| Tweet |
Custom Search
|
|
|
||
 TM 55-1905-223-SDC
Section XIV. SMOKE CLEARANCE
6-26. INTRODUCTION. As smoke is secondary in nature to fire, it should be considered by the
firefighter in combating the fire. The primary objective must be to extinguish the fire and when that has
been accomplished completely, then steps should be taken to remove the smoke and fumes that remain.
A1- though smoke and fumes must be considered hazardous to the breathing of personnel, the
hazard can be completely avoided by the use of oxygen-breathing apparatus. The reduction in
visibility by smoke is a hazard as well as a nuisance which must be endured until the fire has been
completely extinguished.
This procedure differs radically from that practiced ashore where ventilation is used to rid a
building of accumulated heat and smoke, making access easier for rescue and firefighting. Since a
single ventilation system aboard ship frequently serves a number of compartments, premature use might
result in spreading a fire beyond established boundaries. This is further discussed in the following
paragraphs.
Fire that occurs in the open on weather decks does not present such a serious smoke problem, as this
type of fire can normally be combatted from the windward side, the smoke being carried away by air
currents. The problems con-fronted by the firefighter in combating a fire in a below-deck space are more
difficult because of the presence of smoke and fumes. The firefighter's objective must be to extinguish
the fire despite other difficulties.
Generally, there are no effective means for combating smoke or fumes during the progress of an
interior fire. In most instances, ventilation should not be attempted during the progress of a fire in an
effort to improve visibility. The known additional fire hazard resulting from the use of ventilating systems
or ducts during a fire is considered of greater importance than the doubtful improvement in visibility
resulting from their use. To conform with firefighting procedure as explained in this chapter, all ventilating
system closures, both supply and exhaust, are secured in the area where a fire exists. Not only should
ventilating system closures be secured, but electrical systems to blowers and similar devices should be
deenergized also.
Open ventilating ducts, particularly in vertical systems, will act as vents for the fire, thereby prolonging
the life of the fire and contributing to the difficulty of bringing the fire under control. In addition to the
introduction of air (oxygen) to the existing fire, there is always the hazard of spreading the fire by
combustion of dust and other debris which collects in ventilating systems as the result of infrequent or
improper cleaning.
Ventilating ducts which remain open to a compartment in which there is a fire can quite easily become
the vehicle for spreading fire and fumes to areas of the ship which otherwise would be unaffected.
Combustible gasses or fumes passing a sparking motor may easily explode, causing further damage and
possibly additional fires. The foregoing is particularly true when the access to the compartment has been
opened for the purpose of fighting the fire. The open access in combination with an open ventilating duct
will cause a natural draft. Ventilating system closures are provided and fitted to assist in preventing the
spread of smoke and fumes to other parts of the ship as well as for preservation of watertight integrity and
reserve buoyancy.
Change 1
|
||
|
||
