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 Combustion Tables Listed Below. 

 

 

   Combustion Safety Testing
For Gas Appliances



caz1


Combustion Appliances Defined:  any liquid, gas, or solid fuel burning appliances including water heaters, wood stoves, ranges, ovens or stove tops, furnaces, boilers, space heaters, fireplaces, fireplace inserts, and gas logs

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co_furnance

    Pre weatherization combustion safety testing. The Local Agency shall perform a Combustion Safety Test for every combustion appliance prior to installing any conservation measures that alter the building shell, HVAC system, or interior configuration (including comfort air sealing or altering of interior doors) of the dwelling.  An Exhibit 5.3.1A, Combustion Safety Form shall be filled out for each appliance and be present in the client file.

3.0.2    Post weatherization combustion safety testing

The Local Agency shall perform a Combustion Safety Test for every combustion appliance at the conclusion of the weatherization project.

3.0.3    In-progress combustion safety testing

The Local Agency or Subcontractor shall perform a worst-case depressurization test Exhibit 5.3.1B, Technical Support Documentpage 3and draft testpage 6. Line # 13)at the end of the work day when work has been done that alters the building shell, HVAC system, or interior configuration (including comfort air sealing, altering of interior doors) of the dwelling unit.  If the system fails, the Local Agency shall take immediate action before leaving the dwelling unit to ensure that the occupant's health and safety is not compromised.

3.1       Draft and spillage tests

The Local Agency shall perform spillage and draft tests for all natural and induced draft space heating systems and water heaters.  Draft and spillage shall first be tested under worst-case (Exhibit 5.3.1B, Technical Support Documentpage 3) conditions, and then repeated for natural conditions if the appliance fails under worst-case.


3.1.1    Single chimney with multiple appliances

When a chimney is shared by multiple appliances, the appliance with the smallest Btu input rating shall be tested first, and remaining appliances shall be tested in order of increasing input rate.

3.1.2    Multiple fuel sources vented into a single chimney

Multiple fuel sources vented into a single chimney are cause for deferral of services until the situation is corrected.

3.1.3    Draft testing

The Local Agency shall measure vent draft pressure at steady-state operating conditions of all heating and hot water combustion appliances.

Exceptions:

1.        Sealed Combustion or Power Vented (90% +):  No draft measurement required.  Recommend technician confirm draft at termination.  If it is unsafe to access termination point for testing due to the height of the roof or weather conditions an alternative is to access flue products by disconnecting the drain line.

2.        Solid fuel-burning appliances.

3.        Gas fireplace inserts.

1.        Atmospheric or Natural Draft (70%):  Draft testing shall be done in the center of the longest, straightest, accessible section of the vent connector.  Holes made for the purpose of measuring draft shall be drilled using 5/16th bit.  Once test is complete, seal hole with High Temperature RTV silicone caulk.  Cover with aluminum tape or plug with a 3/8 inch tap bolt made of stainless steel or nylon.

2.        Induced Draft (80%):  Draft testing shall be done a minimum of 3 feet downstream of the inducer motor.  The preferred location for CO testing is the same hole used for draft testing.  Holes made for Draft and CO testing shall be drilled using a 5/16th bit.  Once test is complete seal the inner liner with High Temperature RTV silicone caulk and a 3/8 inch tap bolt made of stainless steel or nylon or seal interior hole with RTV silicone and cover exterior hole with aluminum tape.

Appliances shall draft at or above (i.e. have more draft) the minimum acceptable draft level detailed in Table 1.  If the draft test fails, the Local Agency shall make appropriate repairs before proceeding with weatherization services or defer the project until problem is corrected.

Table 1:  Minimum Acceptable Draft Test Action Levels

 

Outside Temperature (degree F)

Draft Pressure Standard (Pa)

<10

-2.5

10-90

(Outside temp / 40) – 2.75*

>90

-0.5

*Calculation is as follows: Divide the outside temp by 40, then subtract 2.75 from this value. The result is the minimum acceptable draft.

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3.1.4    Spillage

TheLocal Agency shall test for spillage on all atmospheric draft appliances.  Local Agency shall measure and record the amount of time it takes for spillage to stop and draft to be established.  Any appliance that continues to spill flue gases beyond the maximum established time limits identified in Table 2 fails the spillage test.  If the unit fails, Local Agency shall make appropriate repairs or defer the project until the problem is corrected.

Induced draft heating systems shall be checked for spillage at the base of the chimney liner or flue.  If a chimney is shared between an induced draft heating system and a natural draft water heater, spillage shall be checked at the water heater draft diverter.

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Table 2:  Maximum Acceptable Appliance Spillage Periods

 

Appliance Type

Spillage Test Period (minutes)

Water Heater, Gravity Furnace, Boiler

1.0

Space Heater

1.0

Forced Air Furnace

1.0

 

 

Exception:  Wood stoves and fireplaces shall not be tested for spillage.


