Services - Technical Consulting
CFS provides a range of consulting services in the following areas:
- Review of onboard installation of CNG cylinders, fleet operation and inspection procedures to prevent in-service cylinder failure and explosion.
- Review of CNG vehicle design to prevent cylinder explosion in a CNG vehicle fire.
- Formulation of standards, codes and regulations at both national and international levels.
- Design verification of CNG cylinders for national design approval or registration.
- CNG cylinder periodic requalification inspection requirements.
- Verification of CNG cylinder production testing and quality assurance.
- Assessment of performance of refuelling stations.
- Suitability of supplied gas for CNG engine/vehicle operation.
- Feasibility studies of CNG vehicle and refuelling station projects.
- Technical, operational and economic evaluation of CNG vehicle projects.
- Project tender specifications (vehicles, refuelling stations, vehicle workshops, parking facilities) - with special emphasis on technical performance, maximum vehicle fuel cylinder service life, cylinder installation safety and vehicle fire safety design). Tender management and evaluation.
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Review of onboard installation of CNG cylinders, fleet operation and inspection procedures
CNG vehicle installation standards provide general guidance on good cylinder installation practice. In addition, gas cylinder requalification inspection standards (e.g. ISO 19078) provide guidance on, and criteria for, inspecting for damage. Nevertheless, cylinder failure has still occurred even on vehicles that have been certified as compliant with the installation standard and periodically inspected by authorised cylinder test stations in accordance with the cylinder inspection standard or the manufacturer's inspection instructions.
More detailed attention needs to be paid to the design of cylinder mounting and installation systems, the operating procedure and inspection procedure to ensure that the cylinder will not incur critical deterioration or damage within the re-inspection interval.
CFS can provide a safety review of onboard CNG cylinder installation systems, and fleet operating and inspection procedures and practice. This review draws on experience gained by CFS in investigations and work with large CNG vehicle fleets that have been faced with cylinder safety issues including vehicle fire and cylinder failure.
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Review of CNG vehicle design to prevent cylinder explosion in a CNG vehicle fire
Certain CNG vehicle designs in certain fire situations may be completely destroyed, with its cylinder(s) catastrophically exploding within minutes. Well documented major CNG vehicle fires have provided much needed guidance on designing a CNG vehicle that will avoid the destructive consequences of a cylinder explosion in a vehicle fire.
Drawing on experience with large CNG vehicle fleets, CFS can provide a fire safety review of CNG vehicle design and emergency response procedures and programs, with the objective of effectively containing CNG vehicle fires and eliminating the possibility of CNG cylinder explosion in a vehicle fire.
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Formulation of standards, codes and regulations
National or industry standards and regulations for CNG continue to evolve in response to ongoing improvements in the technology and additions to the knowledge base of CNG safety.
CFS's Dr Hien Ly has spent nearly 30 years serving on the committees responsible for CNG standards for New Zealand, Australia and ISO standards and ECE regulations. Coupled with the growing knowledge of CNG safety gained from CFS's ongoing monitoring of CNG safety incidents over the last 25 years, CFS is in a unique position to assist countries that are entering the CNG industry to produce:
- the necessary standards and regulations, as well as
- effective regulatory frameworks to ensure CNG system performance and safety.
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Design verification of CNG cylinders
In many countries the regulatory approval of CNG cylinder designs requires that the design be first verified as in compliance with the applicable cylinder standard and suitable for CNG vehicle service.
The cylinder design qualification requirement may be regarded as being 'fulfilled' once the design has been approved by or registered with a regulatory authority. However, CNG cylinder safety incidents still occur in many countries. This indicates that the design verification and/or ongoing production quality monitoring in such cases may have not been effective in ensuring safe design.
Correct design verification not only confirms the correctness of the cylinder design but also protects the business of the importer or distributor of cylinders, by rigorously examining design compliance.
Design verification requires detailed knowledge of the requirements of the applicable CNG cylinder standard (e.g. NZS 5454, ISO 11439, ECE R110, CSA B51 Part 2 or ANSI NGV 2); in particular the design qualification tests.
CFS is in a unique position of being able to offer high quality design qualification services as a result of its long experience in the production of several CNG cylinder standards, and work for a CNG cylinder importing company in Australia.
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CNG cylinder periodic requalification requirements
CNG cylinders, whether on vehicles or at refuelling stations, need to be periodically requalified (i.e. 'retested').
In most jurisdictions the requalification is conducted by authorised CNG cylinder test stations or inspectors. The requalification requirements vary depending on the type of cylinder (e.g. metal or composite) and the applicable cylinder standard. Requalification in accordance with cylinder type and standard requirements helps save costs and avoid unnecessary safety risks.
CFS's services in the cylinder periodic requalification area include:
- Advice on the correct inspection procedure, reporting and documentation.
- Assessment or audit of the facility and work procedure/practice of the cylinder test station or inspector used.
- Assessment of observed cylinder defects and assistance to clients in determining remedial measures (if required) in conjunction with the CNG cylinder manufacturer and the regulatory authorities.
