1、 2014 Standard for Mechanical Performance Rating of Central Station Air-handling Unit Casings Approved by ANSI on May 19, 2015 ANSI/AHRI Standard 1351 (SI) with Addendum 1 ANSI/AHRI STANDARD 1351 (SI)-2014 WITH ADDENDUM 1 Mechanical Performance Rating of Central Station Air-handling Unit Casings Sep
2、tember 2015 Addendum 1 (dated September 2015) of ANSI/AHRI Standard 1351 (SI)-2014, “Changes to ANSI/AHRI Standard 1351 (SI)-2014” is provided as follows. The following changes have been incorporated (deletions are shown by strikethroughs, additions are shown by shading) into the already published 2
3、014 version of ANSI/AHRI Standard 1351 (SI) to avoid confusion: Note: This addendum is not ANSI approved and is currently going through the process to become so. The changes include: 1) Added Section 3.16. Updated all subsequent numbering. 3.16 Pressure Section. A section bounded by a Pressure Chang
4、e Wall and/or the unit end(s) and is designed to operate entirely in Positive Pressure or Negative Pressure. 2) Updated Section 6.1.3. 6.1.3 All access points must be large enough (minimum nominal width 450 mm) for a person to enter or reach in to place instrumentation, including thermal sensors, he
5、ater(s), circulating fan(s), without damaging the test unit (i.e. by enlarging existing openings or creating new ones). One access point is required between end wall and first component (either fan or coil). 3) Updated Table C1. Table C1. Requirements for Test Instrumentation Measurement Measurement
6、 System Accuracy1,2,3,4,5 Display Resolution Selected, Installed, Operated, Maintained in Accordance With Air Temperature 0.21.0C 0.1C ANSI/ASHRAE Standard 41.1 Pressure 2.5 Pa 1.25 Pa ANSI/ASHRAE Standard 41.3 Standard Method for Pressure Measurement Length, width, and height 2.5 mm 1.5 mm ISO/IEC
7、17025 Length, deflection 0.002 0.001 ISO/IEC 17025 Airflow 2.0% of the reading 0.5 L/s ANSI/ASHRAE Standard 41.2 Standard Method for Laboratory Airflow Measurement Power 1.0% of the quantity measured 1.0 W ANSI/ASHRAE Standard 41.11 Standard Methods for Power Measurement Notes: 1. Accuracy requireme
8、nt also applies to volumetric type meters. 2. Measurement system accuracy shall apply over the range of use during testing, as indicated by the Turn Down Ratio determined during calibration, i.e. from full scale down to a value of full scale divided by the Turn Down Ratio. For many types of instrume
9、nts and/or systems this may require exceeding the accuracy requirement at full scale. Percent of Reading = %RDG, %FS = percent of full scale for the measurement instrument or measurement system. If dual requirements are shown in the table, FS and RDG, then both requirements shall be met. 3. Current
10、Transformers (CTs) and Potential Transformers (PTs) shall have a metering accuracy class of 0.3 or better, rated in accordance with IEEE C57.13. 4. Display resolution shown is the minimum requirement (most coarse resolution allowable). Better (finer) resolution is acceptable for instrument or panel
11、displays, or computer screen displays. The display resolution shown is the preferred resolution for data reporting on test reports. 5. Significant figures (also known as significant digits) determined in accordance with Section 7.2 of NIST Special Publication 260-100-1993, “Handbook for SRM Users”.
