Birmingham Public Housing Gas Explosion Research Paper

Imtroduction

Birmingham public housing gas explosion occurred due to gas leakage. The leakage was caused by mechanical damage of the iron cast pipe used for delivering gas. Residents smelled gas leakage, but did not inform the authorities. The odorant used by Alagasco was absorbed in the soil, thereby depleting the smell of the odorant. Mechanical damages of the pipes occurred due to corrosion and mechanical stress exerted by roots. The history of the pipeline at the explosion scene shows that the explosion was related to the pipeline system configuration and installation. However, the evidence, which justifies failures that occurred due to the system configuration become damaged by a blast after the gas explosion, makes it difficult to determine if the gas explosion resulted from gas leakage. However, analysis of the system configuration analysis was not able to justify the cause of the gas explosion. The post-accident test showed that the gas leakage was the primary cause.

Damages and Details of the Gas Explosion

The gas explosion occurred due to the failure of the delivery pipes. The gas explosion occurred on December 17, 2013, in Alabama when natural gas ignited in a two-story duplex (NTSB 2017). The explosion affected the natural gas main pipeline of Alabama Gas Corporation. NTSB (2017) states that the volume of the released gas was 147,000 cubic feet.  The gas pressure was 19 pounds per square inch, but the systems were designed by the manufacturer to hold an allowable maximum compression of 25 pounds per square inch (NTSB 2017). The accident caused three injuries, one death, and damages that amounted to $505,300 in total (NTSB 2017). According to Crowl (2010), damages from explosions occurred due to a blast wave that originated from thermal energy. NTSB (2017) shows that the fire destroyed half of the duplex, unit 80 and unit 79, by damaging the common wall between the two units. The gas explosion blast increased the damage.

Pipeline History

Pipeline history plays a significant role in identifying the cause of the gas explosion in Birmingham Public Housing. Cast iron was used for delivering gas in Marks Village. According to NTSB (2017), two inches diameter pipe delivered gas to units 80 and 79 and the system was installed in 1951. The allowable pressure under the grandfathered rule amounted to 25 pounds per square inch (NTSB 2017). NTSB (2017) states that there existed no historical information on the thickness of the pipes used; however, records show that no pressure testing was conducted during the installation of the gas delivery system since the installation taking place in 1951 did not require pressure testing. Therefore, the history of the pipeline in the region shows how the installation of the delivery system contributed to the gas explosion.

Evidence of Existence of Gas Leakage before Explosion

The region experienced natural gas leakages before the gas explosion occurred.  According to NTSB (2017), residents of units 80 and 79 stated in an interview that they had detected the smell of gas two weeks prior to the gas explosion. The residents made no effort to inform the fire department or Alagasco. NTSB (2017) confirms the lack of cooperation from the residents by proving that no notice was issued. However, the existing evidence shows notification of the fire department concerning the possibility of the natural gas leakage years before the gas explosion. NTSB (2017) indicates that three years prior to the gas explosion Alagasco received gas odor complaints from residents of Marks Village, but not from residents of units 79 and 80. Therefore, there existed a possibility of a gas explosion occurring due to previous failures that were not addressed.

Natural Gas System Examination

Natural gas delivery systems use hard pipes to sustain pressure. The natural gas lines consisted of threaded iron pipes that supplied both units 80 and 79. The investigations conducted by Alagasco show that gas ignition originated in unit 80. NTBS (2017) shows the evidence about the existence of an outside blast that caused front door deformation and the start of the explosion in unit 80. Alagasco’s investigation rejected residents’ opinions that there was prior gas leakage due to the lack of pre-explosion evidence. According to Vodenicharov (2008), pipeline configuration simplifies the geometric analysis of a pipeline failure, but the damages that occur after the failure destroy details used for the identification of the cause. It explains why Alagasco may not have determined the cause of the gas explosion during the emergency response investigations.

