5 Colo. Code Regs. § 1001-15-B-III

Current through Register Vol. 47, No. 18, September 25, 2024

Section 5 CCR 1001-15-B-III - Procedures and Practices to Ensure the Proper Performance of Opacity Inspections

III.A. General Inspection Requirements

III.A.1. All aspects of the inspection must be performed by a licensed diesel emissions inspector. It is the responsibility of the inspector to notify the Department of Revenue of his/her current place of employment.

III.A.2. The inspection shall take place at the address of the station license.

III.A.3. The temperature of the inspection area (or ambient temperature for on-road tests) shall be between 35°F and 110°F (2°C and 43°C) during the inspection. Temperatures during the inspection must be accurately recorded and monitored in a well-ventilated location, away from vehicle engine and exhaust heat sources and out of direct sunlight.

III.A.4. For 1991 and later model year diesel vehicles, the diesel emissions inspector shall perform an inspection for the integrity of the emissions control systems and/or devices as listed on the vehicle's emissions control label or in an emissions control systems application guide. The following system/devices if original equipment manufacturer supplied must be installed, intact and apparently operational:

III.A.4.a. Any fuel injection pump seals and covers.

III.A.4.b. Fuel control systems, utilized to control the air/fuel ratio, including microprocessor/electronic control systems, mechanical systems, hydraulic systems or pneumatic systems.

III.A.4.c. Exhaust aftertreatment device systems.

III.A.4.d. Engine computer controls, related sensors, actuators, malfunction indicator, or service maintenance reminder lights. Engine computer control hardware and software must be original equipment, or must be certified by the aftermarket parts manufacturer in writing with words to the effect of: "Required testing has been performed and the manufacturer warrants that this part will not adversely affect emissions performance." Aftermarket emissions control components must be engineered and built to fit the specific vehicle application.

III.A.4.e. Positive crankcase ventilation, crankcase depression and air box drain equipment, including their hoses, pipes, valves and connectors.

III.A.4.f. The exhaust gas recirculation valve and related coolers, piping and control systems.

III.A.4.g. Related hoses, connectors, brackets, and hardware for these components.

III.A.4.h. Any other emissions-related components for a particular vehicle/engine as listed on a vehicle evaluation form (DR2365) issued by Emissions Technical Center staff.

III.A.4.i. The vehicle shall fail the inspection if the emission control components are found to be tampered, defective, or otherwise rendered partially or completely inoperative. When determining original equipment emissions control systems/devices, the vehicle's under-the-hood emissions control label takes precedence over any other sources of information. Any aftermarket replacement devices and software must be certified by the aftermarket parts manufacturer in writing with words to the effect of: "Required testing has been performed and the manufacturer warrants that this part will not adversely affect emissions performance." Aftermarket emissions control components must be engineered and built to fit the specific vehicle application.

It is the vehicle owner's responsibility to prove the acceptability of aftermarket devices/software, by producing the device/software manufacturer's statement warranting against adversely affecting emissions performance and the applicability of that device/software for the specific vehicle application. In the case where the manufacturer's certification is called to question or is missing, the Division may determine the acceptability of an aftermarket device/software.

III.B. Inspection Procedure for Light-Duty Diesel Vehicles (fourteen thousand pounds GVWR and less)

III.B.1. Preliminary Check of Vehicle

III.B.1.a. Safety check vehicle (tires, drive-line, etc.)

III.B.1.b. Ensure engine lube oil and coolant levels are at proper levels.

III.B.1.c. For vehicles with multiple exhaust outlets, operate engine, observe and determine which emits the heavier exhaust smoke. During testing, monitor the exhaust outlet which emits the heavier smoke, if there is a difference in smoke levels.

III.B.2. Diesel Vehicle Inspection Report Forms (DVIR)

III.B.2.a. The opacity inspector shall accurately identify and enter vehicle and owner information from vehicle to be tested as required on the DVIR.

