ANSI/AHRI Standard 640-2005

IMPORTANTSAFETY DISCLAIMERAHRI does not set safety standards and does not certify or guarantee the safety of any products, components orsystems designed, tested, rated, installed or operated in accordance with this standard/guideline. It is stronglyrecommended that products be designed, constructed, assembled, installed and operated in accordance withnationally recognized safety standards and code requirements appropriate for products covered by thisstandard/guideline.AHRI uses its best efforts to develop standards/guidelines employing state-of-the-art and accepted industrypractices. AHRI does not certify or guarantee that any tests conducted under its standards/guidelines will be nonhazardousor free from risk.Note:This standard supersedes ARI Standard 640-1996.Price $5.00 (M) $10.00 (NM)Printed in U.S.A.©Copyright 2002, by Air-Conditioning, Heating, and Refrigeration InstituteRegistered United States Patent and Trademark Office

FIGURES FOR APPENDICESFigure C1. Test Apparatus for Direct Steam Injection ......................................................... 10Figure C2. Test Apparatus for Heated Tanks ....................................................................... 11

_______________________________________________________________ANSI/AHRI STANDARD 640-2005PERFORMANCE RATING OF COMMERCIAL ANDINDUSTRIAL HUMIDIFIERSSection 1. Purpose1.1 Purpose. The purpose of this standard is to establish for Commercial and Industrial Humidifiers: definitions; classifications;test requirements; rating requirements; minimum data requirements for Published Ratings; marking and nameplate data; andconformance conditions.1.1.1 Intent. This standard is intended for the guidance of the industry, including manufacturers, engineers, installers,contractors, and users.1.1.2 Review and Amendment. This standard is subject to review and amendment as technology advances.Section 2. Scope2.1 Scope. This standard applies to factory-made Commercial and Industrial Humidifiers, as defined in Section 3.2.1.1 Energy Source. This standard applies to electric, gas, or hot water operated Commercial and Industrial Humidifiersincluding those that depend on steam from a central steam boiler.2.1.2 Installation. Commercial and Industrial Humidifiers are intended for installation into an enclosed space or air system.2.2 Exclusions. This standard does not apply to the following:2.2.1 Central System Humidifiers as defined in the AHRI Standard 610 and to Self-Contained Humidifiers as defined inAHRI Standard 620.2.2.2 Portable Humidifiers as defined in AHAM HU-1.Section 3. DefinitionsAll terms in this document shall follow the standard industry definitions in the current edition of ASHRAE Terminology ofHeating, Ventilation, Air Conditioning and Refrigeration unless otherwise defined in this section.3.1 Commercial and Industrial Humidifier (Humidifier). A device designed to add moisture to air.3.1.1 Atomizing Humidifiers. A type of Humidifier intended for duct applications in which water is reduced to minuteparticles and dispersed to air as a fine mist.3.1.1.1 Centrifugal Type Atomizer. Utilizes a high-speed disk to sling water to its rim where it is thrown onto platesor a comb to produce a fine mist.3.1.1.2 Nozzle Type Atomizers. Utilizes a nozzle, compressed-air, water, or air and water, to reduce water to a finemist.a. Compressed Air. Compressed air is forced through an annular orifice at the nozzle tip creating a vortex atthe tip. Water is forced through the center orifice of the nozzle where it is atomized on contact with thecompressed air at the nozzle tip.b. Compressed Air and Water. Compressed air and water are combined inside the nozzle and dischargedonto a resonator to produce a fine mist at the nozzle tip.c. Compressed Water. High pressure pump is used to force water through the orifice of a nozzle to producea fine mist at the nozzle tip.1

ANSI/AHRI STANDARD 640-2005 _______________________________________________________________23.1.1.3 Ultrasonic Atomizer. A piezoelectric transducer immersed in a reservoir of mineral free water. Thetransducer converts a high-frequency electronic signal into a high-frequency mechanical oscillation. The mechanicaloscillation is directed at the surface of the water, where at very high frequencies it creates a fine mist.3.1.2 Direct Injection Steam Humidifiers. A type of Humidifier intended for duct applications in which steam, water vaporunder pressure and at high temperature, is dispersed directly into the air.a. Steam Cup Type. Utilizes a cup and drain mounted beneath the duct. Steam is injected into the sides of a cupallowing most of the moisture of the steam to enter into the air while permitting the condensate to fall into the cup bygravity and into the steam trap.b. Steam Separator Type. Utilizes an enclosed distribution pipe, a separating chamber, an integral control valve, and adrain to distribute steam into the air. Steam is injected directly into the enclosed distribution pipe providing reheat tothe outgoing steam passing through the distributor pipe before being released into the air. The steam then enters theseparating chamber which allows dry steam to pass through the control valve and into the distributor pipe whileallowing condensate to fall by gravity into the drain. The moisture of the steam is reheated while in the distributorpipe before being dispersed into the air.c. Steam Panel Type. Utilizes an integral control valve, a header with multiple distributor pipes, and a drain. Thecontrol valve regulates the amount of steam that is injected into the header, which allows dry steam to pass into thedistributor pipe(s) while allowing condensate to escape through the drain. The moisture of the steam in the distributorpipe(s) is dispersed into the air.3.1.3 Heated Tank Humidifiers. A type of Humidifier which converts tank water to steam using electricity, gas, or steam.The steam is dispersed into a duct system through dispersion manifolds. If the Humidifier is a free standing unit, the steam isdispersed directly into the air space through a fan unit.a. Electrode Type. Utilizes an electric current passing through the water to create heat energy to produce steam.b. Gas Heated Type. Utilizes natural gas or propane as the heating method to convert water to atmospheric steam.c. Infrared Type. Utilizes one or more radiant heat bulbs to create heat energy to produce steam.d. Resistance Type. Utilizes one or more electrical elements to heat the water directly to produce steam.e. Steam-to-Steam Type. Utilizes steam from a central boiler passing through a heat exchanger submersed in water tocreate heat energy to produce steam.f. Hot Water Type. Utilizes hot water from a central boiler passing through a heat exchanger submersed in water tocreate heat energy to produce steam.3.2 Humidification Capacity. The capacity associated with a Humidifier's ability to add moisture to air expressed in lb/h [kg/h] ofcontinuous operation.3.3 Published Rating. A statement of the assigned values of those performance characteristics, under stated Rating Conditions,by which a unit may be chosen to fit its application. These values apply to all units of like nominal size and type (identification)produced by the same manufacturer. The term Published Rating includes the rating of all performance characteristics shown onthe unit or published in specifications, advertising or other literature controlled by the manufacturer, at stated Rating Conditions.3.3.1 Application Rating. A rating based on tests performed at application Rating Conditions (other than Standard RatingConditions).3.3.2 Standard Rating. A rating based on tests performed at Standard Rating Conditions.3.4 Rating Conditions. Any set of operating conditions under which a single level of performance results and which causes onlythat level of performance to occur.3.4.1 Standard Rating Conditions. Rating Conditions used as the basis of comparison for performance characteristics.3.5 "Shall" or "Should". "Shall" or "should" shall be interpreted as follows:3.5.1 Shall. Where "shall" or "shall not" is used for a provision specified, the provision is mandatory if compliance with thestandard is claimed.3.5.2. Should. "Should" is used to indicate provisions which are not mandatory but which are desirable as good practice.

