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Demonstration of Systems Engineering Principles in the process of selecting Environmental Performance Indicators and optimizing Environmental Performance in Industrial Systems.
Assistant Professor Annik Magerholm Fet
Aalesund College/Møre Research
Norway
Abstract
The Systems Engineering Process is the process of bringing a system into being herunder project planning, design, construction and production in a holistic perspective. To accomplish this a step by step iterative process is used, i.e. identification of needs, requirements definition, functional analysis and optimization, design, test and evaluation. These steps represent the basic Systems Engineering Methodology, and they will be employed in the process of selecting environmental performance indicators which in turn can be used to demonstrate optimum environmental performance during the total life cycle of a complicated industrial system, in casu a ship. Today’s engineering education does not give engineers sufficient insight into life cycle thinking and environmental performance of systems.
Emphasize will be put on bringing up indicators which reflect changes over a period of time keyed to environmental problems during different phases in the system life cycle of a ship. A demonstration will be given as to how the performance indicators related to subsystems of the ship and to different phases of its life cycle may prove helpful in the process of measuring and evaluating improvement in environmental performance.
Introduction
The increasing awareness and concern about the environmental impacts associated with the provision of goods and services to society, have induced the need for methods that can give better insight into causes and effects, and which can provide a basis for measuring and control of such impact. The goal is to develop environmentally friendly procedures and processes during planning, construction, operation, building, maintenance and scrapping of a complicated industrial system - in casu a ship.
Today transportation by ship represents approximately 85% of the total amount of the World’s transport of goods. Achievement of a sustainable development in the ship industry, may be obtained by making environmental improvements along the value-chain in the ship industry in a life cycle perspective. All kinds of improvements and reduction of environmental impacts from ships, will contribute to ease the global loads to the environment.
An important challenge to industry is therefore to focus on how their activities and products contribute to the degradation of the environment. For the system ship this involves ship designers, ship yards, ship owners and ship contractors. The problem is to make the priorities right because of conflicts between economical, societal and environmental concerns. Industry also find it difficult to find the best possible solutions due to lack of knowledge about environmental impacts. It will be demonstrated how systems engineering may be a helpful tool to select appropriate performance indicators to be used as a basis for measuring and evaluating environmental performance improvement in a life cycle perspective. The material referred to in this paper is gathered from industrial projects carried out in the ship industry in Norway.
Systems Engineering Methods.
Systems Engineering is a management tool to assist and support policy making, planning and decision making in a holistic perspective. Systems Engineering focus particularly on systems and their interactions, their life cycle and how the systems develop over time. Broadly defined, systems engineering is (Blanchard, 1990): «the effective application of scientific and engineering efforts to transform an operational need into a defined system configuration through the top-down iterative process of requirements definition, functional analysis, synthesis, optimization, design, test and evaluation». A top-down approach is required, viewing the system as a whole, and a life-cycle orientation is required. The identification of system requirements should be emphasized, and an interdisciplinary effort is required. Systems Engineering is defined both as a discipline and as a process (Asbjørnsen, 1992, Blanchard, 1990).
Systems engineering as a discipline.
Systems engineering is the discipline that deals with the analysis and design, the operation and maintenance, of large integrated systems under a total life cycle view. Technology, management, legal aspects, social and environmental issues, finance and corporate strategies are taken care of by a total system integration.
Systems engineering as a process.
Systems engineering is the process of acquiring a system for consumer use, or the process of bringing a system into being. That is the process employed in the evolution of systems from the point when a need is identified through production and / or construction and ultimate deployment of that system for consumer use.
Figure A: The system life cycle of a ship illustrated by four main phases. The Systems Engineering process is illustrated at the right side.
The systems engineering process is illustrated in figure a, and the activities of «bringing a system into being» may be described as indicated to the right in the figure. The life cycle view of the system is central in systems engineering, it covers a total time span of events or a series of activities starting with the initial identification of a consumer need and continuing through project planning, design and development; production or construction; operation, maintenance and support; and ultimately system retirement, reuse, recycling andscrapping.
The systems engineering process may be described by a six step methodology, called the Systems Approach Methodology (SAM), see figure b. Each step will be demonstrated shortly by results from the ship industry.
Figure B: The System Approach Methodology (SAM).
Systems, subsystems and system elements.
Every system has a position in a total system structure, and is made up of elements. A smaller group of elements is called a subsystem, normally a system of lower hierarchical rank than the system, relative to complexity. Subsystems may be characterized by the class they belong to, is part of, is connected to or is interfaced with. In Figure 3 the subsystems «Hull», «Machinery Main Components» and «Main Engine Components», and their related system elements are illustrated.
Figure C: Three subsystems with related system elements in the system ship. The grouping is in accordance to the SFI[1] group system.
Integrated systems and requirements.
