SAFETY OPTIONS
FOR BATTERY TEST CHAMBERS

1. Chamber Pressure Alarm - Standard -

This standard safety feature reduces risk by providing an early indication to test-chamber operators that a battery cell has vented or ruptured or that deflagration or an explosion has occurred inside the testing chamber.

The alarm includes the presence of a differential-pressure switch designed to sense a rapid rise in chamber pressure. When the pressure switch is activated, it immediately will disable the chamber heat and result in an alarm condition. The switch also may be used to activate other safety systems, such as an inert-gas purge, automatic door locks, cryogenic cooling, or fire suppression, if these safety options are present. The switch is field-adjustable.

2. Pressure Relief Ports - Standard -

This standard safety measure reduces the risk of damage to the testing chamber due to the rupture or rapid venting of a battery cell.

Pressure-relief ports protect the testing chamber from a sudden increase in pressure and are designed to prevent permanent damage to the chamber. Ports normally reset automatically after venting, without damage to the port or system.

3. Explosion Venting (NFPA Compliant) - Standard -

This safety option features a pressure-relief-vent panel designed to help mitigate the risk of damage to the testing chamber following a battery-cell rupture or the deflagration of gases or vapors that may be released from leaking or venting cells.

Testing chambers designed with explosion venting have reinforced liners and doors to ensure that they safely can withstand the pressures that may develop during a deflagration event or explosion.

4. Heater Surface Temperature Limiters - Standard -

This standard safety feature is designed to reduce the risk of a thermal-runaway event caused by overheating of the tested product. An over-temperature-protection-control system (OTP) will monitor the process air at the point where it enters the work chamber. If the system detects an out-of-tolerance temperature, the controller will de-energize the heat and cooling systems, and the system will need to be reset manually.

5. Intrinsic Safety Barriers - Standard -

This safety option features an intrinsically safe testing chamber designed to help mitigate the risk of ignition of flammable gases or vapors that may have been released into the chamber through the leaking or venting of battery cells.

The chamber’s design eliminates all sources of ignition from inside the chamber. Intrinsically Safe Chambers include:

• Spark-resistant construction
• Intrinsic safety barriers
• Surface-temperature-limited heaters

Each temperature-limited heater includes a pair of redundant thermocouples and high-limit controllers designed to keep the surface temperature well below the ignition point of the flammable gases or vapors.

6. Temp Limited Electric Heaters - Standard -

Surface temperature limited heaters help to mitigate the risk of hot surface ignition of flammable gases or vapors that may have been released into the chamber through leakage or venting of cells.

Surface temperature limited heating elements shall be employed, to eliminate hot surfaces that could otherwise ignite flammable materials in the process air. A pair of thermocouples is attached directly to the sheath of the heater. The thermocouples are monitored by a pair of redundant temperature controllers. These controllers limit the heater surface temperature to 80% of the auto ignition temperature (in degrees C) for the most flammable material present in the chamber. Where multiple heaters are used, each heater shall have its own set of redundant controllers and associated thermocouples.

7. Emergency Stop

An emergency stop control helps mitigate risk by allowing operators to respond more quickly to abnormal conditions which may be noticed during testing. A large, red, mushroom-shaped emergency stop button allows the operator to quickly shut the system down. If an abnormal condition is detected early and the emergency stop control is actuated, early mitigation may help to prevent the condition from escalating.

8. Rapid Purge System

This optional safety feature helps to mitigate risks associated with the release of harmful or flammable gasses and vapors that may have resulted from leaking or venting of a battery cell. Also referred to as an “emergency purge system,” the Rapid Purge System is designed to dilute and flush harmful gases or vapors quickly from the chamber to prevent damage to the chamber. The system may be used at the end of a normal cycle, before the chamber door opens, or may be programmed to activate only during an alarm condition.

9. NFPA Class "A" Ventilation System

This optional safety feature includes a complete safety-ventilation system designed to prevent flammable vapors from a leaking or venting battery cell from reaching an ignitable concentration in the chamber.

This system is fully compliant with NFPA 86 standards and includes the following safety options:

• Forced-ventilation package
• Spark-resistant construction
• Intrinsic safety barriers
• Timed-purge system
• Explosion venting
• Emergency-stop switch
• Safety-warning placard

10. Inert Atmosphere (NFPA Compliant)

This optional safety feature includes an inert-gas-control system to reduce the oxygen level inside the chamber. An inert-gas atmosphere helps to mitigate the risk of ignition of flammable gases or vapors that may have been released into the chamber through the leakage or venting of battery cells being tested.