_______________________________________________________________ANSI/AHRI STANDARD 640-20053.6 Supplementary Heat. Heat used to enhance evaporation when used in the recirculating system or to heat water for directevaporation.Section 4. Classifications4.1 Commercial and Industrial Humidifiers within the scope of this standard may be classified as shown in Table 1.Table 1. Classification of Commercial and Industrial HumidifiersModel Group Model Designation AHRI TypeCentrifugal TypeAtomizerACAGroup I Nozzle Type AtomizerANAGroup IIUltrasonic AtomizerDirect Steam Injection(Cup Type)Direct Steam Injection(Separator Type)Direct Steam Injection(Panel Type)Heated Tank (ElectrodeType)Heated Tank (Gas HeatedType)Heated Tank (InfraredType)Heated Tank (ResistanceType)Heated Tank (Steam-to-Steam Type)Heated Pan (Hot WaterType)AUAIDS-CIDS-SIDS-PIHT-EIHT-GIHT-IIHT-RIHT-SSIHP-HWSection 5. Test Requirements5.1 Test Requirements. Published Ratings shall be verified by tests conducted in accordance with the test procedure described inAppendix C.5.1.1 Equipment. Humidifiers shall be tested using all components as recommended by the manufacturer.5.1.2 Electrical Conditions. Nameplate voltages are shown in AHRI Standard 110, Table 1. Nameplate voltages for 50 Hzsystems shall include one or more of the utilization voltages shown in IEC Standard 60038. Tests shall be performed at thenameplate rated voltage and frequency unless otherwise specified in this standard.For all dual nameplate voltage equipment covered by this standard, tests shall be performed at both voltages or at the lowervoltage if only a single rating is to be published.3

ANSI/AHRI STANDARD 640-2005 _______________________________________________________________Section 6. Rating Requirements6.1 Published Ratings. Published Ratings shall include Humidification Capacity, power input, and energy input ofSupplementary Heat. Humidification Capacity 1 shall be expressed in lb/h [kg/h] and stated to the nearest 0.1 lb/h [0.05 kg/h].Power input shall be expressed in kW and stated to the nearest 0.1 kW. Where Supplementary Heat other than electric heat isused, the energy input shall be expressed in multiples of 300 Btu/h [87.9 W].6.2 Standard Ratings. Ratings based on data determined by the test requirements prescribed in Section 5 shall be published asStandard Ratings when conducted at the Standard Rating Conditions specified in Table 2.6.3 Application Ratings. Ratings based on data determined by test requirements prescribed in Section 5 and conducted usingRating Conditions other than those specified in 6.2 shall be published as Application Ratings.6.4 Tolerances. To comply with this standard, measured test results shall not be less than 95% of Published Ratings forHumidification Capacity and shall not exceed 110% of Published Ratings for power input or energy input of Supplementary Heat.Where Supplementary Heat (water) is used, the energy input from this source shall not be more than the rated power input.Table 2. Conditions for Standard Rating TestsHumidifier TypeRoom ConditionsRH30%Temp.75.0°F[23.9°C]Duct AirConditions 1RH 30%Temp.75.0°F[23.9°C]Supply WaterTemperature60.0°F[15.6°C]Supply WaterPressure60.0 psi[414 kPa]WaterTemp.Entering200°F[93.3°C]Leaving190°F[87.8°C]Steam PressureEntering: 10 psi [69kPa] CondensateReturn Pressure: 0 psi[0 kPa]Group IAtomizing X X X X XGroup IIDirect SteamInjectionXXHeated Tank X X X X 3 X 2Notes:1.Where applicable, duct airflow velocity is 500 fpm [2.5 m/s] ±2%.2.Where applicable.3.Applicable to hot water type only.1 When converting Humidification Capacity from gal/day to lb/h, one gallon shall be assumed to weigh 8.34 lb. [When convertingHumidification Capacity from kg/h to L/day, one liter of water shall be assumed to weigh 1 kg.]4

_______________________________________________________________ANSI/AHRI STANDARD 640-2005Section 7. Minimum Data Requirements for Published Ratings7.1 Minimum Data Required for Published Ratings. As a minimum, Published Ratings shall consist of the following information:a. Humidification Capacity, lb/h [kg/h]b. Power input, W [kW]c. Energy input of Supplementary Heat, Btu/h [W], where Supplementary Heat other than electric heat is used.As a minimum, Published Ratings shall include all Standard Ratings. All claims to ratings within the scope of this standard shallinclude the statement “Rated in accordance with AHRI Standard 640”. All claims to ratings outside the scope of this standardshall include the statement “Outside the scope of AHRI Standard 640”. Wherever Application Ratings are published or printed,they shall include a statement of the conditions at which the ratings apply.Section 8. Marking and Nameplate Data8.1 Marking and Nameplate Data. As a minimum, the nameplate shall display the manufacturer's name, model designation, andelectrical characteristics.Nameplate voltages for 60 Hz systems shall include one or more of the equipment nameplate voltage ratings shown in AHRIStandard 110, Table 1. Nameplate voltages for 50 Hz systems shall include one or more of the utilization voltages shown in IECStandard 60038.Section 9. Conformance Conditions9.1 Conformance. While conformance with this standard is voluntary, conformance shall not be claimed or implied for productsor equipment within the standard’s Purpose (Section 1) or Scope (Section 2) unless such claims meet all of the requirements ofthe standard and all of the testing and rating requirements are measured and reported in complete compliance with the standard.Any product that has not met all the requirements of the standard shall not reference, state, or acknowledge the standard in anywritten, oral, or electronic communication.5

