Safety of LPG storage



A gas cylinder or tank is a pressure vessel used to store gases at above atmospheric pressure. High-pressure gas cylinders are also called bottles

Materials


For a detailed discussion about the materials for gas cylinders see pressure vessel.

Design codes and application standards along with the cost of materials dictated the choice of steel with no welds for most gas cylinders, treated to be anti corrosive. There have been some newly developed lightweight gas cylinders from stainless steel and composite materials. Due to the very high tensile strength of carbon fiber, these vessels can be very light, but are much more difficult to manufacture

Regulations and cylinder testing


The transportation of high-pressure cylinders is regulated by many governments throughout the world. Various levels of testing are generally required by the governing authority for the country in which it is to be transported. In the United States, this authority is the United States Department of Transportation (DOT). Similarly in the UK, the European transport regulations (ADR) are implemented by the Department for Transport (DfT). For Canada, this authority is Transport Canada (TC). Cylinders may have additional requirements placed on design and or performance from independent testing agencies such as Underwriter's Laboratory (UL). Each manufacturer of high-pressure cylinders is required to have an independent quality agent that will inspect the product for quality and safety.

Within the UK the "competent authority" — the DfT — implements the regulations and appointment of authorised cylinder testers is conducted by UKAS, who make recommendations to the VCA for approval of individual bodies.

There are a variety of tests that may be performed on various cylinders. Some of the most common types of tests are hydrostatic test, burst test, tensile strength, Charpy impact test and pressure cycling.

During the manufacturing process, vital information is usually stamped or permanently marked on the cylinder. This information usually includes the type of cylinder, the working or service pressure, the serial number, date of manufacture, the manufacture's registered code and sometimes the test pressure. Other information may also be stamped depending on the regulation requirements.

High-pressure cylinders that are used multiple times — as most are — can be hydrostatically or ultrasonically tested and visually examined every few years.[5] In the United States, hydrostatic/ultrasonic testing is required either every five years or every ten years, depending on cylinder and its service. Helium gas cylinders have the highest pressures possible when full, around 1000 atmospheres

 


Safety and standards


It would be safer to have cylinders individually achored in a cool place, rather than chained in a cluster in the sun, as seen here.

Because the contents are under pressure and are sometimes hazardous materials, handling bottled gases are regulated. Regulations may include chaining bottles to prevent falling and damaging the valve, proper ventilation to prevent injury or death in case of leaks and signage to indicate the potential hazards If a compressed gas cylinder tips over, causing the valve block to be sheared off, the rapid release of high-pressure gas may cause the cylinder to be violently accelerated, potentially causing property damage, injury, or death. To prevent this, cylinders are normally secured to a fixed object or transport cart with a strap or chain.

In a fire, the pressure in a gas cylinder rises in direct proportion to its temperature. If the internal pressure exceeds the mechanical limitations of the cylinder and there are no means to safely vent the pressurized gas to the atmosphere, the vessel will fail mechanically. If the vessel contents are flammable, this event may result in a "fireball". If the cylinder's contents are liquid, but become a gas at ambient conditions, this is commonly referred to as a boiling liquid expanding vapour explosion (BLEVE).

Medical gas cylinders in the UK and some other countries have a fusible plug of Wood's metal in the valve block between the valve seat and the cylinder. This plug melts at a comparatively low temperature (70 °C) and allows the contents of the cylinder to escape to the surroundings before the cylinder is significantly weakened by the heat, lessening the risk of explosion.

More common pressure relief devices are a simple burst disc installed in the base of the valve between the cylinder and the valve seat. A burst disc is a small metal gasket engineered to rupture at a pre-determined pressure. Some burst discs are backed with a low-melting-point metal, so that the valve must be exposed to excessive heat before the burst disc can rupture.

The Compressed Gas Association publishes a number of booklets and pamphlets on safe handling and use of bottled gases




Comments

Post a Comment

Mock drill

My Energy Sector

The organization of the electrical sector of a country or region varies depending on the economic system of the country. In some places, all electric power generation, transmission and distribution is provided by a government controlled organization. Other regions have private or investor-owned utility companies, city or municipally owned companies, cooperative companies owned by their own customers, or combinations. Generation, transmission and distribution may be offered by a single company, or different organizations may provide each of these portions of the system India's power sector is one of the most diversified in the world. Sources of power generation range from conventional sources such as coal, lignite, natural gas, oil, hydro and nuclear power to viable non-conventional sources such as wind, solar, and agricultural and domestic waste The electric power industry is commonly split up into four processes. These are electricity generation such as a power stati
Read more

My Emergency Evacuation plan

Emergency evacuation is the urgent immediate egress or escape of people away from an area that contains an imminent threat, an on-going threat or a hazard to lives or property. Examples range from the small scale evacuation of a building due to a storm or fire to the large scale evacuation of a city because of a flood, bombardment or approaching weather system . In situations involving hazardous materials or possible contamination , evacuees may be decontaminated prior to being transported out of the contaminated area Emergency evacuation plans are developed to ensure the safest and most efficient evacuation time of all expected residents of a structure, city, or region. A benchmark "evacuation time" for different hazards and conditions is established. These benchmarks can be established through using best practices, regulations, or using simulations , such as modeling the flow of people in a building, to determine the benchmark. Proper planning will use multip
Read more

My Travel and Early time

Travel is the movement of people between relatively distant geographical locations , and can involve travel by foot , bicycle , automobile , train , boat , bus , airplane , or other means, with or without luggage, and can be one way or round trip. Travel can also include relatively short stays between successive movements A travel documentary is a documentary film , television program , or online series that describes travel in general or tourist attractions without recommending particular package deals or tour operators. A travelogue film is an early type of travel documentary, serving as an exploratory ethnographic film . The genre has been represented by television shows such as Across the Seven Seas , which showcased travelogues produced by third parties, and by occasional itinerant presentations of travelogues in theaters and other venues A horse and buggy (in American English ) or horse and carriage (in British English and American English ) refers to a
Read more