August 2017

Design A Better Shaftwall System

Scott Hughes and Thad Goodman

With the continued popularity of high-rise corporate headquarters, institutional buildings and high-density housing, the gypsum shaftwall system, known as the Cavity Shaftwall System, provides economic benefits – and also peace of mind due to its fire-resistant qualities. Originally designed for the 110-story World Trade Center in 1973, the Cavity Shaftwall System replaced heavier, more expensive masonry walls. This shaftwall system utilizes gypsum board framed with metal studs and tracks to enclose elevator shafts, stairwells and service shafts. These shaftwalls withstand the positive and negative air pressure forces exerted by high-speed elevators. Cavity Shaftwall Systems are also ideal for fire-rated, interior partitions where access is restricted to one side and as fire-rated, horizontal membranes.

Advantages Of The Cavity Shaftwall System

Cavity Shaftwall Systems provide many benefits. They easy to install, weather-, sound- and fire-resistant, lighter and more economical than masonry shaft construction. Four to five times lighter than traditional masonry enclosures, lighter gypsum shaftwalls weigh approximately 10 pounds per square foot of wall compared to 40 or 50 pounds per square foot for a masonry wall. Buildings utilizing this shaftwall system require less structural steel and extensive underground support pilings. In addition, the core of the gypsum panels in the Cavity Shaftwall System contains about 21 percent water by weight, creating a fire barrier with 1- to 4-hour fire-ratings from either side. When gypsum board is exposed to fire, the water turns to steam and slows the passage of heat through the assembly, keeping the building safe for a longer period of time.

Installations

Typical installations use 1-inch thick gypsum shaftliner panels inside a minimum 2-1/2-inch metal framing system with an integral space to hold the panels in place on the shaft side. Metal J-tracks are placed horizontally at the top and bottom and vertically at partition ends. They also frame openings. Depending on the fire-rating you are trying to achieve, install one to five layers of 5/8-inch fire-rated gypsum board to the outside of the stud, creating a corridor side of the enclosure.

To construct these lighter weight fire barriers for cavity shaftwalls (1-4 hr.), we recommend Gold Bond® BRAND eXP® Shaftliner. It is an approved component in specific UL fire-rated designs, including G586 (horizontal, 2-hr.) and W419 (vertical, 1-4-hr.).

Questions About The IBC 2009 Code Updates For Buildings?

If you are designing a building of occupancy category III or IV with occupied floors over 75 feet tall and all buildings over 420 feet tall, IBC Section 403.2.3 requires increased impact resistance for exit stairways and elevator hoistway enclosures.

If you have questions, contact your construction design manager for clarification and for assistance with the best and most affordable options for your project.


NGC Construction Guide: Updates!

Important Additions To Our "Fire And Sound Selector"

We have added more designs to the Fire And Sound Selector, including: a 1-hour ceiling membrane (UL Design I504), a 3-hour area separation wall (UL Design W454) and a 1-hour rated floor-ceiling assembly using 3/4" Gold Bond ® BRAND SoundBreak® XP Ceiling Board (UL Design M514).

More New Sections

  • A new section identifying the UL-Core designation of all NGC gypsum board products.
  • A new section identifying National Gypsum products that have achieved GREENGUARD and GREENGUARD Gold Certification.
  • A new section on 3-hour area separation wall assemblies, including installation instructions and details.

To explore the entire updated 14th Edition NGC Construction Guide visit the NGC Design Center.

"There are three choices for shaftwall gypsum liner panels on the market today. Good is the traditional moisture-resistant paper-faced panels. Better is the moisture- and mold-resistant paper-faced panels. Best is the moisture- and mold-resistant shaftliner panel with fiberglass-mat facers like Gold Bond® BRAND eXP® Shaftliner. When the weather outside is frightful, gain peace of mind by specifying a product with a guarantee that the panels can withstand temporary weather exposure during construction for up to 12 months."
- Scott Hughes

"An additional advantage of closing in a full-size freight elevator early in the job process is it can aid in movement of materials and manpower to upper floors, avoiding options of a smaller exterior lift or buck hoist."
- Thad Goodman


Product Overview

Specify This For Cavity Shaftwalls

For peace of mind, specify Gold Bond® BRAND eXP® Shaftliner for lightweight fire barriers for cavity shaftwalls (1-4 hr.) and area separation fire walls (2 hr.). Moisture- and mold-resistant, it is an approved component in specific UL fire-rated designs. Also a pre-rock installation best product, eXP® Shaftliner:

  • Resists the growth of mold per ASTM D3273 with a score of 10 (best possible).
  • Provides superior moisture resistance, without impeding vapor transmission.
  • Is dimensionally stable under changes in temperature and relative humidity and resists warping, rippling, buckling and sagging.

Another good option for 2-hour shaftwall assemblies and 2- and 3-hour wall partitions is Gold Bond® BRAND ¾” Ultra-Shield FS®. This board offers increased resistance to fire and reduces sound transmission. ¾” Ultra-Shield FS®:

  • Reduces labor and material costs by using fewer layers (up to 10 percent).
  • Is UL Classified for fire resistance, surface-burning characteristics and non-combustibility.
  • Is dimensionally stable under changes in temperature and relative humidity and resists warping, rippling, buckling and sagging.

For more information, talk with your construction design manager.


Project Profile

Energy Efficient Corporate Headquarters

Project:
Owner:
Architect:
LEED:
Duke Energy Center, Charlotte, North Carolina
Wells Fargo
tvsdesign
Platinum

Completed in 2010, Duke Energy Center is the second-tallest building in Charlotte, North Carolina. This building’s design incorporates “Workplace of the Future” principles to provide employees with some of the most modern, efficient and sustainable working conditions in the country. These principles include open, collaborative work areas, less energy and water usage, and broad use of natural light. Sustainable features include water-saving plumbing devices, a special water storage system and a green roof. National Gypsum’s Mt. Holly plant supplied gypsum board for this project.

Read More About The Project

Continuing Education

Beat August’s sweltering temperatures by staying inside and fulfilling CEUs. Consider taking:

High Performance Gypsum: Protect Against Mold, Moisture and Exposure
1 hour/AIA HSW CE Hour
Advantages of Using Coverboards in Low-Slope Roofing Assemblies
1 hour/AIA HSW CE Hour

Videos

The Power Of eXP®

See why Gold Bond® BRAND eXP® is the number-one solution for building exteriors!

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Warren Barber
Technical Marketing Manager

Amy Hockett
Architectural Specialist

Scott Hughes
Northeast/Atlantic, Southeast/Gulf

Thad Goodman
Central/Midwest

Pat Grotlisch
West

Frank Fuller
Southwest