12、4) Updated third paragraph of Section C5.3.4. All service access points including access doors and access panels used in lieu of an access door are included in the deflection measurement and shall be installed according to the manufacturers instructions. 5) Updated Section C5.4.3. C5.4.3 Record the
13、location of the Maximum Deflection Point on the casing drawing. Several measurements may be necessary to locate the Maximum Deflection Point. Measure and record the deflection(s) at the identified Maximum Deflection locations and the casing pressure every 5 minutes for 15 minutes. See Figure C7. 6)
14、Updated Section C5.5.1. C5.5.1 The test is valid if any measured pressure, Pi, does not vary from the mean pressure, Pa, more than 25 Pa, or 2%, whichever is greater, if any measured deflection, 1,2,3,4 , during the test does not vary from the average deflection, , by more than 0.25 mm or 5%, whiche
15、ver is greater, and if the difference between the unpressurized final deflection,final ,and the unpressurized starting deflection, start, test does not vary by more than 0.25 mm or 5%, which is greater. 7) Updated Section C6.1.1.1. C6.1.1.1 Method 1: As an assembled unit with the entire unit under n
16、egative or positive pressure. For negative pressure units, inward swinging doors shall be completely sealed and outward swinging doors shall not be sealed. In a negative pressure test, seal off all of the access points on the positive pressure side. For positive pressure units, outward swinging door
17、s shall be completely sealed and inward swinging doors shall not be sealed In a positive pressure test, seal off all of the access points on the negative pressure side.; 8) Added Section C6.5.1.1. C6.5.1.1 If the unit has a Pressure Change Wall, there will be two Casing Air Leakage Ratings, one for
18、the positive pressure section and one for the negative pressure section. 9) Updated Section C6.6.1. C6.6.1 Use the Casing Air Leakage Rate, CLx, to determine rating class. Refer to Table 2, Section 6.4. If the unit has a Pressure Change Wall, there will be 2 Casing Air Leakage Ratings, one for the p
19、ositive pressure section and one for the negative pressure section. 10) Updated Section C7.1.1. C7.1.1 The test shall be performed with distributed internal heat sources and circulating fans as needed to provide uniform internal temperatures. The heat source will be energized to provide a minimum of
20、 17C higher average internal air temperature when compared to external ambient temperature but the internal temperature should not exceed 50 C. The manufacturer shall specify the maximum temperature for testing if the product has a lower maximum allowable internal temperature than 50C. Steady state
21、is defined in Section C7.3.3. See Figures C13, C14, and C15 for some example thermal set-ups. 11) Updated Section C7.2.3 C7.2.3 A minimum of 3 Circulating fans shall be installed inside the unit CSAHU to help achieve and maintain a uniform temperature distribution inside the unit provide adequate ai
22、r mixing to achieve uniform temperature distribution and convection inside the CSAHU. At a minimum, one fan shall be located in each Pressure Section and/or in each section divided by a coil so that circulating air is obtained throughout the entire unit. At minimum, one fan shall be located in each
23、unit section bounded by any pressure change wall, coil, and/or unit end so that circulating air is obtained throughout the entire unit and provides adequate air mixing to achieve uniform temperature distribution inside the unit and simulate unit internal airflow velocities based on 2.5 m/s coil face
24、 velocity. The total airflow delivered by the circulating fan(s) in each unit section shall provide a minimum of 25 L/s per square meter of unit cross-sectional area. Multiple fans may be used to produce the required airflow. 12) Updated Section C7.2.3.1. C7.2.3.1 For example, a unit with a 2 m2 cro
25、ss-sectional area will require at least 3 circulating fan(s) each delivering 2850-3775 at least 500 L/s at free delivery per pressure section bounded by any pressure change wall, coil, and/or unit end. 13) Changed “thermocouple” to “temperature measuring device” throughout document. Ex; C7.2.5 Therm
26、ocouples Temperature measuring devices shall be distributed inside the unit to measure and verify the uniformity of the internal air temperature. Thermocouples Temperature measuring devices shall be distributed outside the unit to measure and verify the uniformity of the external air temperature. 14
27、) Added Figures C13, C14 and C15. Figure C13. CSAHU with No Pressure Change Wall Figure C14. CSAHU with No Pressure Change Wall and Separate Coils Figure C15. CSAHU with Pressure Change Wall 15) Updated Section C7.5.5. C7.5.5 Calculate the Thermal Transmittance with leakage. qtl = qin + ql C15 U = q
28、tlAnet(TaeaiTaiae)C16 Where: qtl = total thermal energy with leakage, W U = Thermal Transmittance, W/mK 16) Added Section C7.5.6. C7.5.6 Calculate the Thermal Transmittance without leakage. qt = qin C17 U = qtAnet(TaiTae)C18 Where: qt = total thermal energy without leakage, W U = Thermal Transmittan
29、ce, W/mK 17) Section C8.1.2 updated. C8.1.2 The test shall be performed at nominal 1.8 0.25 m/s calculated internal air velocity provided by the inside circulating fans with the same circulating fans used for the thermal transmittance test. Price $10.00 (M) $20.00 (NM) Copyright 2014, by Air-Conditi
30、oning, Heating, and Refrigeration Institute Printed in U.S.A. Registered United States Patent and Trademark Office Note: This is a new standard. For I-P ratings, see ANSI/AHRI Standard 1350 (I-P)2014. AHRI CERTIFICATION PROGRAM PROVISIONS Scope of the Certification Program There currently is no AHRI
