Carbon Monoxide and Gasoline Powered Smoke Blowers STRATEGIC MANAGEMENT OF CHANGE

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1 Carbon Monoxide and Gasoline Powered Smoke Blowers STRATEGIC MANAGEMENT OF CHANGE BY: Henry L. Clinton Battalion Chief Las Vegas Fire and Rescue Las Vegas, Nevada An applied research project submitted to the National Fire Academy as part of the Executive Fire Officer Program. December 1999

2 2 ABSTRACT The problem was Las Vegas Fire and Rescue did not know if their employees were being exposed to unacceptable levels of carbon monoxide (CO) during post fire attack operations (overhaul, fire investigation, evidence retrieval etc.). The purpose of this research project was to determine if gasoline powered smoke blowers could reduce carbon monoxide levels inside a structure during post fire attack operations to an acceptable level. The evaluative research method was used. The research questions to be answered were: 1. What is the acceptable level of carbon monoxide in a structure for a firefighter to work in without self contained breathing apparatus? 2. Does a gasoline powered smoke blower introduce a significant amount of carbon monoxide into a structure? 3. Can a gas powered smoke blower reduce the carbon monoxide within a structure to an acceptable level during post fire attack operations? The procedures included a literature review, gathering information from articles, texts, the inter net, and data collected from evaluative testing of the gasoline powered smoke blowers typically used by Las Vegas Fire and Rescue. The research revealed a significant level of carbon monoxide is an atmosphere containing 35 ppm or more. In the positive pressure mode, a gasoline powered smoke blower introduces and maintains a significant amount of carbon monoxide into a structure; it was also

3 3 determined that a gasoline powered smoke blower used in the negative pressure mode can reduce the level of carbon monoxide to an acceptable level. The recommendations were to maintain a regular aggressive offensive interior fire attack using positive pressure ventilation initially. Then, prior to beginning any post fire attack activities where personnel remove their respirators, negative pressure ventilation (NPV) should be initiated and carbon monoxide detectors should be used to monitor and ensure safe CO levels within the structure.

4 4 TABLE OF CONTENTS Page ABSTRACT...2 TABLE OF CONTENTS...4 INTRODUCTION...5 BACKGROUND AND SIGNIFICANCE...6 LITERATURE REVIEW...8 PROCEDURES...11 RESULTS...14 DISCUSSION...18 RECOMMENDATIONS...20 REFERENCES...21 APPENDIX...22

5 5 INTRODUCTION In an effort to remove the heat and harmful gasses from a burning building, Las Vegas Fire and Rescue (LVFR) has been committed to aggressive ventilation techniques using positive pressure ventilation (PPV) and gasoline powered smoke blowers since the mideighties. Gasoline powered smoke blowers have been placed on every engine and truck company in an effort to support the coordinated fire attack. It has been the department s experience that gasoline powered smoke blowers effectively remove smoke from a structure (Mittendorf, 1986). However, after the fire has been knocked down, firefighters at some point remove their self contained breathing apparatus (SCBA) and begin overhaul operations while the smoke blowers continue to run to keep the CO at an acceptable level. The question is whether this is so, or are firefighters being exposed to unacceptable levels of CO by the smoke blowers. This question was discussed by Las Vegas Fire and Rescue Safety Committee s monthly, meeting in May, The problem is; Las Vegas Fire and Rescue does not know if fire personnel are being exposed to unacceptable levels of carbon monoxide during Overhaul operations by LVFR gas powered blowers operating in the positive pressure mode. The purpose of this applied research project is to determine if gasoline powered smoke blowers can reduce CO levels inside a structure to acceptable levels. Current beliefs support the premise that the gas powered smoke blowers introduce CO into the structure we are trying to ventilate, but these premises are not documented, nor is it known whether or not these levels would constitute a significant problem. If these levels