3.2       Heat rise

The Local Agency shall test all forced air heating systems for heat rise.  If the heat rise is outside the manufacturer’s acceptable range the system fails.  If the heating unit fails the heat rise test, The Local Agency shall have the appropriate repairs made or defer the project until the problem is corrected.

Exception:  If manufacturer’s acceptable heat rise range is unavailable, the default acceptable heat rise range is greater than 40° and less than 70° Fahrenheit.

3.3       Carbon monoxide tests

The Local Agency shall perform a CO test in all combustion appliances.  The Local Agency shall measure CO in the undiluted flue gasses in the flue of the appliance, using a digital gauge that measures in parts per million (ppm).  For all combustion appliances, CO shall be measured at steady-state operating conditions.  CO levels must be recorded and appropriate actions taken, as detailed in Table 3.

1.    Atmospheric or Natural Draft (70%):  CO testing shall be done in the undiluted flue products at the heat exchanger cell outlets.

2.   Induced Draft (80%):  CO testing can be done anywhere in the vent connector or at the vent termination if the appliance is vented by itself.  The preferred location for CO testing is the same hole used for draft testing.  Holes made for Draft and CO testing shall be drilled using a 5/16th bit.  Once test is complete seal the inner liner with High Temperature RTV silicone caulk and a 3/8 inch tap bolt made of stainless steel or nylon or seal interior hole with RTV silicone and cover exterior hole with Aluminum tape.

3.  Sealed Combustion or Power Vented (90% +):  CO shall be tested, preferably at the termination.  If it is unsafe to access termination point for testing due to the height of the roof or weather conditions an alternative is to access flue products by disconnecting the drain line.

3.3.1 The Local Agency shall not drill holes in flues for power vented or sealed combustion units. CO shall be measured at the exterior outlet of the flue.

 

 


            Table 3:  Carbon Monoxide Test Action Levels

 

CO Test Result*

 Retrofit Action

0 – 25 ppm

Proceed with work

26 – 99 ppm

Recommend cleaning of appliance burner

100 - 400 ppm

Weatherization work may not proceed until the system is serviced and the problem is corrected

> 400 ppm

Notify owner and occupant in writing. Work may not proceed until the problem is corrected, either by Local Agency or owner.

 

*  CO measurements for undiluted flue gases and range tops

Exception:  Carbon monoxide testing of wood burning appliances flue gases is not required.

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3.3.3    Ambient carbon monoxide

The Local Agency shall monitor ambient CO levels upon entering the combustion appliance zone and during the test period for all appliances.  If ambient levels exceed 9 ppm at any time, turn off the appliance immediately and make appropriate repairs. The maximum allowable ambient CO level in a dwelling where weatherization work has been completed is 9 ppm.

3.4       Combustion appliance zone depressurization

The Local Agency shall perform a worst-case depressurization test in each combustion appliance zone. When combustion appliance zone (CAZ) depressurization limits are exceeded under worst-case conditions, the depressurization shall be brought within acceptable limits as detailed in Table 4.


Table 4:  CAZ Depressurization Limits

 

Venting Condition

Limit* (Pascals)

Stand alone natural draft water heater (including outside chimneys)

-2

Natural draft boiler or furnace vented in combination with water heater

-3

Fireplace

-4

Natural draft boiler or furnace with vent damper commonly vented with water heater

-5

Wood stoves and fireplace inserts, including air tight models with outside combustion air

-5

Individual natural draft boiler or furnace

-5

Induced draft boiler or furnace commonly vented with water heater

-5

Power vented or induced draft boiler or furnace alone

-15

Chimney-top draft inducer;

High static pressure flame retention head oil burner;

Direct vented appliances;

Sealed combustion appliances;

-50

Worst case CAZ depressurization minus baseline pressure

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If reasonable efforts cannot meet or reach the CAZ Depressurization Limits standard, the Local Agency shall document in the client file the actions taken and the education provided to the client.

3.5       Documentation

The Local Agency shall document in the client file repairs and the actions taken to correct all combustion safety failures.

3.6       Un-vented fuel burning space-heating appliances

The Local Agency shall not proceed with weatherization of dwellings that have existing un-vented fuel burning space-heating appliances until they are removed.  The Local Agency shall notify the owners and the occupants of any hazards that exist with un-vented space heaters, and of the program requirements that un-vented space heaters be removed before weatherization services can be delivered.

3.7       Required equipment

The Local Agency shall:

1.        Use a digital manometer to perform all pressure diagnostic-testing measurements.

2.        Use a digital CO measurement device that is capable of measuring 1ppm to 1000 ppm.

3.        Have diagnostic testing equipment calibrated and maintained as recommended by the manufacturer.

4.        Keep on file a record of maintenance and calibration for all diagnostic equipment.

 




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