Thickness: As required by fire-resistance-rated assembly indicated on Drawings.
Type C is a gypsum board enhanced with glass fibers and other ingredients for premium fire protection. The board has a naturally non-combustible gypsum core and paper facings. Because of its strengthened, fire-resistant core, Type C can remain intact for a prolonged period during a fire, preventing further spread of flames and smoke.
Type C is suitable for interior applications only, and should not be used in areas of extreme humidity. Likewise, the board should be protected from exposure to adverse conditions during storage and construction.
Type C meets all the requirements of Type X
Type X does not meet all of the requirements of Type C.
C. Flexible Type :
Manufactured to bend to fit radii and to be more flexible than standard regular-type gypsum board of same thickness, Type X, 1/4 inch thick.
D. Ceiling Type :
Manufactured to have more sag resistance than regular-type gypsum board, Type X, 5/8 inch thick. (Provide moisture-resistant type at wet areas.)
Manufactured with fiberglass mat in lieu of paper to produce greater resistance to damage such as scuffs, scratches, dents, and abrasion, Type X gypsum board.
G. High-Impact Type :
Same as Abuse-Resistant Type except with a core embedded layer of impact resistant mesh for greater resistance to through-penetration (impact resistance), Type X gypsum board.
H. Specialty Multi-attribute Board :
Fireproof, Waterproof, High Impact, and Non-nutrient to mold.
Manufactured from magnesium oxide mineral components.
Dragonboard or approved equal.
I. Moisture & Mold Resistant Gypsum Wallboard
Type X, 5/8 inch thick, for use at Interior Face of Exterior Walls or wherever moisture resistant Gypsum Wallboard is noted.
Georgia Pacific, DensArmor Plus:
A. The inside surface of exterior walls presents growth opportunities for mold, due to lack of air circulation and temperature differential from outside to inside of the wall. Mold-resistant gypsum board such as DensArmor Plus has been tested in accordance with ASTM 3273, and scored a 10, the highest level of performance for mold resistance. The test indicates no mold growth in a 4-week controlled laboratory test. The product incorporates a moisture resistant core and glass mats on the surfaces of the drywall panel instead of paper facings, which denies mold the food source it needs to grow. The product comes with a three-month in-place exposure warranty which means that it can be hung before installing doors and windows.
B. DensArmor Plus(R) moisture- and mold-resistant paperless interior drywall are the first and only gypsum drywall products to be GREENGUARD Indoor Air Quality Certified(R). This certification, recognizes indoor products that have low emissions of volatile organic compounds (VOCs). To be GREENGUARD Certified means that these products will be regularly tested to ensure that chemical and particle emissions meet the GREENGUARD Environmental Institute's emission standards.
Control joints are required in gypsum board partitions and ceilings to prevent cracking caused by stresses induced by movement caused by:
Changes in humidity
Changes in temperature.
Isolation joints are required between flexing structural members and non-structural gypsum board assemblies.
Control joints should be employed in long expanses of partitions at 30-foot intervals, from floor to ceiling. Control joints are recommended at doorjambs, extending from door head to ceiling.
Control joints are required in interior gypsum board ceilings to limit dimensions in either direction to 50 feet, and where ceiling framing changes direction.
Control joints are required in exterior gypsum board soffits to limit dimensions in either direction to 30 feet, and where ceiling framing changes direction.
Include breaking the gypsum board behind the control joint.
Separate framing members should be used on each side of the control joint.
Install a control joint where ever dissimilar construction meets.
Install a control joint to separate the wings of “L”, and “T” shaped ceiling areas.
Reference Standards: Control joints are specified by two reference standards
ASTM C 840, The Standard Specification for Application and Finishing of Gypsum Board
GA-216, the Gypsum Association Recommended Specification for Application and Finishing of Gypsum Board.
Inspite of these specified reference standards, it is not unusual for the contractor to miss them and control joints having to be cut-in after the fact. To avoid this, control joints are a good topic of discussion at a contactor meeting during the rough-in stage so that Architect’s expectations are reiterated prior to installation.
Finish panels to levels indicated below, according to ASTM C 840, for locations indicated:
Level 1 : Embed tape at joints in ceiling plenum areas, concealed areas, and where indicated, unless a higher level of finish is required for fire-resistance-rated assemblies and sound-rated assemblies.
Level 2 : Embed tape and apply separate first coat of joint compound to tape, fasteners, and trim flanges where panels are substrate for tile and where indicated.
Level 4 : Embed tape and apply separate first, fill, and finish coats of joint compound to tape, fasteners, and trim flanges at panel surfaces that will be exposed to view, unless otherwise indicated.
Level 5 : Embed tape and apply separate first, fill, and finish coats of joint compound to tape, fasteners, and trim flanges, and apply skim coat of joint compound over entire surface at the following locations (except where surfaces are to be finished with wall covering):
a. Exposed ceiling, soffit, or wall areas abutting window mullions, skylights, or receiving direct indoor lighting.
b. Wall-board scheduled to be finished with semi-gloss, gloss, epoxy paint, or high build glazed coating.
c. Fiberglass coated glass mat, both faces.
d. Long hallways or corridors.
e. Atriums, Lobbies, Auditoriums and similar large spaces.
Big distinction between Smoke-Tight partitions vs. Smoke Barrier walls:
Smoke-Tight partitions :
Corridor partitions = fully sprinkled building
Corridor walls in a healthcare occupancy that is not fully sprinkled need to be 1-hour rated.
Smoke Barrier partitions :
Used as a separation between smoke zones
Smoke barrier partitions are required to be 1-hour rated..
Healthcare occupancies have a “defend in place philosophy”.
The idea is that when a patient is undergoing a medical procedure and the fire alarm goes off, immediately stopping the procedure and taking the patient out the building is not always in the patient’s best interest.
A better alternative may be to transport the patient to a safe smoke zone with facilities to complete the medical procedure, before taking the patient out of the building.