D - Technical Dictionary

DEAD LOCK                                             
A type of lock which has no door handles or knobs and can be only opened from inside or outside with a key, also called Dead Latch

DICL                                                          
Ductile Iron Cement Lined (Pipe). Often used under roads for potable (drinking) water.

DXF                                                          
Drawing Interchange Format. DXF is used to exchange CAD drawing data with other software applications.

Dada                                                          
A product of the turbulent and cynical post-World War I period, this anti-art movement extolled the irrational, the absurd, the nihilistic, and the nonsensical. The reproduction of Mona Lisa adorned with a moustache is a famous example. The movement is regarded as a precursor of Surrealism. Some critics regard HAPPENINGS as a recent development of Dada. This movement incorporates environment and spectators as active and important ingredients in the production of random events.

Dado                                                          
Lower potion of wall above skirting when finished in contrast to the remainder of the wall.

Dampcourse                                             
A waterproof membrane that protects brickwork or masonry from rising damp.

Damping                                                    
The ability of a building component to diminish the intensity of vibration energy passing through it, and to minimise any vibration being transmitted to a connected element. It is analogous to the absorption of sound in air.

Davenport                                                 
A small writing desk (usually for a lady), with drawers and a sloping, often hinged, writing surface.

Daylight Opening                                      
The clear daylight size that is visible through a glazed window pane.

Daylight Transmittance                             
The percentage of visible light that glazing transmits through a window – a standard clear dual pane without considering whether a window frame has a daylight window – a standard clear dual pane without considering whether a window frame has a daylight transmittance of 82%.

Dead Bolt                                                  
An exterior security lock installed on exterior entry doors that can be activated only with a key or thumb-turn. Unlike a latch, which has a bevelled tongue, dead bolts have square ends.

Dead End                                                  
A portion of a corridor in which the travel to an exit is in one direction only.

Dead Latch                                                
A type of lock which has no door handles or knobs and can be only opened from inside or outside with a key, also called DEAD LOCK

Dead Load                                                 
The dead load of a building is the total load (weight) of the building.

Dead and Live Loads                                
Dead Loads result from the self weight of the materials used. These are permanent loads.Live Loads result from moveable units: people, loose furniture, for example. These are non-permanent loads.

Decibel                                                      
Unit used to measure sound. The human ear can normally detect a decibel change of 1 to 3. Normal conversation is around 60 dB while a 747 jet at takeoff is around 125 dB.

Decibel Loss                                              
A measure of reduction of sound.

Décor                                                        
The general decorative effect (colour-scheme, furnishings, etc) of a room. [French, decoration]

Decoupled Or Discontinuous Construction                                                                    
Physically detaching elements of a wall or other building component from each other to improve sound insulation.

Deflection                                                 
The measure of movement of a member from its static position when subjected to loads.

Deflection Ratio                                         
AS 2047-1996 has a maximum defection limit of span/150 for window structural members.

Delamination                                             
Separation of the plies in a panel due to failure of the adhesive. Usually caused by excessive moisture.

Demolition                                                 
Process entailed by the planned physical destruction of the construction works.

Demolition Drawing                                   
General arrangement drawing which specifies the scope and performance of demolition of a building, and which may also specify parts which shall be dismantled for re-use.

Dentils                                                       
A decorative row of small blocks like teeth along the cornice or fascia.

Design                                                       
A process that uses the products of analysis to produce a specification for implementing a system. A logical description of how a system will work.

Design Process                                         
The Activities entailed by the further conceptual elaboration of the desired Facility (brief), prior to the Production Process

Designated Bushfire Prone Area              
Bushfire prone areas may be designated by a power under legislation. See your building regulatory body.

Detail Drawing                                         
Drawing showing parts of a construction or a component, generally enlarged, and including any specific information about the form and construction or about the assembly and joints.

Dewpoint                                                   
The temperature at which water vapour in air will condense at a given state of humidity and pressure.

Diagram                                                    
Drawing in which graphical symbols are used to indicate the function of the components of a system and their relationships.

Diecast                                                      
The process of forcing molten metal under high pressure into mould cavities (which are machined into dies). Most die castings are made from non-ferrous metals, specifically zinc, copper, aluminium, magnesium, lead, pewter and tin based alloys, although ferrous metal die castings are possible. The die casting method is especially suited for applications where a large quantity of small to medium sized parts are needed, ensuring precise surface quality and dimensional consistency.

