Application of Halons
Halons are used in fire protection because they are effective
fire extinguishing agents, are electrically
non-conductive, leave no solid or liquid residue, are
non-corrosive, and are considered not toxic at
recommended concentrations for occupied areas. However,
halons significantly contribute to the depletion of the
stratospheric ozone layer.
Halons were never produced in Canada and their
importation started around 1965. In Canada, halon 1211 is
used almost exclusively in portable equipment (hand-held
fire extinguishers and, to a limited extent, in larger
capacity wheeled units mainly used at civil and military
airports). Halon 1301 is employed primarily in automatic
fixed systems (also known as total-flooding systems).
These fire protection systems are designed to provide a
fire extinguishing concentration of the agent.
Applications include: computer rooms, telecommunications
facilities, control rooms, shipboard machinery spaces,
aircraft engine nacelles and cargo bays, and other
similar high value fire risks.
Until recently, actual fire fighting and explosion
suppression represented the smallest portion of all halon
releases. Other sources of releases include unwanted
discharge in response to non-fire situations, equipment
leakage, testing, training, and losses during service
procedures.
Modifications in work procedures have already resulted
in significant reductions in halon emissions. In
total-flooding installations, instead of testing for
enclosure integrity by discharge testing, door-fan tests
and other procedures that do not require the use of
halons are currently employed. New training procedures
for aircraft personnel using hand held halon fire
extinguishers has significantly reduced emissions.
Diligence by the facility owner is required to further
reduce emissions caused by unwanted release due to
non-fire events.
3.1 Responsibilities
The owner is responsible for protecting a facility
against fire damage. Similarly, maintaining an existing
fire protection system that uses halons, or searching for
alternatives to halon fire protection, rests with the
owner of the facility.
3.2 Alternatives to Halons
Alternatives are now available for many of the
applications where halons would have been the
extinguishant of choice in the past. However, for some
applications, satisfactory alternatives are not yet
perfected. These include:
- applications with space and/or weight
restrictions (i.e., aircraft, submarines,
military tactical personnel carriers, and so on);
and
- applications where inerting concentrations of
agent must be achieved in occupied areas.
Throughout the world, concerned groups (for example,
the aircraft industry, or the military) are financing
tremendous research and development efforts to find
suitable alternatives to halons.
In the United States, the U.S. Environmental
Protection Agency (U.S. EPA) periodically updates a list
of all acceptable alternatives to halons. Criteria to
determine the acceptability of alternatives includes the
impact on human health and the environment. The list
addresses streaming applications (portables) and the
total-flooding systems (in occupied and non-occupied
applications). Environment Canada concurs with the U.S.
EPA list which is reproduced in Appendix
D.
Alternatives can satisfactorily replace halon 1211 in
most applications with very few exceptions (such as fire
protection on aircraft or submarines). Alternatives to
halon 1301 must be tailored to specific needs.
Consideration should be given to the particular class of
fire hazard when determining alternatives to halons.
National Fire Protection Association standard 2001 lists
minimum requirements for clean agents to replace halons
in total-flooding systems. State-of-the-art detection
systems or compartmentation of protected assets may
alleviate the need to use halons.
Assistance in determining the most suitable choice of
fire protection for a particular fire hazard can be
obtained by consulting existing documentation (see Appendix B - Relevant Codes and
Standards) or a fire protection professional.
3.3 Recycling Halons
Halons can be removed from applications where:
- alternatives to halons provide an acceptable
protection against fire risks;
- there have been changes to the relevant asset
being protected; or
- the asset has reached the end of its useful life.
The recovered halons can then be reconditioned and
recycled to meet the needs of more critical applications
or provide recharge quantities to maintain existing
systems.
The Underwriters' Laboratories of Canada has published
two standards that specifically address halon recycling:
(a) the servicing of halon extinguishing systems and (b)
halon recovery and reconditioning equipment (see Appendix B - Relevant Codes and
Standards).
ATTENTION:
Some provincial legislations now require that only
certified companies can service halon systems. Refer to
the appropriate provincial authority for additional
information.
3.4 Essential Uses
The Parties to the Montreal Protocol have prohibited
the world-wide production of halons since January 1994.
Two exceptions to this world-wide production ban are (a)
developing countries — called "Article 5
countries" — for their domestic needs, and (b)
exemptions for essential uses. Exemptions are granted by
the Parties. Parties to the Montreal Protocol are asked
each year to submit nominations for essential use
exemption 1.
Although producing halons is prohibited around the
world, it should be emphasized that the USE of existing
halons is NOT prohibited.
The essential use exemption grants a Party the
permission to produce (or import) a specified quantity of
newly-manufactured halons for the specified use during
the specified period. To date, all the nominations
submitted to the Parties for an exemption from the
production phase-out have been rejected. The rationale
for the rejection was not the essential characteristics
of the application, but the belief that existing halon
stocks are large enough to accommodate, through
recycling, the more critical needs of fire protection.
The Russian Federation has been granted an essential
use exemption. The exemption is for halon 2402 starting
in 1996 and beyond.
3.5 The Halon Bank
Canada has no physical halon bank where users could
deposit or withdraw halons. The halon bank is a
clearinghouse service administered by the Underwriters'
Laboratories of Canada (ULC).
The halon bank (1-416-757-3611) puts clients in touch
with appropriate companies - halon owners with halon
buyers and vice-versa. The halon bank also provides an
up-to-date selection of information relating to the
conservation and use of halons.
1. At the beginning of every summer, Environment Canada publishes a notice in the
Canada Gazette, Part I, asking users to submit nominations for an essential use exemption.
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