The House As a Chimney Combustion Gas Concentrations from Unvented Fireplaces

The House as a Chimney Combustion Gas Concentrations from Unvented Fireplaces

Jeffrey Gordon Building Research Council University of Illinois

1 HUD Healthy Homes 04 Grant

• Investigate the concentration of combustion gases in houses using “vent- free” gas fireplaces . • Examine the factors that will impact the gas concentrations , on both the generation and dilution sides.

2 Unvented Gas Fireplaces • About 30 million sold in the U.S. since 1980 • Intended use – supplemental heat, not primary heat, and decorative ambiance • Sizing of unit emphasized (40,000 Btu max) • All combustion gases released into home • Popular for cost, ease of installation, efficiency

3 Bridging the Chasm

Industry BS and Others “These things “What are you, are safe. nuts? This is No problem.” crazy”

AGARD report Some anecdotal studies

4 Project Activities

• Field Test 30 houses – combustion gas concentrations • Lab test new and used vent-free fireplaces • Modeling • Survey of Users Analyygsis grew with the richness of the dataset – decay rates, moisture analysis Will focus on the field tests today

5 Gas Concentrations of Concern

• Carbon Dioxide (CO2)

• Water Vapour (H2O) • CbCarbon Monox id(CO)ide (CO)

•NOx, NO, and Nitrogen Dioxide (NO2)

• Oxygen (O2) Did not study particulates or other minor gases

6 BRC Researchers

• Paul Francisco, Co-PI • Jeff Gordon, Co-PI • Bill Rose, Instrument Guru and Scapegoat

7 Experimental Setup

BllVlBall Valve Vacuum pump

Desiccant chamber Rotameter

CO2

Permeation drier

NO2

Heater Ball Valve

Vacuum gauge

Rotameter 8 Instrument Cart

• CO and CO2 - non- dispersive infrared analyzer

•NOx, NO, NO2 – chemiluminescence analyzer

•O2 – paramagnetic analyzer integral to the NOx analyzer • Pumps, rotameters, gau ges, dry ers, bells and whistles All instruments were calibrated at each house 9 HOBO Remote Sensors

• Temp/RH

•CO

•Exterior Temp/RH CO2

10 Field Tests

• Tested 30 homes using unvented gas fireplaces • Measurements every minute for 3-4 days • Indoor combustion gas concentrations:

CO, CO 2, NOx, NO, NO 2, O2, H2O • Also measured temperatures (on/off times of fireplace and primary heating – furnace)

11 Housing Characteristics

House Age House Size Blower Door Fireplace Age (Years) (ft2) (ACH50) (Years) Minimum 3 1195 5.6 0 (4 weeks)

MdiMedian 34 1959 11. 4 4

Maximum 100 3000 26.3 15

All houses in Central Illinois. Usage patterns were equally variable. 12 Threshold Values

Combustion Threshold Value Source Notes Product 250 ppb – 1 hr avg Health Canada NO2 No US standard 110 ppb - 1hravg1 hr avg WHO

9 ppm – 8 hr avg US EPA 9 ppm WHO CO 35 ppm – 1 hr avg US EPA 25 ppm WHO

CO2 3500 ppm Health Canada “Long-term” avg

O “Oxygen depleted 2 19.5% continuous NIOSH (depletion) environment” Also Dewpo in t > 60% RH ASHRAE 55-92 H2O 10 Co 13 What does the data look like? Case Study: House #18

One study of n = 30, but also 30 studies of n = 1 In this case: • One story ranch house • Retired couple • Infrequent fireplace usage – aabecembience

14 What does the data look like? – TtTiliTemperature Timeline Figure 1: Fireplace Use 200 12/11 12/12 12/13 12/14 Fireplace 180 Room Furnace 160 exterior temp F

140

120 F 100 mp ee T

20 156 min 79 minmin 74 minmin 0 39 41 43 222 405 548 731 914 224 407 550 733 916 226 409 552 735 918 1238 1421 1604 1747 1930 2113 2256 1057 1240 1423 1606 1749 1932 2115 2258 1059 1242 1425 1608 1751 1934 2117 2300 1101 15 Carbon Dioxide Timeline Figure 4: CO2 Concentration 4000 12/11 12/12 12/13 12/14

3500 3500 ppm Long Term - Health Canada

3000

2500

2000 ppm

1500

1000 935 ppm - Test period average

500

0 4 34 142 320 458 636 814 952 104 242 420 558 736 914 212 350 528 706 844 1238 1416 1554 1732 1910 2048 2226 1130 1308 1446 1624 1802 1940 2118 2256 1022 1200 1338 1516 1654 1832 2010 2148 2326 1052 16 Carbon Monoxide Timeline

Figure 2: CO Concentration 30 12/11 12/12 12/13 12/14

25 CO ppm CO 1 hour CO 8 hour 20

15ppm CO

10 EPA standard = 9 ppm 8-hr

0 8 20 32 202 344 526 708 850 150 332 514 656 838 214 356 538 720 902 1032 1214 1356 1538 1720 1902 2044 2226 1020 1044 1226 1408 1550 1732 1914 2056 2238 1238 1420 1602 1744 1926 2108 2250 17 Nitrogen Dioxide Timeline