III.B.3. Prepare Vehicle for Opacity Testing

III.B.3.a. Locate vehicle on dynamometer.

III.B.3.b. Secure vehicle with adequate safety restraints such as chains, nylon straps, wheel chocks or tie downs.

III.B.3.c. Locate auxiliary engine cooling fan in front of vehicle radiator or engine cooling inlet, whichever is applicable.

III.B.3.d. Vehicle is to be at a stabilized normal operating temperature. This shall be determined by feeling the top radiator hose, by checking the temperature gauge, and/or operating the vehicle prior to performing the inspection.

III.B.3.e. Zero/span opacity meter following manufacturer's specifications. Clean and recalibrate as necessary before conducting test.

III.B.3.f. Attach pre-calibrated opacity meter to vehicle's exhaust outlet and calibrate meter according to the manufacturer's instructions.

III.B.4. Opacity Testing

Opacity testing of light-duty diesel vehicles involves a dynamometer loaded-mode lug-down test procedure.

Engine temperature and oil pressure are to be closely monitored during all testing. Testing is to be discontinued if engine and vehicle operating parameters are not within acceptable limits.

III.B.4.a. Dynamometer Test Procedure

III.B.4.a.i. Verify smoke opacity meter is set at zero. Start and operate engine at idle rpm. With the dynamometer in an unloaded mode/condition and the vehicle in direct or drive gear (do not use overdrive), slowly increase vehicle speed to 60 mph (plus or minus two mph). Continue to maintain (by manual or automatic control) 60 mph while slowly increasing dynamometer loading until maximum horsepower (hp) is developed at 60 mph. Maintain this wide open throttle speed/load condition for a minimum of 10 seconds (plus or minus four seconds) and record mph, opacity, and hp on Opacity Worksheet. Proceed directly to Step 4.a.iii.

III.B.4.a.ii. NOTE: Vehicles with automatic transmissions are allowed two downshifts to the next lower gear at any point during the dynamometer lugdown test. If a downshift occurs, continue with the test.

III.B.4.a.iii. While maintaining wide open throttle; slowly increase the dynamometer loading until a vehicle speed of 50 mph (plus or minus two mph) is achieved. Maintain this wide open throttle speed/load condition for a minimum of 10 seconds (plus or minus four seconds) and record mph, opacity, and hp on Opacity Worksheet. Proceed directly to Step 4.a.iv.

III.B.4.a.iv. While maintaining wide open throttle; slowly increase the dynamometer loading until a vehicle speed of 40 mph (plus or minus two mph) is achieved. Maintain this wide open throttle speed/load condition for a minimum of ten seconds (plus or minus four seconds) and record mph, opacity, and horsepower.

III.B.4.a.v. Slowly remove dynamometer loading while returning engine to idle. Shut down engine after observing cool down procedure. Note and record residual opacity meter reading on Opacity Worksheet.

III.B.4.a.vi. The inspector shall refer to the opacity standards in Part B, V. of this regulation.

III.B.4.a.vi.A. If the highest opacity reading taken from Steps 4.a.i. through 4.a.iv. exceeds the opacity standard and the opacity meter shift exceeds five percent (5%), clean the lenses, zero meter and repeat the dynamometer test procedure starting at Step 4.a.i. At least one additional test will be conducted at no cost to the motorist.

III.B.4.a.vi.B. If the highest opacity reading taken from Steps 4.a.i. through 4.a.iv. exceeds the opacity standard and the opacity meter zero shift is less than five percent (5%), the vehicle fails the inspection.

III.B.4.a.vii. The inspector shall then enter the highest opacity reading, the opacity meter zero shift, the pass/fail determination, provide an electronic signature and other required information on the DVIR media. Vehicles which comply with the inspection procedures and applicable opacity standards shall be issued a completed CEC.

III.B.5. Vehicle Removal from Dynamometer

III.B.5.a. Detach all test equipment, restraints and remove them from the vehicle.

