IMDG Codes and Symbols

CLASSIFICATION OF DANGEROUS GOODS

The International Maritime Dangerous Goods (IMDG) Code was developed as a uniform international code for the transport of dangerous goods by sea covering such matters as packing, container traffic and stowage, with particular reference to the segregation of incompatible substances.

The Carriage of dangerous goods and marine pollutants in sea-going ships is respectively regulated in the International Convention for the Safety of the Life at Sea (SOLAS) and the International Convention for the Prevention of pollution from Ships (MARPOL).

Relevant parts of both SOLAS and MARPOL have been worked out in great detail and are included in the International Maritime Dangerous Goods (IMDG) Code, thus making this Code the legal instrument for maritime transport of dangerous goods and marine pollutants. As of 1st January 2004, the IMDG Code has become a mandatory requirement.

For all modes of transport (sea, air, rail, road and inland waterways) the classification (grouping) of dangerous goods, by type of risk involved, has been drawn up by the UNITED NATIONS Committee of Experts on the Transport of Dangerous Goods (UN).

Class 1: Explosives

Subclass 1.1: Explosives with a mass explosion hazard

Consists of explosives that have a mass explosion hazard. A mass explosion is one which affects almost the entire load instantaneously.

Subclass 1.2: Explosives with a severe projection hazard

Consists of explosives that have a projection hazard but not a mass explosion hazard.

Subclass 1.3: Explosives with a fire

Consists of explosives that have a fire hazard and either a minor blast hazard or a minor projection hazard or both but not a mass explosion hazard.

Subclass 1.4: Minor fire or projection hazard

Consists of explosives that present a minor explosion hazard. The explosive effects are largely confined to the package and no projection of fragments of appreciable size or range is to be expected. An external fire must not cause virtually instantaneous explosion of almost the entire contents of the package.

Subclass 1.5: An insensitive substance with a mass explosion hazard

Consists of very insensitive explosives with a mass explosion hazard (explosion similar to 1.1). This division is comprised of substances which have a mass explosion hazard but are so insensitive that there is very little probability of initiation or of transition from burning to detonation under normal conditions of transport.

Subclass 1.6: Extremely insensitive articles

Consists of extremely insensitive articles which do not have a mass explosive hazard. This division is comprised of articles which contain only extremely insensitive detonating substances and which demonstrate a negligible probability of accidental initiation or propagation.

Class 2: Gases

Subclass 2.1: Flammable Gas

Gases which ignite on contact with an ignition source, such as acetylene and hydrogen. Flammable gas means any material which is ignitable at 101.3 kPa (14.7 psi) when in a mixture of 13 percent or less by volume with air, or has a flammable range at 101.3 kPa (14.7 psi) with air of at least 12 percent regardless of the lower limit.

Subclass 2.2: Non-Flammable Gases

Gases which are neither flammable nor poisonous. Includes the cryogenic gases/liquids (temperatures of below -100°C) used for cryopreservation and rocket fuels. This division includes compressed gas, liquefied gas, pressurized cryogenic gas, compressed gas in solution, asphyxiant gas and oxidizing gas. A non-flammable, nonpoisonous compressed gas means any material which exerts in the packaging an absolute pressure of 280 kPa (40.6 psia) or greater at 20°C (68°F), and does not meet the definition of Division 2.1 or 2.3.

Subclass 2.3: Poisonous Gases

Gases liable to cause death or serious injury to human health if inhaled. Gas poisonous by inhalation means a material which is a gas at 20°C or less and a pressure of 101.3 kPa (a material which has a boiling point of 20°C or less at 101.3kPa (14.7 psi)) which is known to be so toxic to humans as to pose a hazard to health during transportation, or in the absence of adequate data on human toxicity, is presumed to be toxic to humans because when tested on laboratory animals it has an LC50 value of not more than 5000 ml/m3.

