Directive 2010/26 - Amendment of Directive 97/68/EC on the approximation of the laws of the Member States relating to measures against the emission of gaseous and particulate pollutants from internal combustion engines to be installed in non-road mobile machinery - Main contents

EN

Official Journal of the European Union

L 86/29

Article 14a of Directive 97/68/EC sets out the criteria and the procedure for extending the period referred to in Article 9a(7) of that Directive. Studies carried out in accordance with Article 14a of Directive 97/68/EC show that there are substantial technical difficulties to comply with stage II requirements for professional use, multi-positional, hand-held mobile machinery in which engines of classes SH:2 and SH:3 are installed. It is therefore necessary to extend the period referred to in Article 9a(7) until 31 July 2013.

Since the amendment of Directive 97/68/EC in 2004, technical progress has been made in the design of diesel engines with a view to make them compliant with the exhaust emission limits for stages IIIB and IV. Electronically controlled engines, largely replacing mechanically controlled fuel injection and control systems, have been developed. Therefore, the current general type-approval requirements in Annex I to Directive 97/68/EC should be adapted accordingly and general type-approval requirements for stages IIIB and IV should be introduced.

Annex II to Directive 97/68/EC specifies the technical details of the information documents that need to be submitted by the manufacturer to the type-approval authority with the application for engine type-approval. The details specified regarding the additional anti-pollution devices are generic and should be adapted to the specific after-treatment systems that need to be used to ensure that engines comply with exhaust emission limit stages IIIB and IV. More detailed information on the after-treatment devices installed on the engines should be submitted to enable type-approval authorities to assess the engine’s capability to comply with stages IIIB and IV.

Annex III to Directive 97/68/EC sets out the method testing the engines and determining their level of emissions of gaseous and particulate pollutants. The type-approval testing procedure of engines to demonstrate compliance with the exhaust emission limits of stage IIIB and IV should ensure that the simultaneous compliance with the gaseous (carbon monoxide, hydrocarbons, oxides of nitrogen) and the particulate emission limits is demonstrated. The non-road steady cycle (NRSC) and non-road transient cycle (NRTC) should be adapted accordingly.

Point 1.3.2 of Annex III to Directive 97/68/EC foresees the modification of the symbols (section 2.18 of Annex I), the test sequence (Annex III) and calculation equations (Appendix III to Annex III), prior to the introduction of the cold/hot composite test sequence. The type approval procedure to demonstrate compliance with the exhaust emission limits of stage IIIB and IV requires the introduction of a detailed description of the cold start cycle.

Section 3.7.1 of Annex III to Directive 97/68/EC sets out the test cycle for the different equipment specifications. The test cycle under point 3.7.1.1 (specification A) needs to be adapted to clarify which engine speed needs to be used in the type approval calculation method. It is also necessary to adapt the reference to the updated version of the international testing standard ISO 8178-4:2007.

Section 4.5 of Annex III to Directive 97/68/EC outlines the emissions test run. This section needs to be adapted to take account of the cold start cycle.

Appendix 3 of Annex III to Directive 97/68/EC sets out the criteria for the data evaluation and calculation of the gaseous emissions and the particulate emissions, for both the NRSC test and the NRTC test set out in Annex III. The type approval of engines in accordance with stage IIIB and IV requires the adaptation of the calculation method for the NRTC test.

Annex XIII to Directive 97/68/EC sets out the provisions for engines placed on the market under a ‘flexible scheme’. To ensure a smooth implementation of stage IIIB, an increased use of this flexibility scheme may be needed. Therefore, the adaptation to technical progress to enable the introduction of stage IIIB compliant engines needs to be accompanied by measures to avoid that the use of the flexibility scheme may be hampered by notification requirements which are no longer adapted to the introduction of such engines. The measures should aim at simplifying the notification requirements and the reporting obligations, and at making them more focused and tailored to the need for market surveillance authorities to respond to the increased use of the flexibility scheme that will result from the introduction of stage IIIB.

Since Directive 97/68/EC provides for the type-approval of stage IIIB engines (category L) as from 1 January 2010 it is necessary to provide for the possibility to grant type approval from that date.

For reasons of legal certainty this Directive should enter into force as a matter of urgency.