6 6 area problem, a solution to reduce the CO to an acceptable level is needed. This project should lead to determining the extent of any problems and recommend possible solutions. The evaluative research method was used during this project. The research questions that will be answered are: 1. What is the acceptable level of CO in a structure safe for firefighters to work in without Self Contained Breathing Apparatus (SCBA)? 2. Does a gasoline powered Smoke Blower introduce a significant amount of carbon monoxide into a structure during positive pressure ventilation? 3. Can a gas powered smoke blower reduce the CO level in a structure to an acceptable level? BACKGROUND AND SIGNIFICANCE Of the common products of combustion, CO is the most dangerous to firefighters (Mahony, 1992). The fire service has always been concerned about removing smoke and CO from a burning building in order to increase the survivability of any potential fire victims, especially since more fire deaths occur from CO poisoning than from any other toxic product of combustion (Essentials, 4 th ed.). Adequate ventilation during a fire attack has always been a challenge for the fire service. Gasoline powered gas blowers combined with positive pressure ventilation have been a great benefit in fire fighting tactics. It is generally accepted throughout our industry that it is faster and safer than other ventilation options (Mittendorf, 1986). However, with any gasoline powered tool comes the byproduct of CO (Carbon Monoxide Poisoning, 1999).

7 7 Carbon monoxide is one of the most common industrial hazards today (Carbon Monoxide Poisoning, 1999). CO is a colorless, tasteless, and odorless gas (Bronstein, 1994). The warning signs associated with CO poisoning are late signs, as CO is an insidious gas with firefighter many times unaware he or she is being poisoned (Mahoney, 1992). Now LVFR is looking beyond the safety of the fire victims, and taking a hard look at exposure of firefighters to CO. Generally speaking, after ventilation is initiated and the fire is knocked down at some point the building is cleared of visible smoke. Firefighters will remove their SCBA s and begin overhaul operations, or other post knock down activities. The lack of SCBA use exposes their lungs to residual carbon monoxide within the structure and to the CO that is being introduced into the structure by the gas powered blower. Las Vegas Fire and Rescue has a Safety Committee which meets monthly and is attended by three management and three labor personnel by contract. Their purpose is to address safety issues as they are identified. In a recent meeting, one concern raised was whether or not gas smoke blowers are contributing a significant amount of CO into structures while our personnel (who s lungs are unprotected) are effecting overhaul operations. Additionally, the time period between fire extinguishment and overhaul is when fire inspectors investigate cause, origin and collect evidence if necessary. All this is done with a blower operating in the positive pressure mode still introducing carbon monoxide into their work environment. Las Vegas Fire and Rescue currently practices Positive Pressure Ventilation (PPV) using gas powered blowers. The Safety Committee wants to know if the gasoline

8 8 powered smoke blowers LVFR uses introduce a significant amount of CO into the work environment. This paper is related to the strategic management of change (SMOC) course, as our department may need to change the way ventilation is addressed during fire ground operations. LITERATURE REVIEW A literature review was performed to identify the characteristics, origin, and toxic levels of CO and to determine the exposure hazard firefighters. Federal standards for exposure limits to personnel working in an atmosphere containing CO was evaluated. Proven techniques for PPV as well as test results from other fire department research and subsequent CO levels within a structure were researched. Literature was retrieved from the company that manufactures Las Vegas Fire and Rescue gasoline powered blowers and included a specification sheet. Other material was gathered from the library at the National fire Academy in Emmitsburg, the Internet, Las Vegas Fire and Rescue library, the Hazardous Materials team and from the author s personal library. The literature review revealed that CO is one of the most common products of combustion dangerous to a fire fighter since the gas is both poisonous and flammable (Mahoney, 1992). The more inefficient the burning process, the greater quantity of CO will be produced (Essentials, 4 th ed.). During overhaul procedures, fire is at its most inefficient burning phase. Physical activity increases the body s need for oxygen, increases the danger of CO poisoning (Bronstein, 1994). During these operations,