Class 3: Flammable Liquids

A flammable liquid means a liquid which may catch fire easily or any mixture having one or more components whith any flash point. As example: acetone, diesel, gasoline, kerosene, oil etc. Transportation is strongly recommended at or above its flash point in a bulk packaging. There are three main groups of flammable liquid.

1. Low flash point – liquids with flash point below -18°C

2. Intermediate flash point – liquids with flash point from -18°C. up to +23°C

3. High flash point group – liquids with flash point from +23°C

Class 4: Flammable solids or substances

Subclass 4.1: Flammable solids

For the purpose of this Code, flammable solids means readily combustible solids and solids which may causefire through friction.

Subclass 4.1: Self-reactive substances

Self-reactive substances are thermally unstable substances liable to undergo a strongly exothermic decomposition even without participation of oxygen (air).

Subclass 4.1: Solid desensitized explosives

Solid desensitized explosives are explosive substances which are wetted with water or alcohols or are diluted with other substances to form a homogeneous solid mixture to suppress their explosive properties.

Subclass 4.1: Polymerizing substances and mixtures (stabilized)

Polymerizing substances are substances which, without stabilization, are liable to undergo a strongly exothermic reaction resulting in the formation of larger molecules or resulting in the formation of polymers under conditions normally encountered in transport. Explosives included under class 1 however deactivated or substances specially included under this class by the producer.

Subclass 4.2: Substances liable to spontaneous combustion

Subclass 4.2: Comprises

1 Pyrophoric substances, which are substances, including mixtures and solutions (liquid or solid), which, even in small quantities, ignite within 5 minutes of coming into contact with air. These substances are the most liable to spontaneous combustion; and 2 Self-heating substances, which are substances, other than pyrophoric substances, which, in contact with air without energy supply, are liable to self-heating. These substances will ignite only when in large amounts (kilograms) and after long periods of time (hours or days).

Subclass 4.3: Substances which, in contact with water, emit flammable gases

For the purpose of this Code, the substances in this class are either liquids or solids which, by interaction with water, are liable to become spontaneously flammable or to give off flammable gases in dangerous quantities.

Class 5: Oxidizing substances and organic peroxides

Subclass 5.1: Oxidizing substances

Substances which, while in themselves not necessarily combustible, may, generally by yielding oxygen,cause, or contribute to, the combustion of other material. Such substances may be contained in an article.

Subclass 5.2: Organic peroxides

Organic substances which contain the bivalent –O–O– structure and may be considered derivatives of hydrogen peroxide, where one or both of the hydrogen atoms have been replaced by organic radicals. Organic peroxides are thermally unstable substances which may undergo exothermic self-accelerating decomposition.

Class 6: Toxic and infectious substances

Subclass 6.1: Toxic substances

Toxic substances which are able to cause death or serious hazard to humans health during transportation.

Subclass 6.2: Infectious substances

These are substances known or reasonably expected to contain pathogens. Pathogens are defined as microorganisms (including bacteria, viruses, rickettsiae, parasites, fungi) and other agents such as prions, which can cause disease in humans or animals.

Class 7: Radioactive material

Radioactive material means any material containing radionuclides where both the activity concentration and the total activity in the consignment exceed the values specified in 2.7.2.2.1 to 2.7.2.2.6.

Class 8: Corrosive substances

Class 8 substances (corrosive substances) means substances which, by chemical action, will cause severe damage when in contact with living tissue or, in the case of leakage, will materially damage, or even destroy, other goods or the means of transport.

Class 9: Miscellaneous dangerous substances and articles and environmentally hazardous substances

Substances and articles (miscellaneous dangerous substances and articles) are substances and articles which, during transport, present a danger not covered by other classes.

• Substances which, by inhalation as fine dust, may endanger health

• Substances evolving flammable vapour

• Lithium batteries

• Life-saving appliances

• Capacitors

• Substances and articles which, in the event of fire, may form dioxins

• Substances transported or offered for transport at elevated temperatures

• Environmentally hazardous substances

• Genetically modified microorganisms (GMMOs) and genetically modified organisms (GMOs)

Other substances or articles presenting a danger during transport, but not meeting the definitions of another class.

