Determining Wall Types

Here are my suggestions about determining wall types:

Type  1 or A  – 4 7/8″ (Unrated) 1 Layer 5/8 GWB each side of 3 5/8″ metal stud

• Use this as a wall between room – for example between two offices or classrooms.
• Same assemly as 1-HR rated wall – use 16″ OC studs not 24″ OC
• https://www.usg.com/content/usgcom/en/design-studio/wall-assemblies/assembly-detail.30128.html

Type  2 or B  – 4 7/8″ (1-HR) 1 Layer 5/8 GWB each side of 3 5/8″ metal stud

• Same construction as the first wall type but with a 1 HR rating.  Use this as the primary corridor wall or a wall enclose a group of spaces.
• Same assemly as unrated rated wall – use 16″ OC studs not 24″ OC
• https://www.usg.com/content/usgcom/en/design-studio/wall-assemblies/assembly-detail.30128.html

Type  3 or D  – 6 1/8″ (2-HR) 2 Layers 5/8 GWB each side of 3 5/8″ metal stud

• This can be used to enclose fire rated stairs – except in taller buildings in NYC which must also be impact resistant.  For this use an 8″ Concrete Block.
• Use 16″ OC studs not 24″ OC
• https://www.usg.com/content/usgcom/en/design-studio/wall-assemblies/assembly-detail.30152.html

Type  4 or E  – 9 1/2″ Min – Size Varies as needed” (1-HR) Chase Wall  – 1 Layers 5/8 GWB oneside of 3 5/8″ metal stud (4 1/4″) – (then a 1″ air space minimum for the chase) – and then a second 3 5/8″ metal stud with 5/8″ GWB (4 1/4″) – Total 8 1/2 + 1″ space min = 9 1/2″ minimum

• This is used to run plumbing for water supply and drains.  Toilet drains are 3″ to 4″ diameter depending on the number of toilets it supports.  For a typical sink drain the pipe the pipe is 1 1/2″.  Walls of this kind are often covered by tile – which is considered a finish and not part of the wall type.  It is also common to use “Greenboard” or mold resistant GWB in wet conditions of this kind.  In addition to the thickness of the drain pipe – clamps are required to hold the pipes in place and may require additional room.
• Some architects will run these pipes within the depth of the 3 5/8″ stud and others prefer to leave a space between the metal studs for the drains. Minimum space between the studs is typically 1″.  This creates a wall of 9 1/2″ and requires that the drain pipes be run partially within the thickness of the metal studs requiring the metal tracks to be cut.  A better practice is to leave more than a 1″ space so the pipes can run independently.  For example leaving a 3 1/2″ space will make the wall 12″ (8 1/2″ for studs and GWB + 3 1/2″ = 12″).  Remember that pipes need room to turn and bend and they also need to be secured in place by clamps.
• I typically use 1′ to 1′-2″ face to face of GWB.  The holes in slabs made for the pipes require firesafing.
• As the size varies as needed – In Revit I often make this using two different walls (each 1 layer 5/8″ on 3 5/8″ metal stud) and place this twice and adjust the distance between them – (I will demonstrate)
• Use 16″ OC studs not 24″ OC
• https://www.usg.com/content/usgcom/en/design-studio/wall-assemblies/assembly-detail.30109.html

Type  5 or F – 3 3/4″ (2-HR) GWB Shaft Wall  – 1 Layer 1″ GWB Liner Panel – 2 1/2″ CH Studs – 2 Layers 5/8″ Firecode Type X GWB – 1 1/2″ fireberglass insulation

• Use this for walls around elevator shafts & mechanical shafts.  Can also be used around fire stairs (if they are not required to be impact resistant).
• This wall type uses the special CH metal stud that allows the wall to be installed from the outside.
• Use 16″ OC studs not 24″ OC
• https://www.usg.com/content/usgcom/en/design-studio/wall-assemblies/assembly-detail.30186.html

Type  6A or G1 -4 1/4″ Furring – (Unrated) 1 Layer 5/8″ GWB on 3 5/8″ Metal Stud Frame

• Use this for unrated enclosures around columns or the inner wall of the facade.

Type  6B or G2 -4 7/8″ Furring – (Unrated) 2 Layer 5/8″ GWB on 3 5/8″ Metal Stud Frame

• Use this for unrated enclosures around columns or the inner wall of the facade – when you need more durability.
• The construction can be used to achieve a 1 HR fire rating – but steel columns are better protected by spray on fireproofing

Type  7A or H1 -1 1/2″ Furring – (Unrated) 1 Layer 5/8″ GWB on 7/8″ Metal Furring or Hat Channel

• Typically used when a GWB finish is being added to a solid concrete or concrete block wall.
• The channels are typically run horizontal and the extra room allows for the running of electrical
• https://www.clarkdietrich.com/products/furring-channel-hat-channel

Type  7B or H2 -2 1/8″ Furring – (Unrated) 2 Layers 5/8″ GWB on 7/8″ Metal Furring or Hat Channel

• Same as above but more durable with an extra layer of GWB.
• https://www.clarkdietrich.com/products/furring-channel-hat-channel

Type  8 or J -7 5/8″ actual (8″ Nominal) (2-HR) Rated – Concrete block wall.

• Can be used to replace a shaft wall – and will be more impact resistant.
• https://ncma.org/resource/fire-resistance-ratings-of-concrete-masonry-assemblies/
• A solid concrete – poured in place wall an also be used (but is not a wall type but a detail)