General Notes

1. What is UL Solutions?

a.) UL Solutions provided by Underwriters Laboratories (UL) offer a range of services for safety, sustainability, and compliance in building design, construction, and operation. UL Solutions cover testing for fire safety, energy efficiency, building materials, code compliance, sustainability, and more.

2. Is there a specific UL reference manual at Forum?

a.) To lookup a specific UL number found on an assembly detail, we use the UL Product IQ  tool. Type the UL number in the search bar and select the document name that begins with BXUV followed by the UL number (Ex- BXUV.L546). Sometimes, the document name might not start with BXUV. It is important that no matter what the initial abbreviation is, it must be followed by the UL number. Ensure the associated images and systems in the document match the Forum assembly detail. 

3. What is Sound_STC_IIC?

a.) STC (Sound Transmission Class) is a rating that tells us how effectively a building partition reduces airborne sound. It assesses how well a structure can stop sound from traveling between rooms or areas. Usually, we talk about STC when considering walls, doors, and windows, but it can also apply to floors and ceilings.

b.) IIC (Impact Insulation Class) evaluates how effectively a floor-ceiling structure minimizes the transmission of impact noise, like footsteps, between different levels. It measures how well a flooring system absorbs impact sounds, which is crucial in buildings with multiple stories or areas where foot traffic noise can be disruptive. IIC is particularly relevant to floor and ceiling constructions.

c.) It is essential to use the appropriate metric depending on the type of noise transmission being addressed—STC for airborne sound transmission through walls and similar partitions, and IIC for impact noise transmission through floor-ceiling assemblies.

4. Where do I find references to Sound_STC_IIC?

a.) STC is referenced in the FBC under 1207.2 Airborne sound. STC ratings are documented under the ASTM E90 and must adhere to its guidelines.

b.) IIC is referenced in the FBC under 1207.3 Structure-borne sound. IIC ratings are documented under the ASTM E492 and must adhere to its guidelines.

c.)  The FHA does not reference STC and IIC specifically, but it does utilize the International Residential Code (IRC) which references Appendix AK Sound Transmission

d.)  HUD references STC and IIC in the Sound Transmission Class Guide

5. What is flooring per interior finish schedule notes?

a.) There are multiple flooring options that could be chosen for each assembly when the 'flooring per interior finish schedule/notes' comment is present in the assembly. The Assembly Tool will generate the most common types used at Forum. Per Andrew, our most common floor finishes are:

5. • .079" (2mm) thick LVT plank flooring (7"x48") glued-down to 3/4" Gyp-Crete 2000 by Maxxon poured over AcoustiMat 1/8" thick entangled plastic mat acoustic underlayment

   • The most typical "upgrade" would be same flooring over 1" gypcrete over 1/4" underlayment, only happens about 5% of the time (1-2 projects per year)

6. Which side should unfaced batt insulation be secured to in assemblies similar to FW-1?

a.) Per Andrew, tested assemblies, such as those certified by UL, typically allow for flexibility in the placement of cavity insulation. While attaching the insulation to the underside of the floor deck above is considered the superior method due to its effectiveness, it also requires more labor compared to simply draping it over resilient channels. However, by specifying both options, we request that the contractor provides pricing for each method, allowing our clients the choice that best suits their preferences and budget. In practice, clients often opt for the more cost-effective approach. Unfortunately, contractors sometimes disregard our specifications and issue documents to the client, known as "Contractor Qualifications," outlining what is included and excluded in their construction quote regardless of what our drawings say. The "quals" will often include a note that says something similar to "All ceiling insulation shall be draped over resilient channels".

7. How to handle suspended ceilings within assemblies?

a.) Regarding FW-20 and FW-21 (suspended ceiling), 

• Default method: model both the top and bottom chord of the truss and the ceiling. Then, manually adjust the ceiling air gap to accommodate varying suspended ceiling heights. An (IS0ADJ) layer along with -ADJUSTABLE will be added to the assembly name, signaling the user to manually adjust the interstitial space (air gap).

• Alternative Method: model the top chord of the truss and the ceiling, while omitting the bottom chord and simulating its presence.

8.) What is considered exterior and interior?

a.) Exterior is non-conditioned space. Interior can be either conditioned or non-conditioned.

• If a space is enclosed and not open to the exterior (without opening a window or a door), then it's interior. If the space is open to the outdoors when all windows and doors are closed, it is exterior.

• In the case of a garage below a unit, both are considered interior, while the garage is non-conditioned and the unit is conditioned.

•  Breezeway is a term for a corridor that is unconditioned and open to the exterior on the ends. Breezeways are considered exterior.

• Per Kory, FW-9 is considered exterior because that specific wood floor assembly is primarily used on exposed stairways. An interior stair would most likely use a metal assembly.

9.) What size are the resilient channels and pedestrian traffic coating?

a.) If the thickness of a horizontal assembly material varies depending on manufacturer specifications or engineering requirements, we use default values provided by AR for our design basis.

• Resilient channels: 1/2"

• Pedestrian traffic coating: 0" (membrane)

10.) Why do low slope roofs have an adjustable wood truss layer?

a.) Due to low slope roofs being modeled as a singular element, the truss must have its own structural layer. The truss depth is not specified in the assembly, which requires it to be adjustable.

11.) What orientations are the assemblies drawn in?

a.) Wall assemblies are drawn in plan view

b.) Floor and roof assemblies are drawn in section

12.) Per Andrew, the wood frame tenant separation walls are always load bearing