ASTM E1998-11(2018)
(Guide)Standard Guide for Assessing Depressurization-Induced Backdrafting and Spillage from Vented Combustion Appliances
Standard Guide for Assessing Depressurization-Induced Backdrafting and Spillage from Vented Combustion Appliances
SIGNIFICANCE AND USE
5.1 Although a number of different methods have been used to assess backdrafting and spillage (see NFPA 54, CAN/CGSB-51.71, and 1-4)6 a single well-accepted method is not yet available. At this point, different methods can yield different results. In addition, advantages and drawbacks of different 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 assess backdrafting and spillage. Advantages and limitations of each method are addressed.
5.3 One or more of the methods described in this guide should be performed when backdrafting or spillage from vented combustion appliances is suspected to be the cause of a potential problem such as elevated carbon monoxide (CO) levels or excessive moisture.
5.4 The following are examples of specific conditions under which 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 is added 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 a fan-powered radon mitigation system, is added,
5.4.4 When a residence is being remodeled or otherwise altered to increase energy efficiency, as with various types of weatherization programs, and
5.4.5 When a CO alarm device has alarmed and a combustion appliance is one of the suspected causes of the alarm.
5.5 Depending on the nature of the test(s) conducted and the test results, certain preventive or remedial actions may need to be taken. The following are examples:
5.5.1 If any of the short-term tests indicates a potential for backdrafting, and particularly if more than one test indicates such potential, then the appliance and venting system should be further tested by a qualified technician, or remedial actions could be taken in accordance w...
SCOPE
1.1 This guide describes and compares different methods for assessing the potential for, or existence of, depressurization-induced backdrafting and spillage from vented residential combustion appliances.
1.2 Assessment of depressurization-induced backdrafting and spillage is conducted under either induced depressurization or natural conditions.
1.3 Residential vented combustion appliances addressed in this guide include hot water heaters and furnace. The guide also is applicable to boilers.
1.4 The methods given in this guide are applicable to Category 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 The methods in this guide are not intended to identify backdrafting or spillage due to vent blockage or heat-exchanger leakage.
1.6 This guide is not intended to provide a basis for determining compliance with code requirements on appliance and venting installation, but does include a visual assessment of the installation. This assessment may indicate the need for a thorough inspection by a qualified technician.
1.7 Users of the methods in this guide should be familiar with combustion appliance operation and with making house-tightness measurements using a blower door. Some methods described in this 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 as standard. No other units of measurement are included in this standard.
1.9 This guide does not purport to address all safety concerns, if any, associated with its use. It is the responsibility of the user to establish appropriate safety, health, and environmental practices and to determine the applicability of regulatory limitations prior to use. Carbon monoxide (CO) exposure or flame roll-out may occur when performing certain proc...
General Information
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1998 − 11 (Reapproved 2018)
Standard Guide for
Assessing Depressurization-Induced Backdrafting and
Spillage from Vented Combustion Appliances
This standard is issued under the fixed designation E1998; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.9 This guide does not purport to address all safety
concerns, if any, associated with its use. It is the responsibility
1.1 Thisguidedescribesandcomparesdifferentmethodsfor
of the user to establish appropriate safety, health, and envi-
assessing the potential for, or existence of, depressurization-
ronmental practices and to determine the applicability of
induced backdrafting and spillage from vented residential
regulatory limitations prior to use. Carbon monoxide (CO)
combustion appliances.
exposure or flame roll-out may occur when performing certain
1.2 Assessment of depressurization-induced backdrafting
procedures given in this guide. See Section 7, for precautions
andspillageisconductedundereitherinduceddepressurization
that must be taken in conducting such procedures.
or natural conditions.
1.10 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.3 Residential vented combustion appliances addressed in
thisguideincludehotwaterheatersandfurnace.Theguidealso ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
is applicable to boilers.
mendations issued by the World Trade Organization Technical
1.4 The methods given in this guide are applicable to
Barriers to Trade (TBT) Committee.
Category I (draft-hood- and induced-fan-equipped) furnaces.
The guide does not apply to Category III (power-vent-
2. Referenced Documents
equipped) or Category IV (direct-vent) furnaces.
2.1 ASTM Standards:
1.5 The methods in this guide are not intended to identify
D1356 Terminology Relating to Sampling and Analysis of
backdrafting or spillage due to vent blockage or heat-
Atmospheres
exchanger leakage.
E631 Terminology of Building Constructions
1.6 This guide is not intended to provide a basis for E779 TestMethodforDeterminingAirLeakageRatebyFan
Pressurization
determining compliance with code requirements on appliance
and venting installation, but does include a visual assessment 2.2 CAN/CGSB Standard:
CAN/CGSB51.71 TheSpillageTest—MethodtoDetermine
of the installation. This assessment may indicate the need for a
thorough inspection by a qualified technician. the Potential for Pressure-Induced Spillage from Vented,
Fuel-Fired;SpaceHeatingAppliances;WaterHeaters,and
1.7 Users of the methods in this guide should be familiar
Fireplaces
with combustion appliance operation and with making house-
2.3 ANSI Standard:
tightness measurements using a blower door. Some methods
ANSI Z21.47 Gas-fired Central Furnace
described in this guide require familiarity with differential-
2.4 NFPA Standard:
pressure measurements and use of computer-based data-
NFPA 54 National Fuel Gas Code
logging equipment.