III.B.5.b. Remove vehicle from dynamometer

III.C. Dynamometer Inspection Procedures for Heavy-Duty Diesel Vehicles (Greater than fourteen thousand pounds GVWR.)

III.C.1. Preliminary Check of Vehicle

III.C.1.a. Safety check vehicle (tires, drive-line, etc.)

III.C.1.b. Ensure engine lube oil and coolant levels are at proper levels.

III.C.1.c. Verify proper operation of vehicle tachometer, or mount and connect approved photo tachometer.

III.C.1.d. For vehicles with multiple exhaust outlets, operate engine, observe and determine which outlet emits the heavier exhaust smoke, if there is a difference. During testing, monitor the exhaust outlet which emits the heavier smoke.

III.C.2. Diesel Vehicle Inspection Reports (DVIR)

III.C.2.a. The opacity inspector shall accurately identify and enter vehicle and owner information from vehicle being tested as required on the DVIR.

III.C.2.b. Determine the engine's rated horsepower and attendant rpm and enter on DVIR and also on the opacity worksheet

III.C.3. Prepare Vehicle for Opacity Testing

III.C.3.a. Locate vehicle on dynamometer.

III.C.3.b. Secure vehicle with adequate safety restraints such as chains, nylon straps, wheel chocks or tie downs.

III.C.3.c. Vehicle is to be at a stabilized operating temperature. This shall be determined by feeling the top radiator hose, by checking the temperature gauge, and/or by operating the vehicle prior to performing the inspection.

III.C.3.d. Zero/span opacity meter, following manufacturer's specifications. Clean and recalibrate, as necessary, before conducting test.

III.C.3.e. Attach pre-calibrated opacity meter to vehicle's exhaust outlet and calibrate meter according to the manufacturer's instructions.

III.C.4. Opacity Testing

Dynamometer opacity testing of heavy-duty diesel vehicles involves two separate and distinct test procedures. The two tests are 1) a snap/free no-load acceleration test and 2) a dynamometer loaded-mode lug-down test procedure.

Engine temperature and oil pressure are to be closely monitored during all testing. Testing is to be discontinued if engine and vehicle operating parameters are not within acceptable limits.

NOTE: If the vehicle is equipped with a temperature regulated radiator shutter or modulating fan and its operation is erratic, unstable or questionable, secure the shutter in the open position for the duration of the opacity test.

III.C.4.a. Snap/Free Acceleration Test Procedure

This procedure requires a rapid Wide Open Throttle (WOT) no-load acceleration of the engine from low idle to maximum governed no-load rpm with the transmission in neutral

III.C.4.a.i. Verify the zero setting of the opacity meter. Start and operate the engine at idle rpm.

III.C.4.a.ii. With the transmission in neutral and the engine at idle rpm,

slowly accelerate the engine allowing the engine to reach its maximum stabilized governed speed. Allow the engine to return to idle.

III.C.4.a.iii. Place the opacity meter in the peak hold position.

III.C.4.a.iv. Perform the acceleration procedure as in Step 4.a.ii., but rapidly accelerate the engine. Record on the opacity worksheet the highest or peak smoke opacity reading attained during the procedure.

III.C.4.a.v. Return the engine to idle rpm and shut down engine.

III.C.4.a.vi. Return opacity meter to normal mode (peak hold off) and note zero shift (deviation) reading. Record the peak opacity value obtained in Step 4.a.iv. and the meter zero shift on the DVIR, and proceed to the dynamometer test procedure.

III.C.4.b. Dynamometer Test Procedure

III.C.4.b.i. Verify smoke opacity meter is set at zero. Start and operate engine at idle rpm. With the dynamometer in an unloaded mode/condition, select a gear which will allow the vehicle to attain and maintain a no-load vehicle speed of 60 to 70 miles per hour (mph) at wide open throttle (WOT). It is preferred and recommended that vehicle be operated at the lower end of this mph range whenever possible. If vehicle has a maximum road speed that is less than 60 mph, operate vehicle at the highest mph possible. Upon stabilization, maintain speed for at least ten seconds (plus or minus four seconds) and record engine rpm and mph on opacity worksheet.

