Sequencing • Interior finishing begins when the “shell” of the building is sufficiently weatherproof to protect the interior. • Mechanical, Electrical and Plumbing, (this may also include fire suppression systems) • Vertical runs through a building are typically accommodated by the use of shafts • Horizontal runs through a building are typically placed in raceways or chases
Sequencing, (continued) • Full height partitions and smoke partitions • Partitions “tight to deck” • Fire stopping • Joint covers – building separation joints • Fire safing – perimeter of floor slab
Interior Finish Systems Interior finish systems are selected based upon a number of criteria: Appearance Durability Acoustic Criteria Fire Criteria
Acoustic Criteria • Interior finish materials have an effect upon interior sound quality: noise levels, listening conditions and sound transfer from space to space. The sound transmission is qualified by two measurements: • STC – Sound Transmission Class and • ITC – Impact Transmission Class
Acoustic Criteria • STC – Sound Transmission Class • Measure of sound wave vibrations transferred through the membrane of a wall. STC rating may be reduced by partition details such as dampening clips and resilient mountings that reduce the transfer of vibration from the collection panel through the wall, (typical), assembly or by the addition of sound absorbing insulation, (typically mineral batts), in the wall cavity. • ITC – Impact Transmission Class • Measure of transmission of impact generated noises through a floor/ceiling assembly.
Acoustic Isolation • Construction methods • Solid construction
Acoustic Isolation • Sound attenuation batt insulation • High CAC panels • Isolation clips: resilient channels
Fire Criteria • The code develops requirements for interior finishes with respect to both combustibility and flame-spread. • Combustibility is the surface burning characteristics of a material, and is described using two criteria: the flame-spread rating and the fuel-contributed rating.
Combustibility • The Steiner Tunnel test measures both the flame spread and the amount of fuel contributed by the material as well as the amount of smoke developed. • Flame-spread rating is a measurement of how fast fire moves across the surface of a material • Fuel-contributed rating indicates the amount of combustible substances in the material • Smoke developed rating classifies the material by the amount of smoke given off when it burns
Fire-Resistance Requirements • Interior wall and ceiling finish requirements are governed by occupancy classification in the IBC, table 803.4, (page 797 in the text) • Sprinklered vs. Unsprinklered • Vertical exits and passageways • Exit access corridors • Rooms and enclosed spaces
Fire-Resistance Requirements • Class A materials: flame-spread ratings lie between 0 and 25 • Class B materials: flame-spread ratings between 26 and 75 • Class C materials: flame-spread ratings between 76 and 200. • Smoke-developed ratings may not exceed 450 for any of the three classes.
Fire-Resistance Requirements • The scale of the flame-spread ratings is somewhat arbitrary: cement-asbestos board has a value of 0 while red oak has a value of 100. • Trim materials are removed from application if their total area does not exceed 10% of the total wall and ceiling area of a room.
Fire Resistance Ratings • Fire barriers: a building assembly that meets the required fire resistance rating for separation of occupancies. • Fire walls separate buildings: where the maximum allowable area for a given occupancy is exceeded, multiple buildings may be used.
Fire Resistance Ratings, (continued) • In order to achieve a given fire resistance rating, an assembly is tested in a furnace and subjected to the structural load for which it is designed according to: • 1770° at one hour and 2000° after four hours • In order to achieve the fire resistance rating in hours, the assembly must: • Safely carry the design load, (structural failure) • Must not develop any openings that would permit smoke or gases to penetrate the assembly • Must insulate sufficiently against heat to maintain surface temperatures on the side away from the fire within specified levels.
Fire Resistance Ratings, (continued) • Walls and partitions • Must also pass the “hose test”: a duplicate assembly is subjected to half the fire rated exposure of the original tested part and then subjected to the calibrated stream of a fire hose • This simulates the behavior of an assembly subjected to a fire hose during an actual fire.