Diffuser                                                     
A cover over a light fitting which promotes an even distribution of light through out the area.

Direct Current                                            
A continuous flow of current of the same polarity. Commonly referred to as DC current.

Direct Fix Ceiling                                      
A ceiling system whose soffit is in close proximity to the structural soffit, and generally is fixed to the structural soffit by rigid connection.

Directoire Style                                         
A simplified version of the Louis XVI style in French decorative art, and popular circa 1795-1799 under the Directory (the governing body at the last stage of the French revolution).

Directory                                                   
In computing, is a virtual container within a digital file system, in which groups of computer files and other folders can be kept and organized. A typical file system may contain thousands (or even hundreds of thousands) of folders. Files are kept organized by storing related files in the same folder. A folder contained inside another folder is called a subfolder of that folder. Together, the folders form a hierarchy, or tree structure.

Disabled People                                        
The following is a list of acceptable terminology:
  • Disability - The disadvantage or restriction of activity caused by a society which takes little or no account of people who have impairments and thus excludes them from mainstream activity. Impairment is a characteristic, feature or attribute within an individual which is long term and may or may not be the result of disease, injury or congenital condition.
  • Disabled People - Those people with impairments who are disabled by society, this includes physically impaired people, people with visual impairments, deaf people, people who are hard of hearing, people with learning disabilities and people who have or have had mental health needs or mental distress. Impairment neither causes or justifies disability, which, like racism, sexism and homophobia, is discrimination and social oppression.
  • Terminology To Be Avoided:
    Able Bodied - The preferred term is ‘non-disabled’. ‘Able -bodied’ suggests that all disabilities are physical and ignores unseen disabilities, and that disabled people are not ‘able’.
    Afflicted With - This conveys a tragic or negative view about disability.
    Blind - Lumping everyone together in this way is felt by many to take away their individuality. The most appropriate term to use here is ‘people with visual impairments’, or ‘blind people’.
    Cripple, Or Crippled By Use the term ‘the person has...
    Deaf And Dumb - This phrase is demeaning and inaccurate. Many deaf people use sign language to communicate and ‘dumb’ implies that someone is stupid. Use ‘ a person with a hearing impairment’, or ‘ a deaf person’, or ‘sign language user’.
    Disabled - There is no such thing as ‘the disabled’. Use the term ‘disabled people’.
    Handicapped - This term is inappropriate, with images of begging and disabled people being ‘cap in hand’.
    Invalid - The term literally means ‘not valid’.
    People With Disabilities - The term ‘disabled people’ is the preferred term within the social model of disability. ‘People with disabilities’ infers that the disability ‘belongs’ to the disabled person, rather than ‘disabled person’ which accurately infers that society disables the individual, thus adopting the social model of disability.
    Suffering From - This confuses disability with illness and also implies that a disability may be a personal burden. Increasingly, disabled people view their disability as a positive rather that negative experience.
    Victim Of - This again plays to a sense that disability is somehow a tragedy.
    Wheelchair Bound - Disabled people are not tied into their wheelchairs. People are wheelchair users or someone who uses a wheelchair. A wheelchair offers the freedom to move around and is a valuable tool.

Distressed                                                 
New furniture that has been made to look used, old or rustic. Distressing is variously effected by striking the completed furniture with hard objects (e.g. sharp nails, blunt pieces of metal or wood), by deliberate cracking, by painting or staining imperfections on the wood surface, or by partially rubbing away the surface finish. The technique is also useful for masking defects in both the material used and poor furniture making techniques.

Dome                                                        
A vault erected on a circular base, usually as a hemispherical roof or ceiling. When the dome is erected on a square or rectangular base, resulting in its curved surfaces joining in an apex or ridge, it is called a domical vault. There are many other variations of dome shapes, eg an onion dome bulges outwards from its base (in the shape of an onion).

Door                                                          
A entrance into a building, room or passage; a solid sheet (of wood, metal, glass, etc) hung so that it permits access through or closes up an entrance. A means of approach or access.Some examples are:Automatic Closing Bi-Fold Doors Bi-Pass Doors Fanlight French Doors Horizontal Exit Panelled Door Structural Opening Self-Closing

Door Closer                                               
A device or mechanism to control a door during its opening and closing cycle; may be overhead or floor mounted and either exposed or concealed.

