## STATUS REPORT ON GAS-FIRED WATER HEATER IGNITION OF FLAMMABLE VAPORS

October, 1996

For Additional Information Contact: Donald W. Switzer Directorate for Engineering Sciences (301) 504-0508 ext.1303

NOTE: This documrn! h.: not becIr CPSA n reviewed or acce;p!tir .2; the Co'nmii-ion. , aInituial . -Do' l-l- f U Products Identified Excepted by Firms Notified, _-- . r .~ --. JUnited States CONSUMER PRODUCT SAFETY COMMISSION Washington, D.C. 20207

MEMORANDUM DATE: 

### OCT 

### I 5 1996
TO The Commission Sadye E.Dunn, Secretary Through Eric A. Rubel; General Counsel Pamela Gilbert, Executive Director )~ FROM Ronald L. Medford, Assistant Executive Directork.lt for Hazard Identification and Reduction Donald W. Switzer, Chemical Engineer, ESEE (504-0508 ext. 1303) j_'

SUBJECT Status Report on Gas-Fired Water Heater Ignition ofFlammable Vapors
1. Purposr This status report updates the Commission on industry activities to develop voluntary standard requirements to address the hazard posed by gas-fired water heaters igniting flammable vapors. 2. Background Gas-fired water heaters igniting flammable vapors cause an estimated 1,961 fires each year resulting in an estimated 316'injuries, 17 deaths, and $26 million in property damage for a total societal cost which may be as high as $395 million. Typically, injuries occur when the victim isusing flammable liquids (usually gasoline) for cleaning purposes, or when the liquid leaks or is accidentally spilled near the water heater. Current water heater designs take combustion air from near the floor. When the burner ignites, the vapors in the room are swept into the water heater and ignited (Fig. 1), / which can cause a flashback fire or explosion. On December 15, 1994, Chairman Ann Brown Figure 1 directed the staffto work with the industry to develop the

NOTE: This document hasnotbeen CPSA 6(b)( d Cle reviewved or accepted hbthe Commnision, / Lnitial hJ- Date_ tN 

### I- ::. P : Or Prod'.llct '-necessary standards requirements to address the hazard andto provide periodic progress reports. Inthe last status report, dated March, 1996, staffreported tothe Commission that industry progress was satisfactory. 3. Evaluation ofIndustryActivities Industry has initiated two activities to address the flammable vapor ignition issue. The first is aprogram to develop a performance test methodology toevaluate water heater designs forresistance to flammable vapor ignition. This activity is theprimary focus ofthisstatus report. The second activity is development ofproprietary new designs to reduce thepotential for flammable vapor ignition. 3.1 Status ofTest Methodology Development: The goal ofdeveloping a performance testmethodology is to have uniform criteria against which to evaluate a water heater's resistance toflammable vapor ignition. Ultimately, all residential storage type water heaters will be design certified against these new criteria.
InJuly, 1996, the Gas Research Institute (GRI)published the final report on the methodology development project begun in October 1994. The purpose oftheproject was to develop a test methodology toform the basisfor specific standard requirements to be included inthe American National Standards Institute (ANSI)Standard for Gas-Fired Water Heaters, ANSI Z21.10.1. In the March, 1996, Status Report, staffreported that atotal of$1.4 million had been allocated for standards development activity. GRI hasincreased the amount allocated for this project to approximately $2.0 million to provide additional technical support to the voluntary standards activity, and to support field testing ofproducts. CPSC staffparticipated in developing the test methodology, and believes it to be very stringent. The approach being taken is to inject butane vapors into a chamber containing the water heater tightly controlling the vapor cloud height torepresent different spill scenarios. A water heater isthen operated in the chamber. The appliance is cycled through allits operating conditions including main burner off, main burner on, and cycling. Burner operations are controlled by drawing hot water offthe appliance as done in the home. If, at any time during the test, the vapors are ignited, the designfails the test. Itis, instaffs view, highly unlikely that a water heater certified to this test methodology would ignite vapors in the home. The methodology has beenpresented forreview to the Flammable Vapor Working Group oftheANSI water heater subcommittee. The new technologies being developed may incorporate features that will require changes to the standard in addition to the vapor ignition tests. Atpresent, the new technologies are not sufficiently mature todetermine the exact modifications that will need to be included in the standard. To facilitate this portion ofthe standard revision, those manufacturers involved in developing ignition resistant technologies have agreed to use the proposed test methodology in their product design testing. This servesboth to assure that the
2new technologies will be able topass thefinal test, and to generate experience usingthe test methodology. Waterheater manufacturers have agreed to coordinate their comments on the draft standard provisions through the Gas Appliance Manufacturers Association (GAMA). This will allow different manufacturers with different technologies to coordinate their comments without revealing proprietary information to their competitors. GAMA will present therecommended changes tothe Flammable Vapor Working group at its next meeting, tentatively scheduled for early 1997. This timing isnecessary to allowtime for additional product development testing, fine tuning the methodology, and identifying other necessary changes to the standard. At thattime, staffexpects thatthe major recommended changes to the standard will be adopted. Once the working group has completed developing itsrecommendations, they will beforwarded to thefull ANSI water heater subcommittee for adoption as a draft standard. The water heater manufacturers who sit on the subcommittee are developing therecommendations and CPSC staffexpects that the draft test method will have overwhelming manufacturer support atthe subcommittee level. Since the utilities have also been involved in developing the test methodology, CPSC staff expects support from that quarter as well. Manufacturers estimate itwill require 30 months, including industry review and public review, to finalize therevisions fromthe time thetest methodology isforwarded to the Flammable VaporWorking Group. Based on that estimate, CPSC staffcurrently expects that the revised standard incorporating vaporignition protection will be sent to ANSI in 1999for approval as anational standard. 3.2 Status ofProductDevelopment: In spring, 1995, several water heater manufacturers formed the Water HeaterJoint Research and Development Consortium to develop vapor ignition-resistant water heaters as quickly as possible. Specifics oftheproduct development activities are confidential and are not discussed inthis report. The work to date is within the confidential product development schedule provided to the Commission in December, 1994. 4. Conclusions Staffconcludes that industry progress indeveloping performance requirements fornew vaporignition-resistant water heater designs continues to be satisfactory. A sophisticated test methodology has been developed and appears acceptable to the staff. Barring unforeseen difficulties, a standard testmethod forresistance toflammable vapor ignition isexpected to be available on schedule, before new design water heaters are inproduction. Staffalsoviews the progress in developing new technology water heaters as satisfactory. Staffwill continue toprovide the Commission with written statusreports every six months, or at any point ifproblems develop orprogress becomes unsatisfactory. Staffwill aiso report tothe Commission ifproduct development isdelayed.

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