Technology Demonstration of a 

Prototype Low Carbon Monoxide 

Emission Portable Generator

GIE+Expo, Louisville, KY

October 26, 2012

Janet Buyer

Project Manager, Portable Generators

U.S. Consumer Product Safety Commission

The material contained in this presentation is that of the CPSC staff and has not been reviewed or approved by, 

and may not necessarily reflect the views of, the Commission.

U.S. Consumer Product Safety Commission1
Overview

• What is the U.S. CPSC?

• Generators: Why CPSC Is Concerned

• CPSC Portable Generator Project History

• Technology Demonstration 

• Conclusions

• Q & A

2
U.S. CPSC

3

• CPSC is an independent regulatory agency created “to 

protect the public against unreasonable risks of injury 

associated with consumer products.”1

– Develops voluntary consensus safety standards in cooperation with industry 

– Adopts and enforces mandatory standards or bans consumer products if no 

feasible voluntary standard would adequately protect the public

– Obtains the recall of products and arranges for their repair, replacement, or 

refund

– Conducts research on emerging and potential product hazards 

– Informs and educates consumers through the media, state and local 

governments, private organizations, and responding to consumer inquiries

1 Section 2(b)(1) of the Consumer Product Safety Act, 15 U.S.C. §2051(b)(1).
4

What Is a Consumer Product?

 Jurisdiction over thousands of consumer products under the 

Consumer Product Safety Act

 Excludes some products covered by other federal agencies, such 

as:

– Cars and related equipment (NHTSA)

– Boats (Coast Guard)

– Airplanes (FAA)

– Food, drugs, medical devices, cosmetics (FDA)

– Firearms (ATF)

– Pesticides (EPA)

– Tobacco Products (ATF)
5

Four Types of Safety Concerns

• Product fails to comply with a mandatory 

safety standard or ban under the CPSA

• Product fails to comply with voluntary 

standards relied upon by the Commission

• Product contains a defect which could create 

a “substantial product hazard”

• Product creates an “unreasonable risk” of 

serious injury or death
Generators: Why CPSC Is Concerned

6

6

108

138

121

181

153

168

190

180 180

189

50

82

71

93

67

85

47 49

66

67

22

37

26

47

29

43

14 30 31 32

7 19 20

42

49

41

88 85

62

86

0

20

40

60

80

100

120

140

160

180

200

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Estimated Number of CO Deaths 

Year

Total from all Consumer Products All Heating Systems Furnaces Generators

Estimated Number of Non-Fire Consumer Product Related CO Deaths

Source: Hnatov, Matthew, Non-Fire Carbon Monoxide Deaths Associated with the Use of Consumer Products, 2008 Annual Estimates, U.S. 

Consumer Product Safety Commission, Bethesda, MD, December 2011
44

80

6

21 23

48

57

47

103

95

70

94

67

0

20

40

60

80

100

120

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Nuber of Reported Non-Fire CO Deaths Due to Generators 

Year

Serie

s2

Serie

s1

Reporting for years 2010 and 2011 is considered incomplete and islikely to change in future reports.

Reporting for years 1999-2009 is considered largely complete but may change to a relatively small extent in future reports. 

More Data Supports Our Concern...

7

Number of Reported Non-Fire CO Deaths Due to Portable Generators

Source: Hnatov, Matthew, Incidents, Deaths, and In-Depth Investigations Associated with Non-Fire Carbon Monoxide from Engine-Driven 

Generators and Other Engine-Driven Tools, 1999-2011, July 2012. 
Living space 

(nonbasement)

31%

Attached 

garage or 

enclosed 

carport

24%

Basement or 

crawlspace

28%

Closet, 

doorway, 

inside home no 

further 

information 

reported

11%

Outside home, 

2%

Unknown 

location but at 

home

4%

Fixedstructure 

home 

73%

Non-fixed home 

or temporary 

shelter 

18%

External 

structure at 

home

6%

Unknown or 

other locations

3%

Some of Our Hazard Analysis...

8

8

Location where incident occurred

Specific location of generator in 

incidents that occurred in fixedstructure homes
CPSC Portable Generator Project History

• 2003: Began participation as nonvoting member on STP for UL 2201, to advocate 

for requirements to address CO hazard

• 2004: Hosted roundtable to discuss hazard and solicit ideas

• 2006: Released staff report, “Review of Portable Generator Safety” and 

briefed Commission, recommending that most reliable way to reduce the 

CO poisoning risk is to reduce CO emission rate

Staff’s goal is not to reduce the CO emission rate to make generators safe to run indoors but, 

to reduce it enough, such that CO poisoning symptom onset is delayed, and the rate of 

progression of worsening symptoms is significantly reduced to provide a longer time interval 

for exposed occupants to escape before being incapacitated.