Door Frame                                               
An assembly of members, consisting of jambs and a header, into which a door or doors fit when closed. The door frame may also include transom lights and adjacent sidelights.

Door Handing                                            
Determined by placing your back to the hinge jamb. If the door swings to your left it is a left-handed door.

Door Hardware                                        
 A broad term used to group all the items that are fitted or related to doors, e.g., hinges, locks, padlocks, door closers, pull handles, bolts, stops, and tracks.

Door Holder                                               
A hardware device designed to limit the swing of a door and hold it in an open position.

Door Jamb                                                
One of two vertical members of a door frame. The hinge jamb is the jamb to which the hinges or pivots are mounted; the lock jamb is the jamb at the leading edge of the door where a lock bolt may be engaged.

Door Leaf                                                  
Movable element, which closes and opens doorways.

Door Light                                                  
The glass area in a door.

Door Lock Type                                        
 
  • Anti-Lockout Lock - Outside knob/lever locked or unlocked by inside turn/button or by external key. Closing door or rotating inside knob/lever automatically unlocks outside knob/lever. Inside knob/lever always operable.
  • Classroom Lock - Outside—Opened by knob or lever except when knob or lever is made inoperative by key from outside. The key locks or unlocks the outside knob or lever. Inside—Opened by knob or lever at all times.
  • Combination Lock - Outside and inside knob/lever locked or unlocked simultaneously by outside key or inside turn/button.
  • Entrance Lock - Knobs/levers locked both sides by inside turn/button. External key unlocks both sides.
  • Escape - Always operable from inside.
  • Exit Lock - Outside knob/lever always rigid. No external key. Inside knob/lever always operable.
  • Glass Door Lock - Knobs/levers locked/unlocked from both sides by key.
  • Hotel/Motel Lock - Outside knob/lever always locked. Access by key only at all times. Inside knob/lever always operable. Inside turn snib activates privacy lock-out function. When privacy lock-out function activated, then access is by emergency key only.
  • Night Latch - Latchbolt retracted by key externally or by turn snib internally at all times.
  • Passage Latch - Operable from either side by knob/lever at all times. No locking function.
  • Privacy Latch - Operable from either side except when outside knob/lever is locked by inside turn/button. External emergency release frees outside knob/lever for safety.
  • Storeroom Lock - Outside knob/lever permanently locked. Access by key at all times. Inside knob/lever always operable.
  • Vestibule Lock - Outside knob/lever locked by inside turn/button. Key outside unlocks knob/lever. Inside knob/lever always operable.
Door Opening                                            
The opening dimension of a doorway is measured from inside of jambs and from floor line to underside of frame header. The opening size is usually the nominal door size and is equal to the actual door size plus clearances and threshold height.

Door Schedule                                          
Component range drawing of doors and their hardware, and which may contain information in the form of a table.

Door Size                                                  
Actual The actual width and height of the swing door leaf.Nominal The nominal width and height is measured from inside of jambs and from floor line to underside of frame header.

Door Stop                                                 
A) A moulding or projecting element on a door frame which overlaps the edge of a door, causing it to stop in its closed position.
B) A bumper mounted on the floor or wall to limit the extent of the door opening.

Doorjamb                                                  
The surrounding case into which and out of which a door closes and opens. It consists of two upright pieces, called side jambs, and a horizontal head jamb. These 3 jambs have the "door stop" installed on them.

Doorset                                                      
A complete assembly comprising—The door leaf or leaves including any glazing and other inbuilt features; The door frame, if any, with its fixings to the wall and, for a sliding doorset, with all guides and their respective fixings to the lintel, wall or sill; Any fixed panel and its associated transom or mullion (including the methods of fixing) which is contained within the door frame; and All door hardware.

Doorstop                                                    
A device to limit the opening swing of a door. Also, that part of a door frame against which the door closes.

Doric                                                          
One of five classical orders, recognizable by its simple capital. The Greek Doric column has a fluted shaft and no base; the Roman Doric column may be fluted or smooth and rests on a molded base.

Dormer                                                      
A space which protrudes from the roof of a house, usually including one or more windows.

Dormer Window                                        
A window with a small roof and sides projecting from a larger sloping roof.

