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ACCA manual S             * Patent Pending
                                                                                                                                                                              

OFF-THE-CHARTS (OTC) COMPLIANCE DETAILS AS RELATED TO ICC CODE, AHRI, AND ACCA MANUAL S
THIS INFORMATION IS INTENDED FOR INFORMATIONAL PURPOSES ONLY, TO ASSIST THE USER OF THIS PRODUCT IN DETERMINING WHETHER IT IS COMPLIANT WITH THE REGULATIONS OF THE JURISDICTION IN WHICH THEY INTEND TO USE IT.
(Software author comments in bold italic print)
I INTERNATIONAL MECHANICAL CODE 2009
A. In section M1401.3 Sizing: "Heating and cooling equipment shall be sized in accordance with ACCA Manual S based on building loads calculated in accordance with ACCA Manual J or other approved heating and cooling calculation methodologies." The approval is by the code enforcement official, as in all other referenced "approved's" in the code.
II AHRI SEER Standard 210-240 - PERFORMANCE RATING OF UNITARY AIR-CONDITIONING AND AIR-SOURCE HEAT PUMP EQUIPMENT
A. Section 6.5, Tolerances, reads: "To comply with this standard, measured test results shall not be less than 95% of Published Ratings for performance ratios and capacities." OTC average results, therefore, are twice as accurate as the very ratings from which the manufacturer expanded data is created from.
III ACCA MANUAL S (2014 RELEASE)
A. We fully realize that OTC is NOT an officially ACCA "approved" product, and has not been deemed "ACCA manual S compliant".
B. Section 2-5 states that "Equipment selection and sizing requires values for total and latent cooling capacity for the equipment operating conditions caused by the summer design conditions for outdoor air and indoor air; and when applicable, the effect of return duct loads, and/or engineered ventilation loads." OTC takes these values into consideration, which are generated by manufacturer formulas, which the user may then compare the resulting accuracy against.
C. Appendix 13 States in the first sentence that "The manufacturer's expanded performance data for a particular make, model and size may be approximated by a set of linear equations. Converting a data table to a set of equations has certain uses and advantages. Accuracy, as it relates to the OEM's data set may be good, but not perfect." OTC allows for the comparison to published data and making the small correction of error if desired.
D. Appendix 13 Section 1, use #4 states that "The model may be used for final equipment selection and sizing if the accuracy of the calculation engine is acceptable." OTC is accurate to less than a standard deviation average error of 2.01%, which can then be corrected further if desired. 
E. Appendix 13 Section 1, use #5 states that "An accurate model may be used by a code official to verify final equipment selection and sizing". This has always been the jurisdiction of the state building officials.
F. Appendix 13 Section 1, use #7 states that "A model that has 1% to 10% error (typically 5% or less) over a comprehensive range of operating conditions may be used for preliminary design work." OTC would hope that a building official would use the same 5% criteria to which AHRI is held for SEER determination, in the design capacity calculation as well.
G. Appendix 13, Section 16: Accuracy of Expanded Data: "Models attempt to duplicate OEM data whether it is correct, or not..", "When this is not the case, compare the questionable data with data for similar makes/models of the same size..", " So, the questionable data was discarded, and replaced with data that is consistent with expected tendencies. Discussing data accuracy with an OEM is not a simple matter." OTC realized this early on in discussions as well, and a statistical outlier factor for questionable data was determined in our sampling data set. This number is the basis of the maximum number we allow for results adjustment in our product. IF YOU HAVE MANUFACTURER DATA BEYOND OUR ADJUSTMENT, YOU SHOULD HEED ACCA'S ADVICE, AND CONTACT THE MANUFACTURER.
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NOTE: OTC CALCULATION ERRORS IN 11% OF 3090 SAMPLE POINTS FROM RANDOM MANUFACTURER PRODUCT DATA, 2009-2015, EXCEEDED 5%, 2.4% EXCEEDED 7%, AND 0.2 % EXCEEDED 10%. ONLY ONE SAMPLE POINT EXCEEDED 11% ERROR. Average sheet error from published random expanded data is currently 2.313%. The statistical standard deviation between errors is 1.942%.
THE OTC SHEET IS FOR USE WITH 0.5 THROUGH 7.5 TON AIR-COOLED RESIDENTIAL TYPE SPLIT SYSTEMS, BOTH SINGLE AND TWO STAGE TYPES. SOME RESULTS WITH HIGH ERROR COULD OCCUR IF A SPECIFIC BRAND HAS QUESTIONABLE EXPANDED DATA (OUTLIERS). DO NOT USE THIS SHEET FOR TRUE VARIABLE SPEED (FREQUENCY-DRIVE) COMPRESSOR SYSTEMS EXCEPT FOR MAXIMUM SPEED RATING.
OTC has not been tested with water cooled systems, results may vary.
OFF-THE-CHARTS, COPYRIGHT 2012, KR SERVICES, STATE OF LOUISIANA
US Patent Pending, #15/266,380
Spreadsheet Copyright 2012 by KR Services, State of Louisiana
(Ver. 16.80.32 and 16.80.64)

 

 

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