• 2006: Commission voted to approve ANPR to investigate technologies to reduce 

hazard

• 2007: FR for mandatory label, effective May 2007 

• 2006 to present: Performed, documented, and released report on technology 

demonstration 

9
Mandatory Label

DANGER

Using a generator indoors CAN KILL YOU IN 

MINUTES.

Generator exhaust contains carbon monoxide. 

This is a poison you cannot see or smell.

NEVER use inside a 

home or garage, 

EVEN IF doors and 

windows are open.

Only use OUTSIDE 

and far away from 

windows, doors, 

and vents.

10
Develop Prototype

2-Part Technology Demonstration 

11

Model Health Effects 

on Occupants

Durability Test Engine in 

Generator

Conduct Certification 

Emission Testing at 

End of Life

11

Operate Generator in 

Attached Garage

Determine Time 

Interval for “Egress”
12

University of Alabama

Design specifications:

• Adapt existing emission control technology on 5.0 kW generator

• 30 g/kW-hr target CO emission rate

• Do not negatively impact engine power output, engine durability, maintainability, 

fuel economy, and risk of fire/burn

• Maintain compliance with EPA emission standard to which engine was originally 

certified

Prototype configuration:

• Modified 8.2 kW (11 hp) Class II engine with 500-hour rated useful life, certified to 

EPA Phase 2 standard

• Adapted EMS with closed loop EFI

• Calibrated for stoichiometric (14.6) AFR at all loads

• Integrated 3-way catalyst, primarily to target NOx reduction, into shrouded muffler

Prototype Development

12
Mode 1 2 3 4 5 6

Load Bank Setting (kW) 5.5

*

4.7+ 3.2+ 1.5+ 0.6+ No resistive load

Duration (minutes) 5.5 12.0 17.5 18.0 4.0 3.0

Durability Testing

Hourly Load Profile Applied Throughout 500-hour Durability Program

Mode 1 2 3 4 5 6

Engine Power 100% 75% 50% 25% 10% No load

Weight Factor 0.09 0.20 0.29 0.30 0.07 0.05

Load Profile derived from EPA 6-mode test cycle in 40 CFR part 1065

* highest sustainable load without tripping generator’s circuit breaker (found to be 500 watts greater 

than generator’s advertised rated power output.)

+ derived by applying alternator efficiency curve to engine’s rated power of 8.2 kW

13
• After 500 hours, compared to the unmodified OEM unit, the 

prototype demonstrated:

– 93% reduction of CO

– 30% reduction of HC+NOx

– 20% reduction in average fuel consumption 

– Surface temperature of prototype’s muffler shroud was 110°C max, compared 

to 434°C for the OEM’s unshrouded muffler surface.

• On the prototype engine:

– 220°C max cylinder head temperature, below the engine manufacturer’s limit 

– Exhaust manifold gas temperature at all modes was within the catalyst 

manufacturer’s recommended operating range.

Durability Testing Conclusions

14
Intertek Carnot Emission Services

• Facility is lab-to-lab correlated with EPA and major manufacturer 

emission test facilities. 

• Conducted exhaust emission testing in accordance with EPA regs to 

verify Phase 2 compliance on:

• Prototype engine with muffler with integrated, aged catalyst

• Prototype engine with muffler without catalyst

• Performed tests with the engine installed in the generator

• Determined the engine power achieved for each mode during durability 

program

End-of-Life Emission Testing

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• With catalyst muffler: 

• HC+NOx was 6.7 g/kW-hr → 

• CO was 6.0 g/kW-hr → 95% CO emissions reduction compared to the 

published certification data for the unmodified engine

• <240°C max cylinder head temperature, below the engine manufacturer’s limit 

• Exhaust manifold gas temperature at all modes was within the catalyst 

manufacturer’s recommended operating range

• Delivered a maximum power of 7.9 kW, within 0.3 kW of the advertised rated 

power for the unmodified OEM carbureted engine

End-of-Life Emission Testing Conclusions

16

45% below Phase 2 standard

16% below Phase 3 standard
• Muffler w/o catalyst: 

• HC+NOx was 13.0 g/kW-hr →above Phase 2 standard

• CO was 28.1 g/kW-hr

• Correlation of engine fuel consumption in the generator to the 

dynamometer revealed max sustainable load on generator was 75% of full 

engine power. 