Double Glazing                                          
In general, two thickness's of glass separated by an air space within an opening to improve insulation against heat transfer and/or sound transmission. In factory-made double-glazing units, the air between the glass sheets is thoroughly dried and the space is sealed airtight, eliminating possible condensation and providing superior insulating properties. Glazing that incorporates two panels, separated with an air space, for the purpose of sound or thermal insulation or both.

Double Hung Window                               
A window consisting of two sashes operating in a rectangular frame, in which both the upper and lower halves can be slid up and down. Acounterbalance mechanism usually holds the sash in place. A two sash system where the bottom sash lifts up vertically passing on the inside of the top sash. The top sash lowers vertically.

Double-Acting Door                                  
A door equipped with hardware that permits it to swing to either side of the plane of the frame.

Dovetail Joint                                            
A neat joint between two timbers, the wedge-shaped projections along one edge slotting into the same shaped sockets of the other.

Downdraft                                                 
When a column of air in the chimney reverses its direction.

Downpipe                                                 
A pipe to carry roof water from gutters and roof catchments to drains or storage tanks.

Draftsperson                                            
 A Draftsperson It is an artist skilled in technical drawing. The 'skill' is to draw complex instructions precisely and accurately. The 'art' is to arrange that information in an beautiful, eye pleasing way. Combine these two factors and you have accurate drawings that are easy to use. DRAFTING includes any task that utilizes graphics to convey instructions to another person. Commonly this is associated with the making of plans for structures or mechanical devices before they are built. DISCIPLINES of drafting include: Architectural, Civil, Structural, Plumbing, Cartography, Electrical, Thermodynamics (and HVAC), Mechanical, Hydraulics, Telecommunications, Materials and Aerodynamics. ALTERNATE spelling, meaning the same thing, can be draughtsperson, draughtsman, draftsman, drafter or drafties. CAD, or computer aided drafting, is the modern, principle tool, used by drafters to create drawings or plans. AutoCAD and Microstation are two popular CAD software packages.

Drain Slot                                                  
A hole that is punched or drilled into the sill section that allows drainage of the sill system.

Drain Valve                                               
A component that uses a hinged flap at the drain slot to allow water to drain out and can close under wind pressure to prevent blow back of water through the drainage slots.

Drainage Cell                                            
A durable material used to overlay the membrane to protect it from physical damage and allow the transfer of moisture to relieve hydrostatic pressure. Timber and timber based products are not acceptable.

Drawings                                                   
The graphic and pictorial description of project requirements identifying the form, shape, dimension, and location of materials, products, or systems required for a facility; usually includes floor or area plans, a site plan, vertical elevations and image planes, construction component sections and details, schematic diagrams; may also include schedules.

Drenching                                                  
When applied to external sprinklers on the periphery of a building, such sprinkler heads are intended to wet and keep wet, that is to ``drench, the wall or window of a building during a fire to prevent or minimise the possibility of combustion.

Dresser                                                      
A large piece of case furniture with a shelved upper section. The lower section usually has a central cupboard flanked by drawers or open shelves. Its name comes from the wall tables used in the Middle Ages for dressing or preparing food.

Drip Mould                                                 
An exterior moulding (extrusion or brake shape) contoured for controlling or deflecting dripping water.

Drop Leaf                                                  
Table built with hinged extension leaves that lower when not in use.

Dry Glazing                                               
A method of securing glass in a frame that uses pre-formed resilient gaskets instead of a wet sealant or glazing compound.

Dryer                                                         
A clothes “dryer” makes clothes “drier".

Drywall                                                      
US term for gypsum board or plaster board.

Dual Occupancy                                       
Two residences sharing a single site, either in one building with separate access or in separate dwellings. Often used for extended family occupation, as a bed-sit, as a B&B, or for short term rental.

Dual Window                                             
Two windows joined together, one in front of the other, to provide superior sound control.

Duct                                                           
A tube, structure, or pipe for conveying of air.

Ductility                                                    
 Ductility generally refers to the amount of inelastic deformation which a material or structure experiences before complete failure. Quantitatively, ductility can be defined as the ratio of the total displacement or strain at failure, divided by the displacement or strain at the elastic limit.

Dumb Waiter                                             
A small lift for food and dishes.

Duplex                                                       
An apartment that has two or more storeys connected by a staircase. Also used to describe any single building that contains two separate residences, which are probably better referred to as a semi-detached bungalow or house, or even villas if there are more than two.

Dwelling                                                     
A building or part of a building used as a self contained residence.

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