.gif)
Joint (building)
Encyclopedia
A building joint is a junction where building
elements meet without applying a static load from one element to another. When one or more of these vertical or horizontal elements that meet are required by the local building code
to have a fire-resistance rating
, the resulting opening that makes up the joint must be firestop
ped in order to restore the required compartmentalisation
.
Such joints are often subject to movement, as a function of the building's design basis. For a sample certification listing
indicating fire tested
motion
, click here. Firestop
s must be able to demonstrate the ability to withstand operational movement prior to fire test
ing. Firestops for such building joints can be qualified to UL 2079 -- Tests for Fire Resistance of Building Joint Systems.
Whether or not the building elements forming the joint have a fire-resistance rating, the joint design must still consider the anticipated operational movement of each joint. Timing is also important, as freshly poured concrete shrinks particularly during the first few months of a new building, potentially causing joint size changes.
or precast concrete panels, slow the passage of fire and combustion gases between floors. The firestop at the perimeter slab edge is considered a continuation of the fire-resistance rating of the floor slab. The curtain wall itself, however, is not ordinarily required to have a rating. Fire compartmentalisation
is based upon compartments enclosed on all sides to avoid fire and smoke migration beyond each engaged compartment. A non-fire-resistance rated curtain wall prevents the complete compartment (or envelope) from being fire-resistance rated. The provision of firestopping at the joint of the floor slab and curtain wall can still add to the overall fire safety of the building by slowing the advance of the fire in the building interior from floor to floor. The use of fire sprinklers has been shown to mitigate the spread of fire by keeping the fire from growing to a size large enough to cause structural damage and break the exterior glass. If the building is not equipped with sprinklers, the fire can travel up the outside of the curtain wall if the glass on the floor of fire origin is shattered due to radiant heat, causing flames to lick up the outside of the building, resulting in the glass in floors above to break. Falling glass can endanger pedestrians, firefighters and firehoses below. An example of mode of fire spread is the First Interstate Bank Fire in Los Angeles, California. This building is now the Aon Center
.
The fire leapfrogged up the tower by shattering the glass. The exterior curtain wall aluminium
skeleton holding the glass failed. Exceptionally sound cementitious spray fireproofing also helped to delay and ultimately to avoid the possible collapse of the building, by preventing the steel building structure from reaching the critical temperature at which steel weakens and can no longer hold its intended load. This fire proved the positive, collective effect of both active fire protection
(sprinklers) to control fire size in its incipient stages, and passive fire protection
(fireproofing
) if the fire sprinkler
s are not effective.
or drywall
, meet the underside of the floor slab above, a movement joint results, which can be subject to compression, as the freshly placed concrete
cures and shrinks all over a new building. This joint must be firestopped in a flexible manner. For concrete block walls that are not load-bearing, the contractor is often instructed to stop the wall about 25mm short of the slab above. The drywaller has to fasten a track to the underside of the slab above, which holds the metal studs. The drywall is then either stopped short allowing for a flexible buffer to be inserted or caulked in place, or one may use purpose-made tracks that hold the studs but permit up and down movement without damage to the system.
Building
In architecture, construction, engineering, real estate development and technology the word building may refer to one of the following:...
elements meet without applying a static load from one element to another. When one or more of these vertical or horizontal elements that meet are required by the local building code
Building code
A building code, or building control, is a set of rules that specify the minimum acceptable level of safety for constructed objects such as buildings and nonbuilding structures. The main purpose of building codes are to protect public health, safety and general welfare as they relate to the...
to have a fire-resistance rating
Fire-resistance rating
A fire-resistance rating typically means the duration for which a passive fire protection system can withstand a standard fire resistance test. This can be quantified simply as a measure of time, or it may entail a host of other criteria, involving other evidence of functionality or fitness for...
, the resulting opening that makes up the joint must be firestop
Firestop
A firestop is a passive fire protection system of various components used to seal openings and joints in fire-resistance rated wall and/or floor assemblies, based on fire testing and certification listings....
ped in order to restore the required compartmentalisation
Compartmentalization (fire protection)
Compartmentalization in structures, such as land-based buildings, traffic tunnels, ships, aerospace vehicles, or submarines, is the fundamental basis and aim of passive fire protection....