9 9 firefighters are tired and are exerting heavy physical activity which increases their exposure potential. Additionally, the American Lung Association informs us that any fuel burning appliances such as gas operated tools and gas powered blowers are potential sources of CO, and they recommend avoiding operations of such tools in confined areas to avoid exposure to CO (American Lung Association, 1999). During overhaul, firefighters are being exposed to CO from the fire itself, and also to potential CO from the smoke blowers, Unfortunately carbon monoxide poisoning takes place in an insidious manner giving a firefighter little or no warning that they have absorbed a critically dangerous amount (Mahony, 1992). The routes of exposure to CO are mainly through inhalation with the gas acting primarily on the central nervous system, the cardiovascular system, the respiratory system and the blood stream. The hemoglobin in the blood has a two to three hundred times greater affinity to CO than it does for oxygen. The CO combines with the hemoglobin forming carboxyhemoglobin. Carboxyhemoglobin cannot bind with oxygen, thus poisoning occurs at the cellular level and causes death via hypoxia (Bronstein, 1994). NIOSH (The National Institute for Occupational Safety and Health) makes exposure recommendations to OSHA (Occupational Safety and Health Administration ) for permissible exposure levels for employees. These must be legally adhered to by all employers, and may be listed as TWA (time weighted averages) and STEL (Short term exposure limit) or a ceiling limit (Esposito R., 1999). Regarding CO, NIOSH recommends that an employer follow a TWA exposure limit for its employees of 35 ppm

10 10 during a 40 hr. work week. (10 hours a day for a 40 hour work week.) and a STEL of 200 ppm for any 15 min. period (NIOSH, 1997). Other fire departments have performed extensive tests of PPV, all of which are very one-sided, supporting the use of gasoline powered smoke blowers. In 1989, the North Carolina Department of Insurance completed the first in a series of research projects focusing on the use of PPV. When PPV was performed prior to the fire attack, toxic levels remained significantly lower throughout the structure. The literature continued to claim that PPV could reduce toxicity to keep victims alive long enough for firefighters to find them (Houghs, 1989). The Los Angles City Fire Department conducted a one-and-a-half year test to evaluate the capabilities of smoke ejectors. They concluded that gasoline powered smoke blowers provided velocities and volumes of air movement that is not practical to obtain from commonly available electric powered smoke ejectors (Mittendorf, 1986). Mittendorf also says in 1990 that if an exhaust odor is noticeable, it is an indicator that exhaust contaminants are being allowed to accumulate (Mittendorf, 1990). This last statement leads one to wonder how much contaminants are actually accumulating within the structure, building up toxicity. Even though gasoline powered smoke blowers are clearly effective in rapid smoke and heat removal; smoke and CO are two separate things, and might require different clearing methods. To determine the level of CO resulting while clearing smoke and heat with gasoline powered smoke blowers, it was necessary to perform ventilation tests utilizing gasoline powered smoke blowers used by Las Vegas Fire and Rescue and accurately monitor CO levels during a typical ventilation scenario.

11 11 PROCEDURES The research method employed in this research project is the evaluative method. The procedures used to complete this project included a literature review. Literature references were obtained from the Learning Resource Center at the National Fire Academy, the Internet, the Las Vegas fire and Rescue Library including reference books from the Hazardous Material Response team and the author s personal library. Specific information was solicited from the manufacturer about the gasoline powered smoke blowers used by Las Vegas Fire and Rescue. In addition 13 ventilation tests were performed to record actual CO levels during ventilation performance tests with gasoline powered smoke blowers in both PPV and negative pressure ventilation (NPV) configurations. The tests were performed in two separate structures, an 1800 square foot two story residential home and the burn building at Las Vegas Training Center, which is a 1200 square foot single story structure. The test focused on determining if a gasoline powered smoke blower introduced a significant amount of CO into a structure being ventilated in the PPV mode. The blower used was 5.5 hp., 4 cycle, Tecumseh, with a seven blade 18 fan, smoke blower capable of moving 14,754 Cfm (cubic feet per minute) of air (Super Vac 1999). Both structures were free of any carbon monoxide prior to the test. The smoke blower was set up just as LVFR would in a fire situation. The smoke blower was set far enough back to create a seal around the front door by the cone of air created by the blower.

