Risks and Compliance for Environment for Liquefied Petroleum Gas Operations within Inland Waterways

This article contains massive information about Environmental Risk and Compliance for LPG Operations within Inland Waterways.

Summary

The quest for an efficient fuel, friendly to the environment has been recognized in maritime industry for a long time through improvements of gasoline and diesel by chemical reformulation. Inconvenience posed by these reformulation chemicals is performance problems; cold-start ability, smooth operation and avoidance of vapour lock.

Climate change problem has further aggravated need to use fuel that could contribute to decrease in green house gases and ozone-forming pollutants. Alternative fuels to petroleum have been identified to include:

• compressed natural gas (CNG),
• liquefied petroleum gas (LPG),
• methanol from natural gas (LNG).

Selection of this towards centralized reduction of GHGs will depend on ease of use, performance and cost. LNG cargo is conditioned for long distance transfer while CNG and LPG cargo are conditioned for end user consumption and short distance transfer. It is therefore, clear that promoting the use of CNG will catalyse boosting of economy of coastal ship building and transportation, including environmental friendly utility fuel, and new generation of intermodal transportation and supply chain. Since the danger behind use of this gas could not be either underestimated by virtue regarding coastal operation proximity.

The article will discuss risk and potential regulation that will formulate beyond compliance, decision towards use of top – down risk based design and operations that will reinforce new integrative, efficient, environmental friendly and reliable multimodal and intermodal links advanced concepts for LPG ship operating in coastal and restricted waters.

Introduction

Fuel technology has been dominated with ways to improve gasoline and diesel by chemical reformulation that can lead increase efficiency and additional inconvenience leading to ozone depletion, green house and acid rain forming pollutants.

Likewise, side effects problems posed to transportation vehicles have been dominated by condition and other performance issues, additional inconvenience posed by these reformulation chemicals. Time has shown that the global trend in de-Carbonization of the energy system follow the following path:

COAL > OIL > NATURAL GAS > HYDROGEN.

The drive towards environmentally friendlier fuels points next to Natural Gas (NG) and the infrastructures to support that trend are being pre-positioned by corporate mechanisms and governmental bodies worldwide. NG is cheap and its reserve is plentiful. Natural Gas as fuel is becoming more and more established in urban transport and Power Generation sectors. Its use will also take aggressive approach for all inland vessel including ferries in the eyes of potential environmental compliance new regulations. Internationally its operational record and GHG gas score is rated as GOOD.

However, CNG, LPG and ethanol has been proven to be environmental friendly and has fuel economy of 50 %. This shows that, CNG and LPG have potential for large market for use in niche markets in both developed and developing countries. Other gains from CNG and LPG depend on the amount of associated methane emissions from gas recovery, transmission, distribution, and use. On a full-cycle basis, use of LPG can result in 20-25 % reduction in GHG emissions as compared to petrol, while emission benefits from CNG are smaller – about 15 %.

Furthermore, it is clear that promoting the use of CNG and LPG will be a catalyst to boost economy of coastal ship building, environmental friendly intermodal transportation for supply chain. Efficient and reliable operation can be made afforded by LPG, transportation, supply vessel, tugs to support this potential development.

On the regulatory regime, IMO focus more on operational issues relating to carriage of gas with no specification for CNG and LPG, while the ICG code and class society guidelines elaborate on the design as well as operational consideration. Local administration imposes additional regulation as required for their respective implementation.

Time has revealed that there will be large demands for these gases. This article focus on integrative use of IMO prescriptive goal and risk based standards with holistic consideration of factors require for safe design and operation of LPG ships in inland water. Including hybrid use of elements of FSA AND GBS to prevent, minimize control and guarantee the life span of LPG ships and protection of environment.

The article will discussed top down environmental risk generic risk model and operations of LPG ship. It will describe the characteristics of LPG, regulatory issues and environmental issues driving todays beyond compliance and selection of new technology policy. Since it is the consequence of coincident and incident that leads to environment disaster, the article will discussed issues that allow prevention and control of accident. Since issues relating to global warming, GHG releases is strictly linked to ship energy source, the article will also discuss impact areas and potential new technology and beyond compliance that may be adopted for LPG design and operation.

Natural Gas and LPG

Natural gas in its liquid state is called LNG, or liquid natural gas that comprise of liquid hydrocarbons that are recovered from natural gases in gas processing plants, and in some cases, from field processing facilities. These hydrocarbons involve propane, pentanes, ethane, butane and some other heavy elements. LNG accounts for about 4 % of natural gas consumption worldwide, and is produced in dozens of large-scale liquefaction plants.

Natural gas contains less carbon than any other fossil fuel and, therefore produces less carbon Dioxide (CO₂) when compared to any conventional vehicles. Its usage also results in significantly less carbon monoxide (CO), as well as less combustive organic compounds than their gasoline counterparts.

It is produced by cooling natural gas to a temperature of -260 °F (-160 °C). At this temperature, natural gas becomes liquid and its volume reduces 615 times. LNG has high energy density, which makes it useful for energy storage in double-walled, vacuum-insulated tanks as well as transoceanic transportation.

The production process of LNG starts with Natural Gas, being transported to the LNG Plant site as feedstock, after filtration and metering in the feedstock reception facility, the feedstock gas enters the LNG plant and is distributed among the identical liquefaction systems.

Each LNG process plant consists of:

• reception,
• acid gas removal,
• dehydration removal,
• mercury removal,
• gas chilling and liquefaction,
• refrigeration,
• fractionation,
• nitrogen rejection,
• sulphur recovery units.

LPG and CNG are made by compressing purified natural gas, and is typically stored and distributed in hard containers. Mostly, LPG station is created by connecting a fuel compressor to the nearest underground natural gas pipeline distribution system.

The process through which Liquefied Natural Gas is produced consists of three main steps, namely:

• Transportation of Gas – The best place to install the plant is near the gas source. The gas is basically transported through pipelines or by truck and barge.
• Pre-treatment of Gas – The liquefaction process requires that all components that solidify at liquefaction temperatures must be removed prior to liquefaction. This step refers to the treatment the gas requires to make it liquefiable including compression, filtering of solids, removal of liquids and gases that would solidify under liquefaction, and purification which is removal of non-methane gases.
• Liquefaction of Gas – Today, alternative fuels to petroleum has been identified to include:
  • Compressed Natural Gas (CNG);
  • Liquefied Petroleum Gas (LPG);
  • Methanol from natural gas, coal or biomass;
  • Ethanol from biomass;
  • Electricity and hydrogen.
• However, NG quality may be expressed with the Wobbe Index – Methane Number MN80 (Volume percent hydrogen atoms/carbon atoms) or Methane >= 88 %.