ANSI/AHRI STANDARD 640-2005 _______________________________________________________________APPENDIX A. REFERENCES - NORMATIVEA1 Listed here are all standards, handbooks and other publications essential to the formation and implementation of the standard.All references in this appendix are considered as part of the standard.A1.1 AHAM HU-1-2003, Household Humidifiers, 2003, Association of Home Appliance Manufacturers, 1111 19 th St.,N.W., Suite 402, Washington, DC 20036, U.S.A.A1.2 AHRI Standard 110-2002 (formerly ARI Standard 110-2002), Air-Conditioning and Refrigerating EquipmentNameplate Voltages, 2002, Air-Conditioning Heating and Refrigeration Institute, 2111 Wilson Blvd., Suite 500, Arlington,VA 22201, U.S.A.A1.3 AHRI Standard 610-2004 (formerly ARI Standard 610-2004, Performance Rating of Central System Humidifiers,2004, Air-Conditioning Heating and Refrigeration Institute, 2111 Wilson Blvd., Suite 500, Arlington, VA 22201, U.S.A.A1.4 AHRI Standard 620-2004 (formerly ARI Standard 620-2004, Performance Ratings of Self-Contained Humidifiers forResidential Application, 2004, Air-Conditioning Heating and Refrigeration Institute, 2111 Wilson Blvd., Suite 500,Arlington, VA 22201, U.S.A.A1.5 ANSI/ASHRAE Standard 41.1-1986 (RA 2001), Standard Method for Temperature Measurement, 2001, AmericanSociety of Heating, Refrigerating and Air-Conditioning Engineers, Inc., 1791 Tullie Circle N.E., Atlanta, GA 30329, U.S.A.A1.6 ANSI/ASHRAE Standard 41.2-1987 (RA 92), Standard Methods for Laboratory Airflow Measurement, 1992,American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., 1791 Tullie Circle N.E., Atlanta, GA30329, U.S.A.A1.7 ANSI/ASHRAE Standard 41.3-1989, Standard Method for Pressure Measurement, 1989, American Society ofHeating, Refrigerating and Air-Conditioning Engineers, Inc., 1791 Tullie Circle N.E., Atlanta, GA 30329, U.S.A.A1.8 ASHRAE Terminology of Heating, Ventilation, Air Conditioning and Refrigeration Second Edition, 1991, AmericanSociety of Heating, Refrigerating and Air-Conditioning Engineers, Inc., 1791 Tullie Circle N.E., Atlanta, GA 30329, U.S.A.A1.9 IEC Standard 60038, IEC Standard Voltages, 2002, International Electrotechnical Commission, 3, rue de Varembe,P.O. Box 131, 1211 Geneva 20, Switzerland.APPENDIX B. REFERENCES - INFORMATIVENone.6

_______________________________________________________________ANSI/AHRI STANDARD 640-2005APPENDIX C. METHOD OF TEST FOR COMMERCIAL ANDINDUSTRIAL HUMIDIFIERS - NORMATIVEC1 Purpose. The purpose of this appendix is to specify for Commercial and Industrial Humidifiers: instrumentation;measurement and treatment apparatus; and test procedures for determining their capacity and related performance.C2 Scope. The test procedures are provided for use with Commercial and Industrial Humidifiers, and shall be used for bothStandard Rating determinations and Application Rating determinations by suitable adjustment of Rating Conditions.C2.2 Exclusions. This standard is not applicable to tests conducted in the field or on the production line.C3 Instrumentation.C3.1 Airflow Rate Measuring Instruments. Airflow rate measuring instruments involved in the measurement of airflowshall be in accordance with Section 6 of ANSI/ASHRAE 41.2.C3.1.1 Nozzle Construction. Construction of nozzles shall be in accordance with Figure 6 of ANSI/ASHRAEStandard 41.2. Nozzles shall be sized for a throat velocity not less than 3,000 ft/min [15.24 m/s] nor more than 7,000ft/min [35.56 m/s]. When nozzles are constructed in accordance with ANSI/ASHRAE Standard 41.2 and installed inaccordance with C4.1, they may be used without calibration. If the throat diameter is 5.00 in [127 mm] or larger, thenozzle discharge coefficient, C, may be assumed to be 0.99. For nozzles smaller than 5.00 in [127 mm] in diameter,or where a more precise coefficient is desired, the value shown in Table C1 may be used.Reynolds Number is calculated as follows:Table C1. NozzleDischarge CoefficientsReynoldsNumber,N ReCoefficientof Discharge,C50,000 0.97100,000 0.98150,000 0.98200,000 0.99250,000 0.99300,000 0.99400,000 0.99500,000 0.99N Re = f·V a·D NC1where:f = temperature correction factorV a = velocity of air at nozzle, fpm [m/s]D N = nozzle throat diameter, in [mm]7