31、 certification program for Mechanical Performance Rating of Central Station Air-handling Unit Casing for this Standard. FOREWORD This standard does not include acoustic testing or rating information for Central Station Air-handling Units (CSAHU). The unit must be tested in accordance with ANSI/AHRI
32、Standard 261 (SI) in order to determine actual unit sound power levels, inlet, discharge and casing radiated. CSAHU sound levels are dependent on many factors, for example, fan type, size, and operating conditions, casing construction and casing penetrations, etc. There is often a significant intera
33、ction between the fan and the unit casing which both generates and transmits sound. The prediction of unit sound power from fan-only sound power by applying effects such as casing noise reduction can easily result in errors as large as 15 decibels. IMPORTANT SAFETY DISCLAIMER AHRI does not set safet
34、y standards and does not certify or guarantee the safety of any products, components or systems designed, tested, rated, installed or operated in accordance with this standard/guideline. It is strongly recommended that products be designed, constructed, assembled, installed and operated in accordanc
35、e with nationally recognized safety standards and code requirements appropriate for products covered by this standard/guideline. AHRI uses its best efforts to develop standards/guidelines employing state-of-the-art and accepted industry practices. AHRI does not certify or guarantee that any tests co
36、nducted under its standards/guidelines will be non-hazardous or free from risk. TABLE OF CONTENTS SECTION PAGE Section 1. Purpose 1 Section 2. Scope 1 Section 3. Definitions . 1 Section 4. Classification . 4 Section 5. Test Requirements 4 Section 6. Rating Requirements . 5 Section 7. Minimum Data Re
37、quirements for Published Ratings 9 Section 8. Marking and Nameplate Data 10 Section 9. Conformance Conditions . 10 TABLES Table 1. Casing Deflection Rating Class 6 Table 2. Casing Air Leakage Rating Class . 7 Table 3. Casing Thermal Transmittance Rating Class 8 Table 4. Casing Thermal Bridging Ratin
38、g Class 8 FIGURES Figure 1. Casing Air Leakage Rating Class Chart . 7 APPENDICES Appendix A. References - Normative . 11 Appendix B. References - Informative 12 Appendix C. Method of Test for CSAHU Casings 13 TABLES FOR APPENDICES Table C1. Requirements for Test Instrumentation. . 13 FIGURES FOR APP
39、ENDICES Figure C1. Negative Pressure CSAHU Test Apparatus . . 14 Figure C2. Positive Pressure CSAHU Test Apparatus . . 14 Figure C3. Positive and Negative Pressure CSAHU Test Apparatus . 15 Figure C4. Span Measurement Horizontal Unit . . 16 Figure C5. Span Measurement Vertical Unit. . 17 Figure C6.
40、Span Measurement Pressure Change Wall Unit 18 Figure C7. Deflection Measurement . 19 Figure C8. Thermocouple Temperature Measuring Device Planes 24 Figure C9. Thermocouple Temperature Measuring Device Locations Side View 25 Figure C10. Thermocouple Temperature measuring Device Locations End View . 2
41、5 Figure C11. Typical Thermocouple Temperature measuring Device Mounting. . 26 Figure C12. Typical Thermocouple Temperature measuring Device Shielding. . 26 Figure C13. Example Thermal Testing Set-up for CSAHU with No Pressure Change Wall 26 Figure C14. Example Thermal Testing Set-up for CSAHU with
42、No Pressure Change Wall and Separate Coils. . 27 Figure C15. Example Thermal Testing Set-up for CSAHU with Pressure Change Wall. . 27 _ANSI/AHRI STANDARD 1351 (SI)-2014 1 MECHANICAL PERFORMANCE RATING OF CENTRAL STATION AIR-HANDLING UNIT CASING Section 1. Purpose 1.1 Purpose. The purpose of this sta
43、ndard is to establish for Central Station Air-handling Unit Casings: definitions; classifications; test requirements; rating requirements; minimum data requirements for Published Ratings; operating requirements; marking and nameplate data; conformance conditions. 1.1.1 Intent. This standard is inten
44、ded for the guidance of the industry, including manufacturers, designers, installers, contractors and end users. 1.1.2 Thermal Performance Rating Limitations. Thermal performance ratings are intended to be used only to compare the construction of different Central Station Air-handling Units. The num
45、erical value associated with the rating class cannot be used to predict actual application Thermal Transmittance through casing or the risk of condensation for any specific Central Station Air-handling Unit. 1.1.3 Review and Amendment. This standard is subject to review and amendment as technology a
46、dvances. Section 2. Scope 2.1 Scope. This standard applies to Central Station Air-handling Units (CSAHU) as defined in Section 3.5. 2.2 Exclusions. 2.2.1 This standard does not apply to forced-circulation, free-delivery air-coolers for refrigeration, which are covered in ANSI/AHRI Standard 420. 2.2.
47、2 This standard does not apply to unit heaters intended for free delivery of heated air or to room fan-coils as defined in ANSI/AHRI Standard 440. 2.2.3 This standard does not apply to units that have direct expansion coils incorporated by the manufacturer in a matched split system air-conditioner,
48、or as otherwise defined in the product scope definition of the AHRI Unitary Small Equipment and Unitary Large Equipment Sections and covered in ANSI/AHRI Standard 210/240 or in ANSI/AHRI Standard 340/360. 2.2.4 This standard does not apply to unit ventilators as defined in ANSI/AHRI Standard 840. 2.2.5 This standard does not apply to variable refrigerant flow equipment as defined in ANSI/AHRI Standard 1230. 2.2.6 This standard does not apply to direct expansion (DX) dedicated outdoor air system units as defined in ANSI/AHRI
