1、Designation: E1998 11Standard Guide forAssessing Depressurization-Induced Backdrafting andSpillage from Vented Combustion Appliances1This standard is issued under the fixed designation E1998; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide describes and compares different methods forassessing the potential for, or existence
3、of, depressurization-induced backdrafting and spillage from vented residentialcombustion appliances.1.2 Assessment of depressurization-induced backdraftingand spillage is conducted under either induced depressurizationor natural conditions.1.3 Residential vented combustion appliances addressed inthi
4、s guide include hot water heaters and furnace. The guide alsois applicable to boilers.1.4 The methods given in this guide are applicable toCategory I (draft-hood- and induced-fan-equipped) furnaces.The guide does not apply to Category III (power-vent-equipped) or Category IV (direct-vent) furnaces.1
5、.5 The methods in this guide are not intended to identifybackdrafting or spillage due to vent blockage or heat-exchanger leakage.1.6 This guide is not intended to provide a basis fordetermining compliance with code requirements on applianceand venting installation, but does include a visual assessme
6、ntof the installation. This assessment may indicate the need for athorough inspection by a qualified technician.1.7 Users of the methods in this guide should be familiarwith combustion appliance operation and with making house-tightness measurements using a blower door. Some methodsdescribed in this
7、 guide require familiarity with differential-pressure measurements and use of computer-based data-logging equipment.1.8 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.9 This guide does not purport to address all safetyconcern
8、s, if any, associated with its use. It is the responsibilityof the user to establish appropriate safety and health practicesand to determine the applicability of regulatory limitationsprior to use. Carbon monoxide (CO) exposure or flame roll-outmay occur when performing certain procedures given in t
9、hisguide. See Section 7, for precautions that must be taken inconducting such procedures.2. Referenced Documents2.1 ASTM Standards:2D1356 Terminology Relating to Sampling and Analysis ofAtmospheresE631 Terminology of Building ConstructionsE779 Test Method for Determining Air Leakage Rate byFan Press
10、urization2.2 CAN/CGSB Standards:3CAN/CGSB 51.71 The Spillage TestMethod to Deter-mine the Potential for Pressure-Induced Spillage fromVented, Fuel-Fired; Space Heating Appliances; WaterHeaters, and Fireplaces2.3 ANSI Standards:4ANSI Z21.47 Gas-fired Central Furnace2.4 NFPA Standards:5NFPA 54 Nationa
11、l Fuel Gas Code3. Terminology3.1 Definitions:3.1.1 For definitions of general terms related to buildingconstruction used in this specification, refer to TerminologyE631, and for general terms related to sampling and analysis ofatmospheres, refer to Terminology D1356.1This guide is under the jurisdic
12、tion of ASTM Committee E06 on Performanceof Buildings and is the direct responsibility of Subcommittee E06.41 onAir Leakageand Ventilation Performance.Current edition approved Sept. 1, 2011. Published October 2011. Originallyapproved in 1999. Last previous edition approved in 2007 as E1998 02 (2007)
13、.DOI: 10.1520/E1998-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Canadian General Stand
14、ards Board (CGSB), Sales Center,Place du Portage III, 6B1, 11 Laurier Street, Gatineau, Quebec K1A 1G6, Canada,http:/www.tpsgc-pwgsc.gc.ca/ongc-cgsb/cn-cu-eng.html.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5Availabl
15、e from National Fire Protection Association (NFPA), 1 BatterymarchPark, Quincy, MA 02169-7471, http:/www.nfpa.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2 Definitions of Terms Specific to This Standard:3.2.1 air leakage, n
16、the movement or flow of air throughthe building envelope which is driven by a pressure differentialacross the envelope.3.2.2 air leakage rate, nthe volume of air movement perunit time across the building envelope.3.2.3 airtightness, nthe degree to which the buildingenvelope resists flow of air.3.2.4
17、 blower door, na fan pressurization device incorpo-rating a controllable fan and instruments for airflow measure-ment and building pressure difference measurement thatmounts securely in a door or other opening.3.2.5 Category 1 appliance, nan appliance that operateswith non-positive static pressure a
18、nd with a vent gas tempera-ture that avoids excessive condensate production in the vent(see NFPA 54).3.2.6 Category III appliance, nan appliance that operateswith a positive vent pressure and with a vent gas temperaturethat avoids excessive condensate production in the vent (seeNFPA 54).3.2.7 Catego
19、ry IV appliance, nan appliance that operateswith a positive vent pressure and with a vent gas temperaturethat may cause excessive condensate production in the vent(see NFPA 54).3.2.8 combustion system spillage, nentry of combustionproducts into a building from dilution air inlets, vent connectorjoin
20、ts, induced draft fan case opening, combustion air inlets, orother locations in the combustion or venting system of a ventedcombustion appliance (boiler, fireplace, furnace, or waterheater), caused by backdrafting, vent blockage, or leaks in theventing system.3.2.9 continuous pressure differential,
21、nthe incrementalhouse depressurization due to fans that can be operatedcontinuously, such as furnace blower or supply/exhaust venti-lator.3.2.10 downdrafting, nthe reversal of the ordinary (up-ward) direction of air flow in a chimney or flue when no ventedcombustion appliances are operating (as oppo
22、sed to backdraft-ing, which occurs when vented combustion appliances areoperating).3.2.11 house depressurization, nthe situation, pertainingto a specific location in a house, whereby the static pressure atthat location is lower than the static pressure in the immediatevicinity outside the house.3.2.