III.C.4.b.ii. While maintaining wide open throttle (WOT), slowly increase the dynamometer loading until engine rated rpm (plus or minus 15 rpm) is obtained. Maintain this speed/load for at least ten seconds (plus or minus four seconds) and record the following information: engine rpm, smoke opacity, and horsepower.

III.C.4.b.iii. Maintain wide open throttle (WOT) and slowly increase dynamometer loading until engine is at 90% of rated rpm (plus or minus 15 rpm). Maintain this speed/load for at least ten seconds (plus or minus four seconds) and record data on opacity worksheet; engine rpm, smoke opacity, and hp.

III.C.4.b.iv. Maintain wide open throttle (WOT) and slowly increase dynamometer loading until engine is at 80% of rated rpm (plus or minus 15 rpm). Maintain this speed/load for at least ten seconds (plus or minus four seconds) and record data on opacity worksheet; engine rpm, smoke opacity, and hp.

III.C.4.b.v. Maintain wide open throttle (WOT) and slowly increase dynamometer loading until engine is at 70% of rated rpm (plus or minus 15 rpm). Maintain this speed/load for at least ten seconds (plus or minus four seconds) and record data on opacity worksheet; engine rpm, smoke opacity, and hp. This step concludes the engine loading procedure; do not apply additional loading under any circumstances.

IIIC.4.b.vi. Note: Vehicles with automatic transmissions are allowed two downshifts to the next lower gear at any point during the dynamometer lugdown test. If a downshift occurs, continue with the test.

III.C.4.b.vii. Slowly remove dynamometer loading while returning engine to idle. Shut down engine after observing cool down procedure. Note and record residual opacity meter reading on Opacity Worksheet.

III.C.4.b.viii. The inspector shall refer to the opacity standards in Part B, V. of this regulation.

III.C.4.b.viii.A. If the highest opacity reading taken from Steps 4.b.ii. through 4.b.v. exceeds the opacity standard and the opacity meter zero shift exceeds five percent (5%), clean the lenses, zero meter and repeat the dynamometer test procedure starting at Step 4.B.I. At least one additional test will be conducted at no cost to the motorist.

III.C.4.b.viii.B. If the highest opacity reading taken from Steps 4.b.ii. through 4.b.v. exceeds the opacity standard and the opacity meter zero shift is less than five percent (5%), the vehicle fails the inspection.

III.C.4.b.viii.C. If neither the highest opacity meter reading taken in steps (ii) through (v) nor the opacity meter zero shift exceeds the opacity standard, the vehicle passes the inspection.

III.C.4.b.ix. The inspector shall then enter the highest opacity reading, the opacity meter zero shift, the pass/fail determination, provide an electronic signature, and other required information on the DVIR. Vehicles which comply with the inspection procedures and applicable opacity standards shall be issued a completed CEC.

III.C.4.c. Vehicle Removal from Dynamometer

III.C.4.c.i. Detach all test equipment, restraints and remove them from the vehicle.

III.C.4.c.ii. If the vehicle is equipped with a radiator shutter or modulating fan which has been secured in the open position prior to testing, restore unit to normal operation.

III.C.4.c.iii. Remove vehicle from dynamometer.

III.D. On-Road Inspection Procedures for Heavy-Duty Diesel Vehicles (Greater than fourteen thousand pounds GVWR)

III.D.1. Test Site Requirements and Conditions

In addition to the prescribed test equipment and other requirements, as set forth by this regulation, a test site will only be considered adequate for on-road opacity testing when there is:

III.D.1.a. Approximately three-hundred (300) yards of sound, smooth, paved test lane in a safe, uncongested area on private property (non-public roads).

III.D.1.b. An ambient temperature between 35°F and 110°F (2°C and 43°C) during any given vehicle test procedure.