The measures provided for in this Directive are in accordance with the opinion of the Committee established in Article 15(1) of Directive 97/68/EC,

in Article 9a(7), the following subparagraph is added:

‘Notwithstanding the first subparagraph, an extension of the derogation period is granted until 31 July 2013, within the category of top handle machines, for professional use, multi-positional, hand-held hedge trimmers and top handle tree service chainsaws in which engines of classes SH:2 and SH:3 are installed.’;

Annex I is amended in accordance with Annex I to this Directive;

Annex II is amended in accordance with Annex II to this Directive;

Annex III is amended in accordance with Annex III to this Directive;

Annex V is amended in accordance to Annex IV to this Directive;

Annex XIII is amended in accordance with Annex V to this Directive.

where the auxiliary emission control strategy is activated during the type approval test, sections 8.3.2.2 and 8.3.2.3 shall not apply;

where the auxiliary emission control strategy is not activated during the type approval test, it must be demonstrated that the auxiliary emission control strategy is active only for as long as required for the purposes identified in section 8.3.2.3.

an altitude not exceeding 1 000 metres (or equivalent atmospheric pressure of 90 kPa);

an ambient temperature within the range 275 K to 303 K (2 °C to 30 °C);

the engine coolant temperature above 343 K (70 °C).

by onboard signals, for protecting the engine (including air-handling device protection) and/or non-road mobile machine into which the engine is installed from damage;

for operational safety and strategies;

for prevention of excessive emissions, during cold start or warming-up, during shut-down;

if used to trade-off the control of one regulated pollutant under specific ambient or operating conditions, for maintaining control of all other regulated pollutants, within the emission limit values that are appropriate for the engine concerned. The purpose is to compensate for naturally occurring phenomena in a manner that provides acceptable control of all emission constituents.

the documentation package, annexed to the application for type-approval, shall include a full overview of the emission control strategy. Evidence shall be provided that all outputs permitted by a matrix, obtained from the range of control of the individual unit inputs, have been identified. This evidence shall be attached to the information folder as referred to in Annex II;

the additional material, presented to the technical service but not annexed to the application for type-approval, shall include all the modified parameters by any auxiliary emission control strategy and the boundary conditions under which this strategy operates and in particular:

detailed warnings, explaining possible malfunctions generated by incorrect operation, use or maintenance of the installed engine, accompanied by respective rectification measures;

detailed warnings on the incorrect use of the machine resulting in possible malfunctions of the engine, accompanied by respective rectification measures;

information on the correct use of the reagent, accompanied by an instruction on refilling the reagent between normal maintenance intervals;

a clear warning, that the type-approval certificate, issued for the type of engine concerned, is valid only when all of the following conditions are met:

the amount of reagent remaining in the reagent storage container and by an additional specific signal, when the remaining reagent is less than 10 % of the full container’s capacity;

when the reagent container becomes empty, or almost empty;

when the reagent in the storage tank does not comply with the characteristics declared and recorded in section 2.2.1.13 of Appendix 1 and section 2.2.1.13 of Appendix 3 to Annex II, according to the installed means of assessment.

when the dosing activity of the reagent is interrupted, in cases other than those executed by the engine ECU or the dosing controller, reacting to engine operating conditions where the dosing is not required, provided that these operating conditions are made available to the type approval authority.

direct means, such as the use of a reagent quality sensor.

indirect means, such as the use of a NOx sensor in the exhaust to evaluate reagent effectiveness.

any other means, provided that its efficacy is at least equal to the one resulting by the use of the means of points (a) or (b) and the main requirements of this section are maintained.’

Section 2 of Appendix 1 is replaced by the following:

‘2.   MEASURES TAKEN AGAINST AIR POLLUTION

2.1.   Device for recycling crankcase gases: yes/no (1) …

2.2.   Additional anti-pollution devices (if any, and if not covered by another heading)

2.2.1.   Catalytic converter: yes/no (1)

2.2.1.1.   Make(s): …

2.2.1.2.   Type(s): …

2.2.1.3.   Number of catalytic converters and elements …

2.2.1.4.   Dimensions- and volume of the catalytic converter(s): …

2.2.1.5.   Type of catalytic action: …

2.2.1.6.   Total charge of precious metals: …

2.2.1.7.   Relative concentration: …

2.2.1.8.   Substrate (structure and material): …

2.2.1.9.   Cell density: …

2.2.1.10.   Type of casing for the catalytic converter(s): …

2.2.1.11.   Location of the catalytic converter(s) (place(s) and maximum/minimum distance(s) from engine): …

2.2.1.12.   Normal operating range (K): …

2.2.1.13.   Consumable reagent (where appropriate): …

2.2.1.13.1.   Type and concentration of reagent needed for catalytic action: …

2.2.1.13.2.   Normal operational temperature range of reagent: …

2.2.1.13.3.   International standard (where appropriate): …

2.2.1.14.   NOx sensor: yes/no (1)

2.2.2.   Oxygen sensor: yes/no (1)

2.2.2.1.   Make(s): …

2.2.2.2.   Type: …

2.2.2.3.   Location: …

2.2.3.   Air injection: yes/no (1)

2.2.3.1.   Type (pulse air, air pump, etc.): …

2.2.4.   EGR: yes/no (1)

2.2.4.1.   Characteristics (cooled/uncooled, high pressure/low pressure, etc.): …

2.2.5.   Particulate trap: yes/no (1)

2.2.5.1.   Dimensions and capacity of the particulate trap: …

2.2.5.2.   Type and design of the particulate trap: …

2.2.5.3.   Location (place(s) and maximum/minimum distance(s) from engine): …

2.2.5.4.   Method or system of regeneration, description and/or drawing: …

2.2.5.5.   Normal operating temperature (K) and pressure (kPa) range: …

2.2.6.   Other systems: yes/no (1)

2.2.6.1.   Description and operation: …

Section 2 of Appendix 3 is replaced by the following:

‘2.   MEASURES TAKEN AGAINST AIR POLLUTION

2.1.   Device for recycling crankcase gases: yes/no (2) …

2.2.   Additional anti-pollution devices (if any, and if not covered by another heading)

2.2.1.   Catalytic converter: yes/no (2)

2.2.1.1.   Make(s): …

2.2.1.2.   Type(s): …

2.2.1.3.   Number of catalytic converters and elements …

2.2.1.4.   Dimensions- and volume of the catalytic converter(s): …

2.2.1.5.   Type of catalytic action: …

2.2.1.6.   Total charge of precious metals: …

2.2.1.7.   Relative concentration: …

2.2.1.8.   Substrate (structure and material): …

2.2.1.9.   Cell density: …

2.2.1.10.   Type of casing for the catalytic converter(s): …

2.2.1.11.   Location of the catalytic converter(s) (place(s) and maximum/minimum distance(s) from engine): …

2.2.1.12.   Normal operating range (K) …

2.2.1.13.   Consumable reagent (where appropriate): …

2.2.1.13.1.   Type and concentration of reagent needed for catalytic action: …

2.2.1.13.2.   Normal operational temperature range of reagent: …

2.2.1.13.3.   International standard (where appropriate): …

2.2.1.14.   NOx sensor: yes/no (2)

2.2.2.   Oxygen sensor: yes/no (2)

2.2.2.1.   Make(s): …

2.2.2.2.   Type: …

2.2.2.3.   Location: …

2.2.3.   Air injection: yes/no (2)

2.2.3.1.   Type (pulse air, air pump, etc.): …

2.2.4.   EGR: yes/no (2)

2.2.4.1.   Characteristics (cooled/uncooled, high pressure/low pressure, etc.): …

2.2.5.   Particulate trap: yes/no (2)

2.2.5.1.   Dimensions and capacity of the particulate trap: …

2.2.5.2.   Type and design of the particulate trap: …

2.2.5.3.   Location (place(s) and maximum/minimum distance(s) from engine): …

2.2.5.4.   Method or system of regeneration, description and/or drawing: …

2.2.5.5.   Normal operating temperature (K) and pressure (kPa) range: …

2.2.6.   Other systems: yes/no (2)

2.2.6.1.   Description and operation: …

Section 1.1 is replaced by the following:

1.1.   This Annex describes the method of determining emissions of gaseous and particulate pollutants from the engine to be tested.