Since 1960s, CNG and LPG are recognized as vehicle fuel alternative to oil-based gasoline and diesel fuel that reduces pollution of the air. It is a natural gas compressed to a volume and density that is practical as a portable fuel supply.

Compressed natural gas (CNG) and Liquefies petroleum gas (LPG) are use as:

• consumer fuel for vehicles,
• cooking food,
• heat homes.

There exist a vast number of natural gas liquefaction plants designs, but, all are based on the combination of heat exchanger and refrigeration. The gas being liquefied, however, takes the same liquefaction path. The dry, clean gas enters a heat exchanger and exits as LNG. The capital invested in a plant and the operating cost of any liquefaction plant is based on the refrigeration techniques.

Natural gas is transported through pipelines to refuelling stations and there compressed at a pressure of 3 000 psi with the help of specially installed compressors that enables it to be loaded as gas cylinders for vehicles. The process consists of drawing the natural gas from underground pipelines by the compressor. The composition of pipeline natural gas varies considerably depending on the time of year, pipeline demand, and pipeline system.

It may contain:

• impurities, like oil,
• particulates,
• hydrogen sulphide,
• oxygen or water.

Hence the modern day, quality LPG plant system consists of facilities to address these problems. Using LNG as the feedstock to make CNG and LPG eliminates or mitigates each of the above stated concerns as contains no water or any such impurity. This eliminates the concerns for corrosion, plugging of fuel lines, and the formation of hydrates.

Significant design innovation will involve development of liquefied gas technology that promises lower costs and shorter scheduling time than either Liquefied Natural Gas technology or a pipeline transport as well as provision of unique solution to the development of distressed or stranded gas reserves and alternative to associated gas re-injection.

Liquefied Petroleum Gas (LPG) can also be produced either as a by-product when refining crude oil or direct from the North Seas oil or gas wells. The two most common LPG gases are known as Commercial Propane and Commercial Butane as defined in BS 4250.

Commercial Butane is predominately stored in blue cylinders up to 15 kg and generally used for leisure applications and mobile heaters. Commercial Propane is predominately stored in red cylinders and bulk storage vessels and especially used for heating, cooking and numerous commercial and industrial applications.

LPG has one key characteristic that distinguishes it from Natural Gas. Under modest pressure LPG gas vapour becomes a liquid. This makes it easy to be stored and transported in specially constructed vessels and cylinders.

The combustion of LPG produces Carbon Dioxide (CO₂) and water vapour therefore sufficient air must be available for appliances to burn efficiently. Inadequate appliance and ventilation can result in the production of toxic Carbon Monoxide (CO). All things being equal, it produces much less hydrocarbon compare to diesel.

Hazards associated with LPG ships are linked to the gas characteristics that attract beyond compliances operability and design policy. Selection of this towards centralized reduction of GHGs will depend on ease of use, performance and cost.

Natural Gas properties

Everyone dealing with the storage and handling of LPG should be familiar with the key characteristics and potential hazards.

Matter either in their solid, a liquid or a gaseous form is made from atoms which combine with other atoms to form molecules. Air is a gas, in any gas, large numbers of molecules are weakly attracted to each other and are free to move about in space. A gas does not have a fixed shape or size. Each gas that the air is composed of consists of various different properties that add to the overall characteristics of a particular gas. Gases have certain physical and chemical properties that help to differentiate a particular gas in the atmosphere.

Depending on different properties the gases are used widely in several applications. Below are some of the gas properties – Natural gas may consist of:

• Methane CH₄.
• Ethane C₂H₆.
• Propane C₃H₈.
• Butane C₄H₁₀.
• Carbon Dioxide CO₂.
• Oxygen O₂.
• Nitrogen N₂.
• Hydrogen sulphide H₂S.
• Rare gases A, He, Ne, Xe trace.

Hazards associated with LPG ships are linked to the gas characteristics and beyond compliances operability and design. CNG are a non-toxic gas liquid at -259 °F/-162 °C which ignites at 1350 °F/732 °C. The octane number is 120; it can inflame having a share of 5,3 to 15 % in air. Methane has only 42,4 % of the density of air and thus is lighter and may disappear in case of leakages. The lower heating value is 50 020 kJ/kg, ignition energy is 0,29 Mj.

Natural Gas and LPG

LNG carriers has proven considerable good safe ship in term of designed, constructed, maintained, manned and operated of all the merchant fleet of today. So far they have low accident record and non major has led to release of large amounts of LNG have ever occurred in the history of LNG shipping.

Nevertheless, there have been major concerns regarding safety of LNG shipping and vivid that one catastrophic accident has the potential for serious consequential fatal and environmental damage. Therefore, it became imperative to use IMO Goal – based and risk based instruments to quantify a baseline risk level to identify and evaluate alternative risk control options for improved safety.

Toward zero accident and zero, incident, apart for Normal SOLAS standards for all ships, there is additional regulation for International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk this include The IGC Code.

This Code is applicable to Liquefy carriers which made is made mandatory under the SOLAS Convention. Thus, Risks associated with LPG ships encompass the following areas:

• Loading of LNG.
• Shipping of LNG in special purpose vessels.
• Unloading of LNG at the receiving terminal.
• Third party risks to people on shore or on board.

NG shipping industry is undergoing considerable changes, e. g. an expected doubling of the fleet over a 10-year period, emergence of considerable larger vessels, alternative propulsion systems, new operators with less experience new trading route, offshore operations and an anticipated shortage of qualified and well trained crew to man Liquefies gas carrier carriers in the near future.

With this development, there is tendency gas shipping to experience an increasing risk level in the time to come.

Most IMO previous rules were made on reaction basis, in this age of knowledge employment of the new philosophy to design construct and operate based on risk and considering holistically factors of concern for sustainability and reliability remain a great invention of our time that can save us from worries about tomorrow about LPG ships and shipping.