ANSI/AHRI STANDARD 640-2005 _______________________________________________________________The temperature correction factor “f” shall be determined from Table C2.Table C2. TemperatureCorrection FactorNozzle AirTemperature°F [°C]TemperatureCorrectionFactor, f20 [-6.7] 10.1 [78.2]40 [4.4] 9.30 [72.0]60 [15.6] 8.70 [67.4]80 [26.7] 8.10 [62.8]100 [37.8] 7.50 [58.1]120 [48.9] 7.10 [55.0]140 [60.0] 6.70 [51.9]160 [71.1] 6.30 [48.8]C3.2 Air Pressure Measuring Instruments. Pressure taps and measurement techniques shall be in accordance withANSI/ASHRAE Standard 41.3.C3.3 Mass Flow Measuring Instruments. Mass flow measurements for steam or natural gas shall be made using a primaryelement, such as an orifice plate, a flow nozzle or flow tube, venturi or an averaging pitot tube, to develop a differentialpressure. The accuracy of the mass flow rate measuring instruments shall permit measurements within 2.0% of the quantitymeasured.C3.4 Temperature Measuring Instruments. Temperature measurements shall be made in accordance with ANSI/ASHRAEStandard 41.1, having an accuracy of ± 0.10°F [± 0.05°C] to measure both wet-bulb and dry-bulb temperatures. The smallestgradation is to represent a maximum of 0.2°F [0.1°C].C3.5 Water Quantity Measuring Instruments. Water quantity measurements shall be made with one of the followinginstruments having an accuracy as shown:a. Scale and weigh tank. Weight measurements shall be made with a scale having an accuracy of ± 1.0% of the unit’scapacity, lb/h [kg/h].b. Calibrated pressurized cylinder. Calibration of the cylinder shall be accurate to 1.0% of the unit’s capacity, lb/h[kg/h].C3.6 Water Pressure Measuring Instruments. Water pressure measurements shall be made in accordance withANSI/ASHRAE 41.3 using one or more of the following instruments:a. Manometerb. Bourdon tube gagec. Aneroid pressure gaged. Calibrated pressure transducerC3.6.1 The accuracy of the water pressure measuring instruments shall permit measurements within1.0 psi [7.0 kPa].C3.6.2 Calibration of the Bourdon tube gage shall be with respect to a dead-weight tester or by comparison with amanometer.C3.7 Other Measurements.C3.7.1 Electrical Measurements. Electrical measurements shall be made with instruments having an accuracy of± 1.0% of the value being observed.C3.7.2 Supplementary Heat (Water) Flow Rate Measurements. Flow rate measurements shall be made with aliquid type flow meter having an accuracy of ± 2.0% of the quantity measured.8

_______________________________________________________________ANSI/AHRI STANDARD 640-2005C3.7.3 Supplementary Heat (Steam) Condensate Quantity Measurements. Condensate quantity shall be measuredwith a liquid quantity meter measuring either weight or volume having an accuracy of ± 2.0% of the quantitymeasured.C3.7.4 Time Measurements. Elapsed time measurements shall be made with instruments having an accuracy of± 0.5% of the value being observed.C4 Measuring and Treatment Apparatus.C4.1 Airflow Rate Measuring Apparatus for Air Distribution Systems. Accurate and precise measurement of airflow rate isnecessary to the testing of Humidifiers, which receive air from the space in which they are located and deliver it to an airdistribution system. The Humidifier itself exerts no control over the airflow rate circulated through the duct system, yet theperformance of several types of furnace and duct-mounted Humidifiers is substantially affected by air velocity within thesystem. Airflow rates shall be measured using the apparatus described below. The apparatus shall be constructed asdescribed either in this appendix or in those publications referenced in this standard.The apparatus consists of a fan to serve as supply with variable-speed or damper to control flow rate. It includes a receivingchamber with settling means, one or more airflow measuring nozzles installed in a nozzle plate, a discharge chamber withsettling means, and suitable transformation pieces for connecting the airflow rate measuring apparatus to other sections of theair distribution system. The apparatus shall be constructed in accordance with Section 5.3 of ANSI/ASHRAE 41.2, for freeinlet, ducted outlet test chamber as diagramed in Figure 13, Inlet Chamber Setup for Multiple Nozzles in Chamber.C4.1.1 Setup. The requirements of the airflow rate measuring apparatus, setup for testing, proper connections andconnecting ductwork, design and application of appurtenances such as straighteners, mixers, settling means, samplingdevices, and variable supply or exhaust means, shall be in accordance with Section 7.2 of ANSI/ASHRAE 41.2 forinlet test chamber.C4.2 Air Treatment Apparatus. Each test facility shall be provided with the air treatment apparatus to maintain prescribedconditions of temperature, humidity, duct airflow velocity, and pressure of the air entering the test section in accordance withSection 8.2 of ANSI/ASHRAE 41.2.C4.3 Temperature Measuring Apparatus. Air temperature measurements in ducts and fluid temperature measurementswithin conduits shall be made in accordance with C3.4.C4.4 Water Quantity Measuring Apparatus. Means shall be provided to measure the quantity of supply and waste waterused by the Humidifier under test in accordance with C3.5.C4.5 Supplemental Heat Measuring Apparatus. Means shall be provided to measure the amount of water, steam, orelectricity used to supply Supplementary Heat to a Humidifier with a recirculating coil in accordance with C3.7.1, C3.7.2, orC3.7.3.C4.6 Humidifier Test Sections. Humidifier test sections shall be provided to mount the various classes of Humidifiers.The test sections shall be constructed as described below.C4.6.1 Return Air (Duct or Plenum) Test Sections. Each return air (duct or plenum) test section shall contain adiffusion baffle and airflow straightener to assure uniform air velocity and temperature within the test section. If twoor more humidifier test sections are located in series, the transition and turning fittings connecting them shall bedesigned to minimize disturbances in the air stream. Similar transition and turning fittings shall be used to connect ahumidifier test section to an airflow rate measuring apparatus, heating unit, or other apparatus.C4.7 Plenum and Duct Sections. Plenum and duct sections shall be used to connect the airflow rate measuring apparatuswith other sections of the test apparatus and shall be insulated to prevent heat leakage.All joints and seams in the connecting ducts and between the connecting ducts and adjoining sections of the test apparatusshall be sealed, using tape or other sealants, so that the test apparatus is substantially air tight. Special attention shall be paidto sealing the heating unit of the heating section to prevent air leakage.9