Natural gas leakage may be detected easily. Airgas (2017) states that gas companies should use easily detectable odor when supplying natural gas to aid in identifying possible leakages. Odorizing natural gas enables its detection in the air before it reaches one-fifth of its explosion limit (NTSB 2017). NTSB (2017) states that the company used tertiary butyl mercaptan gas as an odorant. The use of the gas poses a limitation due to the ability of the soil to reduce its detectability in the air. Therefore, the soil absorbed tertiary butyl mercaptan gas and depleted the level of odorant of the natural gas. Olenchuk et al. (2016) confirm that the soil absorbed the odorant. NTSB (2017) states that despite Alagasco’s investigations showing the lack of the gas leakage in unit 80, bar hole tests showed the evidence of the gas leakage in Joppa Court that was situated near the explosion scene. The bar hole test and gas odorant provided the evidence of the previous gas leakage.

Gas leakage caused bubbles in standing water. The evidence of the gas leakage was observed by Alagasco’s employees who detected bubbles originating in standing water. A rock wedged between roots of a tree and cast iron caused a crack in the delivery system that was responsible for the gas leakage (NTSB 2017). The investigations conducted after the incident showed the evidence that the gas explosion occurred due to gas leakage. NTSB (2017) states that a 4-inch pipe that penetrated kitchen of unit 80 had gaps, as well as the annulus below the toilet.  Graphite corrosion that makes pipes brittle appeared on cast iron pipes used for post-accident investigation. External stress corrosion results in the breakage of pipes due to the accumulation of moisture on imperfections on the pipe surface. Stein (2016) states that the corroded pipe causes the gas leakage. Corrosion reduces the physical strength of delivery pipes.

Emergency Response

Emergency response involved the use of fire extinguishers and investigation of the gas explosion. The response time after the 911 call amounted to 5 minutes and after 41 minutes fire extinguishers put out structural fire, but not riser fire (NTSB 2017). Alagasco’s technicians did not determine the possibility of gas leakage because riser fire hindered them from inspecting the sewer pipes near unit 80 (NTSB 2017). Riser fire undermined speed and efficiency of the emergency response team. Riser fire prevented firefighters from gaining access to the collapsed units, which resulted in a delay when rescuing possible survivors. BFRS stopped the gas supply to unit 80. However, riser fire continued burning to prevent the formation of a natural gas cloud that could cause possible re-ignition (NTSB 2017). Fire was the major cause of damage in the gas explosion.

Court Ruling on the Gas Explosion Case

According to the Alabama Court’s ruling, the gas explosion occurred due to the failure of the equipment that was used in the gas delivery system and during installation procedures. According to Adams (2014), the death of Tyrennis Mabry and injuries evoked during the gas explosion occurred due to neglect or actions of the corporation responsible for supplying the gas and maintaining the pipes, as well as due to manufactures of the pipes. Old and newly replaced pipeline pipes are fraught to leakage (Tarzia and Fagan 2015). The court blamed Alagasco for not replacing distribution lines, correcting hazardous conditions, and inspecting the delivery system that caused one death and three injuries (Adams 2014). Manufacturers of the delivery pipes became liable for manufacturing defective tools. The facts in the court showed that NTSB recommended gas suppliers to check the age of pipes in 1990 after the gas explosion in Allentown and that Alagasco did not abide by these recommendations (Adams 2014). Besides, Alagasco had to deal with lawsuits regarding environmental contamination.

Conclusion

Gas leakage caused the explosion in unit 80. The causes of the failure were related to corrosion of delivery pipes and mechanical damage because of roots. The history of the pipeline showed that the pipes were not tested for pressure. The maximum allowable pressure of 25 pounds per inch was not proved. Therefore, the gas leakage may have occurred due to errors in the process of installing of the pipes in 1951. The residents were not able to smell the odorant because the soil absorbed most of it. According to the court ruling, manufacturers of tools used during installation, Alagasco, and people responsible for the system maintenance were found guilty. Putting out structural fire took 41 minutes, but riser fire hindered the emergency team from conducting rescue in time. The inspection was not conducted on the pipes during the installation. The total damages amounted to $505,300. Moreover, one person died and three persons suffered injuries because of the explosion. The residents claimed that they had felt the presence of gas odor before the explosion. However, their ability to smell the gas was affected by the soil that absorbed the gas odorant.

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