1、Designation: E 1998 02 (Reapproved 2007)Standard Guide forAssessing Depressurization-Induced Backdrafting andSpillage from Vented Combustion Appliances1This standard is issued under the fixed designation E 1998; the number immediately following the designation indicates the year oforiginal adoption
2、or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide describes and compares different methods forassessing the potenti
3、al for, or existence 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 appli
4、ances addressed inthis 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 (di
5、rect-vent) furnaces.1.5 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 incl
6、ude a visual assessmentof 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 met
7、hodsdescribed in this guide require familiarity with differential-pressure measurements and use of computer-based data-logging equipment.1.8 This guide does not purport to address all safetyconcerns, if any, associated with its use. It is the responsibilityof the user to establish appropriate safety
8、 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 thisguide. See Section 7, for precautions that must be taken inconducting such procedures.2. Referenced
9、Documents2.1 ASTM Standards:2D 1356 Terminology Relating to Sampling and Analysis ofAtmospheresE 631 Terminology of Building ConstructionsE 779 Test Method for Determining Air Leakage Rate byFan PressurizationE 1827 Test Methods for Determining Airtightness ofBuildings Using an Orifice Blower Door2.
10、2 CGSB Standard:351.71 The Spillage TestMethod to Determine the Poten-tial for Pressure-Induced Spillage from Vented, Fuel-Fired; Space Heating Appliances; Water Heaters, andFireplaces2.3 ANSI Standard:4Z21.47 Gas-fired Central Furnace2.4 NFPA Standard:554 National Fuel Gas Code3. Terminology3.1 Def
11、initionsFor definitions of terms used in this guide,refer to Terminologies E 631 and D 1356.3.2 Definitions of Terms Specific to This Standard:3.2.1 air leakage, nthe movement or flow of air throughthe building envelope which is driven by a pressure differentialacross the envelope.3.2.2 air leakage
12、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 blower door, na fan pressurization device incorpo-rating a controllable fan and instruments for airflow measure-ment and building pressu
13、re difference measurement thatmounts securely in a door or other opening.1This guide is under the jurisdiction of ASTM Committee E06 on Performanceof Buildings and is the direct responsibility of Subcommittee E06.41 onAir Leakageand Ventilation Performance.Current edition approved Aug. 1, 2007. Publ
14、ished August 2007. Originallyapproved in 1999. Last previous edition approved in 2002 as E 1998 02.2For 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 Doc
15、ument Summary page onthe ASTM website.3Available from the CGSB Sales Centre, Ottawa, Canada K1A 1G6.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5Available from National Fire Protection Association (NFPA), 1 Batterymar
16、chPark, 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.3.2.5 Category 1 appliance, nan appliance that operateswith non-positive static pressure and with a vent gas tempera-ture that avoids e
17、xcessive 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 Category IV appliance, nan appliance that operatesw
18、ith 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 connectorjoints, induced draft fan case opening, combustio
19、n 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, nthe incrementalhouse depressurization due to
20、 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 opposed to backdraft-ing, which occurs when vente
21、d 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.3.2.11.1 DiscussionThe pressure difference betwee
22、n 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-airsystem fans, and vented combustion appliances
23、(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, nconditions for house depres-surization created with th
24、e 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 system is under non-positive static vent pressure.
25、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 create house depressurization.3.2.16 pressur
26、e 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 vented to outside.3.2.17.1 DiscussionThe term ve
27、nted 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 assessingbackdrafting and spillage from vented combustio
28、n 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-induced backdraftingand spillage is conducted
29、 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 backdrafting and spillage.Assessments under natural c
30、onditions 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 The guide includes four types of short term tes
31、tsconducted 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-ing events under natural conditions, which invo
32、lves 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 and in-door air quality is described. Because
33、 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-intensive to apply.4.4 A purpose of the guide is
34、to encourage the use ofconsistent procedures for any selected method.5. 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) a single well-accepted method is not yetavailable. At this point, different
35、methods can yield differentresults. In addition, advantages and drawbacks of differentmethods have not been evaluated or described.5.2 To provide a consistent basis for selection of methods,this guide summarizes different methods available to assessbackdrafting and spillage. Advantages and limitatio
36、ns 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 aE 1998 02 (2007)2potential problem such as elevated carbon monoxide (CO)levels or excessive moistur
37、e.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 appliance isadded to a residence,5.4.3 When
38、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 ofweatherization programs, and5.4.5 W
39、hen 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 examples:5.5.1 If any of the short-term te
40、sts 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 5.5.35.5.2 If continuous monitoring indicates that
41、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 include the following:5.5.3.1 At a minimu
42、m, 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 level, can also reduce house depressur-i
43、zation 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 appliance(for example, by providing a
44、 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 tolerate house depressurization.5.6 The und
45、erstanding 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 (5). In the absenceof a single well-ac
46、cepted 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 will enable informed decisions onrelative
47、 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. Principles and Methods6.1 BackgroundResidences
48、 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 build
49、ing 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 of the country than during summer. The changesin depressurization of the house due to outdoor conditions(temperature and wind) often can be greater than changescaused by exhaust appliances. Downdrafting, which can resultfrom house depressurization, is the reversal of the ordinary(upward) direction of air flow in a chimney or flue when no
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