23、11.1 DiscussionThe pressure difference between in-doors and outdoors is affected by building tightness (includingthe distribution of leakage sites across the building envelope),indoor-outdoor temperature difference, local winds, and theoperation of indoor appliances such as exhaust fans, forced-airs
24、ystem fans, and vented combustion appliances (boilers, fire-places, furnaces, or water heaters). Thus, the existence andextent of house depressurization at a specific location variesover time, depending on outdoor conditions and the operationof indoor appliances.3.2.12 induced conditions, ncondition
25、s for house depres-surization created with the use of exhaust fans or blower door.3.2.13 induced draft (ID) fan, na fan used in a ventingsystem that removes flue gases under non-positive static ventpressure.3.2.13.1 DiscussionAn appliance with an ID fan is aCategory I appliance, as its venting syste
26、m is under non-positive static vent pressure.3.2.14 intermittent pressure differential, nthe incrementalhouse depressurization due to fans that are operated intermit-tently, such as clothes dryer, kitchen exhaust or bathroom fan.3.2.15 natural conditions, noutdoor temperature andwind conditions that
27、 create house depressurization.3.2.16 pressure differential, npressure difference acrossthe building envelope, expressed in pascals (inches of water orpound-force per square foot or inches of mercury).3.2.17 vented combustion appliance, nincludes fossil-fuel-fired furnace, boiler or water heater ven
28、ted to outside.3.2.17.1 DiscussionThe term vented combustion appli-ances in this standard excludes fireplaces and gas logs ventedto outside. Also, it does not include appliances such as gasranges or unvented space heaters.4. Summary of Guide4.1 This guide summarizes different methods for assessingba
29、ckdrafting and spillage from vented combustion appliances.For each method the equipment needed, test procedures, datareporting, results and interpretation, and technician and testtime required are presented. Advantages and uncertainties ofeach method are discussed.4.2 Assessment of depressurization-
30、induced backdraftingand spillage is conducted under either induced depressurizationor natural conditions. Depressurization is induced in a resi-dence by deliberately operating exhaust fans or a blower-doorfan. Assessments conducted under induced conditions canindicate only the potential for backdraf
31、ting and spillage.Assessments under natural conditions can indicate actualbackdrafting and spillage events. Assessments under eitherinduced or natural conditions may not be valid for weather,house tightness, or operational conditions beyond those en-countered during the period of measurements.4.3 Th
32、e guide includes four types of short term testsconducted under induced conditions: (1) house depressuriza-tion test with preset criteria; (2) downdrafting test; (3) appli-ance backdrafting test; and (4) cold vent establishment pressure(CVEP) test. A continuous backdraft test to identify backdraft-in
33、g events under natural conditions, which involves continuousmonitoring of vent differential pressures, is also described. Foridentification of spillage events or consequences thereof undernatural conditions, a continuous spillage test that involvescontinuous monitoring of spillage-zone temperatures
34、and in-door air quality is described. Because they are conducted undera variety of naturally occurring conditions, the continuousmethods can provide more definitive results for conditionsunder which tests are conducted. However, the continuousmethods also can be more time-consuming and resource-inte
35、nsive to apply.4.4 A purpose of the guide is to encourage the use ofconsistent procedures for any selected method.E1998 1125. Significance and Use5.1 Although a number of different methods have been usedto assess backdrafting and spillage (see NFPA 54, CAN/CGSB-51.71, and 1-4)6a single well-accepted
36、 method is notyet available. At this point, different methods can yielddifferent results. In addition, advantages and drawbacks ofdifferent methods have not been evaluated or described.5.2 To provide a consistent basis for selection of methods,this guide summarizes different methods available to ass
