Section 1

　

Item 1.1 General. Since 2.4.5 requires that all load points in the appropriate cycle be measured it would not appear acceptable that it be only undertaken at the'most frequently used load point'.

　 Since data must be obtained within 30 days of survey (2.3.4) an extension to 6 months would not appear supportable and indeed could be open to abuse. The understanding that this should however be 30'operating' days would appear to avoid this problem.

　

The time for each mode point is already given in Chapter 5 of the Code (monitor 10 minutes, calculate from final minute) and should be retained for direct monitoring.

　

Item 1.2. The criteria for accepting other measurement principles other than given in Appendix 3 of the Code must be retained as given in 5.4.2.

　

Item 1.2.4.2. Electronic data (read only) should also be an acceptable recording option provided that it is to the satisfaction of the Administration that the data is securely recorded.

　

　

Allowances. It is agreed with EUROMOT (30 September) that the allowances as given in Chapter 6 of the NOx Technical Code should be equally applicable to the direct monitoring method.

　

Deterioration. It has always been understood that as an engine'aged' the NOx emissions will if anything decrease since fuel injection pattern would be compromised and pressures generally will also be decreased. Therefore it is considered that this aspect does not need to be specifically allowed for in the direct monitoring method.

　

Fuel oil quality (nitrogen content & tendency to ignition delay). The comments as given in Panama's previous contribution cover these aspects (plus allowances as given above).

　

Temperature/humidity. Since the only limit as given in Regulation 13 is that under reference conditions the calculations as already given in Chapter 5 of the Code must be used. As per Panama's previous comments it is considered essential that where aspects are already given within the Code that 'new' alternatives must not be specifically created for the direct measurement method.

　

Reliability of monitoring and recording devices. Following the line of the NOx Technical Code as it exists the criteria for reliability of equipment should not be directly addressed by these Guidelines other than the system is to installed (maintained, serviced and calibrated) in accordance with manufacturers instructions. It will be for the shipowner to demonstrate as required compliance with the Code requirements and to do that the onus is on him to obtain a reliable system. As with the Code (Appendix 3 and 4) specific operating criteria are not given, although particularly with slow speed engines, Parent Engine testing may require the siting of analysis equipment in 'site' rather than 'test bed' type conditions - it is their emission measurement performance rather meeting specified environmental criteria which is important.

　

　

While appreciating the comments made regarding the fact that it is the Guidelines which are under consideration by this Correspondence Group and not the NOx Technical Code itself, it is agreed with EUROMOT that it is however necessary to consider how such Guidelines are to function within the overall context of the Code. Particularly that the direct monitoring method will effectively be used to demonstrate that an engine may be so modified in terms of NOx critical components and settings that it longer bears any relationship to the pre-certified engine. Therefore the direct monitoring method must be to the same rigour as the parameter check or simplified measurement methods and hence accorded the same status. The direct monitoring method is not a sub-part of the parameter check method and hence is not to be used as a tamper detecting device (as given in the US comments).

　

In addition that to'draw data only during a certain period before the periodical or intermediate surveys may be insufficient in order to demonstrate continuous compliance' (although 1.2.3 of the Code should be noted) since exhaust emission measurement equipment will always perform better if used on a regular basis and more frequent monitoring requirement, as previously proposed by Panama, is not over onerous.

　

While other types of NOx analyser may be proposed (NOx Technical Code 5.4.2) such equipment will need to be rigorously shown to provide equivalent performance to the HCLD/CLD equipment not only of pure span gases but also on the mix of components typical of exhaust gas.

　

As above since various aspects such as repeatability, zero and span drift etc. are already given within the Code these direct monitoring Guidelines should not develop additional options in such cases.

　

The highlighting of 2.3.5 is supported a defining the limits within which the direct monitoring is to function. The potential usage of direct monitoring within 2.3.11 should also be noted in setting the criteria for this method.

　

Indirect NOx monitoring. This is not seen as being appropriate to the direct monitoring method due to the points as raised above that the purpose of this method is that engine components and settings may (should be expected) to have changed from the as built condition hence it in order to verify that the influence of these indirect measures is still valid it would be necessary to be able to verify that the engine itself was not altered from the condition under which the validity of the indirect monitoring had been established - hence the parameter check would also need to be applied.