The following test cycles shall apply:

Section 1.3.2 is replaced by the following:

‘1.3.2.   NRTC test

The prescribed transient test cycle, based closely on the operating conditions of diesel engines installed in non-road machinery, is run twice:

During this test sequence the above pollutants shall be examined. The test sequence consists of a cold start cycle following natural or forced cool-down of the engine, a hot soak period and a hot start cycle, resulting in a composite emissions calculation. Using the engine torque and speed feedback signals of the engine dynamometer, the power shall be integrated with respect to the time of the cycle, resulting in the work produced by the engine over the cycle. The concentrations of the gaseous components shall be determined over the cycle, either in the raw exhaust gas by integration of the analyser signal in accordance with Appendix 3 to this Annex, or in the diluted exhaust gas of a CVS full-flow dilution system by integration or by bag sampling in accordance with Appendix 3 to this Annex. For particulates, a proportional sample shall be collected from the diluted exhaust gas on a specified filter by either partial flow dilution or full-flow dilution. Depending on the method used, the diluted or undiluted exhaust gas flow rate shall be determined over the cycle to calculate the mass emission values of the pollutants. The mass emission values shall be related to the engine work to give the grams of each pollutant emitted per kilowatt-hour.

Emissions (g/kWh) shall be measured during both the cold and hot start cycles. Composite weighted emissions shall be computed by weighting the cold start results 10 % and the hot start results 90 %. Weighted composite results shall meet the limits.’

Section 3.7.1 is replaced by the following:

3.7.1.   Equipment specification according to section 1.A of Annex I:

3.7.1.1.   Specification A

For engines covered by points (i) and (iv) of section 1.A of Annex I, the following 8-mode cycle (3) shall be followed in dynamometer operation on the test engine:

3.7.1.2.   Specification B

For engines covered by point (ii) of section 1.A of Annex I, the following 5-mode cycle (5) shall be followed in dynamometer operation on the test engine:

The load figures are percentage values of the torque corresponding to the prime power rating defined as the maximum power available during a variable power sequence, which may be run for an unlimited number of hours per year, between stated maintenance intervals and under the stated ambient conditions, the maintenance being carried out as prescribed by the manufacturer.

3.7.1.3.   Specification C

For propulsion engines (6) intended to be used in inland waterway vessels the ISO test procedure as specified by ISO 8178-4:2002 and IMO MARPOL 73/78, Annex VI (NOx Code) shall be used.

Propulsion engines that operate on a fixed-pitch propeller curve shall be tested on a dynamometer using the following 4-mode steady-state cycle (7) developed to represent in-use operation of commercial marine diesel engines.

Fixed speed inland waterway propulsion engines with variable pitch or electrically coupled propellers shall be tested on a dynamometer using the following 4-mode steady-state cycle (8) characterised by the same load and weighting factors as the above cycle, but with engine operated in each mode at rated speed:

3.7.1.4.   Specification D

For engines covered by point (v) of section 1.A of Annex I, the following 3-mode cycle (9) shall be followed in dynamometer operation on the test engine:

Section 4.3.1 is replaced by the following:

‘4.3.1.   Reference speed

The reference speed (nref) corresponds to the 100 % normalised speed values specified in the engine dynamometer schedule of Appendix 4 of Annex III. The actual engine cycle resulting from denormalisation to the reference speed depends largely on selection of the proper reference speed. The reference speed shall be determined by the following formula:

nref = low speed + 0,95 x (high speed – low speed)

(the high speed is the highest engine speed where 70 % of the rated power is delivered, while the low speed is the lowest engine speed where 50 % of the rated power is delivered).

If the measured reference speed is within +/– 3 % of the reference speed as declared by the manufacturer, the declared reference speed may be used for the emissions test. If the tolerance is exceeded, the measured reference speed shall be used for the emissions test (10).

Section 4.5 is replaced by the following:

‘4.5.   Emissions test run

The following flow chart outlines the test sequence:

One or more practice cycles may be run as necessary to check engine, test cell and emissions systems before the measurement cycle.

4.5.1.   Preparation of the sampling filters

At least one hour before the test, each filter shall be placed in a petri dish, which is protected against dust contamination and allows air exchange, and placed in a weighing chamber for stabilisation. At the end of the stabilisation period, each filter shall be weighed and the weight shall be recorded. The filter shall then be stored in a closed petri dish or sealed filter holder until needed for testing. The filter shall be used within eight hours of its removal from the weighing chamber. The tare weight shall be recorded.

4.5.2.   Installation of the measuring equipment

The instrumentation and sample probes shall be installed as required. The tailpipe shall be connected to the full-flow dilution system, if used.

4.5.3.   Starting the dilution system

The dilution system shall be started. The total diluted exhaust gas flow of a full-flow dilution system or the diluted exhaust gas flow through a partial flow dilution system shall be set to eliminate water condensation in the system, and to obtain a filter face temperature between 315 K (42 °C) and 325 K (52 °C).