12 12 Several tests were conducted using exhaust openings the same size as the entrance and exhaust openings twice the size as the entrance as recommended by John Mittendorf in his article in American Fire Journal (Mittendorf, 1990). Using the department s CO monitor (PhD ULTRA ATMOSPHERIC MONITOR) capable of use in hazardous locations class I, Div. I. Groups A,B,C,D. CO readings were taken at the four to five foot levels throughout the structure at 60 second intervals. All tests revealed a significant level of carbon monoxide was introduced and maintained within the structures during PPV. NPV, using the gasoline powered smoke blower was explored by elevating the CO level to two hundred ppm by running the smoke blower inside the structures and monitoring the CO level with the monitor. Next, the smoke blower was placed four feet inside the structure and it blew air out the front door. The original exhaust openings were left identical to those in the PPV tests. The results were a significant drop of CO. Within 2.5 minutes, the CO was at 35 ppm or below in both structures. Next, a smoldering fire situation was created with a portable barbecue and 10 pounds of Kingsford charcoal briquettes. The briquettes were ignited and placed in the northwest corner of the burn building, with the aid of a smoke blower running inside the structure. The CO level was raised to 900 ppm, NPV was set up with the entrance opening and the exhaust openings left the same size. In five minutes the CO level was reduced to 32 ppm and in 15 minutes the structure maintained roughly a CO level of 20 ppm with 10 lb. of charcoal briquettes still burning in the corner of the structure. Limitations

13 13 Weather conditions, barometric pressure were uncontrollable and may have varied from one day to the next which may have affected the tests results. The smoke blower used was a new blower with a Tecumseh 5.5 hp. Motor. Several different types of engines are used in our smoke blowers ranging from 4 hp. to 5.5 hp. Tecumseh and Honda motors. Not only could the age of the blower affect the CO output, but the performance of the Honda motor vs. the Tecumseh motors may vary. Another factor that is uncontrollable is the age and octane of the fuels used throughout the department, as older fuels and fuels with varying octane may affect the efficiency of the motors. Additionally, the 10 pounds of charcoal briquettes may not accurately simulate the CO off-gassing during overhaul.. Definition of terms Cfm: cubic feet per minute, related to a volume of air being moved. Negative Pressure Ventilation: A ventilation technique whereby air is drawn out of a structure via a mechanical fan. The negative pressure created by the fan causes fresh air to be drawn into the structure through controlled openings. PPM: Parts Per Million. ppm Positive Pressure Ventilation: A ventilation technique whereby fresh air is blown into a structure via a mechanical fan, causing increased pressure inside the structure which causes the existing atmosphere inside to exit the structure through controlled openings. STEL: Short Term Exposure Limit, highest allowed concentrated exposure limit in any 15 min. Period (R. Esposito, 1999).

14 14 TWA: Time Weighted Average (NIOSH exposure limit recommended for a 10 hr. Work day 40 hr. Work week) (R. Esposito, 1999). RESULTS 1. What is the acceptable level of carbon monoxide in a structure for a firefighter to work in with out Self Contained Breathing Apparatus? The acceptable level of CO exposure for our employees is no more than 35 ppm. The OSHA standard for exposure to CO prohibits exposure to more than 35 ppm averaged over an 8 hour work day with a ceiling limit of 200 ppm measured over a 15 minute period (Carbon Monoxide Poisoning, 1999). NIOSH exposure limits are a TWA of 35 ppm measured over a 10 hour day and 40 hour week and a ceiling of 200 ppm in a fifteen minute period (NIOSH, 1997). 2. Does a gasoline powered Smoke Blower introduce a significant amount of carbon monoxide into a structure during PPV? Yes it does. During the 13 ventilation tests, six of the tests were in the Positive Pressure mode starting with a CO free structure. The gasoline powered blower introduced and maintained an average of 62 ppm of CO inside the structure (See data in Appendix A). 3. Can a gas powered smoke blower reduce the carbon monoxide to an acceptable level? Yes it can, but not in the positive pressure mode. During four of the tests, the CO level was elevated (by running the blower inside the unventilated structure) to 200 ppm. By placing the blower four feet inside the structure blowing out to create a