Batteries role in stable energy supply and their storage

Balancing power supply and demand is always a complex process. When large volumes of renewables such as solar PV, wind and tidal energy, which can change abruptly with weather conditions, are integrated into the grid, this balancing process becomes even more difficult.

Energy storage can be a valuable resource for the power system in maximising the efficient use of this resource, and add flexibility for electric utilities. Effective energy storage can match total generation to total load precisely on a second by second basis. It can load-follow, adjusting to changes in wind and solar input over short or long time spans, as well as compensating for longterm changes. While fossil plants may take 10 minutes or more to come online, and will consume fuel even on "spinning reserve" standby, storing renewable energy for later use effectively produces no emissions.
 If you have some terrain resp. altitude difference and some water in the vicinity of the generation facility and cheap labor you will be better off pumping water to a reservoir for energy storage. Pump storage is not particularly efficient unless you are talking about MWs.
Ultracapacitors (or supercapacitors) store energy electrostatically by polarising an electrolyte, rather than storing it chemically as in a battery. Ultracapacitors have a lower energy density but a higher power density than standard batteries: they store less energy (around 25 times less than a similarly sized li-ion battery) but can be charged and discharged more rapidly. Although ultracapacitors have been around since the 1960s, they are relatively expensive and only recently began being manufactured in sufficient quantities to become cost-competitive. Ultracapacitors have applications in 'energy smoothing', momentary-load devices, vehicle energy storage, and smaller applications like home solar energy systems where extremely fast charging is a valuable feature.

Batteries have their uses. They are relatively inexpensive, relatively easy to maintain, but if your requirement is a constant load such as database centers or factories, then batteries are not valid UPS sources. If you only need occasional power, then batteries are ok.

Invented in 1859, lead-acid batteries use a liquid electrolyte and are still in common use. They store rather small volumes of energy but are reliable and, above all, cheap. In renewable energy systems multiple deep-cycle lead-acid (DCLA) batteries, which provide a steady current over a long time period, are connected together to form a battery bank.

Several types of batteries are used for large-scale energy storage. All consist of electrochemical cells though no single cell type is suitable for all applications.
In a dry cell battery, the electrolytes are contained in a low-moisture paste. Lithium-ion (li-ion) batteries in particular are the subject of much interest as they have a high energy density, and larger-scale production due to emerging electric vehicle applications is expected to bring down their cost significantly.

Lead acid is the old standby with a proven track record though and is the most used option. Lead acid battery is the popular one that people are using in solar system. Of course, Li-ion or LiFePO4 (and others) battery can be used as well. At this moment, however, performance-price ratio wise, lead acid battery is the best one now. Even in lead acid battery, there are still different technologies. tubular one is like normal flooded lead acid battery, which requires a battery maintenance every 6-8 months. And this battery is also quite popular in India. It's cheap comparing with Gel and AGM lead acid battery. Gel and AGM batteries are maintenance free during the life time. with better performance on deep discharge. If you only have low power consumers you might try lead acid, lithium might be to expensive and your facility to small for flow batteries

Check into Lithium Iron Phosphate batteries. Less impact on the environment (Do not contain Mercury and any heavy metal that do harm to enviromental and human beings).

At today's situation LiFePO4 is a good option. More expensive initially but more cost effective over its life. With LIFEPO4 you would have more cycles but also calendaric lifespan and temperature problems, so really a lot depends on the circumstance. I would also think in alternatives like potential energy if feasible. LiFePO4 batteries can handle wide working temperature (-20°C--60 °C) much better than other. Long-lasting technology: lithium-ion batteries last three times longer than lead-acid batteries.
The advantage of lithium-ion batteries compared to lead-acid batteries is their greater storage capacity and energy density along with low weight and, above all, their long life.The high peaks and extreme loads placed on the accumulator would cause lead-acid batteries to quickly run down. A typical lead-acid battery has a maximum life of 2,000 cycles, In contrast, lithium-ion batteries last around 7,000 complete cycles. For a typical household this would represent more than 20 years - as long as the solar module itself. Lithium-ion batteries are also 50 to 80 per cent less likely to self-discharge and have much higher cycle efficiency, meaning fewer losses and more output for the user."