ANSI/AHRI STANDARD 640-2005 _______________________________________________________________C4.8 Humidifier Test Room. The humidifier test room shall be any room or space in which the desired test conditions canbe maintained within the test operating tolerances.C4.9 Mass Flow Measuring Apparatus. Means shall be provided to measure the quantity of supply and waste steam or gasused by the Humidifier in accordance with C3.3. The mass flow rate may be compensated for temperature and pressure byusing additional temperature and pressure measuring instruments.C4.10 Test Apparatus for Direct Steam Injection Humidifiers. The apparatus consists of a source of steam; a supply sidesteam trap; a shut off valve; a regulator; a pressure gauge; a mass flow measuring apparatus; a receiving chamber withsettling means and steam trap; and a suitable transformation piece for connecting the apparatus to the Humidifier. Theapparatus shall be constructed in accordance with Figure C1.C4.11 Test Apparatus for Heated Tank Humidifiers. The apparatus consists of a source of water, steam, and whereapplicable-natural gas, steam, or hot water. The water supply source consists of a shut off valve and temperature gauge.Water from the water supply source is fed into a pressurized water storage tank resting on a water quantity measuringapparatus used for measuring the quantity of supply water. The water held in the pressurized water storage tank is used as thesupply water to the unit under test using a suitable transformation piece consisting of a pump, pressure regulator and pressuregauge. The electrical supply to the unit under test is monitored using an electrical measuring device. In addition, theapparatus includes a second water quantity measuring apparatus for measuring waste water. The apparatus shall beconstructed in accordance with Figure C2.STEAM SUPPLY20 ft[6.1m] MINPRESSURE REGULATORPRESSURE GAUGECALIBRATED ORIFICE FITTINGHUMIDIFIERVALVEVALVEDRAINTRAP PRESSURE DIFFERENTALMETER OR MANOMETERTRAPWATER DRAINSCALE & CONTAINERTOTAL WATER OUT =WEIGHT OF WATER ATEND OF TEST MINUSWEIGHT OF WATER ATSTART OF TESTFIGURE C1. Test Apparatus for Direct Steam Injection10

_______________________________________________________________ANSI/AHRI STANDARD 640-2005NOTE:COMPOSITION OF THE WATER SUPPLIED ISCONDITIONED TO CONDUCTIVIY, TOTALDISSOLVED SOLIDS, AND TEMPERATUREBEFORE START OF TEST WHEREAPPLICABLE.WATER SUPPLYVALVEPRESSURE REGULATORTIME MEASUREMENT - MEASURES TOTALHOURS OF TESTSUPPLYELECTRICAL MEASURING DEVICEPRESSURE GAUGEMIN. 5 ft [1.5 m] OFSTEAM HOSE WHEREAPPLICABLESTEAMTEMPERATURE INLARGE SCALE & CONTAINER TOTAL WATERIN = WEIGHT OF WATER AT START OF TESTMINUS WEIGHT OF WATER AT END OF TESTHEATED TANKHUMIDIFIERAUXILLARY HEATSOURCE-ELECTRIC,NATURAL GAS,STEAM, OR HOTWATER; WHEREAPPLICABLE.PUMP OPTIONALWATER DRAINSCALE & CONTAINERTOTAL WATER OUT =WEIGHT OF WATER ATEND OF TEST MINUSWEIGHT OF WATER ATSTART OF TESTFIGURE C2. Test Apparatus for Heated TanksC5 Test Procedures.C5.1 Test Methods. The test methods described in this appendix shall be used in determining the Humidification Capacity.C5.1.1Titles of Test Methods. The test methods described are:a. Group I (Atomizing) C5.3b. Group II (Direct steam injection and heated tank) C5.4C5.1.2 Applicability of Test Methods. Humidifiers shall be tested using the method described in C5.1.1 whichmost nearly coincides with the installation method or installation location described in the manufacturer’s installationinstructions.C5.2 Conditions of Test. The following conditions shall be maintained throughout the tests:C5.2.1 Air Pressure in the Air Treatment Apparatus. The air pressure in the air treatment apparatus shall bemaintained as stated, except that a test tolerance of ± 0.01 in H 2 O. [± 2.5 Pa] shall be allowed.C5.2.2 Air Temperatures. The air entering the humidifier test section shall be maintained at the dry-bulb and wetbulbtemperatures selected. During any test, the variation of dry-bulb temperatures shall not be more than 1.0°F[0.6°C] and the variation of wet-bulb temperatures shall be not more than 0.6 °F [0.3°C]. The average of thesetemperatures shall be the test temperatures. These test temperatures shall be within 2.0°F [1.1°C] of the selecteddry-bulb temperature and within 1.0°F [0.6°C] of the selected wet-bulb temperature. (C5.3.5.2 for temperaturecorrection procedure.)11

