Architectural and Engineering Glossary

O
Office Divider

Same as partial height partition. 

Office Landscape Screen

A fixed or movable, free standing, rearrangeable interior space divider;may incorporate sound absorptive properties. 

Office Occupancy

The use of a building for the transaction of business or for similar purposes. 

Officia Map

One legally established by a municipality,which depicts existing  parks,streets, and drainage systems;and reservations and rights of way for the future expansion of these systems usually are depicted.
 

Offlet

Same as grip.

Offsaw

Descriptive of the actual size of a timber after it has been sawn.

Offset

1.A horizontal ledge on a wall (or other member or construction),marking a decrease in its thickness above;also called a watertable.2.A bend in a pipe.3.A change in the direction of a pipeline (other than 90),e.g.,by a combination of elbows or bends,which brings one section of the pipe out of line with but into a line parallel to another section.4.A short line perpendicular to a surveyed line,measured to a line or point for which data are desired,thus locating the second line or point with reference to the first or surveyed line.
 

Offset Bend

In a reinforcing bar,any bend that displaces the center line of a section of the bar to a position parallel to the original bar (the displacement usually is relatively small);commonly used in reinforced concrete columns.

Offset Block

A concrete masonry unit which is not rectangular;usually used as a corner block to maintain the masonry pattern on the exposed face of a single withe wall whose thickness is less than half the length of the unit.

Offset Chimney

Same as stepped back chimney.

Offset Digging

Digging with a ladder ditcher whose boom is displaced from the line of travel of the ditcher.
 

Offset Elbow

A pipe fitting whose shape has the outline of the letter S,used for connecting lengths of straight pipe that are parallel to,but displaced from,each other.

Offset Line

A secondary survey line roughly parallel and close to a primary survey line to which it is referenced in measured offsets.

Offset Pivot

A pin and-socket hardware device with a single bearing contact,by means of which a door is suspended in its frame,allowing it to swing about an axis which normally is located about 3⁄4 in. (1.9 cm) out from the door face.

Offset Screwdriver

A screwdriver whose head is set 90to the shaft.

OG

1.Abbr. for “ogee.” 2.Abbr. for “on grade.” 

Ogee Arch

A pointed arch composed of reversed curves,the lower concave and the upper convex.Compare with nodding ogee arch.

Ogee Plane

A carpenter’s plane with a reverse curved blade for shaping ogee moldings.

Ogee, OG

1.A double curve,formed by the union of a convex and concave line, resembling an S-shape.2.A molding having such a shape,an ogee molding.
 

Ogival Arch

Same as ogee arch.

Ogive

1.In general,a pointed arch.2.Strictly,the diagonal rib in Gothic vaults.

Ohm

The unit of electrical resistance of a conductor such that a constant current of 1 ampere in it produces a decrease in voltage across it of 1 volt.

Ohm’s Law

A law stating that the current in an electric circuit is directly proportional to the electromotive force (voltage) in the circuit and inversely proportional to the resistance in the circuit.

OHS

On drawings, abbr. for “oval headed screw.”

Oil

A lightly viscous neutral liquid belonging to one of three classes:(a) animal oil,(b) mineral oil,or (c) vegetable oil.
 

Oil Buffer

A buffer consisting of a cylinder and a piston or plunger where the oil in the cylinder acts as a medium to absorb and dissipate the kinetic energy of an impact,such as that of a descending elevator car or counterweight acting on the piston or plunger.

Oil Burner

In a furnace or boiler,a burner in which fuel oil is vaporized or atomized and then mixed with air and ignited;the resulting flame is directed upon the surface to be heated.

Oil Color

An oil base paint containing a high concentration of colored pigment;commonly used for tinting paint.

Oil Furnace

A furnace that is fired by oil.

Oil Interceptor

Same as interceptor.

Oil Length

In a varnish,the number of gallons of oil per 100 lb of gum or resin.

Oil Of Turpentine

See turpentine.

Oil Paint

A paint in which a drying oil is the vehicle for the pigment.

Oil Preservative

An oil soluble chemical used to treat wood for protection against decay and insects.Also see creosote,pentachlorophenol.

Oil Separator

In a refrigeration system,a device for separating oil and oil vapor from the refrigerant,usually installed in the compressor discharge line.

Oil Stain

A stain containing dye or pigment mixed with oil or oil varnish which penetrates the surface to be finished.

Oil Switch

Same as oil immersed switch.

Oil Varnish

A high gloss varnish for interior use;made by heating or blending a drying oil with a gum or resin.

Oil White

A house paint pigment consisting of lithopone and white lead or zinc white.

Oil-base Paint

See oil paint.

Oil-bound Distemper

A distemper which contains a drying oil.

Oil-canning, Tin-canning

A slight  buckling in sheet metal,causing a wavy or uneven appearance.

Oil-filled Transformer

A liquid immersed transformer in which the liquid is a hydrocarbon or mineral oil.

Oil-immersed Fuse

A fuse that is either totally or partially immersed in an insulating dielectric liquid of a transformer or switchgear.

Oil-immersed Switch

A switch which is immersed in a special insulating fluid,usually oil.

Oil-immersed Transformer

See oil filled transformer.

Oilet

See oillet.

Oillet, Oillette

A small opening,or circular loophole,in a fortification of the Middle Ages.

Oilstone

A fine grained stone used to impart a sharp edge on tools;oil is used to lubricate the rubbing surface.

Oilstone Slip

See gouge slip.