Flammable gases incidents

H Account of accident, dangerous occurrence or flammable gas incident - see note 10... 

A similar incident occurred on a solids drier. Before maintenance started, the end cover was removed, and the inlet line was disconnected. When maintenance was complete, the end cover was replaced, and at the same time the inlet pipe was reconnected. The final job was to cut off the guide pins on the cover with a cutting disc. The atmosphere outside (but not inside) the drier was tested, and no flammable gas was detected. While cutting was in progress, an explosion occurred in the drier. Some solvent had leaked into the inlet pipe and then drained into the drier [19]. 

It is usual to test for the presence of flammable gas or vapor with a combustible gas detector before maintenance, especially welding or other hot work, is allowed to start. The following incidents show what can happen if these tests are not carried out or not earned out thoroughly. Large pieces of equipment or those of complex shape should be tested in several places, using detector heads at the ends of long leads if necessary (see Section 5.4.2 d). 

An incident occurred because area A foreman issued a permit for work to be done on a flow transmitter in a pipeline in area B. Area B foreman issued a permit for grinding in area B. He checked that no flammable gas was present and had the drains covered. He did not know about the work on the flowmeter. A spark set fire to a drain line on the flowmeter, which had been left open. 

On many occasions employees have entered a cloud of flammable gas or vapor to isolate a leak. In the incident described in Section 7.2.1 (d), this was done to avoid shutting down the plant. More often, it has been done because there was no other way of stopping the leak. The persons concerned would have been badly burned if the leak had ignited while they w ere inside the cloud. 

A similar incident occurred in a tank truck used to cany waste liquids. While it was being filled with a nonflammable liquid and the driver was standing on the top, smoking, an explosion occurred, and the manhole cover was thrown 60 m. On its previous Journey the tank truck had carried a waste liquid containing dissolved flammable gas. Some of the gas was left in the tank and was pushed out when it was filled with the next load. For other examples see Reference lO. 

The PSM Rule requires all PrHAs to address "any previous incident which had a likely potential for catastrophic consequences in the workplace," 29 CFR 1910.119(e)(3)(ii). An incident is an unplanned event that may or may not result in injuries and/or loss. For example, an incident might involve a flammable gas leak that does not ignite. An accident, on the other hand, is an unplanned event that actually leads to personal injury, property damage, environmental damage, and/or business interruption losses, such as the ignition of a flammable gas leak resulting in burns and fire damage. 

On October 30, 1998, a flammable gas release led to gas migration to a non-electrically classified Electrical and Instrumentation (E l) Room. The flammable gas was ingested into the exterior heating and ventilation inlet duct. When the 480 volt primary power switch, within the E l room was remotely shut off, an explosion resulted. The E l module explosion led to a subsequent fire in adjacent production buildings. There were no injuries to personnel. The root cause of the incident was determined to be the failure of management systems... 

The effect of overpressure on the surface of a structure depends on its natural frequency. For a detonation wave the incident shock wave will be reflected at a higher level, followed by a rarefaction wave. The magnitudes of the resulting multiplication factors are presented in Ref 5 which should be consulted for further discussion of this and related subjects. Flammable gas explns do not normally give rise to amplified reflection waves. A more recent discussion on the characterization and evaluation of accidental explns was published by Strehlow and Baker (Ref 44a)... 

Sharing the incident details with hundreds of mechanics, chemical process operators, and supervisors within the chemical complex. This training included stressing the proper flammable gas detection strategy. [3]... 

The EPA standard lists 46 flammable materials that are gases at 25°C (77°E) and atmospheric pressure, and 17 Class lA flammable liquids (that have flash points below 22.8°C/73°F and have boiling points below 37.8°C/100°F). This standard requires an evaluation of at least one worst case explosion involving a listed flammable gas, vapor, or liquid and one or more alternative explosions. It may be necessary to evaluate several possible explosions to determine which of them would give the greatest distance to the endpoint of 1.0 psig overpressure, and this scenario would then be the worst case incident. 

The Flixborough nylon plant accident in the UK (1974) was caused by an open-air explosion of a flammable gas released into the air. It killed the 28 plant employees present and caused extensive property damage in the surrounding area. The failure to perform a full technical assessment of a modification was given as the main cause of the event. The Seveso pesticide plant accident in Italy (1976) is well known for the dangerous release of dioxin due to poor plant safety features and to the underestimation of the possibility of a runaway reaction. The Bhopal incident in India (1984), at another pesticide plant, killed an estimated 4000 (although the total number is still unknown). This disaster was attributed to too large an inventory of toxic substances and to very poor staff attention to the operability of safety features. 

The analysis of 141 Polymer Foam incidents, shows that 12 incidents were foimd to be related with Flammable Gas as burning material. Hence we purchased commercially available Polymer Foam Board (XPS), and then made some experiments to find the evidence of flammable gas, released from the foam block, as the incident records showed. 

In this paper. Lifecycle Physical Hazards of Extruded Polystyrene was extracted based on the Polymer Foam incident information, where the ignition sources were mainly Spark from Welding and Spark from Static Electricity. Regarding Burned Material, 8.5% were based on Flammable Gas. It seems to be released fix>m Polymer Foam, because Non-Flammable Gas is not used anymore, nowadays. 

In 1980s, since Flammable hydrocarbon blowing gas was used only for EPS, when Warehouse Accident happened, there was no possibility of this kind of incident to other Polymer Foam. However, nowadays, due to global warming problem. Flammable Hydrocarbons are used to most Polymer Foams. Hence it is necessary to take care for the Physical Hazards of Flammable Gas in case of handling Polymer Foam Board. 

External fire. May be prompted by flammable gas or vapor liquid, solid, metal, wood, or waste material pyrophoric material and presence of ignition source such as sparks, static, friction, hot spots, welding, lightning, auto ignition, or furnace. Immediate consequence engulfment, thermal radiation, fire damage, smoke, domino effect (where one incident is the primary cause for several other incidents). 

Over the years a considerable amount of knowledge has developed on the means by which the risks can be controlled, so much so that serious incidents arising from electrical ignition are now infrequent. The purpose of this chapter is to explain the principles of the main techniques. The first section covers flammable gas/air mixtures, and later the risks associated with explosions in dust-laden atmospheres are considered. The chapter does not cover the broader issues associated with controlling risk from flammable and explosive atmospheres, such as substituting for non-flammable materials where possible and containing the flammable materials to avoid the formation of an explosive atmosphere the intention is to explain what needs to be done to control the risk of ignition from electrical equipment. 

No one realized, when a site for the furnace was decided, that flammable vapors could come out of the cooling tower. Direct contact condensers are not common, but flammable vapors can appear in many cooling towers if there are leaks on water-cooled heat exchangers. After the incident, a combustible gas detector was mounted permanently between the furnace and the tower (Figure 2-8). 

As vent collection systems normally contain vapor/air mixtures, they are inherently unsafe. They normally operate outside the flammable range, and precautions are taken to prevent them from entering it, but it is difficult to think of everything that might go wrong. For example, an explosion occurred in a system that collected flarmnable vapor and air from the vents on a number of tanks and fed the mixture into a furnace. The system was designed to run at 10% of the lower explosion limit, but when the system was isolated in error, the vapor concentration rose. When the flow was restored, a plug of rich gas was fed into the furnace, where it mixed with air and exploded [17]. Reference 34 describes ten other incidents. 

Incident The loss of containment of material or energy, e.g., a leak of a flammable and toxic gas. 

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