WARM Program Combustion Safety Testing Field Training October 21, 2008 Holiday Inn Conference Center, New Cumberland, PA
Controversial and Confusing Action Levels vary Terminology varies What do you do with unvented appliances? What do you do with coal stoves? How do you seal test holes? How far should WARM go to fix problems?
WARM Procedure Combustion safety testing has been required as part of the WARM program for many years. The procedure and action levels have recently been changed slightly.
Why Focus on Combustion Safety Now? Due to high natural gas and oil prices, more WARM customers have switched to using electric space heaters for their primary or sole heat. They then qualify for air sealing and insulation if their winter seasonal use is at least 2,000 kWh. But they likely have a gas water heater and may still use their fossil fuel heating system…. So… if you air seal a home with a fossil fuel system, ……..
Why Now? Continued So….. When air sealing or insulation is installed in a home with fossil fuel heating or water heating systems, the air exchange across the thermal boundary will (should) be reduced as part of the WARM installed measures. Any planned reduction in air flow (CFM -50Pa) means the combustion appliances must be checked BEFORE air sealing to be sure they are operating safely…. And they need to be checked AFTER air sealing to be sure they still operate safely.
Because… Air is needed for proper combustion. When air flow is restricted, combustion appliances can be starved for air. If a combustion appliance is starved for air, it wont burn properly and/or it pulls its combustion air down the flue and back-drafts. Back-drafting (spillage) is dangerous because the flue gasses contain CO and other bad things. We want to be sure the appliances operate safely.
Why Now? continued Also, if a customers summer seasonal use is at least 2,000 kWh, they qualify for cooling load reduction measures, including insulation and air sealing measures. These customers may have fossil fuel heating systems and/or water heaters.
More Why Now? Utilities and other PA programs are requiring Energy Auditors and Field Technicians to be BPI Building Analyst 1 Certified. Following BPI Standards for combustion testing and safety makes sense in PA right now.
Which WARM Customers Get Combustion Testing? Typical jobs: Defacto electric heat jobs Electric heat jobs with gas water heaters AC jobs receiving air sealing or insulation
Combustion Testing Includes: CO testing: ambient air, combustion appliance zone (CAZ), flues Gas leak detection Spillage and flame roll-out evaluation CAZ depressurization Draft evaluation Gas range testing
Combustion Safety Testing Audit Form Page 18 Combustion Safety Tests must be performed if: Conventionally vented combustion appliances exist and Air sealing is done – to reduce cooling load or to reduce heating load
Procedure COMBUSTION SAFETY SEPTEMBER, 2008 This section includes specifications relating to combustion appliance testing, related services and measures, and instructions for action when an unsafe condition is discovered. COMBUSTION SAFETY TESTING PROCEDURE The WARM Program Service Delivery Contractors and QA contractors must follow the most current Building Performance Institute (BPI) Combustion Safety Test Procedure for Vented Appliances and Combustion Safety Test Action Levels which served as a basis for this detailed procedure. For the purposes of this document, BPIs Combustion Safety Test Procedure for Vented Appliances, dated 4/07, BPIs Technical Standards dated 2/28/05, and BPIs Combustion Safety Test Action Levels document dated 4/07 were used. …….
The Big Picture Why Perform Combustion Safety Tests? When inadequate oxygen is present, in addition to CO2 being formed, Carbon Monoxide (CO) can be formed. This is our main concern. Carbon rich fuels, like Fuel Oils, can also lead to Carbon Particles, or Smoke, being produced.