15 15 negative pressure within the structure, the CO level was reduced to less than 35 ppm in less than 2.5 minutes. The final test was done with a simulated smoldering fire using a barbecue with 10 pounds of charcoal briquettes. The CO level was elevated to 900 ppm prior to initiating NPV. Within five minutes after initiating NPV, the CO level was reduced to 32 ppm, which is lower than required federal standards. After 15 minutes, the CO level is the structure averaged eighteen ppm with the charcoal briquettes still burning. Results of the Gasoline Powered Blower Tests. The first seven blower tests were performed in an 1800 square foot two story single family dwelling. The winds were calm, and the temperature was 80 degrees Fahrenheit. The blower used throughout the tests was a 5.5 hp. 4 cycle Tecumseh with a seven bladed 18 inch fan. The atmosphere was monitored for CO using a PhD ULTRA ATMOSPHERIC MONITOR. Test #1. PPV was run into a carbon monoxide free structure, with the entrance approximately 20 square feet, and the exhaust openings the same size. The blower set back far enough to create a seal at the front door with a cone of air. Within 2 minutes the CO, was 58 ppm; after 12 minutes, the CO level remained at 57 ppm. Test #2 This test began where the first test stopped at 57 ppm. The exhaust openings were doubled, and after 11 minutes the CO remained at 52 ppm. Test #3 This NPV test was initiated to see if the CO level from test #2 could be reduced. The blower was brought four feet into the house and directed out the front door. Within

16 16 one minute, the CO level was reduced to 8 ppm; in four minutes, the CO level was reduced to 3 ppm. Test #4. The windows were opened to double the front door opening, and the CO level was raised to 200 ppm by first running the blower inside the closed structure. NPV was initiated, and within one minute the CO level was reduced to 57 ppm, at two minutes the CO level was reduced to 17 ppm, and in eight minutes to 4 ppm. Test #5. A PPV test with the exhaust openings 1 ½ times the size of the front door was done. Within one minute, the CO level was 41 ppm and at four minutes it was 62 ppm. Test #6. Continuing with the 62 PPM, and increasing the exhaust openings to twice the size of the front door, the CO level continued to raise to 73 PPM and then leveled off at 70 ppm. Test #7. NPV was initiated at the end of Test #6, by bringing the blower four feet inside the structure and directing the air out of the structure. Within 38 seconds, the CO level was reduced to 35 PPM. By five minutes, the CO level was 5 ppm. The remaining tests were performed on a single story 1200 sq. ft. Single story structure, same temperature and no winds. The same gas powered blower and monitoring equipment was employed. Test #8, PPV test was executed with exhaust openings twice the size of the entrance. Within two minutes, the CO level was 45 ppm and in eight minutes, the CO level was 61 ppm. Test #9. A PPV test was executed with exhaust openings equal to the entrance.

17 17 Within two minutes, the CO level was up to 51 ppm; after 20 minutes it leveled off at 68 ppm. Test #10. Continuing with the conclusion of test #9, the exhaust opening was increased to twice the size of the entrance. After six minutes the CO level registered at 66 ppm. Test #11. A NPV test was done with the CO level raised to 200 PPM, the window openings twice the size as the door opening. NPV was initiated and within one minute the CO level was reduced to 132 ppm; in three minutes 24 PPM; in five minutes the CO level was reduced to 13 ppm. Test #12. Another NPV test was executed with ventilation openings the same size, and with the CO level elevated to 200 PPM. The CO level was reduced to 35 ppm in two minutes and reduced to 8 ppm in six minutes. Test #13. The CO level was built up to 900 ppm, using 10 lb. of charcoal briquettes and running the smoke blower inside the structure and then initiating NPV while leaving the 10 pounds of charcoal burning in the corner to simulate CO produced after the knock down of a fire. Within five minutes, the CO level was reduced to 32 ppm and in 18 minutes leveled off at 18 ppm. The final conclusion is that gasoline powered smoke blowers used in the positive pressure mode introduce and maintain more than a significant amount of CO (35 ppm) into the structures we are ventilating. However, if used in the negative pressure mode, the smoke blower has the capability to reduce the CO levels within the structures we are working in to below OSHA standards, even with a smoldering fire within the structure.

