MIL-DTL-24688A
APPENDIX A
A.5.3 Flame spread. Along with visual observations, flame spread may be assessed using thermocouples along
the entire simulated pipe array. Spaced 2 feet on center, the thermocouples shall be installed along both the vertical
and horizontal portions of the piping assembly. All of the thermocouples shall be a maximum of 24 gauge, Type K,
thermocouples. Each thermocouple shall have a bare bead.
A.5.4 Air flow. Air movement both in and out of the compartment shall be measured in the vent opening by
two bi-directional probes. One probe shall be located 8 inches from the top of the doorway and a second probe shall
be located 18 inches above the deck. Both probes shall be located along the centerline of the vent. (These may be
eliminated if HRR measurements are performed in a hood/exhaust system.)
A.5.5 Gas concentrations. Gas analyzers provide a continuous monitoring of oxygen (O2), carbon monoxide
(CO), and carbon dioxide (CO2) concentrations of gases exiting the test compartment. The oxygen concentration
shall be measured via a paramagnetic oxygen analyzer while the CO and CO2 concentrations shall be measured via
infrared process analyzers. The sampling probe shall be located along the vertical centerline of the vent and 8 inches
(0.20 meter) below the top of the vent opening.
A.5.6 Smoke. Three laser/photocells or equivalent instruments shall be used to assess the smoke production
within the compartment. The path length shall be 3.3 feet, and they shall be placed horizontally at 3.84, 5.35, and
6.56 feet above the deck and near the center of the compartment.
A.5.7 Target array. In order to assess the potential for the pipe insulation materials to cause secondary
ignitions due to melting, dripping, or falling pieces, a target array of wood excelsior shall be placed on the deck of
the compartment beginning 1 foot away from the corner of the wood crib, under the horizontal pipe run, and extend
the full length of the horizontal pipe run.
A.5.8 Weight loss. In order to assess the amount of insulation consumed during the test, each pipe shall be
weighed prior to insulation being applied, weighed in its final insulated test configuration, and weighed at the
conclusion of the test.
A.5.9 Heat release rate. The heat release rate of the fire inside the compartment shall be measured. The
technique to be used is at the discretion of the testing laboratory, but it should be based on oxygen depletion
calorimetry. Use of hood/exhaust system for the performance of the procedure is allowed.
A.5.10 Data collection. Data obtained during the test shall be recorded at intervals not to exceed 5 seconds.
A.6 DOCUMENTATION
A.6.1 Video. A video record shall be made of each test and shall cover the full duration of the tests. The
camera shall be located outside of the compartment vent providing a full view of the test array. When necessary, the
camera may be relocated to document unusual test developments.
A.6.2 Photographs. A series of photographs shall, as a minimum, be taken before and after each test showing
the arrangement of the test pipes.
A.6.3 Damage sketches. In order to more effectively show the extent of pipe insulation damage, post-test
sketches shall be made of each tested configuration. This may involve the removal of the exterior lagging (when
required) and exposing and measuring the damaged insulation.
A.7 INSTALLATION OF TEST MATERIALS
A.7.1 Installation of test materials. The pipe installation shall be installed on the ½-inch pipes. The insulation
on the vertical riser section shall extend past the threaded end cap, and a plug or cap of the same insulation shall be
adhered in place over the pipe cap. All butt joints and seams shall be sealed using the appropriate adhesives.
Figure A-8 shows an elevation view of a typical installed insulation. If lagging/adhesives are used, then the cure
time as specified by the manufacturer shall be allowed prior to testing.
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