Systems may be viewed as a combination of some or all of the four different disciplines of roughly equal importance (Asbjørnsen, 1995); the disciplines of Technology that include the physical equipment (Hardware), the discipline of Financial Science that include the monetary aspects (Economics), the discipline of Information Science that include instruction, rules and computer programs (Software), the discipline of Social Science that include human factors, psychology and sociology (Personnel, bioware). A system is also an integrated part of the environment, and can not be analyzed without taking the interactions with its environment into account. The environment may be subject to impact locally, regionally or globally. A system described by its integrated parts, is illustrated in figure d. All requirements to systems, both functional, operational, and physical, to hardware, software bioware and economics should aim at reducing environmental impacts in each phase of the life cycle. A flowchart must reflect the activities that are related to the overall performance of the system.
System Boundaries.
Also system boundary identification is necessary before the system is taken under study. Material, energy and information crossing the boundaries are defined as inputs to or outputs from the system.
Figure D: A system regarded as a combination of four different disciplines (hardware, software, bioware and technology) as an integrated part of the environment. The arrows indicates interactions between the system and the environment.
Results.
Data for the subsystem «Hull» and its system element «External Material Protection» are used in this demonstration. Only the interactions between hardware and the environment are taken into account. In a complete demonstration the other parts of the system, economic, bioware and software, must be considered as well, see figure d. Only results from the phases construction and operation in the system life cycle are presented. The results are presented in accordance with the System Approach Methodology as illustrated in figure b.
Identified needs.
The construction of the ship involves the shipyard and some suppliers. Actual customers/ interested parties are neighbors, employers, insurance companies, authorities etc. Based on requirements from these, the needs were formulated as answers to «What is needed», «Why is it needed» and «How may the need be satisfied» A summary of answers is given in table a.
Table A: Identified needs to the «hardware» of the element «External Material protection».
What is needed: / Construction phase: Construct ship with less impact on the environment; air, water, land use, natural resources, flora, fauna, humans, (less emissions of sand dust, noise and paint dust to the environment caused by the process surface protection).Operational phase: Operate ships with less impact on the environment, air, water, land use, natural resources, flora, fauna, humans, (less leakage of heavy metals from coatings).
Why is it needed: / People are worried about their health conditions due to bad quality of water and air, there are limited areas for landfill of waste, insurance companies have economical expenses because of pollution, the authorities are committed to international agreements and so on.
How may the need be satisfied: / Changes in processes, changes in materials and in routines, procedures and techniques.
Defined performance requirements.
External material protection involves the activities sandblasting, polishing and painting. The operational, functional and physical performance requirements in accordance to interactions system - environment, were described as shown for sandblasting in table b. These requirements are set to the hardware part of a system. In addition requirements to the other integrated parts, see Figure 4, must be described.
Table B: Examples of performance requirements set to «External material protection».
Performance requirements / External surface protection; sandblastingOperational / Under operation the emissions of sand, dust and noise to the environment should be minimized.
Physical / Sand should not contain toxic substances, the sand should be reusable, the packaging should be reusable or recyclable.
Functional / Sandblasting shall clean and rub the steel to specified degree, SA 2.0
Specified Performances.
The today’s situation with respect to sandblasting was described and illustrated by mass flowchart, see figure e.
Figure E: Mass flow diagram for the process of sandblasting outside hull. (Fet, 1994).
Similar flow sheets were made for painting and polishing and for leakage of heavy metal from the bottom coating to the sea. Due to the linkage between the smoothness of the hull and the amount of used fuel for the ship, also information about emissions from main machinery systems were collected. The seriousness of emissions to air must be weighted against emissions of heavy metal to the sea.
The importance of the various environmental impacts locally, regionally and globally, was evaluated by means of weight factors attributed to each type of impact. The weight factors were based on requirements decided by interested parties and expert insight into these matters. Examples are given in table c.
Table C: Weighting of the environmental impact caused by external material protection.
Process: / Areas of evaluationImportance graded from
1 (least) - 5 (most serious) / Local / Regional/National / Global
Component of the environment: / Construction / Normal operation / Maintenance / Construction / Normal operation / Maintenance / Construction / Normal operation / Maintenance
- Air
- Water
- Land
- Natural resources
- Flora
- Fauna
- Humans
The next challenge was to classify the environmental impact by the effects on climate change, depletion of ozone layer, acidification, eutrofication, ecotoxicity, photo-oxidant formation, land use and loss of biodiversity, here also included human health and risk factors. This was demonstrated by appropriate tables and represent the specification of the environmental performance of the selected subsystem in two phases of the system life cycle.
In this demonstration it was focused on the local form of environmental impacts. The performance improvements requirements were listed as shown in table d next page.
Based on environmental performance improvements specification, two scenarios were described, «High pressure water blasting» and «Enclosed blasting». The operational, functional and physical performance requirements were established based on calculated measures of environmental performances. The information, calculated and measured, was then analyzed and optimized.
