H3R Clean Agents
  • DECOMMISSIONING A HALON SYSTEM
    1
    Decommissioning is a Two Step Process

    Decommissioning a Halon system from service is usually a two-step process. The first step, field decommissioning, takes place at the site where the fire protection system is located. During this step, the Halon cylinders are disconnected from the system hardware such as manifolds and piping. The second step usually takes place offsite and involves reclaiming the Halon agent from the removed cylinders.

    2
    Purpose of Decommissioning

    Decommissioning is undertaken to remove the existing Halon system from service, replace the Halon system with an alternative means of fire protection, and/or recover the Halon from the system so it can be made available for use in other applications. As Halon supplies become increasingly scarce, decommissioned Halon supplies will be an important source to meet the future fire protection needs of critical applications.
    3
    Who Should Perform Decommissioning

    Proper decommissioning procedures are required to assure that vital Halon resources are not inadvertently discharged into the atmosphere during the recovery process and to maintain a safe working environment for individuals involved in the decommissioning process. Accordingly, the decommissioning of Halon systems should only be performed by properly trained personnel.

    Since Halon is stored in cylinders under pressure, they must be handled with great care. If the cylinder is improperly handled and the pressure is released in an uncontrolled manner, the cylinder can act as a projectile potentially causing serious injury or death to people working with the cylinder or bystanders in the vicinity. Uncontrolled pressure release can occur by damaging the cylinder valve or by inadvertently activating the discharge mechanism. In either case, the cylinder contents are discharged in a dangerous and uncontrolled manner that could result in serious injury and death.

    The importance of decommissioning Halon systems only by trained and experienced professionals cannot be understated. Documented incidents of injury or death have been reported in Canada and the United States. In Canada, a service technician was killed while starting to recover Halon from a cylinder. His death was linked to improper safety procedures while performing the recovery operations.

    In the United States, the FSSA reports that in all incidents reported to them, the cause of the accidents were attributed to improper handling of the cylinders by untrained and unqualified personnel. In all of these accident incidents, actuating devices had not been removed from the valves and anti-recoil devices and protection caps were not installed prior to removal of the cylinders from service. Therefore, FSSA adamantly recommends the following guidelines(1):

    • Only qualified and experienced fire suppression system service professionals should perform decommissioning activities.
    • Decommissioning personnel should be thoroughly trained in safe handling procedures as well as proper procedures related to disabling, removing, transporting, shipping, and emptying Halon cylinders.
    • All relevant procedures specified in manufacturer's Owner's, Service, Operation, and Maintenance manuals should be followed.
    • Cylinder brackets should NOT be removed and cylinders should NOT be disconnected from system piping, or moved or shipped, without first disabling the actuation devices and providing protective caps and anti-recoil devices.
    Halon systems have been manufactured for over 20 years, in many places around the world, and by many different companies. As a result, many different types and models of valves and activation mechanisms are installed in Halon systems. Because of this diversity, it can be difficult to know exactly how a particular valve mechanism works or the proper procedures for safe decommissioning. Even fire protection professionals may not have encountered all possible valve designs and configurations. Ideally, systems should be decommissioned by those who installed and serviced them; however, this is not always possible. In any case, the procedures outlined in the Operations and Maintenance Manuals, Owners Manuals, Service Manuals, etc., provided by the manufacturer for the specific type of equipment installed must be followed.
    4
    Potential Risks Associated with Decommissioning

    Despite the different manufacturer types and models of valves and cylinders, the risks associated with decommissioning Halon systems fall into three main categories, independent of the system type or manufacturer: 1) risks due to pressurized cylinders; 2) risks associated with heavy objects; and 3) risks associated with Halon exposure.

    1. The most important hazards are the inherent risk of working with pressurized gaseous agents

    Since Halon is stored in cylinders under pressure, they must be handled with great care. If the cylinder is improperly handled and the pressure is released in an uncontrolled manner, the cylinder can act as a projectile potentially causing serious injury or death to people working with the cylinder or bystanders in the vicinity. Uncontrolled pressure release can occur by damaging the cylinder valve or by inadvertently activating the discharge mechanism. In either case, the cylinder contents are discharged in a dangerous and uncontrolled manner that could result in serious injury and death.

    Halon storage cylinders are designed to discharge through system pipework in less than 10 seconds. Obviously, it follows that the discharge rates of unconnected cylinders must be less than 10 seconds. The risk of damage from unimpeded agent discharge in confined or unconfined spaces is high. Mass flows through system pipework are up to 20 kg/sec (44 lbs/sec) for large cylinders². In cases of cylinder discharge without pipework, the mass flows are much higher. Once the cylinder valve is open, it generally cannot be closed.

    The predominant causes of accidental discharge of Halon systems include (1) accidental automatic firing at the releasing panel/remote, (2) accidental manual activation at the cylinder/remote, (3) accidental operation of the cylinder valve, (4) damage to the discharge head/neck, and (5) high cylinder temperature above the working pressure.

    This document is aimed at providing guidance in order to minimize the risks associated with working with gaseous agents. Remaining sections will discuss the failure points as well as suggest practical guidelines for personnel involved in decommissioning Halon systems.

    2. Other hazards also exist related to the physical risk of moving or transporting heavy pressurized cylinders.

    Risks associated with the Halon storage cylinders themselves can be attributed to their weight (a fully charged Halon storage container may weigh as much as 700 kgs or 1500 lbs). Moving and transporting these large cylinders can prove to be cumbersome and difficult. Accidental dropping or improper lifting can cause injury to handling personnel and could result in an uncontrolled release of the pressure.

    3. Risks associated with Halon 1301 exposure also exist.

    Several other inherent safety issues are associated with Halon system decommissioning activities such as cylinder removal and Halon reclamation. These dangers are caused by the agent itself and completely independent of the system type. The immediate dangers associated with accidental discharge of Halon include dizziness and anesthesia and/or cardiac sensitization. Cardiac sensitization occurs when a chemical causes an increased sensitivity of the heart to adrenaline producing sudden life-threatening, irregular heart beats (arrhythmia) and even heart attack, in severe cases. Toxicological risks associated with Halon exposure can be significant and can even cause death, if the exposure is at high concentrations.

    1 FSSA Safety Alert, October 28, 1993 (See page 16-17 for full text of FSSA Safety Alert)

    2 Jeffs, S. E., "Life After Halons: The Safe Approach to Decommissioning Existing Halon Systems Both in the Field and in the Workshop," Fire Protection Industry Association of Australia, not dated.