1.8 The values stated in SI units are to be regarded as
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
standard. No other units of measurement are included in this
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
standard.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Available from Canadian General Standards Board (CGSB), 11 Laurier St.,
This guide is under the jurisdiction of ASTM Committee E06 on Performance Phase III, Place du Portage, Gatineau, Quebec K1A0S5, Canada, http://www.tpsgc-
of Buildings and is the direct responsibility of Subcommittee E06.41 on Air pwgsc.gc.ca/ongc-cgsb.
Leakage and Ventilation Performance. Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
Current edition approved July 1, 2018. Published July 2018. Originally approved 4th Floor, New York, NY 10036, http://www.ansi.org.
in 1999. Last previous edition approved in 2011 as E1998 – 11. DOI: 10.1520/ Available from National Fire Protection Association (NFPA), 1 Batterymarch
E1998-11R18. Park, Quincy, MA 02169-7471, http://www.nfpa.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1998 − 11 (2018)
3. Terminology system fans, and vented combustion appliances (boilers,
fireplaces, furnaces, or water heaters). Thus, the existence and
3.1 Definitions:
extent of house depressurization at a specific location varies
3.1.1 For definitions of general terms related to building
over time, depending on outdoor conditions and the operation
construction used in this specification, refer to Terminology
of indoor appliances.
E631,andforgeneraltermsrelatedtosamplingandanalysisof
3.2.12 induced conditions, n—conditions for house depres-
atmospheres, refer to Terminology D1356.
surization created with the use of exhaust fans or blower door.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 air leakage, n—the movement or flow of air through
3.2.13 induced draft (ID) fan, n—a fan used in a venting
the building envelope which is driven by a pressure differential
system that removes flue gases under non-positive static vent
across the envelope.
pressure.
3.2.13.1 Discussion—An appliance with an ID fan is a
3.2.2 air leakage rate, n—the volume of air movement per
Category I appliance, as its venting system is under non-
unit time across the building envelope.
positive static vent pressure.
3.2.3 airtightness, n—the degree to which the building
3.2.14 intermittent pressure differential, n—the incremental
envelope resists flow of air.
house depressurization due to fans that are operated
3.2.4 blower door, n—a fan pressurization device incorpo-
intermittently, such as clothes dryer, kitchen exhaust or bath-
rating a controllable fan and instruments for airflow measure-
room fan.
ment and building pressure difference measurement that
3.2.15 natural conditions, n—outdoortemperatureandwind
mounts securely in a door or other opening.
conditions that create house depressurization.
3.2.5 Category 1 appliance, n—an appliance that operates
3.2.16 pressure differential, n—pressure difference across
with non-positive static pressure and with a vent gas tempera-
the building envelope, expressed in pascals (inches of water or
ture that avoids excessive condensate production in the vent
pound-force per square foot or inches of mercury).
(see NFPA 54).
3.2.17 vented combustion appliance, n—includes fossil-
3.2.6 Category III appliance, n—an appliance that operates
fuel-fired furnace, boiler or water heater vented to outside.
with a positive vent pressure and with a vent gas temperature
3.2.17.1 Discussion—The term vented combustion appli-
that avoids excessive condensate production in the vent (see
ances in this standard excludes fireplaces and gas logs vented
NFPA 54).
to outside. Also, it does not include appliances such as gas
3.2.7 Category IV appliance, n—an appliance that operates
ranges or unvented space heaters.
with a positive vent pressure and with a vent gas temperature
that may cause excessive condensate production in the vent
4. Summary of Guide
(see NFPA 54).
4.1 This guide summarizes different methods for assessing
3.2.8 combustion system spillage, n—entry of combustion
backdrafting and spillage from vented combustion appliances.
products into a building from dilution air inlets, vent connector
For each method the equipment needed, test procedures, data
joints, induced draft fan case opening, combustion air inlets, or
reporting, results and interpretation, and technician and test
otherlocationsinthecombustionorventingsystemofavented
time required are presented. Advantages and uncertainties of
combustion appliance (boiler, fireplace, furnace, or water
each method are discussed.
heater), caused by backdrafting, vent blockage, or leaks in the
4.2 Assessment of depressurization-induced backdrafting
venting system.
andspillageisconductedundereitherinduceddepressurization
3.2.9 continuous pressure differential, n—the incremental
or natural conditions. Depressurization is induced in a resi-
house depressurization due to fans that can be operated
dence by deliberately operating exhaust fans or a blower-door
continuously, such as furnace blower or supply/exhaust venti-
fan. Assessments conducted under induced conditions can
lator.
indicate only the potential for backdrafting and spillage.