ANSI/AHRI STANDARD 640-2005 _______________________________________________________________C5.2.3 Duct Airflow Velocity. The duct airflow velocity in the vicinity of the unit under test shall not exceed 500fpm [2.5 m/s] ±2% with the Humidifier installed.C5.2.4 Electrical Supply Source. Humidifiers which require electrical energy for proper operation shall beconnected to a supply of the proper voltage and frequency as measured at the electrical terminals of the Humidifier.A watt meter shall be installed in the electrical circuit when a Humidifier is connected to an electrical supply circuit.The voltage supplied to the electrical terminals of the Humidifier shall be maintained and a test tolerance of ± 1%shall be allowed.C5.2.5 Steam Supply Source. The steam supply source shall be directly connected to the Humidifier, and thesteam control valve on the Humidifier shall regulate the steam flow rate. The pressure of the steam entering thesteam control valve shall be maintained and a test tolerance of ± 1% shall be allowed.C5.2.6 Natural Gas Supply Source. The gas supply source shall be directly connected to the Humidifier, and thegas control valve on the Humidifier shall regulate the gas flow rate. The composition of the natural gas shall be suchthat its heating value is within the range of 1,000 to 1,050 Btu/ft 3 [37,260 to 39,130 kJ/m 3 ]. The pressure of the gasentering the gas control valve shall be maintained within the pressure range specified by the manufacturer and a testtolerance of ± 0.1 psi [± 0.7 kPa] shall be allowed.C5.2.7 Units with Supplementary Heat (Steam). The pressure of the feed steam entering the recirculating coil shallbe maintained and a test tolerance of ± 0.1 psi [± 0.7 kPa] shall be allowed.C5.2.8 Units with Supplementary Heat (Water). The pressure of the feed water entering the recirculating coil shallbe maintained. (A test tolerance of ± 1.0 psi [± 7.0 kPa] shall be allowed.) The temperature of the feed waterentering the recirculating coil shall be maintained and a test tolerance of ± 4.0°F [± 2.2°C] shall be allowed.C5.2.9 Water Supply Source. The water supply source shall be directly connected to the Humidifier, and the watercontrol valve on the Humidifier shall regulate the water flow rate. The pressure of the water entering the watercontrol valve shall be maintained and a test tolerance of ± 5.0 psi [± 34 kPa] shall be allowed. The temperature of thewater entering the water control valve shall be maintained and a test tolerance of ± 2.0°F [± 1.1°C] shall be allowed.C5.2.9.1 Heating Tank Humidifiers. The composition of the water supplied to Heated Tank Humidifiersshall be such that its total dissolved solids content is within the range of 85 to 170 ppm.C5.2.9.1.1 Heating Tank Humidifiers (Electrode Type). The composition of the water suppliedto electrode type Heated Tank Humidifiers shall be such that its conductivity is within the rangeof 300 to 315 μMHO's/cm 3 .C5.2.10 Direct Steam Injection. The Humidifier shall be tested using the maximum orifice size offered in themodel group and fitted with a minimum 4.0 ft [1.2 m] manifold or multiples if required.C5.3 Group I (Atomizing) Test Method. This test method is used to determine the Humidification Capacity of a Humidifierwhich is installed in the return air duct system or the return air plenum system of an air distribution system. In either case, theHumidifier shall be installed in the humidifier test section in accordance with manufacturer's written instructions.C5.3.1Test Apparatus. The test apparatus is composed of the following components where applicable:a. Airflow rate measuring apparatus for air distribution systems (C4.1)b. Air treatment apparatus (C4.2)c. Temperature measuring apparatus (C4.3)d. Water quantity measuring apparatus (C4.4)e. Supplemental heat measuring apparatus (C4.5)f. Humidifier test sections (C4.6)g. Plenum and duct sections (C4.7)h. Humidifier test room (C4.8)C5.3.2 Air Velocity. The air velocity in the return air duct system or the return air plenum system shall bemaintained at 500 fpm [2.54 m/s] or as recommended by the manufacturer based on 75.0°F [23.9°C] dry-bulb12

_______________________________________________________________ANSI/AHRI STANDARD 640-2005temperature and 56.5°F [13.6°C] wet-bulb temperature as measured at the air measuring device section throughoutthe test. (A test tolerance of ± 20 fpm [± 0.10 m/s] shall be allowed.) The air velocity shall be uniform. Nodiverters, plates, or air directing devices, other than those supplied with the Humidifier by the manufacturer, shall beused to direct air at a higher-than-average velocity either toward or away from the Humidifier under test.C5.3.2.1 The cross-sectional area shall be the cross-sectional area of the humidifier test section measured12.0 in [305 mm] upstream of the test unit and perpendicular to the direction of airflow.C5.3.3 Performance Test. The Humidifier to be tested shall be installed in the humidifier test room as described inC4 and the air temperatures, water temperatures, water pressures for the test shall be maintained as described in C5.1.C5.3.3.1 Water Supply Source Adjustment. If the water measuring apparatus prescribed in C4.4 does notpermit supply and waste water flow rate determination while the Humidifier is connected to the watersupply source, the procedure described below shall be followed. The purpose for adjusting the water flowrate is to establish the water level that is to be maintained in a Humidifier which has a float orbalanced-pan valve, or the water flow rate for a Humidifier equipped with an electric water control valve(solenoid valve).C5.3.3.1.1 Water Level Determination. A Humidifier which contains a reservoir shall beinstalled in the test section and adjusted in accordance with the manufacturer'srecommendations. It shall be operated in the humidifier test section while connected to thewater supply source described in C5.2.9. The water level in the reservoir shall be observed.After it has remained constant during an operating period of not less than 30 minutes, a waterlevel line shall be marked on the reservoir. This reservoir water level shall be maintained duringthe capacity test.C5.3.3.1.2 Water Flow Rate Determination. A Humidifier which utilizes an electric watercontrol valve shall be adjusted in accordance with the manufacturer's recommendations. (Analternative procedure is to remove the water control valve from the Humidifier and to adjust theflow rate in accordance with the manufacturer's recommendations.) The water control valveshall be opened electrically, and the water flow rate through the valve shall be determined usingC4.4. The period of the preliminary test shall be not less than 30 minutes.C5.3.3.2 Connection for Capacity Test. The Humidifier under test shall be connected to the waterquantity measuring apparatus described in C4.4.a. Humidifiers having a float or balanced pan valve shall be adjusted to maintain the water leveldetermined in C5.3.3.1.1.b. Humidifiers having an electric water control valve shall be adjusted or the water-controlsupply source shall be controlled so that it equals the water flow rate determined in C5.3.3.1.2.C5.3.3.3 Data to Be Recorded. All data required to determine the Humidification Capacity of the unitshall be observed and recorded where applicable.C5.3.3.3.1 Air Pressures. Air pressures or a differential pressure shall be observed andrecorded at the following locations:a. Static pressure drop across flow nozzle, (p v ), in H 2 O [Pa]b. Absolute pressure of air entering flow nozzle, (P n ), in Hg [kPa]c. Pressure in return air duct or return air plenum humidifier test section belowatmospheric pressure, in H 2 O [kPa]C5.3.3.3.2 Air Temperatures. Dry-bulb and wet-bulb temperatures entering the Humidifier, °F[°C].a. Air entering flow nozzlesb. Air entering return air duct or return air plenumc. Air entering supply air plenum or supply air duct13

