Very few things in anyone’s life are more irritating than excessive noise resulting in a person’s inability to hear. This is particularly so in a school where the need to hear clearly, with a minimum of interference and distraction is mandatory for learning. Excessive noise results in a student’s inability to concentrate, creates an uncomfortable learning environment, inhibits focus and encourages stress. Teacher-student communication is interfered with the student typically “tuning out”. Teachers and often students find the need to “speak louder”
In a typical classroom, four types of sounds (or “noise”) are present.
- Outside noise from playgrounds, roads, airplanes, yelling etc.
- Impact Noise from objects being dropped, heels on terrazzo or tile floors, dolly wheels, maintenance personnel activities etc.
- Equipment Noise from HVAC systems, sound transfer through ductwork, computers, laboratory equipment etc.
- Internal noises from teachers speech, overlapping conversations, typical classroom activities
Architects using “proven” acoustical design assemblies that are verified by published manufacturer’s ASTM test results are the primary sources of information for products considered for use in all building design. The standard of acoustical integrity most relied upon is STC as determined by ASTM E-90. It is important therefore that the tests as presented by manufacturer’s be reliable, complete, verifiable and unambiguous. If a student is unable to learn, if a teacher is unable to teach, if an environment is acoustically unacceptable due to noise then it is not a stretch to suggest that an entire life and career may be negatively affected. As a manufacturer of acoustic operable wall systems that are used to divide teaching and meeting areas in schools we take this responsibility seriously.
But times have changed with some manufacturers now pursuing a higher laboratory STC number rather than an STC that illustrates the acoustic integrity of their partition. This pursuit of a higher number is based on the belief or premise that all specifiers look at is the number – the higher the better - and do not read the body of the test which describes how the number was obtained. They are doing what they have to do just to get a higher number. For example
- ASTM E-90 states “Any test specimen that is to typify a wall shall be large enough to include all the constructional elements in their normal size and in a proportion of normal use”. For years the accepted standard was a 9’ tall X 14’ wide test specimen: a minimum of 4 panels, a typical lead panel, a final closure panel and two intermediate panels. But ASTM E-90 only requires what amounts to a minimum 8’ X 8’ test specimen so some manufacturers are now testing 2 panel openings that cannot incorporate all essential elements which in our opinion results in an inaccurate and inflated STC value. This complies with the test procedure but does not in our opinion typify an operable wall.
- ASTM E-90 allows for manufacturers to withhold information in the test description that is of a “proprietary nature”. But much of this missing “proprietary” information is necessary for the user to properly evaluate the credibility of the test results. We suggest that readers read the tests, determine what is missing and ask to see this information before accepting the test results and product.
- ASTM E-90 clearly says that the specimen if it is to be identified as an operable wall “shall be opened and closed at least five times”. Some manufacturers are now excluding this statement from the test results saying that the test description does not require it to be included or that it is “proprietary”. If the description does not include this statement then it is not an operable wall.
- Some manufacturers are submitting sound tests that were conducted as far back as 1984 and 1993. These are tests that were completed 35 years ago. Are they still viable? Does anyone really believe that a 30+ year old test describes what is actually being produced to day to say nothing about how the test procedure has changed over that many years?
Moderco’s position is simple. We believe that all sound tests should as a minimum be conducted be in an accredited laboratory on a 14’ X 9’ specimen, 4 panels including all standard components with the test description including all ASTM E-90 mandated topics.
When selecting an operable wall product especially one for an educational facility where acoustics is critical for a proper teaching-learning environment and process, where literally the future of the students may be at stake, it is imperative that specifiers choose carefully. Do more than read the “number”: read the test! Moderco pledges to be upfront and honest, to openly provide complete and accurate information when it comes to the acoustic quality of our products.
Please call if you have questions.