37、essbackdrafting and spillage. Advantages and limitations of eachmethod are addressed.5.3 One or more of the methods described in this guideshould be performed when backdrafting or spillage fromvented combustion appliances is suspected to be the cause of apotential problem such as elevated carbon mon
38、oxide (CO)levels or excessive moisture.5.4 The following are examples of specific conditions underwhich such methods could be performed:5.4.1 When debris or soot is evident at the draft hood,indicating that backdrafting may have occurred in the past,5.4.2 When a new or replacement combustion applian
39、ce isadded to a residence,5.4.3 When a new or replacement exhaust device or system,such as a downdraft range exhaust fan, a fireplace, or afan-powered radon mitigation system, is added,5.4.4 When a residence is being remodeled or otherwisealtered to increase energy efficiency, as with various types
40、ofweatherization programs, and5.4.5 When a CO alarm device has alarmed and a combus-tion appliance is one of the suspected causes of the alarm.5.5 Depending on the nature of the test(s) conducted and thetest results, certain preventive or remedial actions may need tobe taken. The following are examp
41、les:5.5.1 If any of the short-term tests indicates a potential forbackdrafting, and particularly if more than one test indicatessuch potential, then the appliance and venting system should befurther tested by a qualified technician, or remedial actionscould be taken in accordance with 5.5.3.5.5.2 If
42、 continuous monitoring indicates that backdrafting isoccurring, and particularly if it indicates that spillage isoccurring that impacts indoor air quality (for example, elevatedCO concentrations or excessive moisture in the house), thenremedial action is indicated.5.5.3 Possible remedial actions inc
43、lude the following:5.5.3.1 At a minimum, a CO alarm device could be installedin the house.5.5.3.2 Limiting the use of devices or systems that increasehouse depressurization, such as fireplaces and high-volumeexhaust fans. Proper sealing of any air leakage sites, especiallyat the top floor ceiling le
44、vel, can also reduce house depressur-ization at the lower levels of the house.5.5.3.3 Partially opening a window in the furnace or appli-ance room, if available. Keeping the door nearest the applianceroom open at all times or putting louvers in the door.5.5.3.4 Providing increased makeup air for the
45、 appliance(for example, by providing a small duct or opening to theoutdoors near the appliance).5.5.4 If remedial actions are not successful, then consider-ation can be given to correcting or replacing the venting systemor, if necessary, replacing the spilling appliance with one thatcan better toler
46、ate house depressurization.5.6 The understanding related to backdrafting and spillagephenomena is evolving. Comprehensive research using asingle, reliable method is needed to better understand thefrequency, duration, and severity of depressurization-inducedspillage in a broad cross section of homes
47、(5). In the absenceof a single well-accepted method for assessing the potential foror occurrence of backdrafting or spillage, alternative methodsare presented in this guide. The guide is intended to fosterconsistent application of these methods in future field work orresearch. The resultant data wil
48、l enable informed decisions onrelative strengths and weaknesses of the different methods andprovides a basis for any refinements that may be appropriate.Continued efforts along these lines will enable the developmentof specifications for a single method that is acceptable to allconcerned.6. Principl
49、es and Methods6.1 BackgroundResidences can be depressurized due tooperation of exhaust equipment and imbalanced air distributionsystems, as well as local weather. The extent of housedepressurization depends on the capacity of the exhaust equip-ment, the degree of imbalance in the air distribution system,and the airtightness of the building envelope. Outdoor tem-peratures also can affect the depressurization of the house. Forexample, the natural depressurization of a house would be afew to several pascals greater under winter conditions in thenorthern parts o