ANSI/AHRI STANDARD 640-2005 _______________________________________________________________C5.3.3.3.3 Airflow Rate. Airflow rate measurement data shall be recorded in accordance withSection 9 of ANSI/ASHRAE 41.2.C5.3.3.3.4 Electric Power Input. Power input (including transformer) shall be recorded in W[kW]. Electric energy input shall be calculated from this data and expressed in Btu/h [W].C5.3.3.3.5 Time. The time of each reading and the elapsed time between successive readingsof all data, h [s].C5.3.3.3.6 Water Temperatures and Water Pressures.a. Water temperature entering and leaving the Humidifier, °F [°C]b. Water pressure during test or during preliminary water adjustment, psig [kPagage]C5.3.3.3.7 Water Quantity. Weights or water flow ratesa. Supply water to Humidifier, lb or gal [kg or L]b. Waste water, lb or gal [kg or L]c. Recirculating water (where used), lb/h or gal/h [kg/h or L/h]C5.3.3.4 Procedure. After prescribed Rating Conditions for the test have been attained, no less than fivesets of readings shall be taken. The duration of the test shall not be less than thirty minutes. The test shallbe continued until the weight or volume of water evaporated or injected into the Humidifier is within 5% forfour successive test readings.C5.3.4 Test Results. The Humidification Capacity of the Humidifier under test shall be determined using C5.3.5.2and shall be the average Humidification Capacity of four successive test runs complying with this section.C5.3.5Capacity Rating Calculations.C5.3.5.1 Calculation of Velocity in the Test Section. The test unit airflow rate through the test sectionshall be calculated in accordance with Section 11 of ANSI/ASHRAE 41.2. In order to provide a uniformbase for expressing Humidification Capacity, the total airflow rate at experimental conditions is thenconverted to a flow rate at Standard Rating Conditions.C5.3.5.1.1 Calculation of Specific Volume at the Nozzle. The specific volume of the air-vapormixture at the nozzle shall be calculated as follows:vv ' =1 n x1 + W 1or =29.92vn+ WPn(1Pb)n⎡ v= ⎢1x⎢1+ W⎣ 1⎡ 101vor = ⎢n⎢ P (1 + W⎣ nPb)n29.92 460 + txan⎛ p ⎞ 460 + t+ ⎜ v⎟ a1⎝ 13.62 ⎠101+⎤⎥⎥⎦pv273 + t ⎤xan⎥273 + ta1 ⎥⎦C214

ANSI/AHRI STANDARD 640-2005 _______________________________________________________________C5.3.5.1.8 Calculation of the Airflow Rate of the Humidifier Under Test. The airflow rate forthe Humidifier under test shall be calculated as follows:Qa= Qan⋅'v 1'v nC9C5.3.5.1.9 Correct Airflow Rate to Standard Airflow. To correct the airflow rate to standardairflow the following equation shall be used:QsQ= aC10'K ⋅(v)21C5.3.5.1.10 Calculation of Air Velocity in Test Section. The air velocity in the test section shallbe calculated as follows:VtQ= s v '⋅ nA vtnC11where:A n = Nozzle throat area, ft 2 [m 2 ]A t = Cross-sectional area of test section, ft 2 [m 2 ]C n = Nozzle discharge coefficientK 1 = 1096 [1.414]K 2 = 0.075 [1.200]P b = Barometric pressure, in Hg [kPa]P n = Nozzle throat pressure, in Hg [kPa]p v = Velocity pressure at nozzle throat or static pressure difference across nozzle, in H 2 O[Pa]Q a = Airflow rate at test unit, cfm [m 3 /s]Q an = Measured airflow rate at nozzle, cfm [m 3 /s]Q s = Measured airflow rate of standard air at test unit, scfm [standard m 3 /s]t a1 = Air entering test unit dry-bulb temperature, °F [°C]t ’ a1 = Air entering test unit wet-bulb temperature, °F [°C]t a2 = Air leaving test unit dry-bulb temperature, °F [°C]t ’ a2 = Air leaving test unit wet-bulb temperature, °F [°C]t an = Air entering nozzle dry-bulb temperature, °F [°C]v n = Specific volume of air at dry-bulb and wet-bulb temperature conditions existing atnozzle but at standard barometric pressure, ft 3 /(lb of dry air) [m 3 /(kg of dry air)]v ’ n = Specific volume of air at nozzle, ft 3 /(lb of moist air) [m 3 /(kg of moist air)]V t = Air velocity in test section, ft/min [m/s]v ’ 1 = Specific volume of air at dry-bulb and wet-bulb temperature conditions existing in testsection, ft 3 /lb [m 3 /kg]v 1 = Specific volume of air entering test section, ft 3 /lb [m 3 /kg]W n = Specific humidity ratio of air at nozzle, (lb moisture)/(lb of dry air), [(kg ofmoisture)/(kg of dry air)]W 1 = Specific humidity ratio of air entering test section, (lb moisture)/(lb of dry air), [(kg ofmoisture)/(kg of dry air)]16

_______________________________________________________________ANSI/AHRI STANDARD 640-2005W s1 = Specific humidity ratio of air at saturation at wet-bulb temperature entering test section,(lb moisture)/(lb of dry air), [(kg of moisture)/(kg of dry air)]W sn = Specific humidity ratio of air at wet-bulb temperature at nozzle, (lb moisture)/(lb of dryair), [(kg of moisture)/(kg of dry air)]C5.3.5.2 Calculation of Humidification Capacity. The Humidification Capacity shall be calculated usingthe following equation:H m † = K 1·F (H s - H t )C12where:FF§ = (t r – t ’ r)/(t t – t ’ t) = temperature correction factor C13H m = Humidification Capacity, lb/h [kg/h]H S = Water supply rate, lb/h [kg/h]H t = Waste water rate, lb/h [kg/h]K 1 = 1.000 [0.264]t r = Return air dry-bulb temperature at Rating Conditions,°F [°C]t' r = Return air wet-bulb temperature at Rating Conditions,°F [°C]t t = Return air dry-bulb test temperature, °F [°C]t' t = Return air wet-bulb test temperature, °F [°C]C5.4 Group II (Direct Steam Injection and Heated Tank) Test Method. This test method is used to determine theHumidification Capacity of a Humidifier that is placed on a bench and connected in accordance with the manufacturer’swritten instructions.C5.4.1Test Apparatus. The test apparatus is composed of the following components where applicable:a. Temperature measuring apparatus (C4.3)b. Water quantity measuring apparatus (C4.4)c. Supplemental heat measuring apparatus (C4.5)d. Humidifier test room (C4.8)e. Mass flow measuring apparatus (C4.9)f. Test Apparatus for Direct Steam Injection Humidifiers (C4.10)g. Test Apparatus for Heated Tank Humidifiers (C4.11)C5.4.2 Performance Test. The Humidifier to be tested shall be installed in the humidifier test room as described inC4, and the air temperatures, water temperatures, water pressures, gas pressures, steam pressure, and natural gaspressure required for the test shall be maintained as described in C5.C5.4.2.1 Connection for Capacity Test (Heated Tank). Heated Tank Humidifiers under test shall beconnected to the water quantity measuring apparatus described in C4.4 for both supply and waste water.a. Humidifiers having a float or balanced pan valve shall be adjusted to maintain the water leveldetermined in C5.3.3.1.1.b. Humidifiers having an electric water control valve shall be adjusted or the water controlsupply source shall be controlled so that it equals the water flow rate determined in C5.3.3.1.2.† Other consistent units, such as gal/day [L/day] may be used.§Dry-Bulb and Wet-Bulb Temperatures. Temperatures t t and t' t are the average of the actual test temperatures entering thetest section (C5.2.2) immediately before entering the Humidifier under test. Temperatures t r and t' r are the rated temperaturesat the same point.17