III.D.1.c. An opacity inspector licensed by the Department of Revenue and in possession of a valid opacity inspector license.

III.D.1.d. A driver, knowledgeable in the operation of the vehicle to be tested and in possession of a valid operator's license relative to that vehicle. (Refer to Part B, IV.B.3)

III.D.2. Vehicle Preparation

Prior to proceeding with the actual opacity testing of the vehicle, the following guidelines must be followed:

III.D.2.a. Verify that the vehicle to be tested meets the program definition of a heavy-duty vehicle (Greater than fourteen thousand pounds GVWR).

III.D.2.b. Vehicle is to be equipped with a speedometer in good working order.

III.D.2.c. Perform a safety inspection of the vehicle's brakes, tires and driveline for defects or unsafe conditions.

III.D.2.d. Enter the requested vehicle/owner information on the Diesel Vehicle Inspection Report (DVIR).

III.D.2.e. Determine the engine's rated horsepower and attendant rpm and enter on DVIR and also on the opacity worksheet.

III.D.2.f. Securely mount the test/reference tachometer and interface it with the approved strip chart recorder which is to be located in the vehicle's cab. Ensure that all wires and cables do not pose any potential safety hazards.

III.D.2.g. Securely attach the approved/registered opacity meter to the vehicle's exhaust piping. If a full-flow opacity meter is to be used, ensure that the optical pickup head is attached in such a manner that the opacity meter's emitter and detector light path is perpendicular to the vehicle's direction of travel and is centered approximately 5" plus or minus 1" from the exhaust outlet. Interface the meter with the strip chart recorder. Follow the calibration procedures prescribed by the equipment manufacturers.

III.D.3. Test Procedures

The on-road opacity testing of heavy-duty diesel vehicles involves two separate and distinct test procedures. The two tests are 1) a snap/free no-load-mode acceleration test and, 2) either an on-road load-mode acceleration test or an on-road loaded-mode brake lug-down test.

III.D.3.a. Snap/Free Acceleration Test Procedure

This procedure requires a rapid Wide Open Throttle (WOT) no-load acceleration of the engine from low idle to maximum governed no-load rpm with the transmissions in neutral.

III.D.3.a.i. Verify the zero settings of the opacity meter and chart recorder.

Start and operate the engine at idle rpm.

III.D.3.a.ii. With the transmission in neutral and the engine at idle rpm,

slowly accelerate the engine allowing the engine to reach its maximum stabilized no-load governed speed. Allow the engine to return to idle.

III.D.3.a.iii. Place the opacity meter in the peak hold position.

III.D.3.a.iv. Perform the acceleration procedure as in Step 3.a.ii., but rapidly accelerate the engine. Record on the opacity worksheet the highest or peak smoke opacity reading attained during the procedure.

III.D.3.a.v. Return the engine to idle rpm and shutdown engine.

III.D.3.a.vi. Return opacity meter to normal mode (peak hold off) and note zero shift (deviation) reading. Record the peak opacity value obtained in Step 3.a.iv. and the meter zero shift on the DVIR, and proceed to the on-road test; either acceleration or lugdown procedure, as applicable.

III.D.3.b. On-Road Acceleration Opacity Test Procedure

III.D.3.b.i. Verify smoke opacity meter and chart recorder/digital recording device are set at zero. Start and operate engine at idle rpm.

Select a gear which will permit the vehicle to accelerate under WOT from a moving position (approximately 900 to 1000 engine rpm) up to maximum engine rpm in no less than seven seconds. This step is vital in order to ensure that the engine will be operated in an rpm range and time frame which will allow sufficient time and engine loading in order to accurately monitor the vehicle's smoke opacity levels.

III.D.3.b.ii. Bring the vehicle to a stop and shutdown the engine. Verify the zero settings of the opacity meter and the strip chart recorder. Clean the monitoring unit as necessary.