Table D. Environmental performance improvements specifications.
Sandblasting / Paint systemsConstruction: /
- Reduce noise emissions,
- Reduce the amount of inhaleable dust in air
- Reduce the amount of sand to disposal
- Only reusable packaging should be delivered
Reduce the amount of solvent
Minimize the use of toxic materials
Normal operation: / Reduced leakage of heavy metal to ocean
Reduced leakage of heavy metal in ports
- Any other surface protection system should not increase emission to air from fuel
Maintenance: / The same requirements as under construction. /
- No leakage of heavy metal to sea when cleaning hull bottom
- The same requirements as listed under construction
Analyzing and optimizing, environmental performance indicators.
The specified environmental performance improvements requirements made the baseline for the selected environmental performance indicators. By comparing the measured and calculated values of the environmental performance indicators against the original values, the environmental performance improvements were presented. There are many examples of trade offs methods. (Asbørnsen, 1992). In this analysis the trade off was done by using a scalar objective function based on grades. The difference between the original value and the new value, was calculated and multiplied by the weight factor and divided by the sum of weights. The results as listed in the shaded columns in the trade off table, table e, are measures of the performance of each of the scenario. Negative values indicated good environmental performance improvements, positive values indicated bad environmental performance improvements. The values may also be aggregated to one single index.
Table E: Trade off table for different alternatives to sandblasting
Environmental performance indicators / Weight-factor / Today's perfor-mance / High pressure water- blasting / Enclosed sand- blastingw / x / x1 / / x2 /
Noise emissions, dB in distance 100m / 5 / 85 / 100 / 2.68 / 65 / -3.57
Surface roughness, SA / 5 / 2.0 / 2.0 / 0 / 2.0 / 0
Dust in air, distance 100m, ppm / 5 / 1000 / 0 / -178.57 / 300 / -125
Sand use kg/ 100 m2 / 1 / 1000 / 0 / -35.71 / 250 / -26.79
Use of water liters/100 m2 / 1 / 0 / 1000 / 35.71 / 0 / 0
Energy use J/100 m2 / 1 / 500 / 700 / 7.14 / 300 / -7.14
Cost, man hours / 100 m2 / 3 / 1 / 2 / 0.11 / 1 / 0
Cost, equipment / 100 m2 / 4 / 1000 / 2000 / 142.86 / 3000 / 285.71
Weight of equipment kg/unit / 3 / 10 / 30 / 2.14 / 10 / 0
By the analyzed indicators, an impression was given where to put further effort to achieve improvements. This is an iterative process and should be performed until there is an accepted «design» or the requirements are met, optimized to a certain degree of satisfaction. Limitations in the optimization process, are however economy and time. Analyses related to the other parts of the system, see Figure 4, are however not discussed here.
Designing and solving, verification and testing.
The last steps in the SAM (see Figure 2), design and solve, verify and test, are not yet resolved and will therefore only be described briefly. By the weighted results of the performance indicators, different alternatives for improvements may be ranged. A recommended approach related to the initial requirements should be given. Based on the evaluation of environmental performance improvements, an optimized combination of different technical solutions should be achieved. The findings arrived at through these steps may take the form of conclusions and recommendations to the designer, the ship owner, the shipyard etc. The description must include every information necessary to design, construct, operate, maintain and dismantle the ship in the most optimal way in accordance with the environmental performance requirements initially formulated. A test program should then be performed and the feedback should be registered and evaluated also considering economical, informational and sociological aspects.
Summary and discussion.
The results presented here are based on the data for a platform supply vessel with a known operational profile and a defined maintenance plan. For other ships, the operational program may differ. This study was limited to only one element of the hull, external material protection. The process is however the same for other elements and subsystems. The needs should be identified, both operational, functional and physical requirements should be described for each system element and for each phase in the system life cycle. The environmental impacts related to processes should be weighted on the base of the views from interested parties and scientific insight. The next step is to characterize the interactions with the environment by the kind of impact they cause. By specified environmental performance in accordance to the today’s practice, a set of environmental performance indicators should be established. The measurements of the indicator will then be evaluated and analyzed, and this information may be aggregated to one index. Through iterations the situation can be optimized. Before the alternatives are ranged and recommended, a sensitivity, risk and uncertainty analysis should be performed. Economical, sociological and informational aspects as integrated parts of a system, must be taken into account. The documented results are then recommendations to the ship designer, shipowner, shipyard etc., on how to act to improve environmental performance in a life cycle perspective.
One of the goals was to establish a set of environmental performance indicators covering the total system life cycle for each part of an integrated system, both technology, economy, information and humans. So far only environmental performance indicator related to technology for one subsystem in the phases construction and operation are established. By taking all phases of the life cycle into account, the measures of these indicators will give information about environmental performance during the total life cycle of that system. Similar approach may be used for other subsystems. Finally aggregated performance indicators may be developed.