.
Qualification requirements
Certification listing
A certification listing is a document used to guide installations of certified products against which a field installation is compared to make sure that it complies with a regulation, such as a building code...
indicating fire tested
Fire test
A fire test is a means of determining whether or not fire protection products meet minimum performance criteria as set out in a building code or other applicable legislation. Successful tests in laboratories holding national accreditation for testing and certification result in the issuance of a...
motion
Motion (physics)
In physics, motion is a change in position of an object with respect to time. Change in action is the result of an unbalanced force. Motion is typically described in terms of velocity, acceleration, displacement and time . An object's velocity cannot change unless it is acted upon by a force, as...
, click here. Firestop
Firestop
A firestop is a passive fire protection system of various components used to seal openings and joints in fire-resistance rated wall and/or floor assemblies, based on fire testing and certification listings....
s must be able to demonstrate the ability to withstand operational movement prior to fire test
Fire test
A fire test is a means of determining whether or not fire protection products meet minimum performance criteria as set out in a building code or other applicable legislation. Successful tests in laboratories holding national accreditation for testing and certification result in the issuance of a...
ing. Firestops for such building joints can be qualified to UL 2079 -- Tests for Fire Resistance of Building Joint Systems.
Whether or not the building elements forming the joint have a fire-resistance rating, the joint design must still consider the anticipated operational movement of each joint. Timing is also important, as freshly poured concrete shrinks particularly during the first few months of a new building, potentially causing joint size changes.
Perimeter slab edge
Firestopping at the "perimeter slab edge", which is gaps between the floors and the backpan of the curtain wallCurtain wall
A curtain wall is an outer covering of a building in which the outer walls are non-structural, but merely keep out the weather. As the curtain wall is non-structural it can be made of a lightweight material reducing construction costs. When glass is used as the curtain wall, a great advantage is...
or precast concrete panels, slow the passage of fire and combustion gases between floors. The firestop at the perimeter slab edge is considered a continuation of the fire-resistance rating of the floor slab. The curtain wall itself, however, is not ordinarily required to have a rating. Fire compartmentalisation
Passive fire protection
Passive fire protection is an integral component of the three components of structural fire protection and fire safety in a building. PFP attempts to contain fires or slow the spread, through use of fire-resistant walls, floors, and doors...
is based upon compartments enclosed on all sides to avoid fire and smoke migration beyond each engaged compartment. A non-fire-resistance rated curtain wall prevents the complete compartment (or envelope) from being fire-resistance rated. The provision of firestopping at the joint of the floor slab and curtain wall can still add to the overall fire safety of the building by slowing the advance of the fire in the building interior from floor to floor. The use of fire sprinklers has been shown to mitigate the spread of fire by keeping the fire from growing to a size large enough to cause structural damage and break the exterior glass. If the building is not equipped with sprinklers, the fire can travel up the outside of the curtain wall if the glass on the floor of fire origin is shattered due to radiant heat, causing flames to lick up the outside of the building, resulting in the glass in floors above to break. Falling glass can endanger pedestrians, firefighters and firehoses below. An example of mode of fire spread is the First Interstate Bank Fire in Los Angeles, California. This building is now the Aon Center
Aon Center (Los Angeles)
Aon Center is a 62-story, Modernist office skyscraper located at 707 Wilshire Boulevard in downtown Los Angeles, California. Designed by Charles Luckman, and completed in 1973, the rectangular black building with white trim is remarkably slender for a skyscraper in a seismically active area. It is...
.
The fire leapfrogged up the tower by shattering the glass. The exterior curtain wall aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
skeleton holding the glass failed. Exceptionally sound cementitious spray fireproofing also helped to delay and ultimately to avoid the possible collapse of the building, by preventing the steel building structure from reaching the critical temperature at which steel weakens and can no longer hold its intended load. This fire proved the positive, collective effect of both active fire protection
Active fire protection
Active fire protection is an integral part of fire protection. AFP is characterised by items and/or systems, which require a certain amount of motion and response in order to work, contrary to passive fire protection.-Fire suppression:...