III.D.3.b.iii. With the transmission in the selected gear (as described in Step 3.b.i.) and the strip chart recorder in record mode, accelerate the vehicle under WOT from a road speed equivalent of 900 to 1000 engine rpm up to maximum engine rpm. Maintain maximum rpm for a few seconds in order to allow for stabilized conditions.

III.D.3.b.iv. Bring the vehicle to a safe controlled stop, shut down engine and discontinue the recording. Note and record on the opacity worksheet, 1) the highest opacity reading observed between maximum engine rpm and 70 percent (70%) rated rpm and, 2) the opacity meter/chart recorder zero shift (deviation) reading.

III.D.3.b.v. The inspector shall refer to the opacity standards in Part B, V. of this regulation.

III.D.3.b.vi. If the highest recorded opacity taken from Step 3.b.iii. through 3.biv. exceeds the opacity standard and the opacity meter/chart recorder zero shift (deviation) exceeds five percent (5%), clean the lenses, zero meter and repeat the acceleration test procedure starting at Step 3.b.iii. At least one additional test will be conducted at no cost to the motorist.

III.D.3.b.vi.A. If the highest opacity reading taken from Steps 3.b.iii. through 3.b.iv. exceeds the opacity standard over the required time period, with five percent (5%) or less zero shift, the vehicle fails the inspection.

III.D.3.b.vi.B. If neither the highest opacity meter reading taken in Steps 3.b.iii. through 3.b.vi. nor the zero shift exceeds the opacity standard, the vehicle passes the inspection and the inspector shall proceed directly to Step 3.b.xi..

III.D.3.b.vi.C. If the highest opacity meter reading exceeds the opacity standard with five percent (5%) or less zero shift, but for less than the required time period, the vehicle will require additional testing as follows.

III.D.3.b.vii. Verify the zero settings of the opacity meter and strip chart recorder. Clean the monitoring unit as necessary.

III.D.3.b.viii. Accelerate the vehicle as in Step 3.b.iii., however, the vehicle's acceleration must be temporarily restrained (10 ± 4 seconds) at that rpm point in the procedure where the highest opacity reading was observed. Decreased throttle is not to be used to slow the vehicle's rate of acceleration. The vehicle's service brakes should be utilized for that purpose. Opacity and rpm must be accurately recorded at this time.

III.D.3.b.ix. Bring the vehicle to a safe controlled stop, shut down engine, and discontinue the recording. Note the highest opacity meter reading and the opacity meter/chart recorder zero shift.

III.D.3.b.x. If the highest opacity meter reading taken from Steps 3.b.viii. and 3.b.ix. exceeds the opacity standard and the opacity meter/chart recorder zero shift (deviation) exceeds five percent (5%), clean the lenses, zero meter and repeat the acceleration test procedure starting at Step 3.b.viii.

III.D.3.b.x.A. If the highest opacity reading taken from Steps 3.b.viii. through 3.b.ix. exceeds the opacity standard over the required time period, with five percent (5%) or less zero shift, the vehicle fails the inspection.

III.D.3.b.x.B. If neither the highest opacity meter reading taken in Steps 3.b.viii. through 3.b.ix. nor the opacity meter zero shift exceeds the opacity standard, the vehicle passes the inspection.

III.D.3.b.xi. The inspector shall then enter the highest opacity reading, the opacity meter/chart recorder zero shift, the pass/fail determination, provide an electronic signature, and other required information on the DVIR. Vehicles which comply with the inspection procedures and applicable opacity standards shall be issued a completed CEC.

III.D.3.c. On-Road Brake Lug-Down Test Procedure

III.D.3.c.i. Verify smoke opacity meter and chart recorder are set at zero.

Start and operate engine at idle rpm.

III.D.3.c.ii. Select a gear which will permit the vehicle to attain a road speed of 15 to 25 mph with the engine at maximum rpm, wide open throttle (WOT). Due to the many variables, this gear selection process is basically a trial and error effort. Bring the vehicle to a stop and shut-down the engine.