4.5.4.   Starting the particulate sampling system

The particulate sampling system shall be started and run on by-pass. The particulate background level of the dilution air may be determined by sampling the dilution air prior to entrance of the exhaust into the dilution tunnel. It is preferred that background particulate sample be collected during the transient cycle if another PM sampling system is available. Otherwise, the PM sampling system used to collect transient cycle PM can be used. If filtered dilution air is used, one measurement may be done prior to or after the test. If the dilution air is not filtered, measurements should be carried out prior to the beginning and after the end of the cycle and the values averaged.

4.5.5.   Checking the analysers

The emission analysers shall be set at zero and spanned. If sample bags are used, they shall be evacuated.

4.5.6.   Cool-down requirements

A natural or forced cool-down procedure may be applied. For forced cool-down, good engineering judgement shall be used to set up systems to send cooling air across the engine, to send cool oil through the engine lubrication system, to remove heat from the coolant through the engine cooling system, and to remove heat from an exhaust after-treatment system. In the case of a forced after-treatment cool down, cooling air shall not be applied until the after-treatment system has cooled below its catalytic activation temperature. Any cooling procedure that results in unrepresentative emissions is not permitted.

The cold start cycle exhaust emission test may begin after a cool-down only when the engine oil, coolant and after-treatment temperatures are stabilised between 20 °C and 30 °C for a minimum of 15 minutes.

4.5.7.   Cycle run

4.5.7.1.   Cold start cycle

The test sequence shall commence with the cold start cycle at the completion of the cool-down when all the requirements specified in section 4.5.6 are met.

The engine shall be started according to the starting procedure recommended by the manufacturer in the owner's manual, using either a production starter motor or the dynamometer.

As soon as it is determined that the engine is started, start a “free idle” timer. Allow the engine to idle freely with no-load for 23 ± 1 s. Begin the transient engine cycle such that the first non-idle record of the cycle occurs at 23 ± 1 s. The free idle time is included in the 23 ± 1 s.

The test shall be performed according to the reference cycle as set out in Annex III, Appendix 4. Engine speed and torque command set points shall be issued at 5 Hz (10 Hz recommended) or greater. The set points shall be calculated by linear interpolation between the 1 Hz set points of the reference cycle. Feedback engine speed and torque shall be recorded at least once every second during the test cycle, and the signals may be electronically filtered.

4.5.7.2.   Analyser response

At the start of the engine the measuring equipment shall be started, simultaneously:

If raw exhaust measurement is used, the emission concentrations (HC, CO and NOx) and the exhaust gas mass flow rate shall be measured continuously and stored with at least 2 Hz on a computer system. All other data may be recorded with a sample rate of at least 1 Hz. For analogue analysers the response shall be recorded, and the calibration data may be applied online or offline during the data evaluation.

If a full flow dilution system is used, HC and NOx shall be measured continuously in the dilution tunnel with a frequency of at least 2 Hz. The average concentrations shall be determined by integrating the analyser signals over the test cycle. The system response time shall be no greater than 20 s, and shall be coordinated with CVS flow fluctuations and sampling time/test cycle offsets, if necessary. CO and CO2 shall be determined by integration or by analysing the concentrations in the sample bag collected over the cycle. The concentrations of the gaseous pollutants in the dilution air shall be determined by integration or by collection in the background bag. All other parameters that need to be measured shall be recorded with a minimum of one measurement per second (1 Hz).

4.5.7.3.   Particulate sampling

At the start of the engine the particulate sampling system shall be switched from by-pass to collecting particulates.

If a partial flow dilution system is used, the sample pump(s) shall be adjusted so that the flow rate through the particulate sample probe or transfer tube is maintained proportional to the exhaust mass flow rate.

If a full flow dilution system is used, the sample pump(s) shall be adjusted so that the flow rate through the particulate sample probe or transfer tube is maintained at a value within ± 5 % of the set flow rate. If flow compensation (i.e. proportional control of sample flow) is used, it must be demonstrated that the ratio of main tunnel flow to particulate sample flow does not change by more than ± 5 % of its set value (except for the first 10 seconds of sampling).

NOTE: For double dilution operation, sample flow is the net difference between the flow rate through the sample filters and the secondary dilution airflow rate.