Fire Resistance Ratings, (continued) • Penetrations • Openings in rated ceiling, floor and wall construction are restricted in size and must be protected against the passage of fire • Fire rated doors and frames • Fire dampers • Fire stops
Underwriters Laboratory • 1-hour rating UL U305 Drywall System • 2-hour rating UL U301 Drywall System • http://www.usg.com/resources/handbooks/ViewSection.do?bookId=1&chapterNum=10§ionNum=3
Penetrations • Partition tight to deck and wall penetrations
Penetrations • 2-hour rated wall assembly
Penetrations • Partition wall assembly
Penetrations • Structurally reinforced penetration through wall assembly
Cost • First Cost: • Installed cost of the finish • Of paramount importance when the budget is tight or the expected ownership of the lifespan of a building is short • Life-cycle cost • Cost that includes the first cost, but also includes the expected lifetime of the finish, maintenance, fuel costs, monetary inflation and the replacement cost of the finish. • Of paramount importance when the building owner expects to maintain ownership over an extended period of time.
Interior Walls and Partitions • Interior Walls • Fire Walls • Shaft Walls • Fire Barriers • Smoke Partitions • Some additional rated assemblies • Exit access: corridors and egress stairs • Dwelling unit separations
Interior Walls and Partitions • Partition Walls • Non-bearing partition walls
Plaster • Term typically applies to “gypsum” plaster, but may also be applied to other systems, including stucco. • Gypsum is quarried, crushed, dried and then ground into a fine powder; then heated to 350° F. in a process called “calcining” • Product is rehydrated and is able to re-crystallize quickly.
Calcination • When a gypsum building component is subjected to fire, a thin surface layer is calcined and disintegrates • In the process, this layer absorbs heat and gives off steam, both of which have a cooling effect on the fire. • Slow process: thin layer by layer
Plaster and Plaster Systems • Plaster • Plaster • Gypsum plaster • Gauging plaster • Keenes cement • Molding plaster • Lime and Portland Cement Plasters • Finish lime • Portland cement lime - stucco
Plaster Systems • 2-coat: requires a rigid lath substrate • Brown coat • Finish coat • 3-coat: preferred • Scratch coat • Brown coat • Finish coat
Veneer Plaster • Veneer plaster board, (“blue board”) • Plaster is applied to a specially prepared gypsum board in two successive layers • The first thin “veneer” coat is followed immediately by a “skim” coat that is then troweled to the desired finish texture
Plaster Systems • 2-coat • 3-coat • veneer
Gypsum Board • Types • Gypsum board • Water-resistant gypsum board • Type-X: reinforced with glass fibers, when exposed to a severe fire, the fibers hold the calcined gypsum in place to continue to act as a barrier to fire. • Foil-backed: includes an integral vapor retarder in exterior wall assemblies
Gypsum Board, (continued) • Types, (continued) • Type-C: a proprietary version of Type-X, typically a thinner application of Type-C may be used instead of Type-X to achieve the same protection. • Coreboard: 1” thick panel used in shaft applications, (24” panels rather than 48”) • High Impact: 5/8” Type-X panel with polycarbonate film bonded to the back.
Gypsum Board, (continued) • Typical thicknesses: • ¼”: used for backing applications and in multiple layers to achieve tight radius curves • 5/16”: modular construction to reduce shipping weight • ½”: the most common, used where joist or stud spacing is 24” or less on center • 5/8”: also limited to joist or stud spacing is 24” or less on center, often used for additional stiffness or fire rating • ¾”: Type-X can achieve a 2-hour rating with ¾” on one side of the partition, only.
Gypsum Board Partition Systems • 1-hour partition • 1-hour partition with an STC of 60-64 • 2-hour partition • 4-hour partition • (page 832)
Specifying Gypsum Board • Gypsum board wall finishes have standardized levels of finish that are included in the drawing specifications: • Level 0: attached boards only, no tape • Level 1: joints covered in tape set in joint compound • Level 2: a finish coat of compound over the tape and accessories, (garages, warehouses) • Level 3: a second coat of compound, (prior to textured coating) • Level 4: a third coat, (flat paints, light wallcoverings) • Level 5: skim coat
Finish Ceilings • “Tightly Attached” Ceilings • Suspended Ceilings