Lithium batteries. Flat plate (automotive) wet cells are rated for C20 discharge. Tubular (traction) batteries are rated for C10 discharge but can be discharged at higher rate, but the effective capacity decreases. However, LiPO4 batteries can be charged and discharged at C3 and even C1 rate and the loss of capacity is much lower. They can also be discharged down to 80% without significant loss of life and can operate at higher temperatures. They have a flatter characteristics compared to lead acid.

One technology that is now attracting considerable interest is large-scale battery storage.

Vanadium Redox Batteries (VRBs) are a particularly clean technology, with high availability and a long lifecycle. Their energy density is rather low - about 40 Wh per kilogram - though recent research indicates that a modified electrolyte solution produces a 70 percent improvement in energy density. Vanadium prices are volatile, though, with the increased demand for battery use likely to stress supply.

Flow batteries are emerging energy storage devices that can serve many purposes in energy delivery systems. They can respond within milliseconds and deliver significant quantities of power. They operate much like a conventional battery, storing and releasing energy through a reversible electrochemical reaction with an almost unlimited number of cycles. The active chemicals are stored in external tanks, and when in use are continuously pumped in a circuit between the reactor and tanks. The great advantage is that electrical storage capacity is limited only by the capacity of the tanks. Flow batteries have existed for some time, but have used liquids with very low energy density (the amount of energy that can be stored in a given volume). Because of this, existing flow batteries take up much more space than fuel cells and require rapid pumping of their fluid, further reducing their efficiency. 

Molten salt batteries (or liquid sodium batteries) offer both high energy density and high power density. Operating temperatures of 400-700°C, however, bring management and safety issues, and place stringent requirements on the battery components.

Researchers at Case Western Reserve University are using iron to create a scalable energy storage system that can service a single home or an entire community. Robert Savinell, professor of chemical engineering at Case Western, calls it the rustbelt battery. Since the cost of iron is as little as 1 percent of that of vanadium, the iron-based battery is estimated to cost US$30/kWh, well below a $100/kWh goal set by Sandia National Laboratories. A large-scale 20-MWh iron-based flow battery would require two storage tanks of about 250,000 gallons (950 m³), and could supply the power needs of 650 homes for a day.

Estimating Size For A Solar System

Rooftop Solar Panel array at the Kuppam i-Community Office (Photo credit: Wikipedia)

Sizing a system includes the following steps:-

Step 1 Estimating Electric Loads

Qty X Volts X Amps X Hours(h) = Watts(W) X Hourss (H) = Watt- Hour(WH)

Step2 Sizing & Specifying Batteries

BC ={(Power of the appliance X Working time)/System Volatage} X Consecutive rainy days X System safety factor (1.4-1.8)

Step3 Sizing and Specifying an solar array

Power of the solar module= {(Power of the appliance X Working time)/System Voltage} X Attrition factor(1.6-2.0)

Step 4 Specifying a controller

The controller must operate a system efficiently while meeting the needs of the user. According to manufacturer's specification. The controller must handle under a short circuit of array and normal working.

Step 5 Sizing and specifying inverter

Calculate the total connected watts, determine the maximum surge watts required. The choosing inverter should meet the system's wattage specifications, budget, and other requirements.

Step 6 Sizing System Wiring

System wiring should be designed to endure system current, minimize voltage drop, meet safety codes, and provide protection from environment.