18 18 DISCUSSION The literature review supported what is common knowledge information within our industry, that CO is a killer (Mahony, 1992), that the burning process produces CO. The more inefficient the burning process the greater the quantity of CO produced (Essentials, 4 th ed.). The study reinforced the American Lung Association claims that gas operated power tools produce CO (American Lung Association, 1999). The gasoline powered blowers introduced a significantly higher amount of CO into a structure than NIOSH standards allow (NIOSH, 1997). Since firefighters will at some point remove their SCBA to complete their fire ground activities, Las Vegas Fire and rescue will traditionally continue to operate the blowers in the positive pressure mode. The department is exposing our firefighters, employees and/or civilians who may enter the structure to higher levels of CO than is safe. There are alternative ways to reduce the CO levels within these structures to below the OSHA and NIOSH recommended TWA and STEL. Even though we will employ these alternative techniques, it will be necessary to utilize CO detectors as CO is a colorless, odorless, and tasteless gas (Bronstein, 1994). Undetectable by human senses. There is no real way to ensure that the gas is not a health hazard except by a dependable monitoring device. Firefighters have known for a long time that exposure to the products of combustion are harmful. It is recognized throughout the industry that smoke or CO is a killer on the fire ground. This study confirms that gasoline powered smoke blowers introduce and maintain a higher concentration of CO than Federal standards will allow

19 19 when they are used in the positive pressure configuration. Additionally, it was discovered when the smoke blower was used in the negative pressure configuration, CO levels measured within the structure remain significantly lower than the 35 ppm federal standards require. Las Vegas Fire and Rescue will need to change the way we address structural ventilation in regard to any post fire, overhaul, and fire investigation activities. Las Vegas Fire and Rescue does not wish to expose it s employees to any more CO than is necessary or reasonable. It is unrealistic to wear SCBA until all overhaul activities are concluded. At some point, it becomes counter-productive. It has been normal procedure in the past to remove SCBA during overhaul to facilitate activities. Reducing the amount of CO exposure is possible by using the gasoline powered blowers currently used by the department. However, continuing with current practices of maintaining PPV during overhaul will knowingly expose firefighters to higher levels of CO than allowed by federal standards. RECOMMENDATIONS Based on the data collected during the ventilation tests with our gasoline powered smoke blowers, firefighters are being exposed to a significant level of CO during overhaul operations, and other post fire attack activities such as fire investigation and evidence retrieval. Wearing SCBA during initial fire attack sufficiently protects the employee as they enter a carbon monoxide rich environment.

20 20 The recommendations for the future are to continue operating as is done now, with an aggressive interior fire attack using gasoline powered smoke blowers and PPV. Then: Switch from PPV to NPV after initial fire activities have concluded, but prior to any post fire attack activities begin. Purchase and utilize CO detectors to monitor and ensure CO levels are at or below federal standards. There are inexpensive and accurate monitors available on the market. Future readers would be advised to test the after market exhaust extensions. The manufacturers of the smoke blowers claim they can route the exhaust away from the draft created by the fan. If these exhaust extensions work as they claim, there would be no need to change over to NPV.

