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Oakum |
Loose hemp
or jute fiber that's impregnated with tar or pitch and used to caulk
large seams or for packing plumbing pipe joints |
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Occupancies |
The
classifications given to structures for the National Building Code by
the American Insurance Association. These include assembly, business,
education, high hazard, industrial, institutional, mercantile,
residential, and storage. |
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Occupational Safety and Health
Act |
A law whose purpose is to assure as far as possible that every working
person in the U.S. and its possessions will have safe and healthful
working conditions, thereby preserving our human resources. |
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Occupational Safety and Health Administration [OSHA] |
A federal
agency within the U.S. Department of Labor responsible for establishing
and enforcing standards regarding the exposure of workers to safety
hazards or harmful materials that they may encounter in the work
environment, as well as other matters that may affect the safely and
health of workers. |
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Odor threshold |
The lowest
concentration in the atmosphere that can be detected by the human sense
of smell. Often, this is a poor indicator of toxicity risk. The greatest
dilution of a sample with odor-free water to yield the least definitely
perceptible odor. |
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Offensive tactics |
Aggressive
leak, vapor control, and fire control tactics designed to quickly
control or mitigate the problem. Although increasing risks to emergency
responders, offensive tactics may be justified if rescue operations can
be quickly achieved, if the spill can be rapidly confined or contained,
or if the fire can be quickly extinguished. |
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Office occupancy
|
The
occupancy or use of a building or structure or any portion thereof for
the transaction of business or the rendering or receiving of
professional services. |
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Officer |
The ICS title for the personnel
responsible for the Command Staff positions of Safety, Liaison, and Public
Information. Any member of the fire service with supervisory
responsibilities, company-officer level and above. |
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Ohmmeter |
A device to measure the resistance across a
load. They are never used on a live circuit. It is used to track down broken
wires. |
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Ohm's
law
|
States that, in a given circuit, the amount
at current in amps is equal to the pressure in volts divided by the
resistance in ohms. The formula is: I (Current) = V voltage or V = I x R R
resistance or R = V/I |
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Oil |
Any of numerous mineral, vegetable and
synthetic substances and vegetable and animal fats that is generally
slippery, combustible, viscous, liquid or liquefiable at room temperature. |
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Olfactory |
Pertaining to the sense of smell. |
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On Center |
The measurement of spacing for studs,
rafters, and joists in a building from the center of one member to the
center of the next. |
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Open head system |
A fire protection sprinkler system having
open heads without fusible links and controlled by a valve that may be
operated manually or by a thermostatic device. |
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Open up |
To ventilate a smoke-filled building or room
to aid in the advance of hose lines and extinguishment of the fire and to
avoid concentration of the unburned heated smoke and gases. Also used in
reference to forcible entry. |
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Operational Period |
The period of time scheduled for
execution of a given set of operation actions as specified in the Incident
Action Plan. Operational Periods can be of various lengths, although usually
not over 24 hours. |
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Operations Section |
The Section responsible for all
tactical operations at the incident. Includes Branches, Divisions and/or
Groups, Task Forces, Strike Teams, Single Resources, and Staging Areas.