3.2.10 downdrafting, n—the reversal of the ordinary (up-
Assessments under natural conditions can indicate actual
ward)directionofairflowinachimneyorfluewhennovented backdrafting and spillage events. Assessments under either
combustion appliances are operating (as opposed to
induced or natural conditions may not be valid for weather,
backdrafting, which occurs when vented combustion appli- house tightness, or operational conditions beyond those en-
ances are operating).
countered during the period of measurements.
3.2.11 house depressurization, n—the situation, pertaining 4.3 The guide includes four types of short term tests
to a specific location in a house, whereby the static pressure at
conducted under induced conditions: (1) house depressuriza-
that location is lower than the static pressure in the immediate
tion test with preset criteria; (2) downdrafting test; (3) appli-
vicinity outside the house.
ancebackdraftingtest;and(4)coldventestablishmentpressure
3.2.11.1 Discussion—The pressure difference between in- (CVEP) test.Acontinuous backdraft test to identify backdraft-
doors and outdoors is affected by building tightness (including ingeventsundernaturalconditions,whichinvolvescontinuous
the distribution of leakage sites across the building envelope), monitoring of vent differential pressures, is also described. For
indoor-outdoor temperature difference, local winds, and the identification of spillage events or consequences thereof under
operation of indoor appliances such as exhaust fans, forced-air natural conditions, a continuous spillage test that involves
E1998 − 11 (2018)
continuous monitoring of spillage-zone temperatures and in- 5.5.3 Possible remedial actions include the following:
doorairqualityisdescribed.Becausetheyareconductedunder
5.5.3.1 Ataminimum,aCOalarmdevicecouldbeinstalled
a variety of naturally occurring conditions, the continuous
in the house.
methods can provide more definitive results for conditions
5.5.3.2 Limiting the use of devices or systems that increase
under which tests are conducted. However, the continuous
house depressurization, such as fireplaces and high-volume
methods also can be more time-consuming and resource-
exhaust fans. Proper sealing of any air leakage sites, especially
intensive to apply.
at the top floor ceiling level, can also reduce house depressur-
ization at the lower levels of the house.
4.4 A purpose of the guide is to encourage the use of
consistent procedures for any selected method.
5.5.3.3 Partially opening a window in the furnace or appli-
ance room, if available. Keeping the door nearest the appliance
5. Significance and Use
room open at all times or putting louvers in the door.
5.1 Although a number of different methods have been used 5.5.3.4 Providing increased makeup air for the appliance
toassessbackdraftingandspillage(seeNFPA54,CAN/CGSB- (for example, by providing a small duct or opening to the
51.71, and 1-4) a single well-accepted method is not yet outdoors near the appliance).
available. At this point, different methods can yield different
5.5.4 If remedial actions are not successful, then consider-
results. In addition, advantages and drawbacks of different
ationcanbegiventocorrectingorreplacingtheventingsystem
methods have not been evaluated or described.
or, if necessary, replacing the spilling appliance with one that
can better tolerate house depressurization.
5.2 To provide a consistent basis for selection of methods,
this guide summarizes different methods available to assess
5.6 The understanding related to backdrafting and spillage
backdrafting and spillage. Advantages and limitations of each
phenomena is evolving. Comprehensive research using a
method are addressed.
single, reliable method is needed to better understand the
5.3 One or more of the methods described in this guide frequency, duration, and severity of depressurization-induced
should be performed when backdrafting or spillage from spillage in a broad cross section of homes (5). In the absence
vented combustion appliances is suspected to be the cause of a of a single well-accepted method for assessing the potential for
potential problem such as elevated carbon monoxide (CO) or occurrence of backdrafting or spillage, alternative methods
levels or excessive moisture. are presented in this guide. The guide is intended to foster
consistent application of these methods in future field work or
5.4 The following are examples of specific conditions under
research. The resultant data will enable informed decisions on
which such methods could be performed:
relative strengths and weaknesses of the different methods and
5.4.1 When debris or soot is evident at the draft hood,
provides a basis for any refinements that may be appropriate.
indicating that backdrafting may have occurred in the past,
Continuedeffortsalongtheselineswillenablethedevelopment
5.4.2 When a new or replacement combustion appliance is
of specifications for a single method that is acceptable to all
added to a residence,
concerned.
5.4.3 When a new or replacement exhaust device or system,
such as a downdraft range exhaust fan, a fireplace, or a
6. Principles and Methods
fan-powered radon mitigation system, is added,
5.4.4 When a residence is being remodeled or otherwise
6.1 Background—Residences can be depressurized due to
altered to increase energy efficiency, as with various types of
operationofexhaustequipmentandimbalancedairdistribution
weatherization programs, and
systems, as well as local weather. The extent of house
5.4.5 When a CO alarm device has alarmed and a combus-
depressurization depends on the capacity of the exhaust
tion appliance is one of the suspected causes of the alarm.
equipment, the degree of imbalance in the air distribution
system, and the airtightness of the building envelope. Outdoor
5.5 Dependingonthenatureofthetest(s)conductedan
...
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