　

Measurements such as maximum combustion pressure are already given in the NOx Technical Code as a means by which fuel pump timing may be checked (appendix 7) but within the parameter check method not as a substitute.

　

　

While at this time direct monitoring may not seen attractive to ICS it is also probable that the simplified measurement method is at least equally unattractive however it is a given option and therefore the necessary Guidelines need to be developed. Furthermore it is considered most important that at this time the Guidelines as developed are objective driven (as with the NOx Technical Code) rather than a restrictive prescriptive type control, particularly since the equipment to be used within these Guidelines has generally yet to be produced. Should these Guidelines turn out to be unduly restrictive then it may be that such equipment would not be developed and the option for other than the parameter check method lost.

　

In time with the development of sensors which do not require skilled operators, reliable and robust in operation, with self calibrating/fault reporting and other such developments plus the change from the current practice where exhaust gas analysers of the HCLD/CLD type are often individually produced to one where they are, at least in marine terms, 'mass produced' the cost and complexity will be reduced (as with consumer electronics). Certainly it would be expected that the direct monitoring method as it may evolve would be less time consuming than for example boiler water tests.

　

What the direct monitoring method cannot be is a'cheap' version. As above it must have equal standing with the existing two onboard NOx verification procedures and must therefore be to the same standard which will inevitably require something more than a simple 'Fyrite' type instrument, particularly since the only limit is the application cycle weighted value under the given reference conditions.

　

As to the value of a direct monitoring method to shipowners it would be suggested that over the life of an engine it will enable the shipowner to have a much more flexible approach to spare parts, reconditioning of parts, adoption of alternative components, resetting of adjustments, etc. than would otherwise be the case with the parameter check method as currently universally used, particularly since technical files using that method are, and will be, in the first instance prepared by the original equipment manufacturer and hence necessarily typically tied to obtaining spare parts from the OEM.

　

Furthermore in the case of'major conversion' as defined (particularly the'substantial modification' as defined) shipowners may find for such engines installed on ships built before 1.1.2000 (i.e. not pre-certified) that the direct monitoring method is more easily applied and used that the parameter check method.

　

Hence it will be a case of balancing the pros and cons of the parameter check method and the direct monitoring method to determine which, for a particular shipowner, ship, engine, service etc. is the most attractive.

Panama's comments on U.S. comments

　

　

This is read as needing to avoid measurement during transient conditions which due to the problems in correlating the various factors (including sensors with differing time lags) which affect NOx emissions, when quantified on a g/kWh basis, render such measurements unrepresentative of the actual (steady state) NOx emissions.

　

Annex VI, Regulation 13, makes no specific control of NOx emissions in coastal or other specifically designated areas, unlike Regulation 14. Therefore it is not seen that there is any limit value other than that given in Regulation 13 which, as per Panama's previously advised comments, must be recognised as being a cycle weighted average under steady state conditions.

　

Furthermore, as shown by studies such as Lloyd's Register's Marine Exhaust Emission Research Programme Phase II, NOx emissions do not tend to peak, as with HC emissions, under transient conditions. Instead there is a initial general change on change of load followed by a period of adjustment of lower magnitude while the engine system (and charge air/scavenge air cooling) settles at the new load level. That NOx emissions in g/kWh for a particular engine may increase with decreasing load is accepted but that is already allowed for by the use of four, five or eight load points in the test cycles which therefore include low load conditions.

　

As above the whole purpose of the direct monitoring method is to allow the engines NOx critical components and setting to be altered (tampering) but only to the extent that the engines application cycle weighted NOx emission value under the given reference conditions is within the Regulation 13 limit value.

　

The development of a system which correlates initial test bed performance to actual performance by use of conversion factors ignores the whole point of the direct monitoring method which is seen as allowing alternative components and settings to be used. Since it could only be verified that the engine was unchanged from the initial condition (from which those correction factors were obtained) by some form of parameter check method this approach would appear to need both methods to be applied to result in a reliable finding.

　

The comment by the United States (to Japan 1.2.1) re'simple handling and maintenance' etc, that these are not to be enforced by regulation but will be determined by buyer/seller interaction, are fully supportive and correct in an objective driven Guideline. Same applies to US comment re 1.2.3.