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Organophosphates |
Synthetic organic pesticides that contain
carbon, hydrogen and phosphorous; toxic to humans because they prevent
proper transmission of the nerve impulses; a compound with a specific
phosphate group which inhibits acetycholinesterase; used in chemical warfare
and as an insecticide. Examples include Parathion and Malathion. |
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Oriented Strand Board (OSB) |
A manufactured 4' X 8' wood panel made out of
1"- 2" wood chips and glue. Often used as a substitute for plywood |
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Origin |
See Point of Origin or Area of Origin |
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OS&Y valve |
A type of outside screw and yoke valve used
on piping or in pits connected to sprinkler systems. The position of the
stem shows the valve to be either open or closed. |
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OSHA
|
Occupational Safety and Health
Act/Occupational Safety and Health Administration. |
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OSHA PPE standard
|
This standard is contained in 29 CFR 1910,
Subpart 1, and includes General Requirements (.132); Eye and Face Protection
(.133); Respiratory Protection (.134); Head Protection (.135); Occupational
Foot Protection (.136); Electrical Protective Devices (.137); Hand
Protection (.138); and Non-Mandatory Compliance Guidelines for Hazard
Assessment and PPE Selection (Appendix B). Other OSHA Occupational Safety
and Health Regulations have specific paragraphs dealing with PPE, including
HAZWOPER (.120); Blood-Borne Pathogens (.130); Electrical Safety (.335);
Welding, Cutting and Brazing (.252); and Electrical Power Generation (.269). |
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Out of service |
A
piece of apparatus is not in a position to respond to an alarm. Generally,
the apparatus needs fuel or water or is out for routine maintenance. |
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Out-of-Service
Resources |
Resources assigned to an incident
but unable to respond for mechanical, rest, or personnel reasons.
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Outrigger
|
Structural
load-carrying members attached to and extending outward from the main
longitudinal frame members of a trailer; stabilizers for elevating
apparatus. An extension of a rafter beyond the wall line. Usually a
smaller member nailed to a larger rafter to form a cornice or roof
overhang. |
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Outside sprinkler
|
A sprinkler system with open heads,
automatically or manually operated, to protect a structure or window
openings against a severe exposure hazard. Also called Water Curtain. |
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Outside standpipe |
A standpipe riser on the exterior of a
building and equipped with a fire department siamese connection |
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Overhang
|
Outward projecting eave-soffit area of a
roof; the part of the roof that hangs out or over the outside wall. See also
Cornice. |
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Overhaul
|
Commonly viewed as "cleaning up" after a fire, overhaul is the process
of putting a structure in the safest condition following a
fire. Additionally, it is during the overhaul phase of an incident that
firefighters verify that the fire has not extended into unknown areas
and that hidden "hot spots" are extinguished. |
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Overload |
Operation of
equipment in excess of normal, full-load rating, or of a conductor in
excess of rated ampacity, which, when it persists for a sufficient
length of time, would cause damage or dangerous overheating. A fault,
such as a short circuit or ground fault, is not an overload. |
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Overpack
|
The act of putting a smaller container into a
bigger one to prevent product leakage; often used for product transport or
disposal after a hazardous materials incident has occurred. The larger of
two containers of which the smaller fits into the larger/ the larger can be
sealed. |
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Oxidizer |
A chemical, other than a blasting agent or
explosive, that initiates or promotes combustion in other materials, thereby
causing fire either of itself or through the release of oxygen or other
gases; any substance that will oxidize. Most oxidizers are compounds of
oxygen. Fluorine, chlorine, and bromine are elements that are also used as
oxidizers. Also referred to as an oxidizing agent, causes another substance
to lose electrons. Oxygen is the most common oxidizer in our environment.
Oxidizers are said to be reduced when they gain the electrons lost by the
material, which they are oxidizing. |
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Oxygen |
An element constituting 21 percent of the
atmosphere by volume that occurs as a diatomic gas, O2, combines with most
elements, is essential for plant and animal respiration, and is required for
nearly all combustion. |
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Oxygen Deficiency
|
Insufficient oxygen to support life or to
support flame. When oxygen content of the air falls below 16 percent, flame
production is reduced and Firefighters are in danger of asphyxiation from
oxygen deficiency; below six percent, breathing ceases. In addition to
oxygen deficiency, there is danger from smoke, heat, and gases unless
firefighters are protected by SCBA; and these conditions may become serious
before oxygen deficiency is acute. |
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Oxygenator
|
A simplified, convenient oxygen
administration system for home use where prolonged administration of oxygen
is necessary. See Inhalator. |
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Oxygen-enriched atmosphere
(Fire Protection) |
Any atmosphere in which the concentration of
oxygen exceeds 21 percent by volume, or the partial pressure exceeds 160
millimeters of mercury, or both. |