The International convention for the Safety of Life at Sea (SOLAS) is the fundamental IMO instrument that deal with regulation requirement for basic construction and management for all types of ships. It covers areas like are:

• stability,
• machinery and electrical installations,
• fire protection,
• detection and extinction systems,
• life-saving appliances and Surveys and inspections.

SOLAS also contains a number of other codes related to safety and security that applies to shipping in general.

Examples of these are:

• the Fire Safety Systems Code (FSS Code),
• the International Management Code for the Safe Operations of Ships,
• the International Ship and Port Facility Security Code (ISPS Code).

These codes imply requirements aiming at enhancing the safety on LNG shipping activities as well as shipping in general.

Classification society rule rules apply for structural strength while special code for ships carrying liquefied gas included in the SOLAS regulations, the IGC code. Other IMO regulations pertaining to safety are contained in the International convention on Load Lines which addresses the limits to which a ship may be loaded, the International Convention for the Prevention of Collisions at Sea (COLREG) addressing issues related to steering, lights and signals and the International Convention on Standards of Training, Certification and Watch keeping for Seafarers (STCW Convention) which addresses issues related to the training of crew.

The International Convention for the Prevention of Pollution from Ships (MARPOL) addresses issues related to marine and air pollution from ships. These regulations are applicable to all ships as well as LPG ships. The issue of global warming has initiated MARPOL Annex VI and there is indication that more will follow.

Maritime regulations for liquefy gas regulation

IMO regulation regarding carriage of gas was never specifically defined for Safety is an important issue for LNG, CNG or LPG carriers. However, safety regulations exist in order to ensure the LPG ships are safe. Thus Gas carriers need to comply with a number of different rules that are common to all ship types, as well as a set of Safety regulations particularly developed for ships carrying liquefied gas and their crew as well as site selection and design of LNG terminals. This include:

Issues relating to control of traffic near ports, local topology and weather conditions, safe mooring possibility, tug capability, safe distances and surrounding industry and population and training of terminal staff.

These considerations contribute to enhance the safety of LPG shipping in its most critical phase, i. e. sailing in restricted waters or around terminal and port areas.

The IGC code prescribes a set of requirements pertaining to safety related to the design, construction, equipment and operation of ships involved in carriage of liquefied gases in bulk. The IACS unified requirements for gas tankers were partly derived from the IGC code.

The code specifies the ship survival capability and the location of cargo tanks. According to the type of cargo, a minimum distance of the cargo tanks from the ship’s shell plating is stipulated in order to protect the cargo in case of contact, collision or grounding events. Thus the code prescribes requirements for ships carrying different types of liquefied gas, and defines four different standards of ships, as described in Table 2.

LNG carriers are required to be ships of type 2G and all LNG carriers should be designed with double hull and double bottom. While 2C describe.

The IGC code requires segregation of cargo tanks and cargo vapour piping systems from other areas of the ship such as machinery spaces, accommodation spaces and control stations, and prescribes standards for such segregation.

It provides standards for cargo control rooms and cargo pump-rooms are as well as standards for access to cargo spaces and airlocks. It defines requirements for leakage detection systems and for the loading and unloading arrangements.

Different types of cargo containment systems for are permitted by the IGC code, and the two main – Types of containment systems in use in the world liquefied tanker fleet are membrane tanks and independent tanks. Membrane tanks are tanks which consist of a thin layer or membrane, supported through insulation by the adjacent hull structure.

The membrane should be designed in such a way that thermal expansion or contraction does not cause undue stress to the membrane. The independent tanks are self-supporting in that they do not form a part of the ship’s hull.

The IGC code defines three categories of independent tanks:

• Type A;
• Type B;
• Type C.

Type C tanks are pressure tanks and will not be required for LNG vessels since LNG are transported at ambient pressure. Regardless of what containment system is used, the tanks should be design taking factors such as internal and external pressure, dynamic loads due to the motions of the ship, thermal loads and sloshing loads into account, and structural analyses should be carried out.

A separate secondary barrier is normally required for the gas liquefied gas containment systems to act as a temporary containment of any leakage of LNG through the primary barrier.

For membrane tanks and independent type A tanks, a complete secondary barrier is required. For independent type B tanks, a partial secondary barrier is required, whereas no secondary barrier is required for independent type C tanks. The secondary barrier should prevent lowering of the temperature of the ship structure in case of leakage of the primary barrier and should be capable of containing any leakage for a period of 15 days.

Additional requirements regarding insulation and materials used for the cargo containment systems as well as construction and testing, piping and valving etc. are included in the IGC code.

The IGC code also requires certain safety equipment’s to be carried on board LPG carriers. These include ship handling systems such as:

• positioning systems,
• approach velocity meters,
• and automatic mooring line monitoring and cargo handling systems such as:
  • emergency shutdown systems (ESD),
  • emergency release system (ERS).

In addition, systems for vapour and fire detection, fire extinguishing (dry chemical powder) and temperature control are required.

Finally, the code contains operational requirements related to i. e. cargo transfer methods, filling limits for tanks and the use of cargo boil-offs as fuel as well as requirements on surveys and certification.

Equivalents to the various requirements in the code are accepted if it can be proven, e. g. by trials, to be as effective as what is required by the code. This applies to:

• fittings,
• materials,
• appliances,
• apparatuses,
• equipment’s,
• arrangements,
• procedures etc.,

but it is noted that no operational options or procedures can be accepted as an alternative to requirements related to:

• fittings,
• materials,
• appliances,
• apparatuses or equipment’s.

In addition to the numerous regulations, codes, recommendations and guidelines regarding gas carriers issued by IMO, there are extensive regulations, recommendation and guidelines under international and local umbrella related to safety LPG shipping exist that undoubtedly contributing to the high safety standard and the good safety record that has been experienced for the fleet of LNG carriers.

E. G. standards of best practice issued by SIGTTO (The Society of International Gas Tanker & Terminal Operators).

Training requirement

Any person responsible for, or involved with, the operation and dispensing of LPG should have an understanding of the physical characteristics of the product and be trained in the operation of all ancillary equipment. Thus acquiring sufficient crew with the required level of experience, training and knowledge of LNG are believed to be one of the major safety-related challenges to the maritime LNG industry in the years to come.

In addition to strict regulations on the ship itself, there are also extensive international regulations specifying the necessary training and experience of crew that operate LPG carriers. These include the international rules on training requirements are contained in regulations such as the STCW 95 and the ISM code, tanker familiarization training as well as flag state or company specific training requirements that go beyond these international regulations.

