1. Chapter 23 Interior Walls & Partitions

2. Interior Partitions Performance Criteria  Strength  Fire Resistance  Durability  Acoustical Isolation Materials  Metal or wood studs faced with plaster or gypsum board  Concrete block (CMU) or structural clay tiles

3. Types of Interior Partitions Fire Walls Shaft Walls Fire-Rated Walls Smoke Barriers “Other” Non-bearing and/or non-rated

4. Elements common to Fire Walls, Shaft Walls, Rated Walls & Smoke Walls Wall Assembly is tested (often by UL)  Materials (type, size, composition, etc.)  Installation (method, application, anchorage, etc)  Actual construction must comply Extend from rated assembly to rated assembly Wall Penetrations are Restricted  Opening size, material used, installation, operation  Opening assembly also rated  EX: fire dampers, pipe selves, door closures, etc.

5. Fire Walls Restricts the Spread of Fire (area to area) Extends from Foundation through Roof  Must abut a non-combustible roof, or  Extend above the roof (generally 32”) Divide the Building into “smaller units”  Each unit considered a separate blg for code  EX: Wood framed apartment complex

6. Fire wall

7. Shaft Walls Enclose multi-story openings  Elevators, stairways, mechanical chases Composition - masonry, plaster or drywall Typically:  Higher fire rating (2hr+)  Restricting floor-to-floor fire migration  Primary means of egress (exit for blg.) Gypsum Shaft wall Advantages  Lighter, installed dry  Can be erected from floor outside the shaft 1” Gypsum shaftwall panel C-H Stud Typically 1/2” or 5/8”

8. Shaftwall Construction In an Elevator Shaft

9. Gypsum Shaftwall Construction in a stairwell Stairway

10. Fire-Rated Walls Restrict the spread of fire in an area (typ. 1-2 hr) May not extend from foundation to roof, but must Be floor to floor (or floor to fire-rated assembly) Fire-rated Walls Separate:  Mixed occupancies/use or tenant spaces  Dwelling units  Guest rooms in hotels, dormitories, hospitals, etc.  Enclose stairways & exit corridors Composition; typically metal framing with multiple layers of drywall

11. Fire Rated Assemblies Often tested by UL Construction must “match” UL assembly (excerpt from UL book)

12. (excerpt from UL book)

13. Smoke Barriers Protect occupants from smoke (the #1 killer)  Continuous, air -tight assembly  Openings - self-closing doors (rated) Typically - Fire Walls also qualify as smoke barriers

14. “Smoke” caulking @ MPE penetrations

15. Partition Framing Wood or Metal framing Wood  Use limited by the building codes  Fire treated wood - expensive Metal Framing  Typically cold-formed metal studs  Most UL assemblies use metal studs  Commercial work - almost exclusively

16. Plaster Generic term - Cementitious substances ( w/ or w/o gypsum) Plaster Systems  Over Expanded Metal Lath (3-coat)  Scratch coat - cover lath  Brown coat - add thickness, smooth base  Finish Coat  Applied to CMU (lath or bonding agent)  Veneer Plaster - thin coat over a gypsum board base  Stucco - similar, but accessories must resist the elements

17. Plaster Wet System Relatively expensive system Typical uses  Spaces with High Moisture  Surfaces where Impact Resistance is req’d

18. Gypsum Board Gypsum:  Major component of many building interiors  Advantages  In comparison w/ alternatives -durable and light  Resists passage of sound  Inexpensive  Highly fire resistant  Disadvantage - soluble in water Gypsum Board  Form of most gypsum used

19. Gypsum Board Names: Gypsum wallboard, plasterboard, drywall Sizes:  4’ x 8’ to 14’  1/4” to 1” thick Types  Regular  Water Resistant  Type X (rated assemblies)  Foil-backed (acts as VB)  Coreboard (1’ thick)  Others

20. Gypsum Board Edges: Tapered Edges (most common) Allows joints to be “finished” (concealed)

21. Gypsum Board Installation Install partition framing MPE partition rough-in Hang gypsum drywall (screws, ring-shank nails) Finish gypsum drywall joints, edges, & corners  corner beads, metal trim, and accessories  Tape (& bed)- 1st coat & tape  2nd coat  Finish - 3rd/final coat (may require sanding 1st)  Sand

22. Corner Beads “ Crimped” Screwed Nailed Crimped Nailed

23. Tape & Bed Coat

24. Second Coat

25. Application

26. Sanding

27. Joint Compound ‘Stilts’ Joint ‘Tape’

28. Gypsum Products & Sustainability Gypsum: not renewable, but plentiful Gypsum mined – habitat & overburden issues Synthetic gypsum – from recycled materials Embodied energy is low Gypsum paper face mostly recycled material Approx. 10% is waste – large % to a landfill Gypsum dust; nuisance & discomfort Gypsum products have extremely low emissions