The average temperature and pressure at the gas meter(s) or flow instrumentation inlet shall be recorded. If the set flow rate cannot be maintained over the complete cycle (within ± 5 %) because of high particulate loading on the filter, the test shall be voided. The test shall be rerun using a lower flow rate and/or a larger diameter filter.

4.5.7.4.   Engine stalling during the cold start test cycle

If the engine stalls anywhere during the cold start test cycle, the engine shall be preconditioned, then the cool-down procedure repeated; finally the engine shall be restarted, and the test repeated. If a malfunction occurs in any of the required test equipment during the test cycle, the test shall be voided.

4.5.7.5.   Operations after cold start cycle

At the completion of the cold start cycle of the test, the measurement of the exhaust gas mass flow rate, the diluted exhaust gas volume, the gas flow into the collecting bags and the particulate sample pump shall be stopped. For an integrating analyser system, sampling shall continue until system response times have elapsed.

The concentrations of the collecting bags, if used, shall be analysed as soon as possible and in any case not later than 20 minutes after the end of the test cycle.

After the emission test, a zero gas and the same span gas shall be used for re-checking the analysers. The test will be considered acceptable if the difference between the pre-test and post-test results is less than 2 % of the span gas value.

The particulate filters shall be returned to the weighing chamber no later than one hour after completion of the test. They shall be conditioned in a petri dish, which is protected against dust contamination and allows air exchange, for at least one hour, and then weighed. The gross weight of the filters shall be recorded.

4.5.7.6.   Hot soak

Immediately after the engine is turned off, the engine cooling fan(s) shall be turned off if used, as well as the CVS blower (or disconnect the exhaust system from the CVS), if used.

Allow the engine to soak for 20 ± 1 minutes. Prepare the engine and dynamometer for the hot start test. Connect evacuated sample collection bags to the dilute exhaust and dilution air sample collection systems. Start the CVS (if used or not already on) or connect the exhaust system to the CVS (if disconnected). Start the sample pumps (except the particulate sample pump(s), the engine cooling fan(s) and the data collection system.

The heat exchanger of the constant volume sampler (if used) and the heated components of any continuous sampling system(s) (if applicable) shall be preheated to their designated operating temperatures before the test begins.

Adjust the sample flow rates to the desired flow rate and set the CVS gas flow measuring devices to zero. Carefully install a clean particulate filter in each of the filter holders and install assembled filter holders in the sample flow line.

4.5.7.7.   Hot start cycle

As soon as it is determined that the engine is started, start a “free idle” timer. Allow the engine to idle freely with no-load for 23 ± 1 s. Begin the transient engine cycle such that the first non-idle record of the cycle occurs at 23 ± 1 s. The free idle time is included in the 23 ± 1 s.

The test shall be performed according to the reference cycle as set out in Appendix 4 to Annex III. Engine speed and torque command set points shall be issued at 5 Hz (10 Hz recommended) or greater. The set points shall be calculated by linear interpolation between the 1 Hz set points of the reference cycle. Feedback engine speed and torque shall be recorded at least once every second during the test cycle, and the signals may be electronically filtered.

The procedure described in previous sections 4.5.7.2 and 4.5.7.3 shall then be repeated.

4.5.7.8.   Engine stalling during the hot start cycle

If the engine stalls anywhere during the hot start cycle, the engine may be shut off and re-soaked for 20 minutes. The hot start cycle may then be rerun. Only one hot re-soak and hot start cycle restart is permitted.

4.5.7.9.   Operations after hot start cycle

At the completion of the hot start cycle, the measurement of the exhaust gas mass flow rate, the diluted exhaust gas volume, the gas flow into the collecting bags and the particulate sample pump shall be stopped. For an integrating analyser system, sampling shall continue until system response times have elapsed.

The concentrations of the collecting bags, if used, shall be analysed as soon as possible and in any case not later than 20 minutes after the end of the test cycle.

After the emission test, a zero gas and the same span gas shall be used for re-checking the analysers. The test will be considered acceptable if the difference between the pre-test and post-test results is less than 2 % of the span gas value.

The particulate filters shall be returned to the weighing chamber no later than one hour after completion of the test. They shall be conditioned in a petri dish, which is protected against dust contamination and allows air exchange, for at least one hour, and then weighed. The gross weight of the filters shall be recorded.’

Appendix 3 is amended as follows:

Sections 1.5 and 1.6 are replaced by the following:

Section 1.7 is deleted.