ID#10095 made on
EQc9 - Enhanced acoustical performance
LEED BD+C: Schools
The STC 50 rating between core learning spaces required by ANSI S12.60-2002 challenges a wall assembly that has been the standard for public school construction in Ohio for decades. The construction o...
The STC 50 rating between core learning spaces required by ANSI S12.60-2002 challenges a wall assembly that has been the standard for public school construction in Ohio for decades. The construction of Otsego PK-5 is no exception as an 87,000 square foot combination masonry bearing and steel frame construction requiring durability, student security, ease of maintenance, and structural integrity on a predetermined budget developed and co-funded by the Ohio School Facilities Commission.
The design team has enlisted the services of a professional acoustician and reviewed the options for STC 50 wall construction. We have been advised against sand and grout filling CMU walls due to the difficulty it creates for future renovation, the unnecessary weight it adds to the building, and the uncertainty of knowing whether or not the fill was done properly. We feel that heavy weight block (48 lbs. or more) is not a practical building material due to the weight it adds to the building as well as increased construction time and labor. Additionally, enlarging the wall thickness between classrooms is not feasible due to the predetermined square footage requirements of the building set by the Ohio School Facilities Commission. The School District and design team strongly feel that metal stud and gypsum wall board construction, either as furring or stand alone construction will not provide the longevity required of classroom walls in a public school system and will quickly become a maintenance issue.
ANSI S12.60-2010 has acknowledged this design/construction dilemma by including a footnote in Table 4 (the equivalent of ANSI S12.60-2002 Table 2) associated with the STC 50 requirements for #Other enclosed or open-plan core learning space#etc.# which states, #A 20 cm (8#) concrete masonry unit wall having a surface weight area density of at least 180 kg/m2 painted and sealed on both sides, acoustically sealed at the entire perimeter and extending from the floor slab to the structural deck above, is an acceptable alternate assembly that conforms to the intent of 18.104.22.168#. 22.214.171.124 being Table 4 # Minimum STC ratings required for single or composite wall and floor-ceiling assemblies that separate a core learning space from an adjacent space.
Please note that ANSI S12.60-2010 Table 4 has also included an exception to the STC 53 requirement for core learning spaces adjacent to toilet rooms that states,# These requirements do not apply to toilets opening only into the core learning space and used only by occupants of the core learning space#, a condition that was found acceptable by a Credit Interpretation Ruling dated 4/21/2009 under LEED for Schools 2007 IEQ Prerequisite 3, Minimum Acoustical Performance.
Otsego Local School District and the design team respectfully request that the above referenced normal weight 8# CMU wall construction now accepted by ANSI S12.60-2010 be considered suitable for compliance with the STC 50 rating requirement between core learning spaces associated with LEED for Schools 2009 IEQ Credit 9 Enhanced Acoustical Performance.
The project team is asking whether a wall construction (20 cm (8 in) concrete masonry unit wall having a surface weight area density of at least 180 kg/m2 painted and sealed on both sides, acoustically sealed at the entire perimeter and extending from the floor slab to the structural deck above) now accepted by ANSI S12.60-2010, is suitable for compliance with the STC 50 requirement for this credit.
Yes, the use of the 2010 version of ANSI S12.60 is acceptable for this credit.
Related Addenda (Corrections & Interpretations)