III.D.3.c.iii. Verify the zero settings of the opacity meter and strip chart recorder. Clean the monitoring unit as necessary.

III.D.3.c.iv. With the vehicle operating at WOT in the selected gear as described in Step 3.c.ii. and the chart recorder in record mode, maintain WOT and slowly begin loading the engine by means of the vehicle's service brakes. The loading is to be applied linearly throughout an engine rpm range which extends from maximum engine rpm down to 70 percent of the engine's rated rpm in a time span which encompasses no less than ten seconds.

III.D.3.c.v. Note: Vehicles with automatic transmissions are allowed two downshifts to the next lower gear at any point during the brake lug-down test. If a downshift occurs, continue with the test.

III.D.3.c.vi. Bring the vehicle to a safe controlled stop, shut down engine and discontinue the recording. Note and record 1) the highest opacity reading observed between maximum engine rpm and 70% rated rpm and, 2) the opacity meter/chart recording zero shift (deviation) reading.

III.D.3.c.vii. The inspector shall refer to the Opacity Standards in Part B, V. of this regulation.

III.D.3.c.viii. If the highest opacity meter reading taken from Steps 3.c.iv. through 3.c.vi. exceeds the opacity standard and the opacity meter/chart recorder zero shift exceeds five percent (5%), clean the lenses, zero meter and repeat the brake lugdown test procedure starting at Step 3.c.iv. At least one additional test will be conducted at no cost to the motorist.

III.D.3.c.viii.A. If the highest opacity meter reading taken from Steps 3.c.iv. through 3.c.vi. Exceeds the opacity standard over the required time period with five percent (5%) or less zero shift, the vehicle fails the inspection.

III.D.3.c.viii.B. If neither the highest opacity meter reading taken in Steps 3.c.iv. through 3.c.vi. nor the opacity meter zero shift exceeds the opacity standard, the vehicle passes the inspection and the inspector shall proceed directly to Step 3.c.xiii.

III.D.3.c.viii.C. If the highest opacity meter reading exceeds the opacity standard with five percent (5%) or less zero shift but for less than the required time period, the vehicle will require additional testing as follows.

III.D.3.c.ix. Verify the zero settings of the opacity meter and chart recorder,

clean the monitoring unit as necessary.

III.D.3.c.x. Again, operate the vehicle as in Step 3.c.iv.; however restrain the vehicle for ten, plus or minus four, seconds (10 ± 4 seconds) by means of the vehicle's service brakes at the rpm point in the procedure where the highest opacity reading was observed.

III.D.3.c.xi. Bring the vehicle to a safe controlled stop, shut down engine and discontinue the recording. Note the highest opacity meter reading and the opacity meter/chart recorder zero shift.

III.D.3.c.xii. If the highest opacity meter reading taken from Steps 3.c.x. and 3.c.xi. exceeds the opacity standard and the opacity meter/chart recorder zero shift exceeds five percent (5%), clean the lenses, zero meter and repeat the brake lugdown test procedure starting at Step 3.c.x.

III.D.3.c.xii.A. If the highest opacity meter reading taken from Steps 3.c.x. and 3.c.xi. exceeds the opacity standard over the required time period with five percent (5%) or less zero shift, the vehicle fails the inspection.

III.D.3.c.xii.B. If neither the highest opacity meter reading taken in Steps 3.c.x. through 3.c.xi. nor the zero shift exceeds the opacity standard, the vehicle passes the inspection.

III.D.3.c.xiii. The inspector shall then enter the highest opacity reading, the opacity meter/chart recorder zero shift, the pass/fail determination, provide an electronic signature, and other required information on the DVIR. Vehicles which comply with the inspection procedures and applicable opacity standards shall be issued a completed CEC.

III.E. The Division has the authority to determine the applicability of this regulation for unique testing situations not specifically addressed in this regulation.

5 CCR 1001-15-B-III

39 CR 18, September 25, 2016, effective 10/15/2016

41 CR 21, November 10, 2018, effective 11/30/2018