The competence level of Liquefied gas crew has generally been regarded as quite high compared to that of other ship types. A study presented in demonstrates that the performance score of crew on board gas and chemical tankers are the best among cargo carrying ships, second only to that of passenger vessels.

STCW 95 contains minimum training requirements for crew engaged in international maritime trade. In particular, Chapter V of the STCW code contains standards regarding special training requirements for personnel on certain types of ships, among them liquefied gas carriers.

One requirement for masters, Officers and ratings assigned specific duties and responsibilities related to cargo or cargo equipment on all types of tankers, e. g.

LNG tankers, is that they shall have completed an approved tanker familiarization course. Such a course should as a minimum cover the following topics:

• Characteristics of cargoes and cargo toxicity.
• Hazards and Hazard control.
• Safety equipment and protection of personnel.
• Pollution prevention.

This course must provide the theoretical and practical knowledge of subjects required in further specialized tanker training. Specialized training for liquefied gas tankers should as a minimum include the following syllabus:

• Regulations and codes of practice.
• Advanced fire-fighting techniques and tactics.
• Basic chemistry and physics related to the safe carriage of liquefied gases in bulk.
• Health hazards relevant to the carriage of liquefied gas.
• Principles of cargo containment systems and Cargo-handling systems.
• Ship operating procedures including loading and discharging preparation and procedures.
• Safety practices and equipment.
• Emergency procedures and environmental protection.

In addition to these training requirements, masters, chief engineering officers, chief mates, second engineering officers and any persons with immediate responsibilities for loading, discharging and care in transit of handling of cargo in a LNG tanker are required to have at least 3 months sea service on a liquefied gas tanker.

Due to the extensive training requirements and experience level of their personnel, the maritime LNG industry claims that the crew sailing the LNG fleet are among the best in the world. However, a shortage of experienced LNG crew is foreseen in the near future especially with the expected growth of the LNG fleet.

Transportation of LNG in inland water

LPG and CNG AND LNG are next in line of alterative for transportation to gasoline because of their associated environmental benefits including reduction of GHGs. Thus, it is more useful for countries with natural gas resources and a relatively good gas distribution system. LPG has been explored in the 1930s but it’s used has been slowed because of favourable economy of petroleum. However, the current threat of climate change has increased the focus on alternative transport fuels which include.

Countries with programmes on the use of CNG and LPG as a transport fuel include the:

• USA;
• Canada;
• UK;
• Thailand;
• New Zealand;
• Argentina;
• Pakistan.

CNG and LPG are used in both private vehicles and transport fleets. It is estimated that about 250 million vehicles are using this fuel worldwide, and its use is on the increase, representing 2 % of total global transport fuel use.

The advantages of using LPG are:

• Environmental friendliness;
• Reduced engine maintenance cost;
• Improved engine and fuel efficiency.

However, limitations are the following:

• Storage containment;
• High cost of conversion;
• Need for high skill operate.

Each category of this required thorough and holistic risk and goal based design and operability assessment for safety, reliability and protection of environment.

Environmental concern for beyond compliance

Over the last decade, each passing years has been augmented concerned about issue of environment importance in design, construction, operation and beneficial disposal of marine articraft the overriding force is increasing the resources of the planet that we live and that only a few are renewable. This accumulated to production that has elements of long-term sustainability of the earth.

Precipitated effect over the year has call for public awareness and translated into impact through these the following manners:

• Regulations: public pressure on governmental and non-governmental organization regulation due to untold stories of disaster and impact, the public is very concerned and in need of fact that if the quality of life of people enjoy is to be sustained, for them and the future generation then the environment must be protected. conspicuous issue, expertise and finding of regulations make them to go extra length on unseen issue, contrasting between the two, while commercial force act on hat will be forth problems.
• Ship Concept design – is very important in shipping and it account for 80 % of failure, therefore compliance and making of optimal design has a great impact in ship whole life cycle. The impact of environment in ship design is very difficult because of large numbers of uncertainties. Environmental impact hat need to be taken into considerations in concept design can be classified into the following.
• Operations: considering limiting life cycle of ships at estimate of 25 years, issues relating to the following are equally not easy to quantify in design work, even thus a lot of research effort has been set on move on this, but the call of the day require allowable clearance and solution to be given to the following:
  • Known emission;
  • Accidental;
  • Ballast waste;
  • Coating.
• Commercial forces: where company that or product that operate in an un-environmentally friendly way, people are prone to spurn the company’s products and service, therefore having impact on company return on investment.
• Construction and Disposal – use of meticulous scantling and factors worth consideration with the ship at the end of her life cycle.

Shipboard environmental protection should Pollution Prevention (P²) or Pollution Control.

• Pollution Prevention: use fewer environmentally harmful substances and generate less waste on board.
• Pollution Control: increase treatment, processing, or destruction of wastes on board.

The basic P² principles follow:

• eliminating the use of environmentally harmful chemicals,
• and reducing the amount of waste we generate on board is often better that treating it on board.

The environmental benefits relating to climate change are given in the Table below:

Emission is inherent consequence of powered shipping, fuel oil burning as main source, continuous combustion machineries – boilers, gas turbines and incinerators. And this made the following issue very important:

• Worldwide focus of fuel -> exhaust gas emission law by IMO and introduction of local rules.
• Emission limits driving evolution to development and adaptation to new technology.
• Solution anticipated to maintenance of ship life cycle at average of 25 years.
• Focus is currently more on, NO_x and SO_x – HC, COx and particulate will soon join.
• Consideration involve not only fuel use and design but also OPERATIONAL ISSUE.

The table below shows the environmental regulatory demand of our time for ships:

Hybrid use of goal based and risk based design towards beyond compliance

It is clear that the shipping industry is overfilled with rules and recent environmental issues are have potential to initiate new rules, this made firms to selectively adopt “beyond compliance” policy that are more stringent than the required extant law due to.

Beyond compliance policy are mostly due to intra – firm process – which could be power based or leadership based. It draw insight from institutional theory, cooperate social performance perspective, and stakeholder theory that relate to internal dynamic process. While external create expectation an incentive for manager, intra firm politics influence how managers perceive, interpret external pressure and act on them.