Dynamometer testing at mode 1 does not represent consumer use. The CO 

emission rate of the engine at the loads it achieves in the product is what is 

important. The prototype engine produced less than 25 grams/hour of CO 

at each mode of the load profile applied to the generator.

End-of-Life Emission Testing Conclusions

17
Develop Prototype

2-Part Technology Demonstration 

18

Model Health Effects 

on Occupants

Durability Test Engine in 

Generator

Conduct Certification 

Emission Testing at 

End of Life

18

Operate Generator in 

Attached Garage

Determine Time 

Interval for “Egress”
Operate Generator in SFH Attached Garage

National Institute of Standards and Technology (NIST)

4 scenarios tested to compare prototype with catalyst to OEM unit

(varied by positions of bay door, utility door, HVAC fan)

19

Garage

generator
20

Garage and Family Room CO Concentration Profiles

Garage Bay Door Fully Closed, Garage/Utility Room Door Fully Closed, and HVAC Fan On 20

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

21000

22000

0 30 60 90 120 150 180 210 240 270 300 330 360 390

CO (ppm)

Time (min)

CO in garage from unmodified unit

CO in FAM from unmodified unit

CO in garage from prototype

CO in FAM from prototype

Unmodified unit stopped and forced venting initiated Prototype stopped and forced venting initiated

 97%

reduction
0

10

20

30

40

50

60

70

80

90

100

0 30 60 90 120 150 180 210 240 270 300 330 360 390

COHb (%)

Time (minutes)

COHb in garage from unmodified unit

COHb in FAM from unmodified unit

COHb in garage from prototype

COHb in FAM from prototype

Health Effects Modeling

21

Death

Mild symptom 

onset

Obvious symptom 

onset

Incapacitation
0

10

20

30

40

50

0 30 60 90 120 150 180 210 240 270 300 330 360 390

COHb (%)

Time (minutes)

COHb in garage from unmodified unit

COHb in FAM from unmodified unit

COHb in garage from prototype

COHb in FAM from prototype

Time Intervals for “Egress”

22

8 min in 

garage

29 min 

in FAM

96 min 

in garage

FAM doesn’t reach 20% COHb in 6 hrs of engine run time

Incapacitation

(loss of chance 

for self-rescue)

Obvious 

symptom

onset

For these tests, if a CO alarm were in the MBR:

- With the unmodified unit in the garage, the CO concentration in the garage at the time of alarm activation would be 18,500 ppm. This would incapacitate anyone who entered the garage within 3 

minutes.

- With the prototype in the garage, the CO alarm activation criteria was not met. However, staff projects that it would activate at 400 minutes, assuming the CO in the MBR remained above 70 

ppm. The CO in the garage at that time is projected to be below 1,200 ppm, a level defined by NIOSH as being Immediately Dangerous to Life and Health (IDLH, “An acute respiratory exposure 

that poses an immediate threat of loss of life, immediate or delayed irreversible adverse effects on health, or acute eye exposure that would prevent escape from a hazardous atmosphere within 

30 minutes.”.

 Time (minutes)
Conclusions

• Prototype reduced the CO emission rate by 93% - 97% → more time for victims to 

escape.

• Dependent on human behavior, but additional time expected to result in fewer 

deaths.

• Urging manufacturers to voluntarily implement CO emission reduction control 

strategies to produce a significantly reduced CO emission rate when installed in the 

product. 

• Prototype used same commercially available, low-cost EMS used in Asian market 

for powered scooters and small motorcycles and used by EPA in Phase 3 

development work over 6 years ago. 

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Questions?

• Staff report “Technology Demonstration of a Prototype Low CO Emission 

Portable Generator” available online at: 

http://www.cpsc.gov/library/foia/foia12/os/portgen.pdf

(Or go to www.cpsc.gov and search for “Technology Demonstration”)

• Please send your comments to CPSC’s Office of the Secretary, 

cpsc-os@cpsc.gov by November 13, 2012.

• For further info:

 Janet Buyer, Project Manager

 jbuyer@cpsc.gov 

 301-987-2293

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