Combustion Diagram The ideal operating range is a setting with excess air. IncompleteComplete Excess Fuel Excess Air Flue gas components Ideal operating range ofburners CO 2 O 2 Eff. Stoichiometric line Courtesy of Bill Spohn, Testo
Combustion Testing Video 16 minute video demonstrating the combustion safety testing procedure
What is flue gas? carbon hydrogen sulfur oxygen nitrogen water Oxygen(20.9%) water vapor Nitrogen (79%) Carbon dioxide CO 2 Carbon monoxide CO Sulfur dioxide SO 2 O 2 - balance Nitrogen oxide NO x Water vapor H 2 O Smoke (oil systems) fuel-residual ashes fuel air How is it formed? Courtesy of Bill Spohn, Testo
What is Carbon Monoxide ? CO originates from incompletely (oxidized) burnt carbon (fuel). It is very dangerous for human and animals, because it prevents the absorbstion of oxygen in the blood stream. Reasons for the formation: - fuel rich mixture - Improper venting - too early cooling of the flame (1128 F) CO is expressed in parts per million (ppm). Courtesy of Bill Spohn, Testo
CO Sources Fuel burning furnaces and hot water heaters Fuel burning boilers Fuel burning space heaters Kitchen ranges & ovens Auto emissions Attached garages Fireplaces Tobacco smoke Courtesy of Bill Spohn, Testo
Characteristics of CO Odorless Colorless Tasteless Mixes well in air Does not stratify Follows air flow in a structure Poisonous Courtesy of Bill Spohn, Testo
CO Health Effects 35 ppm NIOSH Permissible Exposure Limit – 8 hours 200 ppmNIOSH Ceiling– 15 minutes 200 ppmSlight headache with 2-3 hours 400 ppmHeadache within 1-2 hours 800 ppmSickness & twitching of limbs within 1- 2 hours; unconsciousness in 2 hours 1,600 ppmHeadache within 20 minutes; death within 2 hours 3,200 ppmDeath in 30 minutes 6,400 ppmDeath in 10-15 minutes 12,800 ppmDeath in 1-3 minutes Courtesy of Bill Spohn, Testo
Types of Furnaces Atmospheric – Natural Draft Buoyancy Creates NEGATIVE Pressure in Flue Induced Draft Fan Creates NEGATIVE Pressure in Flue Power Draft –Power Vent Fan Creates POSITIVE Pressure in Flue Condensing Sealed combustion
Calculating Combustion Efficiency Natural Gas Light Oil Heavy Oil Propane Wood Ambient Temp (combustion air) Oxygen O 2 StackTemp fuel Air Temp The analyzer uses the oxygen and net temperature measurements in fuel specific equations to give the efficiency, CO2 and excess air readings. Courtesy of Bill Spohn, Testo
Venting Types Video 17 minute Gas Venting video
Gas Appliance Categories Cat. I fan-assisted gas appliance: negative pressure, a high vent temperature avoiding condensation and an integral fan drawing combustion air through chamber Cat. I gas appliance: negative pressure, a high vent temperature, Cat. II gas appliance: –negative pressure, low vent temperature causing excessive condensation Cat. III gas appliance: –positive vent pressure in the vent, a high vent temperature Cat. IV gas appliance: - positive vent pressure in the vent low vent temperature causing excessive condensation Courtesy of Bill Spohn, Testo
Unvented Appliances – Test Air- Free or Undiluted Gas Ranges CO Hot-Pot www.karg.com Gas Ovens Test CO Air free, undiluted Courtesy of Bill Spohn, Testo
Sealing Test Holes For double wall (B-vent) flue pipes, letters from vent manufacturers say to use high temperature, non-hardening sealant to plug the hole on the inner sleeve. Do the same for the outer sleeve, but cover with a patch of aluminum tape over the sealant. For single wall flue pipes, use the same, or metal plugs.
What If A Test Fails? If a test fails before air sealing and/or insulating: follow procedure – no air sealing until the problem is fixed If a test fails after air sealing and/or insulating: follow procedure – fix the problem
What Information is Important? Combustion Efficiency 02, Temperature, Fuel Reduce Fuel Cost - Savings To determine Operating Condition Diluting effects of excess air (NO, NO2, SO2, CO) Weight of pollutant (lbs/Mbtu) Carbon Dioxide (CO 2 ) O 2 Reference (3%, air free) Emission Conversions Excess Air Extra Air for Combustion Courtesy of Bill Spohn, Testo
Typical Readings Gas Fired Power Burners Oxygen : 3 % - 6 % Carbon Dioxide:8.5 % - 11 % Stack Temp : 275 ºF to 570 ºF Draft: -.02WC to -.04WC in the Stack Carbon Monoxide:<100 ppm (diluted) Always Follow Mfrs Specifications Courtesy of Bill Spohn, Testo
Typical Readings Oil Fired Power Burners Oxygen (cast iron cone): 4% - 7 % Oyygen (flame retention): 3%-6% Carbon Dioxide10 – 12.5% Stack Temp (60-79 AFUE): 400 ºF to 600 ºF Stack Temp (80 plus AFUE): 330 ºF to 450 ºF Stack Temp (90 plus AFUE): Less than 125ºF Draft: -.02WC Overfire Carbon Monoxide:< 50 ppm (diluted) Always Follow Mfrs Specifications Courtesy of Bill Spohn, Testo