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Photo voltaic Technology

Scientists have known of the photovoltaic effect for more than 150 years. Photovoltaic power generation was not considered practical until the arrival of the space program. Early satellites needed a source of electrical power and any solution was expensive. The development of solar cells for this purpose led to their eventual use in other applications.

DISCOVERY AND DEVELOPMENT OF PHOTOVOLTAIC POWER

The photovoltaic effect has been known since 1839, but cell efficiencies remained around 1% until the 1950s when U. S. researchers were essentially given a blank check to develop a means of generating electricity onboard space vehicles. Bell Laboratories quickly achieved 11% efficiency, and in 1958, the Vanguard satellite employed the first practical photovoltaic generator producing a modest one watt.

In the 1960s, the space program continued to demand improved photovoltaic power generation technology. Scientists needed to get as much electrical power as possible from photovoltaic collectors, and cost was of secondary importance . Without this tremendous development effort, photovoltaic power would be of little use today.

Early photovoltaic development

YEAR	DEVELOPMENT
1839	Antoine-César Becquerel, a French physicist, discovered the photovoltaic effect. In his experiments he found that voltage was produced when a solid electrode in an electrolyte solution was exposed to light.
1877	W.G. Adams and R.E. Day observed the photovoltaic effect in solid selenium. They built the first selenium cell and published “The action of light on selenium,” in Proceedings of the Royal Society.
1883	Charles Fritz built what many consider to be the first true photovoltaic cell. He coated the semiconductor selenium with an extremely thin layer of gold. His photovoltaic cell had an efficiency of less than 1%.
1904	Albert Einstein published a paper on the photoelectric effect .
1927	A new type of photovoltaic cell was developed using copper and the semiconductor copper oxide. This device also had an efficiency of less than 1%. Both the selenium and copper oxide devices were used in applications such as light meters for photography.
1941	Russell Ohl developed the silicon photovoltaic cell. Further refinement of the silicon photovoltaic cell enabled researchers to obtain 6% efficiency in direct sunlight in 1954 .
1954	Bell Laboratories obtained 4% efficiency in a silicon photovoltaic cell. They soon achieved 6% and then 11%.
1958	PV cells were first used in space on board the Vanguard satellite.

CONVERTING SUNLIGHT TO ELECTRICITY

A typical photovoltaic cell consists of semiconductor material (usually silicon) having a pn junction as shown in figure

Sunlight striking the cell raises the energy level of electrons and frees them

from their atomic shells. The electric field at the pn junction drives the electrons into the n region while positive charges are driven to the p region. A metal grid on the surface of the cell collects the electrons while a metal back-plate collects the positive charges.

POWER OUTPUT AND EFFICIENCY RATINGS

The figures given for power output and efficiency of photovoltaic cells, modules, and systems can be misleading. It is important to understand what these figures mean and how they relate to the power available from installed photovoltaic generating systems.

Power Ratings

Photovoltaic power generation systems are rated in peak kilowatts (kWp). This is the amount of electrical power that a new, clean system is expected to deliver when the sun is directly overhead on a clear day. We can safely assume that the actual output will never quite reach this value.

System output will be compromised by the angle of the sun, atmospheric conditions, dust on the collectors, and deterioration of the components. When comparing photovoltaic systems to conventional power generation systems, one should bear in mind that the PV systems are only productive during the daytime. Therefore, a 100 kW photovoltaic system can produce only a fraction of the daily output of a conventional 100 kW generator.

Efficiency Ratings

The efficiency of a photovoltaic system is the percentage of sunlight energy converted to electrical energy. The efficiency figures most often reported are laboratory results using small cells. A small cell has a lower internal resistance and will yield a higher efficiency than the larger cells used in practical applications. Additionally, photovoltaic modules are made up of numerous cells connected in series to deliver a usable voltage. Due to the internal resistance of each cell, the total resistance increases and the efficiency drop to about 70% of the single-cell value. Efficiency is higher at lower temperatures. Temperatures used in laboratory measurements may be lower than those in a practical installation.




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