The Inert Atmosphere system includes a pressure regulator, high and low solenoid valves, and flow meters with integral-needle valves to set the desired flow rates. A pressure-check valve on the chamber safely vents exhaust gases through a threaded NPT connection so they may be piped away from the chamber. An adjustable timer controls the length of the initial rapid-purge cycle.

11. Solvent Monitor (Hydrocarbons and solvents)

This optional safety feature monitors the concentration of flammable gases inside the testing chamber. If the vapor concentration exceeds a preset value, a set of high-limit alarm contacts will open. The alarm outputs are interlocked with the chamber heat, and, if the contacts open, the chamber’s heating system immediately is disabled, and visual and audible alarms are activated. If other safety options, such as the Rapid-Purge System, are present, the Solvent Monitor may be used to initiate further actions to reduce the vapor concentration.

Operator intervention is needed to reset the system.

12. Gas Analyzers (H2, O2, CO2, CO)

This optional safety feature is designed to sense the presence of specific gases (such as hydrogen, oxygen, carbon dioxide, and carbon monoxide) in the testing chamber, and when concentrations reach specified levels, to deliver visual and/or audible alarms and initiate corrective actions.

Alarm outputs from the gas analyzer can be interlocked with the chamber’s heating system to shut down the heat automatically when pre-set levels are reached. Gas Analyzers also may be used to activate a Fire-Suppression System, Rapid-Purge System, Rapid Cryogenic Cooling, etc. if these systems are present.

Operator intervention is required to reset the system.

13. Remote Shutdown

This optional safety equipment allows a customer to disable the testing chamber’s heaters or to shut down the entire system remotely via a set of dry contacts, if the customer’s external equipment detects abnormal conditions.

14. Automatic Door Locks

This safety option prevents access to the testing chamber during a normal cycle or when an alarm condition has been detected. Automatic Door Locks can be used to prevent the release of a flammable atmosphere from the chamber into an unclassified area, where it could reach ignition sources. The locks can be used in combination with other optional safety features, such as a timed, rapid purge. Automatic Door Locks also may be programmed to latch only if a gas analyzer senses an abnormal concentration of a specific gas and remain latched until the concentration is reduced to a safe level.

15. Product Monitoring Thermocouples

This safety option features additional, product-monitoring thermocouples to help provide early mitigation of the risks associated with a pending, thermal-runaway condition.

These additional thermocouples are placed in direct contact with the product being tested. Each probe is monitored by its own high-limit controller, with alarm contacts set to open if the product’s temperature exceeds a pre-set limit. The alarm contacts are interlocked with the testing chamber’s heating system, and heating automatically is inhibited if the temperature exceeds the established threshold.

In addition, output contacts from this safety feature may be used to activate other, optional safety features, such as rapid cryogenic cooling or fire suppression, if they are present. Customers also may request auxiliary contacts (at an increased cost for this option?) that will allow remote activation of additional actions.

16. Rapid Cryogenic Cooling

This safety option may help to provide early mitigation of the risks due to a pending or ongoing thermal-runaway condition. The system is designed to dump LN2 or CO2 quickly and directly onto the test samples. Customer inputs can be provided to trigger the cooling system remotely, based on the temperature of the thermocouples attached to the test sample. In the event that a cell being tested vents, the inert gas associated with this safety option may help to mitigate against a resulting fire by reducing the oxygen concentration below a combustible level.

17. Fire Suppression (Water, Halon, CO2, LN2)

This safety option is designed to control a fire by displacing oxygen and applying a cooling effect directly to the product being tested. Some fire-detection packages also provide output contacts that allow automatic initiation of additional actions, such as activating fire alarms or notifying the fire department.

18. Alarms (Audible, Visual, Output Contacts)

This standard safety feature includes audible and visual (tower light) alarms that quickly alert testing-chamber operators of an abnormal condition.

This package also allows remote monitoring of alarm conditions and remote implementation of automatic, corrective actions.

19. Heater Surface Temperature Limiters

Each temperature-limited heater includes a pair of redundant thermocouples and high-limit controllers designed to keep the surface temperature well below the ignition point of the flammable gases or vapors.