Flatz520, Arizona

Location:  Maricopa, Arizona
Owner/Operator: Z Modular

Z Modular is a fully integrated self-development company using innovative modular building and construction processes. Z Modular controls the entire project life cycle, from site development to leasing, ensuring predictable outcomes. The pre-fabricated modules that make up Z Modular properties are up to 90% completed in off-site manufacturing facilities before being transported to the property location for final assembly and finishing. Z Modular operates 4,000+ apartment units and currently has multiple projects underway to provide high-quality housing in growth markets.

One project that Z Modular developed is FLATZ520, a 380 unit, luxury apartment community offering studio, 1, or 2-bedroom suites in Maricopa, Arizona, along with a wealth of onsite amenities including a resort style pool, pet park, fitness center and private entertainment space equipped kitchenette.

HGC visited the development located at 45760 W Village Parkway in Maricopa, Arizona to perform both airborne and impact sound transmission testing between modules. The testing was conducted in order to evaluate the acoustical performance of the typical suite-demising wall and floor/ceiling systems, with respect to International Building Code (IBC) requirements, and for internal information regarding the airborne and impact sound transmission performance of Z Modular’s typical proprietary assemblies. Each of the tested assemblies were found to exceed the minimum IBC requirements.

Airborne Sound Transmission: Apparent Sound Transmission Class (ASTC) / Normalized Noise Isolation Class (NNIC)

Sound Transmission Class (STC) is an integer rating commonly used to evaluate a building partition’s ability to resist airborne sound transfer (e.g., talking, televisions, etc.) at the 1/3 octave band frequencies from 125 to 4000 Hz. STC ratings relate to the laboratory tested demising assembly, while ASTC ratings correspond to the same assembly tested under field conditions. Similarly, NNIC ratings correspond to the measured noise reduction between two spaces, normalized to standard room conditions typical of residential or office spaces.

A field test to determine the rating of a partition is performed in general accordance with ASTM standard E-336,“Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings.” This test is performed by placing a sound source on one side of the tested assembly, measuring sound levels at several locations in the source room, and at several locations in the receiver room on the other side of the assembly. Measurements are also taken to determine the ambient sound in the receiver room, and reverberation time measurements along with the room and partition geometries are used to determine the acoustical absorption of the receiver room.

Section 1206.2 of the International Building Code (IBC) requires that all walls, partitions, and floor/ceiling assemblies separating dwelling and sleeping units from each other, or from public or service areas, shall have an acoustic performance rating of not less than NNIC-45, if field tested in accordance with ASTM E336.

Impact Sound Transmission: Apparent Impact Insulation Class (AIIC) / Normalized Impact Sound Rating (NISR)

 Impact Insulation Class (IIC) is an integer rating commonly used to evaluate a building partition’s ability to resist structure-borne impact sound transfer (i.e., walking, shuffling) at one-third octave band frequencies between 100 to 3150 Hz. IIC ratings relate to the laboratory tested demising building assembly, while AIIC ratings correspond to the same assembly tested under field conditions. Similarly, NISR ratings correspond to the measured isolation from impact sound transfer, normalized to standard room conditions typical of residential or office spaces.

Standardized field impact insulation testing is conducted pursuant to the methodologies described by ASTM E-1007, “Standard Test Method for Field Measurement of Tapping Machine Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support Structures”. For this test, a standard tapping machine is placed in the source room, in four different orientations per the standard. The resulting sound pressure levels are measured at several locations in the receiver room for each orientation using a sound level analyzer in the room directly below and averaged.

Section 1206.3 of the International Building Code (IBC) requires that all floor/ceiling assemblies between dwelling and sleeping units, or between a dwelling or sleeping unit and a public or service area within the structure, shall have an acoustic performance rating of not less than NISR-45, if field tested in accordance with ASTM E-1007 for impact noise.

Each of the tested assemblies were found to exceed the minimum IBC requirements

Acoustical consulting services delivered included:

• Field testing to determine the rating of a partition is performed in general accordance with ASTM standard E-336,“Standard Test Method for Measurement of Airborne Sound.
• Standardized field impact insulation testing conducted pursuant to the methodologies described by ASTM E-1007, “Standard Test Method for Field Measurement of Tapping Machine Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support Structures”.
• Evaluation of the acoustical performance of typical suite-demising systems, with respect to International Building Code (IBC) requirements Attenuation between Rooms in Buildings.”
• Apparent Sound Transmission Class (ASTC) Testing
• Normalized Noise Isolation Class (NNIC) Testing
• Apparent Impact Insulation Class (AIIC) Testing
• Normalized Impact Sound Rating (NISR) Testing