Policy towards beyond compliance fall into 2 categories:

1. (I) whether they are now required by law but they are consistent with profit maximization;
2. (II) requirement by law and firm are expected to comply by them.

Towards sustainable reliability, it is also preferable to use stochastic and probabilistic methods that could help improve in the existing methodology this method involve absolutism that will cover all uncertainty complimented by historical and holistic matrix investigation. Hybridizing models is also the best solution of sustainable maintenance of navigation channel. Beyond compliance towards Meeting required safety level and life cycle and environmental protection required systematic employment of hybrid of GBS, using the FSA risk models.

Below is the general step of FSA and GBS which can be apply for above described characteristic of LPG Ships.

Components of goal based standards

Goal-based standards (GBS) are ship safety standards comprising five tiers:

• Tier I – consists of goals expressed in terms of safety objectives defined by risk level.
• Tier II – consists of requirements for ship features/capabilities, defined by risk level, that assure achievement of ship’s safety objectives.
• Tier III – (the process of verification of Tier IV and V Compliance with Tier II) is deleted at this point and the concept is added in the form of a note underneath reading: Tier IV and V are to be verified for compliance with Tier II.
• Tier IV – consists of rules, guidelines, technical procedures and programs, and other regulations for ship designing and ship operation needs, fulfilment of which satisfies ship’s feature/capability requirements.
• Tier V – consists of the code of practice, safety and quality systems that are to be applied to guarantee the specified by the rules quality level.

Sustainable risk assessment

Sustainability remain a substantial part of assessing risk and life cycle of ships – however, they are very complex and require long time data for accurate. Environmental risk – Environmental impact assessment procedure is laid out by various environmental departments and will continue to remain similar except that the components of risk area cover different uncertainty to sustain a particular system are different.

EIA has been a conventional process to identify, predict, assess, estimate and communicate the future state of the environment, with and without the development in order to advise the decision makers the potential environmental effects of the proposed course of action before a decision is made.

Read also: Safety Critical Equipment Controls in Oil and Gas Industry

FSA is improvised version of EIA where holistic consideration, community participation, expert rating, cost benefit analysis and regulatory concerned are core part of the philosophy leading to reliable decision making and sustainable system design and operation. In risk assessment, serenity and probability of adverse consequence (HAZARD) are deal with through systematic process that quantitatively measure, perceive risk and value of ship using input from all concerned-waterway users and experts.

RISK = Hazard × Exposure (an estimate on probability that certain toxicity will be realized).

HAZARD: Anything that can cause harm (e. g. chemicals, electricity, natural disasters).

Severity may be measured by:

• No. of people affected.
• Monetary loss.
• Equipment downtime.
• Area affected.
• Nature of credible accident.

Risk ranking – assignment risk index according to level of risk, the tables bellow shows an example of risk matrix with assignments of risk level identifies by number index.

Risk management is the evaluation of alternative risk reduction measures and the implementation of those that appear cost effective where Zero discharge = zero risk, but the challenge is to bring the risk to acceptable level and at the same time, derive the max Benefit.

In order to select between alternative technical or regulatory solutions to specific problems the first three FSA steps (HAZID, risk assessment, RCOs) can fit into the development of high-level goals (Tier I) and functional requirements (Tier II) of GBS. Equally, the last three steps (RCOs, CBA, and Recommendations) could feed into Tiers IV and V of GBS.

Components of formal safety assessment

1 FSA targets

• Identification of potential hazard scenarios and Major impact to ship Shipping and ship design which could lead to significant safety or operability consequences as well recent call for policies chance and procedures major effects.
• Verification if current design, construction and operations ensure that risk from identified scenarios meet risk acceptability criteria.
• If not, to recommend additional FSA process and available technology for control and protection that can reduce risk to suitable level.

2 Step 1 – HAZID

The HAZID (step 1 of the FSA) should be conducted an in a technical meeting including brainstorming sessions from various sectors within the LPG industry, i. e. ship owner/operator, shipyard, ship design office maritime engineering consultancy, equipment manufacturer, classification society and research centre university.

Common identifiable hazards are:

• Emissions to air, water and soil.
• Shipboard cargo tank and cargo handling equipment.
• Storage of tanks and Piping.
• Safety Equipment’s and Instruments.
• Ruder failure in inland water.
• Crew fall or slip on board.
• Fault of navigation equipment’s in inland water.
• Steering and propulsion failure.
• Collision with ship including Passing vessel hydro dynamic effects.
• Terrorist attack or intentional incident.
• Potential Shortage of crew.
• Navigation and berthing procedure.

The results from the HAZID should be recorded in a risk register stating total number of hazards, different operational categories. The Hazards and Risks in Usage of Land Transport in Oil and Gas Industrytop ranked hazards according to the outcome of the HAZID can be selected and given respective risk index based on qualitative judgement by the HAZID participants from diverse field of expert. It should emphasise on the study existing situations and regulations including policies in place, present performance, flaws and survey on parties feeling on acceptability and procedures.

3 Step 2 – Hazard Analysis

The risk analysis (step 2 of the FSA) comprises a thorough investigation of accident statistics for liquefy gas carriers as well as risk modelling utilizing event tree methodologies for the most important accident scenarios.

Based on the survey of accident statistics and the outcome of the HAZID leading to generic accident scenarios recommendation for further risk analysis.

The risk analysis essentially contains two parts, i. e. a frequency assessment and a consequence assessment. The frequency assessment, involve estimation of frequency of generic incidents using reasonable accident statistics derived from the selected accident scenarios which should also be compared with similar studies for liquefy gas carriers as well as other ship. The consequence assessment should be performed using event tree methodologies.

Risk models can be developed for each accident scenario and event trees constructed according to these risk models utilizing:

• accident statistics,
• damage statistics,
• fleet statistics,
• simple calculations,
• and modelling and expert opinion elicitation.

The frequency and consequence assessments provide the risk associated with the different generic accident scenarios which can be summarized in order to estimate the individual and societal risks pertaining to liquefy gas carrier operations and design.

Based on available accident statistics and results from the HAZID, eight generic accident scenario umbrellas that required deep analysis are:

1. Collision;
2. Fire or explosion;
3. Grounding;
4. Contacts;
5. Heavy weather/loss of intact stability;
6. Failure/leakage of the cargo containment system;
7. Incidents while loading or unloading cargo LPG;
8. Emission ship power sources.