(sprinklers) to control fire size in its incipient stages, and passive fire protection
Passive fire protection
Passive fire protection is an integral component of the three components of structural fire protection and fire safety in a building. PFP attempts to contain fires or slow the spread, through use of fire-resistant walls, floors, and doors...
(fireproofing
Fireproofing
Fireproofing, a passive fire protection measure, refers to the act of making materials or structures more resistant to fire, or to those materials themselves, or the act of applying such materials. Applying a certification listed fireproofing system to certain structures allows these to have a...
) if the fire sprinkler
Fire sprinkler
A fire sprinkler system is an active fire protection measure, consisting of a water supply system, providing adequate pressure and flowrate to a water distribution piping system, onto which fire sprinklers are connected...
s are not effective.
Head-of-Wall (HOW)
Where fire-resistance rated wall assemblies, be they masonryMasonry
Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone, marble, granite, travertine, limestone; concrete block, glass block, stucco, and...
or drywall
Drywall
Drywall, also known as plasterboard, wallboard or gypsum board is a panel made of gypsum plaster pressed between two thick sheets of paper...
, meet the underside of the floor slab above, a movement joint results, which can be subject to compression, as the freshly placed concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
cures and shrinks all over a new building. This joint must be firestopped in a flexible manner. For concrete block walls that are not load-bearing, the contractor is often instructed to stop the wall about 25mm short of the slab above. The drywaller has to fasten a track to the underside of the slab above, which holds the metal studs. The drywall is then either stopped short allowing for a flexible buffer to be inserted or caulked in place, or one may use purpose-made tracks that hold the studs but permit up and down movement without damage to the system.
See also
- ConcreteConcreteConcrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
- Penetration (firestop)Penetration (firestop)A penetration, in firestopping, is an opening, such as one created by the use of a cast-in-place sleeve, in a wall or floor assembly required to have a fire-resistance rating, for the purpose of accommodating the passage of a mechanical, electrical or structural penetrant. The penetration may or...
- SealantSealantA sealant may be viscous material that has little or no flow characteristics and stay where they are applied or thin and runny so as to allow it to penetrate the substrate by means of capillary reaction...
- FirestopFirestopA firestop is a passive fire protection system of various components used to seal openings and joints in fire-resistance rated wall and/or floor assemblies, based on fire testing and certification listings....
- Curtain wallCurtain wallA curtain wall is an outer covering of a building in which the outer walls are non-structural, but merely keep out the weather. As the curtain wall is non-structural it can be made of a lightweight material reducing construction costs. When glass is used as the curtain wall, a great advantage is...
- Passive fire protectionPassive fire protectionPassive fire protection is an integral component of the three components of structural fire protection and fire safety in a building. PFP attempts to contain fires or slow the spread, through use of fire-resistant walls, floors, and doors...
- Active fire protectionActive fire protectionActive fire protection is an integral part of fire protection. AFP is characterised by items and/or systems, which require a certain amount of motion and response in order to work, contrary to passive fire protection.-Fire suppression:...
- Mineral woolMineral woolMineral wool, mineral fibers or man-made mineral fibers are fibers made from natural or synthetic minerals or metal oxides. The latter term is generally used to refer solely to synthetic materials including fiberglass, ceramic fibers and stone wool...
- Packing (firestopping)Packing (firestopping)Packing is the process and/or the materials used in filling both service penetrations and building joints with backer materials as approved components within a firestop.-Purpose:...
- Fire sprinklerFire sprinklerA fire sprinkler system is an active fire protection measure, consisting of a water supply system, providing adequate pressure and flowrate to a water distribution piping system, onto which fire sprinklers are connected...
- ArticulationArticulation (architecture)Articulation, in art and architecture, is a method of styling the joints in the formal elements of architectural design. Through degrees of articulation, each part is united with the whole work by means of a joint in such a way that the joined parts are put together in styles ranging from...