Figure 6: NO2 Concentration 0.8 12/11 12/12 12/13 12/14

0.7 NO2 ppm NO2 1 hour

060.6

0.5 mm

0.4 NO2 pp

0.3

Health Canada = 250 ppb 1 hr avg

0.2

WHO = 110 ppb 1 hour avg 0.1

0 12 27 134 311 448 625 802 939 149 326 503 640 817 954 204 341 518 655 832

1238 1415 1552 1729 1906 2043 2220 2357 1116 1253 1430 1607 1744 1921 2058 2235 1131 1308 1445 1622 1759 1936 2113 2250 1009 1146 18 Dewpoint Temperature Timeline

Figure 7: DewPoint Temp 55 12/11 12/12 12/13 12/14

50 Condesation potential of double pane window @ 10 F outside

40 F pp Tem 35 mantel Dewpt F Nextrm Dewpt 30 midrm Dewpt

9 0 2 50 4 4 5 1238 1 24 1 17 2011 2 113 34 6 8 9 846 34 1 1 3 1117 1 12 2 5 6 19 16 1850 2 2 454 5 7 8 9 2352 72 9 5 0 2 22 72 0 0 4 Ti me 1 14 1 1 6 20 2231 333 60 835 0 11 Oxygen Timeline

Figure 5: Oxygen Concentration

21 12/11 12/12 12/13 12/14

20.75

20.5

20.25

% 20 22 O

19.75

19.5 NIOSH O2 Threshold = 19.5%

19.25

19 4 34 142 320 458 636 814 952 212 350 528 706 844 104 242 420 558 736 914 1238 1416 1554 1732 1910 2048 2226 1130 1308 1446 1624 1802 1940 2118 2256 1022 1200 1338 1516 1654 1832 2010 2148 2326 1052 20 Vent-Free Field Tests Results

CO CO2 NO2 O2 H2O FIELD TEST >35> 35 >9> 9 > 3500 > 250 >110> 110 SUMMARY ppm ppm ppm ppb ppb <19.5 DP > 1hr avg 8hr avg test avg 1hr avg 1hr avg % 10 Co Year 1 Count 0 2 0 7 11 0 4 Field Tests % 0.0% 13.3% 0.0% 46.7% 73.3% 0.0% 26.7% (n=15) Year 2 Count 04061313 Field Tests % 0.0% 26.7% 0.0% 40.0% 86.7% 6.7% 20.0% (n=15) All Count 0 6 0 13 24 1 7 Field Test % 00%0.0% 20. 0% 00%0.0% 43. 3% 80. 0% 33%3.3% 23. 3% (n=30) 21 N = 30 Conclusions • 20% of homes exceeded the 8-hour avg. threshold for CO, typicall y durin g extended use of the fireplace. Only one of these exceeded 10.1 ppm. None of the homes exceeded the 1-hour avg. threshold of 35 ppm.

• Most problematic combustion product was NO2. 43% exceeded the 250 ppb threshold. 80% exceeded the 110 ppb threshold. • Humidityyp was not a problem in an y house. • Oxygen depletion was rare, and never triggered the oxygen depletion sensor. One house fell below the 19. 5% t hres ho ld. 22 N = 30 Conclusions

• Primary vs. Secondary heating . This was an elusive distinction. Some occupants turned down the thermostat to the furnace. In many cases, proximity to fireplace overrode the furnace thermostat. Fireplace was often the prihtimary heat source. OhOne house use ditd it exclusively as primary, and had extremely high

CO2 and NO2 levels • When the fireplace is operating it usually acts as primary – furnace does not operate

23 Gas Concentration Factors

• Generation – Size (BTU/hr) of appliance – Duration of Use – High vs. low settings – Maintenance – Primary vs. Secondary heat source – Continuous vs. Cycling operation – Insulation – heat loss

24 Gas Concentration Factors

• Dilution – Air change rate (blower door test) – House size, CAZ size – Ventilation provided at installation – Supplemental ventilation during operation (window use, door use) – Age of house

25 Conclusions: Correlations

• Correlations. Based on single and multi- variable analysis, there was no specific house or fireplace characteristic that predicted the concentration of any of the combustion gases. • None of these factors had a statistically significant correlation to any gas concentration or accumulation rate • IdiIndicator o f many i iflnfluences, too sma llfll of a dataset to extricate causality

26 Relationship between gases

• All gas accumulation rates were highly correlated, EXCEPT for CO. • Suggests that all gases but CO are purely from basic combustion • CO has o ther con tr ibu tors

27 CO vs . NOx

• Common belief:

– Cooler flame leads to higher CO, lower NOx

– Hotter flame leads to lower CO, higher NOx • Does not consider additional contributors tCOdto CO producti on