The first five generic accident scenarios are general in the sense that they involve all types of ships, while 6 and 7 accident scenarios are specific to gas carriers and 8 concerned new environmental issue driving compliance and technology for all ships. Selected accident scenarios to investigate frequency assessment could provide a sufficiently accurate estimate of initiating frequencies for the eight selected accident scenarios. Figure 4 shows risk model for explosion case.

Identification of accident scenario that is significant to risk contribution should consider use of:

• Holistic risk assessment of major treat using IMO Formal safety assessment (FSA), and Goal Based Model including application of stochastic and,
• probabilistic and deterministic methods to increase reliability and reduce uncertainties as much as possible this including using tool comprising foreseeable scenarios and scenario event, such tolls are:
  • Accident modelling model,
  • Estimation of risk, accident frequency and consequences.

4 Step 3 – Risk Control

Risk control measures are used to group risk into a limited number of well thought out practical regulatory options:

• Specification of risk control measures for identified scenarios.
• Grouping of the measures into possible risk control options using:
  • General approach – which provides risk control by controlling the likelihood of initiation of accidents, and may be effective in preventing several different accident sequences, and;
  • Distributed approach – which provides control of escalation of accidents, together with the possibility of influencing the later stages of escalation of other, perhaps unrelated, accidents. And this followed by assessment of the control options as a function of their effectiveness against risk reduction.

5 Step 4 – Cost Benefit Assessment (CBA)

Risk-Cost Benefit analysis to deduce mitigation and options selection Proposed need for new regulations based on mitigation and options:

• CBA quantification of cost effectiveness that provide basis for decision making about RCO identified, this include the net or gross and discounting values.
• Cost of equipment, redesign and construction, documentation, training, inspection maintenance and drills, auditing, regulation, reduced commercial used, operational limitation (speed, loads).

6 Step 5 – Decision Making

This step involves:

• Discussion of hazard and Basic Info about Liquefied Petroleum Gas Vessels and Risks while Shipping a Cargoassociated risks.
• Review of RCO that keep ALARP.
• Compare and rank RCO based on associated cost and benefit.

Specification of recommendation for decision makers output could be used for “beyond compliance” preparedness and rulemaking tools for regulatory bodies towards measures and contribution for sustainability of the system intactness, our planet and the right of future generation.

Uncertainty

Uncertainty will always be part of our activities because of limitation of knowledge of unseen in real world settings, issues associated with uncertainty are normally:

• Influences on recovery process.
• Test of new advancements.
• Influence on policy.
• Address system changes over time.
• Services & resources.

Estimating uncertainty could be obtained through the relation: validation – uncertainty, policy issues and rating:

R(P1c) = R(E1) × W(E1, P1) + R(E2) × W(E2, P1) + R(E4) × W(E4, P1),

where:

• R = rating;
• E = environmental factor;
• P = Policy factor.

Uncertainty is necessary because of highly variable nature of elements and properties involved with the situation requires simulate extreme condition and model – using combination mathematical modelling and stochastic techniques while considering all factors in holistic manner that cover:

• Risk areas and assessment – taking all practical using historical data’s and statistics that include all factors – Public health (people > other species).
• Mitigation to risk assessment and risk areas – this involves making permanent changes to minimize effect of a disaster – immediacy: (Immediate threat > delayed threats).
• Prefer and no option choice – as prophesied my Newton – time travel in space, no matter what one thing must compensate for the other.
• Panel of expert – reach out to those who are capable to extend hand and do the right thing at the risk area – uncertainty (More certain > less certain).
• Community participation – educate and all concern about the going and lastly place firm implementation and monitoring procedure. Adaptability (Treatable > untreatable).
• Emergency response – provide monitoring and information facilities and make sure necessary information is appropriately transmitted and received to all.

Risk acceptability criteria

The diagram below gives overall risk reduction areas identification and preliminary recommendation, in order to assess the risk as estimated by the risk analysis, appropriate risk acceptance criteria for crew and society for LPG tankers should be established prior to and independent of the actual risk analysis.

The overall risk associated with LPG carriers should be concentrated in the reduction desired areas ALARP, where cost effective risk reduction measures should be sought in all areas. three areas or generic accident scenarios where which together are responsible for about 90 % of the total risk are:

• collision,
• grounding,
• and contact,

and they are related in that they describe situation where by the LPG vessel can be damaged because of an impact from an external source support inland water as another vessel or floating object, the sea floor or submerged objects, the quay or shore or bad weather.

By studying the risk models associated with these scenarios, four sub-models in particular stands out where further risk reduction could be effective. These are the accident frequency model, the cargo leakage frequency model, the survivability model and the evacuation model.

Particularly, related to collision, grounding and contact, it is recommended that further efforts in step 3 of this FSA focus on measures relating to:

• Navigational safety. Improvements.
• Manoeuvrability. Improved manoeuvrability. Extended use of tugs might reduce the frequency of contact and grounding events near the terminals.
• Collision avoidance, i. e. warning boats in busy waters to clear the way for the LPG carrier.
• Cargo protection. Measures to prevent spillage through enhancing the cargo containment system’s ability to maintain its integrity.
• Damage stability. Reducing the probability of sinking though enhancement of survival capabilities in damaged condition.
• Evacuation arrangements and associated consequence through improvements relating to evacuation procedures, escape route layout or lifesaving appliances. Figure show the CBA balancing process curve for sustainable design.

$Acceptable quotient = \frac{BENEFIT}{RISK/COST}.$

Risk control options (step 3 of the FSA) were identified and prioritized at technical workshops; in all, three workshops were held in conjunction with the identification and selection of risk control options for further evaluation and cost benefit assessment. This part of the FSA also contained a high-level review of existing measures to prevent accidental release of gas.

The economic benefit and risk reduction ascribed to each risk control options should be based on the event trees developed during the risk analysis and on considerations on which accident scenarios would be affected. Estimates on expected downtime and repair costs in case of accidents should be based on statistics from shipyards.

Beyond compliance ship design

Existing design tools cannot, at least with any degree of reliability, be used to design a vessel and ensure it will ensure environmental reliability for LPG ships and operation in shallow or restricted waters. This is because of the extreme on-linearity of hull and propulsion characteristics under these conditions. In general, naval architects and marine engineers are educated and equipped with knowledge, skills, and design processes that permit continuous checking and balancing of constraints and design trade-offs of vessel capabilities as the design progresses.

