP Submission 2007).  The
homogenous mixture of nitrogen and water exits the emitter at speeds
varying from 210 to 520 meters/minute, depending on the distance from
the emitter.  Each emitter can protect up to 70 cubic meters of volume,
and multiple emitters may be combined to protect a single space.  

To ensure that use of the Victaulic Vortex System® in the applications
listed above will not pose unacceptable risks to workers or the general
public, worst case occupational exposure at end-use , worst case
occupational exposure (during manufacturing, installation and
maintenance), and general population exposure analyses were performed.

Table 1 provides the composition of the Victaulic Vortex System®.

Table 1.  Composition of Victaulic Vortex Systema

Component	Chemical Formula	CAS No.	Weight Percent

Water	H2O	7732-18-5	62.6%

Nitrogen Gas	N2	7727-37-9	37.4%

	a Source: Victaulic Vortex System® SNAP Submission 2007

The remainder of this risk screen is organized as follows:

Section 2 of this report summarizes the results of the risk screen for
the Victaulic Vortex System®;

Section 3 presents atmospheric modeling and potential environmental
risks; 

Section 4 assesses the toxicity of the substitute;

Section 5 discusses occupational exposure during manufacturing,
installation, and maintenance; 

Section 6 assesses risks associated with general population exposure;
and 

Section 7 assesses the emissions of volatile organic compounds.

2.	Summary of Results

The Victaulic Vortex System® is recommended for SNAP approval as a
total flooding device in normally occupied or unoccupied spaces for
Class A and B fires.  EPA recommends that Section VIII of the
Occupational Safety & Health Administration (OSHA) Technical Manual be
consulted for information on selecting the appropriate types of Personal
Protective Equipment (PPE) recommended (OSHA 1999).  The risk screen
indicates that the use of the proposed substitute in normally occupied
or unoccupied spaces will be less harmful to the atmosphere than the
continued use of Halon 1301.  Additionally, the risk to the general
population is expected to be below levels of concern for non-cancer
risks.  For applications of this and all other water mist/inert gas fire
suppression equipment, EPA recommends that the latest editions of
National Fire Protection Agency (NFPA) Standards 750 and 2001 be
followed.

3. 	Atmospheric Modeling

This section presents an assessment of the potential risks to
atmospheric integrity posed by the use of the Victaulic Vortex System®
as a total flooding system in normally occupied or unoccupied areas.  
As indicated in Table 2, the ozone depleting potential (ODP) and global
warming potential (GWP) of each of the constituents of the Victaulic
Vortex System® is zero.  The GWP and ODP of the compounds in the
Victaulic Vortex System® are well below the GWPs of previously
SNAP-approved fire-suppression agents (e.g. HFCs and other high-GWP
fluids).  Accordingly, use of the Victaulic Vortex System® is not
expected to pose any significant adverse atmospheric impacts.

Table 2.  ODP and 100-Year GWP of the Victaulic Vortex System
Constituents

Constituent	

ODP	

100-Year GWP



H2O	

0	

NAa



N2	

0	

0

a During accidental release, water in the Victaulic Vortex System® is
present as a liquid and has no GWP.  In the presence of a fire, water in
the Victaulic system is in vapor form.  Although water vapor is a
greenhouse gas, human activities are not thought to directly affect the
average global concentration of water vapor (EPA, 2002).  There is no
IPCC published GWP for water vapor.

4.	Toxicity of Substitute

The primary health concern for agents containing inert gases, including
nitrogen gas, is asphyxiation due to reduced oxygen concentrations upon
accidental release of the system.  To determine whether asphyxiation
will be a toxicity threat, the Victaulic Vortex System® design
parameters were analyzed.  Victaulic conducted fire suppression tests to
measure the oxygen concentrations at the time of flame suppression for
both Class A and B fires.  Table 3 presents the results of Victaulic’s
fire testing.  

Table 3.  Summary of Victaulic’s Fire Tests

Fire Class	Test Type	Extinguishing Concentrationa



% O2 /% air (v/v)b	% N2 /% air (v/v)c

Class A 	Wood Crib	16.0	23.6

	Polypropylene (PP)	15.5	26.0

	Acrylonitrile Butadiene Styrene (ABS)	15.8	24.6

	Polymethyl Methacrylate (PMMA)	14.0	33.2

Class B 	Heptane tell tale fires	15.6	25.5

	Heptane pan fires	15.5	26.0

a Source: Victaulic Vortex System® SNAP Submission 2007.

b O2 levels are experimentally measured.  

c N2 levels are calculated based on experimentally measured O2 levels. 
These values are exclusive of atmospheric nitrogen, i.e. represent the
concentration of nitrogen from the Victaulic Vortex System®

only in the air.	