ANSI/AHRI STANDARD 640-2005 _______________________________________________________________C5.4.2.2 Connection for Capacity Test (Direct Steam Injection). Direct Steam Injection Humidifiersunder test shall be connected to a mass flow measuring apparatus described in C4.9. Condensate shall bemeasured using the method described in C3.7.3.C5.4.2.3 Water Supply Source Adjustment. If the water measuring apparatus prescribed in C4.4 does notpermit supply and waste water flow rate determination while the Humidifier is connected to the watersupply source, the procedure described below shall be followed. The purpose for adjusting the water flowrate is to establish the water level that is to be maintained in a Humidifier which has a float orbalanced-pan valve, or the water flow rate for a Humidifier equipped with an electric water control valve(solenoid valve).C5.4.2.3.1 Water Level Determination. A Humidifier which contains a reservoir shall beinstalled in the test section and adjusted in accordance with the manufacturer'srecommendations. It shall be operated in the humidifier test section while connected to thewater supply source described in C5.2.9. The water level in the reservoir shall be observed.After it has remained constant during an operating period of not less than 30 minutes, a waterlevel line shall be marked on the reservoir. This reservoir water level shall be maintained duringthe capacity test.C5.4.2.3.2 Water Flow Rate Determination. A Humidifier which utilizes an electric watercontrol valve shall be adjusted in accordance with the manufacturer's recommendations. (Analternative procedure is to remove the water control valve from the Humidifier and to adjust theflow rate in accordance with the manufacturer's recommendations.) The water control valveshall be opened electrically, and the water flow rate through the valve shall be determined usingC4.4. The period of the preliminary test shall be not less than 30 minutes.C5.4.2.3.3 Water Supply Adjustment for Supplemental Heat using a Recirculating Coil. Thewater or steam flow rate through the recirculating coil of a Humidifier using such a coil forSupplementary Heat shall be adjusted as necessary to maintain the required inlet watertemperature during the test.C5.4.2.4 Steam Supply Source Adjustment. The steam flow rate through the Humidifier or recirculatingcoil or Humidifiers using such a coil for Supplementary Heat shall be adjusted as necessary to maintain therequired inlet steam pressure during the test.C5.4.2.5 Natural Gas Supply Source Adjustment. The natural gas flow rate through the Humidifier shallbe adjusted as necessary to maintain the required inlet gas pressure during the test.C5.4.3 Data to Be Recorded. All data required to determine the Humidification Capacity of the unit shall beobserved and recorded where applicable.C5.4.3.1 Electric Power Input. Power input (including transformer), W [kW]. Electric energy input shallbe calculated from this data and expressed in Btu/h [W].C5.4.3.2 Natural Gas Supply Input. Natural gas consumption, Btu/ft 3 [kJ/m 3 ].C5.4.3.3 Time. The time of each reading and the elapsed time between successive readings of all data, h[s].C5.4.3.4 Water and Steam Temperatures and Pressures.a. Water temperature entering and leaving the Humidifier, °F [°C]b. Water temperature entering and leaving the recirculating coil (recirculating coil onHumidifiers using such a coil for Supplementary Heat), °F [°C]c. Water pressure during test or during preliminary water adjustment,psig [kPa gage]d. Steam pressure entering unit (where used), psig [kPa gage]18

_______________________________________________________________ANSI/AHRI STANDARD 640-2005C5.4.3.5 Water Quantity. Weights or water flow ratesa. Supply water to Humidifier, lb or gal [kg or L]b. Waste water, lb or gal [kg or L]c. Recirculating water (where used), lb/h, or gal/hr [kg/h or L/h]C5.4.3.6 Condensate Quantity. Condensate leaving the Humidifier, lb or gal [kg or L].C5.4.4 Procedure. After prescribed Rating Conditions for the test have been attained, no less than five sets ofreadings shall be taken. The duration of the test shall not be less than thirty minutes. The test shall be continueduntil the weight or volume of water evaporated or injected into the Humidifier is within 5% for four successive testreadings.C5.4.5 Test Results. The Humidification Capacity of the Humidifier under test shall be determined using C5.4.6.1and shall be the average Humidification Capacity of four successive test runs complying with this section.C5.4.6Capacity Rating Calculations.C5.4.6.1 Calculation of Humidification Capacity. The Humidification Capacity, except for DirectInjection Steam Humidifiers, shall be calculated using the following equation:H m † = K 1 (H s - H t )C14where:H m = Humidification Capacity, lb/h [kg/h]H S = Water supply rate, lb/h [kg/h]H t = Waste water rate, lb/h [kg/h]K 1 = 1.000 [0.264]C5.4.6.1.1 Direct Injection Steam Humidifiers. Humidification Capacity, for Direct InjectionSteam Humidifiers, shall be calculated using the following equation:Hm= ms− mcC15where:m c = mass flow of condensate, lb/h [kg/h]m s = mass flow measurement for steam, lb/h [kg/ h]† Other consistent units, such as gal/day [L/day] may be used.19