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Verification of CNG cylinder production testing and quality assurance
Verification of production test results and quality assurance is critical to the quality and safety of cylinders in service.
Production testing is normally witnessed by a contracted independent inspection agency. However, there have been instances where the witnessing has been found not to be consistency, which has given rise to gaps in the verification of production tests. This has allowed lapses in material and process quality to go undetected and contributed to a number of in-service cylinder failures.
CFS can perform the checking of the setup and operation of the quality assurance (QA) system of CNG cylinder production and production testing processes. This check can also include the monitoring of the consistency of the witnessing activities of the independent inspection agency. The implementation of a good, effective QA program is a strong contributor to the safety of the produced cylinders.
This checking is of vital importance in protecting the manufacturer/importer/ distributor against cylinder defects or failure.
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Assessment of performance of refuelling stations
Both new and existing refuelling stations should be assessed to ensure that their specified performance is achieved. This will confirm that the asset owner gets value for money, and that unexpected financial losses will be avoided.
In particular, the consistency of CNG fuel metering, be it at the fuel dispensers or bulk fuel transfer points used in mother-daughter systems, has been found to be an issue refuelling stations in several countries even with the use of approved meters. Given the low profit margins of many refuelling stations, inconsistent metering between station inlet meters and CNG meters may result in reduced station profit or in the worst cases, trading losses.
The assessment of refuelling station performance can include:
- Confirmation of compression capacity
- Compression energy used (e.g. kWh/m3 gas compressed)
- Inlet gas metering accuracy
- CNG vehicle dispenser metering accuracy
- Mother-daughter station inlet and delivery gas meters or accounting methods
- Correct temperature compensation of fast refuelling pressure for the given composition of the supplied gas
- Adequacy of safety control of the fuel dispensing system
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Suitability of supplied gas for CNG engine/vehicle operation
Gas vehicle and engine manufacturers routinely specify the composition of the gas to be used with their equipment.
Natural gas composition is not constant. It can vary from site to site and from time to time even within the same site. In some cases this variation can cause engine/vehicle performance losses (due to inadequate gas Wobbe index), or in the worst case, engine failure (due to inadequate gas knock rating).
Using gas composition analyses from the gas supplier and the composition specified by the vehicle/engine manufacturer, CFS can advise on the suitability of the gas for the given engine/vehicle (or conversely, the suitability of a proposed vehicle/engine for use with gas of known composition limits).
The control of particles entrained in CNG fuel has important implications for onboard CNG equipment performance and safety. For example, onboard receptacle check valves and pressure regulators can be very sensitive to the particulate size and content of the incoming gas. As this issue is not always well attended to, preventable onboard system malfunctioning due to entrained particulates in the fuel has continued to plague some CNG vehicle fleets.
CFS provides the review of the refuelling system and equipment design, installation, operating and maintenance procedures to ensure unacceptable levels of particulates are prevented from entering the onboard gas system.
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Feasibility studies of CNG vehicle and refuelling station projects
A proposed CNG vehicle or refuelling project needs to be initially assessed for its technical and commercial feasibility.
A feasibility study of a proposed project will:
- Indicate whether the technology and project configuration to be used will be technically and operationally feasible, and
- Confirm whether the projected costs and revenues - including government financial or taxation support - will be realistic (based on competitive pricing of equipment and services), and the resultant economics will be sufficiently attractive.
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Technical, operational and economic evaluation of CNG vehicle projects
CNG vehicle projects, both the pilot stage and permanent operating stage, will benefit from objective evaluation to ensure that technical, operational and economic issues are determined in a timely manner.
Quite often CNG projects have deviated from initial planning estimates or projections. Actual in-service evaluation affords the opportunity to identify the deviations early and enable rapid improvements to be made for minimum operational issues and costs, and maximum operability and economic benefits.
CFS International can assist clients in performing the evaluation using methodologies already proven by large, experienced CNG vehicle fleets.
One type of technical evaluation is that of the environmental characteristics/benefits of the CNG vehicles. CFS International can manage for the clients an evaluation of the exhaust emission performance of their CNG vehicles of up to bus and truck sizes, using approved emissions measurement labs.
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Tender specification, tender management and evaluation
Major CNG procurement projects require an effective competitive tender to ensure adequate, appropriate technical and safety performance, as well as the lowest practicable capital and operating costs. Both vehicle supply/conversion and refuelling station supply should be subjected to the open, competitive tender process.
On the commercial side, the tender specification and evaluation need to focus on the least cost solutions that adequately meet technical performance requirements. This requires intimate knowledge and experience with CNG technical and safety issues, and established low cost solutions. These evaluations draw on experience with major procurement projects.
Examples of low cycle cost of CNG equipment are the correct specification of on-board CNG cylinders for the maximum allowable service life; and the fire safety of CNG vehicles to avoid costly capital and operational expenses associated with safety incidents. For refuelling stations, low overall cycle cost can be obtained by well designed systems and well designed operating and maintenance practices.
CFS has participated in the competitive tender process of major CNG fleet and facility procurement projects in Australia and Asia. CFS will bring this experience to customers' tenders to produce the highest level of technical and operational performance at the most competitive costs.
