Appendix E. Example Glovebox Fire Detection Systems.

DOE-STD-1066-99

Appendix E. Example Glovebox Fire Detection Systems.

This appendix provides examples of detection devices that may be useful for glovebox fire detection

systems.

Figure 1 is a wiretype line heat and fire detector. The system uses two, individually encased actuators

in a heat sensitive material. The actuators are twisted together to impose a spring pressure between

them and then wrapped with a protective tape and finished with an outer covering. A small electric

current passes continuously through the lines. At the critical or operating temperature, the heat sensitive

jacket yields to the pressure and allows the actuators to contact each other, triggering the alarm.

Figure 2 shows a thermal detector. These may be purchased as fixed-temperature or rate-compensated.

Thermal detectors are also available for explosion-proof and weatherproof applications. For glovebox

applications, thermal detectors with all-welded stainless steel shells should be used.

Figures 3 and 4 are examples of two design devices used for remote testing of standard, stem-type heat

detectors mounted in gloveboxes.

Tests were recently performed for DOE's Rocky Flats Environmental Technology Site to determine what

time lag would be experienced as a result of the heater and clamp assembly used for testing the

detectors (Figure 3). In the tests, the unmodified, stem-type detector had a response time index (RTI)

of 40 and the modified unit (with the heater and clamp) had an RTI of 100. For the modified unit to

operate satisfactorily, the installation should be on an 8-foot (2.44-meter) spacing (rather than 11-foot

[3.36-meter] spacing as permitted for the unmodified unit). The unit shown in Figure 4 has not been

tested.

Figure 5 illustrates a "Well-type" temperature detector. Note that this is not considered a "fire detector"

in the conventional sense, although it is credited under certain circumstances with a fire warning

capability.

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