The intended result of the process is the best design given the basic requirements of speed, payload, and endurance nor where the waste is going. Focus is not placed on top down model of generic design based on risk where all areas of concerned are assess at different stages of design spiral as well as risk of environmental consequence for risk involved in operability in restricted water. Operational wise recent time has seen real attempt to fully integrate human operational practices with vessel design.

Evolving simulation technology however give hope required assessment of extreme engineering to mitigate extreme condition as well as envisaged uncertainty.

Incorporating risk assessment and goal based design for environmental protection and accident prevention as an important part of ship design spiral for LPG ship would seem a necessary step to enabling proper trade-offs in vessel design for reliability and other demand of time.

The result is that design decisions that can compromise environment and collision are decided in favour of other factors. Only consideration of the full range of ship and terminal design and human factors relationships that affects LPG ships will produce an efficient and safe environmental friendly marine transportation system of LPG. Now that the new issue of environment is around, then we have to squeeze in more stuff in the spiral.

In shipping and associated industries, ship protection and marine pollution are respectively interlinked in terms of safety and environment, conventionally; ship safety is being deal with as its occurrence result to environmental problem.

Likewise, for many years, less attention has been given to ship life cycle, material properties, and frequency matching with the environment has resulted to corrosion. Also ship scraping, and what happen to the environment after ship scraping, yes a lot of recycling, but little or no attention is given to the residual material that find their ways to pollute the clean beautiful sea. Other areas of concern are channel design criteria ships, controllability in dredged channels, and ship manoeuvrability as a consideration in the Design Process.

All in all, preventive and control incorporating sensible measures in ship design can only optimize method and give us confidence on our environment. Focal areas that are will need revolutionary changes in ship design for LPG Ships are:

• Material selection to withstand structural, weight, economical lifecycle anticorrosion and fouling.
• Ascertain the IGC requirements for LPG carriers and special design considerations.
• Consideration of critical load cases for each structure component as well as corrosion.
• Design considerations and general requirements Internal cargo pressures according to the IGC Code.
• Vertical supports, anti-rolling keys, anti-floating keys and anti-pitching keys.
• Standard design load cases for yielding and buckling Standard design load cases for fatigue. Acceptance criteria Fatigue strength assessment.
• Thermal stress analysis around supports.
• Incorporating ship simulation at early stage of ship design.
• Validation of applied loadings and the responses to structural scantly towards withstanding structural function, reliability, integrity, weight, economical lifecycle using Structural FE Analysis.
• Incorporation manoeuvring ship simulation at early stage of design iteration.

Beyond compliance cargo tank design

Pressure vessel is storage tank designed to operate at pressures above 15 p. s. i. g. Common materials held and maintained by pressure vessels include:

• air,
• water,
• nitrogen,
• refrigerants,
• ammonia,
• propane,
• and reactor fuels.

Due to their pressurizing capabilities, they are often used to store chemicals and elements that can change states. For this reason gas property is important in their design, the walls of pressure vessels are thicker than normal tanks providing greater protection when in use with hazardous or explosive chemicals.

Important parameters to consider when specifying pressure vessels include the capacity, the maximum pressure and the temperature range:

• The capacity is the volume of the pressure vessel – The maximum pressure is the pressure range that the vessel can withstand.
• The temperature ranges indicate the temperature of the material that the container can withstand. Built – in temperature control system. This helps to keep volatile chemicals in inert states. At times it may also change the state of the chemicals to make transportation easier.

Pressure vessel with temperature controls have gauges to allow for reading of internal pressures and temperatures. These gauges are available with a variety of end connections, levels of accuracy, materials of construction, and pressure ranges.

There are mainly two types of pressure vessels:

Spherical Pressure Vessel – these pressure vessels are thin walled vessels. This forms the most typical application of plane stress. Plane of stress is a class of common engineering problems involving stress in a thin plate. It can also be called as simplified 2D problems.

Cylindrical Pressure Vessel – this vessel with a fixed radius and thickness subjected to an internal gage pressure, the vessel has an axial symmetry.

Analyses of LPG tanks design required of advantage of finite element modelling with fluent and other CFD software using static, dynamic, thermal and nonlinear analysis. To prove the structural integrity of the tank designs for structural and seismic loading as well as assesses leakage and burn-out scenarios.

Tank analyses should include:

• Leakage and double walled piping modelling.
• Prestress/post-tensioning and Burn-out modelling.
• Relief valve heat flux modelling Static analysis.
• Wind loading and modal and seismic analysis.
• Temperature modelling prediction of stresses loading as well as other environmental safety.
• Stress and thermal analysis of marine loading arm.

Beyond compliance HAZOP and FMEA

Operability must follow Hazards associated with LPG ships. HAZOP and FMEA risk assessment following FSA procedure recommended to be followed. Beside this the following operational requirement are expected to exercise all the time for all operation activities.

Use of Personal Protective Equipment (PPE) – owing to its rapid vaporisation and consequent lowering of temperature, LPG, particularly liquid, can cause severe frost burns if brought into contact with the skin. PPE appropriate for use with LPG must always be worn when the refuelling operation is taking place.

• Neoprene gloves, preferably gauntlets (or similar, impervious to LPG liquid).
• Safety gear – footwear, Goggles or face shield. Long sleeved cotton overalls.

Gas Equipment – equipment’s associated with gas works that require regular look after are:

• gas dryer,
• heat exchanger,
• storage and container,
• gas reactors,
• gas compressor type,
• gas liquefier,
• dust filter,
• air separation column,
• filling manifold distillation column.

Expansion engines suction filter, after cooler, moisture absorber air compressor.

Housekeeping – housekeeping is one of the most important items influencing the safety of the Colour Gas Installation.

No smoking – no naked lights or other sources of ignition, including the use of mobile phones, pagers, or radio transmitters, are permitted in the vicinity of the installation.

• Do not ignore the hazard signs or remove them (Or put your emergency sign here).
• The area must be kept free from long grass, weeds, rubbish, and other readily ignitable or hazardous materials.
• All emergency exits and gangways to be kept clear at all times.

