Design of Automatic Deluge Fire Protection System for Explosive …
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Friction hazard—The uncured propellant should have friction sensitivity low
enough that shear stresses in the mixer will not ignite the propellant, and the cured
propellant should have a friction sensitivity low enough that normal handling operations are not likely to ignite the propellant. Composite propellants used worldwide
today have substantial amount of metal powder as an ingredient. This increases the
friction hazard of composite propellants. Of the techniques available for characterization, a form of the pendulum-and-slide friction tester is preferred. If the friction
force is less than 5 kg m, it is considered as very sensitive and if the friction force is
between 5 and 17.5 kg m, it is considered as moderately sensitive.
Spark hazard—The propellant should have spark sensitivity low enough that the
normal static charge of a human body discharge will not ignite the propellant. The
propellant in both the cured and uncured states should be characterized for spark
sensitivity. The spark apparatus should be calibrated against materials of known
spark sensitivity. A sufficiently large number of samples should be run in order to get
a statistically significant set of data. The propellant should not have a spark sensitivity
less than 0.015 J.
Auto ignition hazard—The propellant should have an autoignition point so high
that its probability of autoignition is low under the thermal environment to which it
will be exposed. Also, the propellant should not develop so high internal temperature
during cure or from degradation chemical reactions that there is danger of autoignition. Composite propellants autoignition temperature lies in the range 280–310 °C.
The curing temperature of these temperatures should be half or less than half of the
autoignition temperature.
The consequences of fire in processing facility are deflagration, detonation,
confined explosion, unconfined explosion, boiling liquid expanding vapor explosion,
and dust explosion.
2 Methodology
To design fire protection system, inputs are required based on the nature of chemical
and reactivity of chemicals used in the building. The parameters are class of chemicals
to decide the hazardous nature. Once hazardous nature is known, it is easy to design
firefighting systems in the facility. If building is low hazardous, it can be planned
with hydrants and water monitors. If building is medium hazardous, it can be planned
with sprinkler alarm valve. If building is high hazardous, then it has to be planned
with deluge system which is automated.
353
Friction hazard—The uncured propellant should have friction sensitivity low
enough that shear stresses in the mixer will not ignite the propellant, and the cured
propellant should have a friction sensitivity low enough that normal handling operations are not likely to ignite the propellant. Composite propellants used worldwide
today have substantial amount of metal powder as an ingredient. This increases the
friction hazard of composite propellants. Of the techniques available for characterization, a form of the pendulum-and-slide friction tester is preferred. If the friction
force is less than 5 kg m, it is considered as very sensitive and if the friction force is
between 5 and 17.5 kg m, it is considered as moderately sensitive.
Spark hazard—The propellant should have spark sensitivity low enough that the
normal static charge of a human body discharge will not ignite the propellant. The
propellant in both the cured and uncured states should be characterized for spark
sensitivity. The spark apparatus should be calibrated against materials of known
spark sensitivity. A sufficiently large number of samples should be run in order to get
a statistically significant set of data. The propellant should not have a spark sensitivity
less than 0.015 J.
Auto ignition hazard—The propellant should have an autoignition point so high
that its probability of autoignition is low under the thermal environment to which it
will be exposed. Also, the propellant should not develop so high internal temperature
during cure or from degradation chemical reactions that there is danger of autoignition. Composite propellants autoignition temperature lies in the range 280–310 °C.
The curing temperature of these temperatures should be half or less than half of the
autoignition temperature.
The consequences of fire in processing facility are deflagration, detonation,
confined explosion, unconfined explosion, boiling liquid expanding vapor explosion,
and dust explosion.
2 Methodology
To design fire protection system, inputs are required based on the nature of chemical
and reactivity of chemicals used in the building. The parameters are class of chemicals
to decide the hazardous nature. Once hazardous nature is known, it is easy to design
firefighting systems in the facility. If building is low hazardous, it can be planned
with hydrants and water monitors. If building is medium hazardous, it can be planned
with sprinkler alarm valve. If building is high hazardous, then it has to be planned
with deluge system which is automated.