An obstruction means anything that impedes, reduces or changes the flow and direction of water. An obstruction can impede this flow on its own or by catching or collecting debris carried by water, causing floods to flow downstream that can cause damage or be detrimental to life and property.
Occupational Safety and Health Administration (OSHA)
OSHA is a US government agency that regulates and enforces the safety and health of employees, particularly in hazardous occupations such as firefighting and restoration work. OSHA is also responsible for the qualification and certification of personnel protective equipment (PPE).
An odor is a scent or a substance that affects the sense of smell. Odors can be pleasant or can be disagreeable as in the case of sewage or smoke. Deodorizers are used to mask odors after restoration work.
An off-channel area is a portion of a stream that is outside the main flow and is considered relatively calm compared to the main flow.
An ohm is a unit of electrical resistance where 1-volt of voltage produces 1-ampere of current.
Oil is a hydrocarbon liquid that is obtained by drilling though sedimentary layers filled with marine matter from the Carboniferous era. It is a colloquial term for petroleum. Most oils can burn in air and generate heat. It can also be converted to other forms of fuel (ex: fuel oil, diesel oil, gasoline, etc.) by a variety of processes.
Oils are used as fuels for heating, lighting, combustion engines and other purposes. Oils can also be produced through biological methods such as biodiesel, which is quickly gaining market share as an alternative fuel.
An omnivore is an organism that eats and consumes both plants and animal matter.
In restoration terms, on-location refers to the process of restoring an item at the loss site like a home or commercial establishment that experienced damage.
The start of a particular restoration can be referred to as onset.
Open Drying Process
Open drying is the process of drying out a structure after water damage through opening windows and doors to increase natural airflow inside the structure. Open drying, however, is not recommended unless the outside humidity is 50 percent or lower.
Open Web Steel Joist
An open web steel joist is a roofing steel truss that has a criss-cross pattern.
Open wiring refers to the bank of wires that is supported by porcelain insulators instead of a conduit and is generally used in industrial settings to feed machinery. Open wiring is an important checkpoint during restoration work and should be initially considered to avoid electrocution.
Operation and Maintenance (O & M)
O & M are activities required to maintain the effectiveness and integrity of remedial or mitigation work in a particular structure or area.
An organic substance contains carbon or compounds of carbon and can be made up of living organisms or the products of their decomposition.
Soil that has more than 12 to 18 percent organic carbon is classified as organic soil, but this would still depend on clay content.
Organophosphates are currently the most popular forms of pesticides that can kill pests by destroying their nervous systems.
The term other residential refers to hotels or motels where the normal stay of an occupant could be six months or more. A residential building is permitted as an incidental office, a professional private school, or studio occupancy, with the agreement that the total area of such occupancy is less than 25 percent of the total floor area of the building.
An outfall refers to the mouth or the outlet of a particular river, stream or lake. It can also refer to the outlet of a structure's drain or sewer and is the discharge point for wastewater.
Oxidation is the process of removing hydrogen atoms or electrons from a compound or the addition of oxygen atoms to create oxides. This process applies to metals (ex: iron converts to rust or iron oxide), nonmetals (ex: sulfur is converted to sulfur oxide), and organic matter (ex: carbon is converted carbon oxide; hydrogen is converted to hydrogen oxide).
An oxidizer is a substance that gives up oxygen readily. It can be a hazardous material when combined with adjacent fuel which can start or feed a fire.
An oxidation agent, also called an oxidant, oxidizer or oxidiser, is a chemical compound that readily transfers oxygen atoms that results to the conversion of metals, nonmetals, and organic matter to oxides.
An oxyacid is a type of acid wherein the hydrogen atom attaches to the oxygen atom resulting in a created atom that is attached to the central atom. An example is sulfuric acid and is used for several industrial and cleaning purposes.
Oxygen is an element with an atomic symbol of O and is an odorless and colorless gas. Oxygen is the third most abundant element in the universe next to hydrogen and helium. It is the most abundant element by mass in the Earth's crust.
Major molecules in living organisms contain oxygen such as proteins, carbohydrates and fats. It is also present in inorganic compounds that make up animal shells, teeth and bone. Oxygen in the form of O2 is vital to life and is used in all cellular respiration. It is produced from water by algae and through photosynthesis by plants.
Ozone, with the symbol of O3, is a form of oxygen having three molecules and is an oxidizing agent with a weak chlorine odor. It is produced naturally through sunlight and lightning. At ground level, ozone can irritate the respiratory system and it can be considered an air pollutant.
However, ozone is an important part of the stratosphere as it creates a protective layer that hangs 10 to 50 kilometers above the planet’s surface. This layer shields the Earth from the sun’s harmful ultraviolet radiation.
An ozone hole is a thinning of the stratospheric layer of ozone over Antarctica. It was once naturally occurring during springtime, but the ozone hole has been enlarged by CFCs and other pollutants and has grown into the size of the moon.