	

To determine the minimum design concentration for the Victaulic Vortex
System®, a 30 percent safety factor was applied to the extinguishing
concentrations presented in Table 3.  The extinguishing concentration
resulting from the PMMA and heptane pan fire tests were the highest, and
to be conservative these concentrations were used to determine the
minimum design concentration for Class A and B fires, respectively (see
Table 4).  

Table 4.  Minimum Design Concentration for Class A and B Firesa

Class of Fire	Based on Extinguishing Concentration for:	Minimum Design
Concentration (% N2/% air (v/v))b, c

Class A	PMMA Fire	43.2%

Class B	Heptane pan fire	33.8%

a Source: Victaulic Vortex System® SNAP Submission 2007.

b Minimum design concentration was estimated by applying a 30 percent
safety factor to the extinguishing concentrations shown in Table 3. 

c N2 levels are calculated based on experimentally measured O2 levels. 
These values are exclusive of atmospheric nitrogen, i.e. represent the
concentration of nitrogen from the Victaulic Vortex System® only in the
air.

Because the Victaulic Vortex System® can be designed to ensure that the
oxygen concentration in any protected space will not fall below 12
percent over the 5 minute discharge period, the Victaulic Vortex
System® is considered safe for both Class A and B fires in normally
occupied or normally unoccupied spaces for inert gases.  System design
should be undertaken in accordance with NFPA 2001 Guidelines (NFPA,
2007). 

5.	Occupational Exposure During Manufacture, Installation, and
Maintenance

The potential for personnel exposure during manufacture, installation,
and maintenance are examined in this section.  According to information
provided in the Victaulic SNAP application, workers may be exposed to
nitrogen gas during filling of the high pressure cylinders (Victaulic
Vortex System® SNAP Submission 2007).  The submitter reported exposure
concentrations of less than 1 percent in air during the disconnection of
filling hoses.  An exposure of 1 percent nitrogen, assuming an air-tight
room, would lower oxygen levels to 20 percent, which is above “oxygen
deficient levels” of 19.5 percent as defined by OSHA in its Respirator
Protection Standard (29 CFR 1910.134).  

During installation or maintenance of Victaulic Vortex System®,
inadvertent discharge may occur.  Under these circumstances, oxygen
concentration would be expected to decline over time.  To ensure that
exposures are minimized, it is recommended that Victaulic provide safety
training for technicians to minimize the occurrence of an inadvertent
discharge.  Training should also be provided regarding egress from the
space should such a discharge occur.

6.	General Population Exposure

Given the large natural quantities of nitrogen and water in the
atmosphere, it is unlikely that an accidental release of the Victaulic
Vortex System® will affect the average atmospheric concentrations of
these gases.  As such the Victaulic Vortex System® is not believed to
pose a toxicity threat to the general population.  

7.        Volatile Organic Compound Analysis

The constituents of the Victaulic Vortex System® are not considered
VOCs for purposes of local air quality.    

8.	References

EPA.  1994. Risk Screen on the Use of Substitutes for Class I
Ozone-Depleting Substances: Fire Suppression and Explosion Protection
(Halon Substitutes).  Stratospheric Protection Division.  March 1994. 

EPA, 2002.  Inventory of U.S. Greenhouse Gas Emissions and Sinks:
1990-2000.

IPCC (Intergovernmental Panel on Climate Change), 2005.  Special Report
on Safeguarding the Ozone Layer and the Global Climate System: Issues
Related to Hydrofluorocarbons and Perfluorocarbons, Special Report of
the Intergovernmental Panel on Climate Change, Cambridge, England, 2005.
 Available at:   HYPERLINK
"http://arch.rivm.nl/env/int/ipcc/pages_media/SROC-final/SpecialReportSR
OC.html" 
http://arch.rivm.nl/env/int/ipcc/pages_media/SROC-final/SpecialReportSRO
C.html 

NFPA, 2007. NFPA 2001: Standard on Clean Agent Fire Extinguishing
Systems.  2008 Edition.  Available at:   HYPERLINK
"http://www.nfpa.org/freecodes/free_access_document.asp" 
http://www.nfpa.org/freecodes/free_access_document.asp 

OSHA.  1999.  OSHA Technical Manual.  Department of Labor.  Occupational
Safety & Health Administration.  January 20, 1999.  Available online at:
  HYPERLINK "http://www.osha.gov/dts/osta/otm/otm_toc.html" 
http://www.osha.gov/dts/osta/otm/otm_toc.html   

Victaulic Vortex System® SNAP Submission 2007. Significant New
Alternatives Policy Program Submission to the United States
Environmental Protection Agency, 2007. 

January 23, 2008

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