Gas Storage – gas storage facility is a vital factor in offsetting seasonal fluctuations in demand and safeguarding gas supplies at all times. Gas storage plays a vital role in maintaining the reliability of supply needed to meet the demands of consumers. LPG gases are explosive and are stores carefully and properly with extra attention and effort to avoid any kind of injury.

The following are important hazard risk measured to follow for gas storage:

• Transportable gas containers should be stored in well-defined areas and should be segregated according to the hazard presented by the contents.
• Contents of cylinders should be easily identifiable.
• Persons involved should receive training regarding handling of cylinder, potential risks and hazards from cylinder and contents.
• Gases can be stored in pressure vessels, cylinders, trailer, vaporizer and tanks. These are stored away from flammable materials and electrical outlets.
• Account should be taken of external dangers such as adjacent work operations under different managerial control or the possibility of mechanical damage due to traffic knocks.
• The gases should not be subjected to any sort of physical damage or corrosion.
• Emergency procedures should be established.

In the present times, many new next generation systems are being developed in order to cater to the growing need for operational flexibility required by various gases and gas-fired power generation customers all across the globe.

The exploration, production, and transportation of gases takes time, and most of the times the gas that reaches its destination is not always needed right away, so it is injected into underground gas storage facilities. Gas storage systems can either be located near market centres that do not have a ready supply of locally produced gas or can be transported in the form of specifically designed containers and vessels.

These gas storage facilities should have following characteristics:

1. Low Maintenance and easy to operate.
2. Trouble Free Operation.
3. Sturdy Design and long operative life.
4. Low Working Pressure and Low Operating Cost.
5. Easy availability of spare parts and Low power consumption.

First Aid – treatment must be carried out immediately by placing the casualty gently under slowly running cool water, keeping it there for at least 10 minutes or until the pain ceases or cover the affected parts with light, dampened or wet material. Encourage the affected person to exercise any fingers, toes or legs that are affected to increase circulation. In severe cases, tissue damage will take place before medical aid can be obtained. In all but the most minor cases, professional medical treatment should be sought.

Inhalation – LPG vapour is mildly narcotic, inhalation of high concentrations will produce anaesthesia. Prolonged inhalation of high concentrations will cause asphyxiation. The emergency treatment for inhalation is to move the casualty to fresh air, keeping them warm and at rest. In chronic cases, where there is a loss of consciousness give oxygen, or if breathing ceases give artificial respiration. In all but the minor cases, professional medical treatment should be sought immediately.

Eyes – immediately flush eyes with plenty of tepid water for at least 15 minutes. Hold eyelids apart while flushing to rinse the entire surface of eye and lids with water. Seek medical attention immediately.

Skin – a strong refrigerant effect is produced when liquid LPG comes into contact with the skin. This is created by the rapid evaporation of the liquid, and it can cause severe frostbite, depending on the level of exposure.

Emergency prepareness

IN THE EVENT OF FIRE – the fact that LPG is used as a safe and valuable heating source in millions of homes show there is chances to controlling and preventing a fire involving LPG. To minimize the possibility of outbreak of fire, it is of key importance to provide good plant design and layout, ensure sound engineering and good operating practice, and provide proper instruction and training of personnel in routine operations and actions to be taken in an emergency.

1. Shut all valves on tank or cylinders and emergency control valve outside the building by turning clockwise.
2. Call the Fire Service and refer to presence of LPG tank.
3. Keep tank cool by water spray, if possible.

GAS LEAKAGE – damaged vessels and cracks can result in leakage or rupture failures. Potential health and safety hazards of leaking vessels include poisonings, suffocations, fires, and explosion hazards. Rupture failures can be much more catastrophic and can cause considerable damage to life and property. The safe design, installation, operation, and maintenance of pressure vessels in accordance with the appropriate codes and standards are essential to worker safety and health.

1. Shut the emergency control valve outside your building.
2. Extinguish all sources of ignition.
3. Shut all cylinder valves or the gas isolation valve on top of the tank.
4. Do not operate electrical switches.
5. Open all doors and windows. Ventilate at low level as LPG is heavier than air.

In line with Global warming, evolving, since air emission is linked to machineries emerging new technology for efficient and low air pollution power source for ships including LPG Ships are:

• Alternative energy.
• Alternative fuel and dual fuel engines.
• Infusion of water mist with fuel and subsequent gas scrubbing units for slow speed engines.
• Additional firing chamber.
• Potential for gas turbine complex cycle.
• Potential for turbocharger diesel engine.
• Compound cycle with:
  • gasified fuel,
  • external compressor,
  • combustion with pure oxygen
• Exhaust after treatment for medium speed engines.

Above all Appliances should be serviced according to the manufacturer’s recommendations by a competent person.

Environmental technology

1. Development real time simulation help in the mitigation most of the accident and cover issues of uncertainty.
2. Development in automation technology help in installation of emergency shut down mechanism.
3. Advent of advance communication technology further give hope for improvise protection prevention and control.
4. Prospect of Container unitized LPG ships.

Conclusion

In today, environmentally conscious world there is already so much pressure on stake holder in shipping industry, especially ship carrying flammable gases like LPG to avoid accident and incident and the consequence of which could lead to catastrophic long term environmental disaster at design and operation stage of their operations on the environment. And potential for more laws prevent and put necessary control in place is evident. However, the risk based and goal based philosophy and subsequent use of available and new technology in an age of Innovation and information technological where activities in relation to speed, safety, reliability, miniaturization, cost, mobility and networking in most industries has been facilitated to help us optimize our system at design, operation and other factors of life cycle accountability process in order to come up with sustainable system.

The answer to this lies on “Beyond compliance” policy using IMO FSA and GBS tool to meet future law requirement and aid effective development of rules that satisfy all concern. Functional requirements for liquid gas carrier design and operations in restricted water can be adequately developed from a design, human elements and construction point of view using adequate technical background as well as ergonomic design principles.

Authors

Oladokun Sulaiman Olanrewaju – PhD, CEng, CMarEng

Oladokun Sulaiman Olanrewaju, is a PhD researcher in marine technology, he currently holds the position of Lecturer at Malaysian Maritime Academy. He is responsible for Training Education, Research and Consultancy.
Linkedin

Dr. Ab. Saman Ab Kader

Dr. Ab. Saman Ab Kader, is Professor of marine technology, He currently holds the position of Director of Training and Education at Malaysian Maritime Academy. He is responsible for training education, research and consultancy.