Hydrocarbon fires flash fire

Thermal radiation hazards result from liquid hydrocarbon pool fires, flash fires, turbulent jet fires, and fireballs (BLEVE). A release may be ignited immediately or some time later, and the ignition source may be at the point of release or at a distance downwind, as shown in Figure 2.2. Gas venting... 

Mixing cellulose esters in nonpolar hydrocarbons, such as toluene or xylene, may result in static electricity buildup that can cause a flash fire or explosion. When adding cellulose esters to any flammable Hquid, an inert gas atmosphere should be maintained within the vessel (132). This risk may be reduced by the use of conductive solvents in combination with the hydrocarbon or by use of an antistatic additive. Protective clothing and devices should be provided. 

Mathematical estimates are available that can calculate the flame and heat effects (i.e., size, rate and duration) for pool, jet and flash hydrocarbon fires. These estimates are based on the "assumed" parameter of the material release rate. To some extent, the ambient wind speed also has a varying influence. 

Industry literature typically cites concern with open air explosions when 4,536 kgs (10,000 lbs.) or more of flammable gas is released, however, open air explosions at lower amounts of materials are not unheard of. When the release quantity is less than 4,536 kgs (10,000 lbs.), a flash fire is usually the result. The resulting fire or explosion damage can cripple a hydrocarbon processing facility. Extreme care must be taken to prevent the release of hydrocarbon from vessels resulting in vapor releases and resultant blast overpressure. Measures such as hydrotesting, weld inspections, pressure control valves, adequate pressure safety valves, etc., should all be prudently applied. 

Because of the large amount of heat release from combustion, gas explosions always involve high temperature rise. For example, the maximum flame temperatures for hydrogen and methane are 2045°C and 1875°C, respectively.f l Even for weak deflagrations in fuel-lean mixtures near the LFL, the flame temperatures of hydrocarbons are in the range of 1300-1350°C (p. 330 in Ref9 (). This is why even weak deflagrations such as flash fires can cause severe burn injuries. 

Though there do not seem to be any generally available technical reports, there are genuine stories of explosions and burn accidents caused by the inadvertent formation and subsequent decomposition of hydrates of hydrocarbons in railway tank cars in the cold climate of Canada. Incidents occurred due to the practice of washing empty tank carr following their use for transporting liquid hydrocarbons. In a cold winter climate, it is possible to form hydrates with small amounts of hydrocarbon residues, which later decompose when the tank car warms up, e.g., when exposed to sunshine. For example, the clathrate hydrate of isobutene (2-methyl-propene, b.p. -6.9" C) needs only 1.12 bar at 273 K to be stable. Precautions were not taken around such nominally clean and empty tankers, and exposure to sparks or naked flames led to flash fires and explosions. While the main content of the tankers was butane, other hydrocarbons were present. In another kind of industrial accident, a worker was killed by H2S gas liberated from H2S hydrate residue in a heavy water production plant, during a shutdown for maintenance. 

Precaution Combustible solid powd. material may form explosive dust-air mixts. incompat. with strong oxidizers mixing in a nonpolar hydrocarbon can cause static buildup which can cause flash fire Hazardous Decomp. Prods. Combustion prods. CO2, CO FIMIS Flealth 0, Flammability 1, Reactivity 0 Storage Keep container closed CAP-482-20 [Eastman]... 

In a deflagration the flammable mixture burns relatively slowly. Flame propagation is mainly determined by molecular diffusion and turbulent transport processes. Mixtures of hydrocarbons and air burn in the absence of turbulence, i.e. under laminar or almost laminar conditions, with flame speeds of the order of 5-30 m/s. If there is no confinement this is too slow to produce tangible overpressures and only a flash fire is produced. That is why there is always turbulence involved in a vapour cloud explosion (turbulent flame speeds 100-300 m/s), which increases the rate of combustion and hence the overpressure [12]. 

Engineering and design standards are the first step towards safety, and, if a failure should occur, we protect our workers with the best available personal protective equipment. Given that most of our industry handles flammable hydrocarbons, fire retardant workwear has become standard protective equipment. And it works We have had many case studies from flash fire incidents where injury to workers has been greatly reduced thanks to their fire retardant clothing. .. These same workers can, however, be exposed to other hazards such as hot fluids or steam. There is adequate protective clothing for these hazards as well, but protection might not yet be adequate where workers are exposed to these multiple hazards within the same job. .. They need PPE that will protect from both. 

CAN/CGSB-155.20-2000. Workwear for protection against hydrocarbon flash fire. Ottawa Canadian General Standards Board 2000. 

This Webcast will discuss the recent advances in protective performance testing of flame resistant clothing, focusing on new groundbreaking research on the duration and energy of actual hydrocarbon flash fires outdoors. This research was able to quantify how long these events last and how much energy they release, and HD video of the work will be used extensively. 

The second section covers the largest and most comprehensive hydrocarbon flash fire burn series ever conducted at an independent lab. This testing ran for 4 years atthe University of Alberta, and involved several hundred flash fires. An instrumented manikin predicted extent, severity and location of any resultant body burn injury, allowing detailed analysis of protective performance. Most major FR fabric types and weights were examined at multiple exposure levels, including meta-aramids, meta-aramid/rayon blends, FR cottons, FR cotton/polyamide blends. Polybenzimidazole and its blends with para-aramid and para-aramid/rayon, disposables, outerwear, and more. Extensive video coverage accompanies the data, and post-exposure garment samples will be shown as well. 

According to OSHA, there is a lower potential for flash fires during rig-up and drilling operations that have not reached gas and hydrocarbon-producing zones. The potential for flash fires increases when the drilling process hits formations or zones of hydrocarbons and gas. 

Potential exposures to flash fires occur when drilling accesses an active gas or hydrocarbon zone because the pressure from underground gas or hydrocarbon could kick the well fluids up the hole to the drilling rig floor or platform. If this kick is not contained or controlled by the blowout preventers (BOP) or rig engineering controls, there is a high potential of flash fire due to the presence of ignition sources on or in the vicinity of the drilling platform. 

A potential for flash fire exists once active gas or hydrocarbon zones are reached. Appropriate FRC shall be worn by exposed employees working on the well site prior to drilling into identified gas or hydrocarbon zones. CSHOs should verify that employees are wearing FRC in advance of reaching such zones. 

The next simplest ether is the ether with the simplest alkane as one of the hydrocarbon backbones and the next alkane, which is methyl ethyl ether. Its molecular formula is CH3OC2H5. It is a colorless gas with the characteristic ether odor. It has a flash point of 31 °F, and an ignition temperature of only 374°F. This property, of course, makes it an extreme fire and explosion hazard. 

---