• Does not necessarily mean NO2

28 CO vs NO/NO2 Ratio

12 R2 = 0.4858 ee 10

8 -hour averag -hour 88

6 Max C0 C0 Max

0 0 5 10 15 20 25 30 35 40 45 50 NO2/NOx % 29 AFewNA Few N = 1Examples1 Examples

• What about an old leaky house? • 26.3 ACH50 • 2ldfil2 year old fireplace • Constant cycling on thermostat

30 Fireplace Room Temp Figure 1: Fireplace Use Exterior Temp 180 2/5 2/6 2/7 2/8

160

140

120

100 Temp F Temp 80

0 101 301 501 701 901 101 301 501 701 901 101 301 501 701 901 1501 1701 1901 2101 2301 1101 1301 1501 1701 1901 2101 2301 1101 1301 1501 1701 1901 2101 2301 31 CO ppm CO -1hr average Figure 2 : CO C oncent rati ons CO -8hr average

10 2/5 2/6 2/7 2/8

9 EPA standard = 9 ppm 8-hr avg

5 O ppm CC

1 1 1 1 1 1 1 1 1 1 31 31 31 31 31 01 31 01 31 01 3 10 33 60 83 20 43 70 931 30 531 80 1501 17 2001 22 1101 13 1601 18 2101 23 12 14 17 19 22 32 Figure 3:3: CO2CO2 Concentrations Concentrations CO2 exteriorexterior CO2 ppm Hariba

4000 2/5 2/6 2/7 2/8

3500 3500 ppm Long Term - Health Canada

3000

2500

2000 2 ppm OO C

1500

1153 ppm Test Period Average 1000

500

0 101 301 501 701 901 101 301 501 701 901 101 301 501 701 901 1501 1701 1901 2101 2301 1101 1301 1501 1701 1901 2101 2301 1101 1301 1501 1701 1901 2101 2301 33 House Example #3 – Site 26

• 12.5 ACH50 • 15 year old fireplace • CliCycling on thermos tttat • Installed in tight basement

34 furnace Figure 1: Fireplace Use fireplace room exterior temp 220 1/22 1/23 1/24 1/25

200

180

160

140

120

Temp F Temp 100

0 30 30 30 230 430 630 830 230 430 630 830 230 430 630 830 1030 1030 1230 1430 1630 1830 2030 2230 1030 1230 1430 1630 1830 2030 2230 1630 1830 2030 2230

35 CO ppm CO 1 hour Figure 2: CO Concentrations CO 8 hour

25 1/22 1/23 1/24 1/25

EPA standard = 9 ppm 8-hr O ppm CC

0 30 30 30 230 430 630 830 230 430 630 830 230 430 630 830 1630 1830 2030 2230 1030 1230 1430 1630 1830 2030 2230 1030 1230 1430 1630 1830 2030 2230 36 CO2 Interior Figure 4: CO2 Concentrations CO2 Exterior

5000 1/22 1/23 1/24 1/25

4500

4000

3500 Health Canada = 3500 ppm long-term

3000 m 2500 2 pp OO C 2000 2045 ppm - Test period average

1500

1000

500

0 30 30 30 230 430 630 830 230 430 630 830 230 430 630 830 1030 1230 1430 1630 1830 2030 2230 1030 1230 1430 1630 1830 2030 2230 1630 1830 2030 2230 37 House Example #4 – Site 20

• 9. 2 ACH50 • 2 year old fireplace • RtilRuns continuously – usedihtd as primary heat • Week-long test

38 Furnace Fireplace Figure 1: Fireplace Use Exterior Room

200 1/25 1/26 1/27 1/28 1/29 1/30 1/31 2/1

180

160

140

120

100 emp F TT

0 300 700 300 700 300 700 300 700 300 700 300 700 300 700 1500 1900 2300 1100 1500 1900 2300 1100 1500 1900 2300 1100 1500 1900 2300 1100 1500 1900 2300 1100 1500 1900 2300 1100 1500 1900 2300 39 CO ppm CO 1hr average Figure 2: CO Concentrations CO 8hr average

15 1/25 1/26 1/27 1/28 1/29 1/30 1/31 2/1

9 EPA Standard = 9 ppm 8hr average O ppm C

0 300 700 300 700 300 700 300 700 300 700 300 700 300 700 1500 1900 2300 1100 1500 1900 2300 1100 1500 1900 2300 1100 1500 1900 2300 1100 1500 1900 2300 1100 1500 1900 2300 1100 1500 1900 2300 40 CO2 ppm CO2 exterior Figure 4: CO2 Concentrations

4000 1/25 1/26 1/27 1/28 1/29 1/30 1/31 2/1

3500 3500 ppm Long Term Health Canada

3000 2798 ppm Test Period

2500

2000 O2 ppm O2 CC

1500

1000

500

Thanks for listening in.

Jeffrey Gordon [email protected] Data, not Full Report available at: Dogma http://brc.arch.uiuc.edu/billrose /FinalReport.pdf http://brc.arch.uiuc.edu/billrose /Apps_all.pdf