21 21 REFERENCES American Lung Association. (1999, June).Carbon Monoxide. American Lung Association Fact Sheet [On-line]. Available: Bronstein, A. C., Currance, P. L. C. Merrick (Eds.). (1994). Emergency Care For Hazardous Materials Exposure. (pp ). Carbon Monoxide Poisoning. (1999, June). OSHA Fact Sheet. [On-line]. Available: http// Essentials Of Firefighting (4 th ed.). (1998). (pp.88-91). Oklahoma State University: Fire Protection Publications. Esposito, R. (Ed.). (1999). Geniums Hand Book of Safety, Health, and Environmental Data for common hazardous substances. Schenectady, New York: Genium Publishing Corporation. Houghs, L. D. (1989, December). Positive-Pressure Ventilation in a Test Setting. Fire Engineering, Houghs, L. D. (1989, December). Positive-Pressure Ventilation in a Test Setting. Fire Engineering, Mahony, E. (1992). Fire Chemistry. In L. Griffiths (Ed.), Fire Suppression Practices And Procedures. (pp. 3). Englewood Cliffs, New Jersey: Brady a Prentice Hall Division. Mittendorf, J. (1986, December). Smoke Ejector Study: A Blow-By-Blow Report. Firehouse, 30-34, 94. Mittendorf, J. (1990, May). Ventilation Tools: The Strong and Sharp of it. American Fire Journal, NIOSH Pocket Guide to Chemical Hazards. (1997). (pp ). Washington, D.C.: U.S. Govt. Printing Office. Super Vac. (1999). Super Vac Positive Pressure Ventilator Specifications G4. [Brochure]. P.O. Box 87, Loveland, Colorado.

22 22 APPENDIX A Gasoline Powered Blower Test 1800 square foot two story residential structure. 0 winds, 80 degrees Fahrenheit. Blower used: 5.5 hp. 4 cycle Tecumseh motor with a 7 blade 18 inch fan. Atmospheric Monitor: PhD ULTRA ATMOSPHERIC MONITOR. Test #1 Positive Pressure Ventilation into a structure clear of carbon monoxide, entrance and exhaust openings the same size, blower set back far enough to create a seal with the cone of air from the blower. Readings taken every sixty seconds at about the five foot level. Min. PPM 2: : : : : : : : : : :00 57 Test #2 continues with the Exhaust openings doubled. 13: : : : : : : : : : : :00 52

23 23 Test #3 begins with the conclusion of test #2. The blower is moved four feet into the structure and placed to blow air out the front door in the negative pressure mode. Min. PPM 26: : : :00 3 Test #4 began by elevating the carbon monoxide level inside the structure (by running the blower inside) to 200 ppm and initiating negative pressure ventilation. The window openings were opened to double the front door opening. 1: : :00 No reading 4:00 No reading 5:00 9 6:00 7 7:00 6 8:00 4 Test #5 PPV with exhaust openings 1 ½ the size of the front door. 1: : : :00 62 Test #6 initiated by increasing the exhaust opening to twice the size of the front door. 5: : : : : : : :00 70 Test #7 initiated at 70 ppm from test #6. Negative Pressure Ventilation. The blower is brought into the structure four feet and placed to blow air out the front door.

24 24 Min. PPM (00:38) 35 1: : :00 8 4:00 8 5:00 5 The remaining tests were performed with the same equipment, except the structure utilized is a 1200 square foot single story structure. Winds 0, Temp 80 degrees. Test #8 Positive Pressure Ventilation with exhaust openings twice the size of the entrance. 1: : : : : : : :00 61 Test #9 Positive Pressure Ventilation with openings equal to the entrance opening. 1: : : : : : : : : : : : : : : : :00 70 Min. PPM

25 25 18: : :00 68 Test # 10 Continuing with test #9 but increasing the openings to twice the size of the front door. 1: : : : : :00 66 Test #11 Negative Pressure Ventilation, carbon monoxide level elevated to 200 ppm, Window openings twice the size as the front door, blower four feet inside the structure blowing air out the front door. 1: : : : :00 13 Test #12 Negative Pressure Ventilation, openings the same size, blower four feet inside the structure blowing air out the front door. 1: : : : : :00 8 Test #13 Carbon Monoxide built up to 900 ppm using 10 lb. of charcoal briquettes and running the smoke blower inside the structure. Then initiating negative pressure ventilation leaving the 10 pounds of charcoal burning in the corner of the structure to simulate the carbon monoxide produced during overhaul. 1: : :00 53 Min. PPM 4:00 --

26 5: :00 blower turned from vibration, CO level in the room elevates, blower properly repositioned, test continues. 7: : : : : : : : : : : :