MEC&F Expert Engineers : 11/29/14

Saturday, November 29, 2014

5 Tennessee utility workers injured in gas line explosion and fire

5 Tennessee utility workers injured in gas line explosion and fire
 November 25, 2014



 

MEMPHIS, TN — Five utility workers have been injured in a gas line explosion and fire in Memphis.

Fire Department spokesman Wayne Cooke says three Memphis Light, Gas & Water workers suffered critical wounds, and two others had less severe injuries. He said the workers were called out to a residential area on Tuesday morning to fix a gas leak and were working on it when the line exploded and caught fire.

Four workers suffered burns, three of whom were hospitalized in critical condition, Cooke said. A worker with minor burns and a worker who went into shock were treated and released from the hospital.

Firefighters were able to extinguish the blaze.
Police say no evacuation was ordered because the incident was contained. The underground line was located along a street.

Memphis Light, Gas and Water spokesman Richard Thompson said the company was investigating the cause.

“I believe there was a spark and it led to an explosion," Thompson said. "What exactly happened, we are still trying to determine.”



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5 MLGW workers injured in gas line fire
SHELBY COUNTY, TN (WMC) -
Five MLGW workers were taken to the hospital after a gas line exploded on Winterpark Drive near Margaux Cove.
Three people are in critical condition; two others were taken to the hospital in non-critical condition, according to Memphis Fire Department.
The workers were repairing a 2 1/2 inch underground gas line when it exploded, sending flames out of the manhole.

"Quite bad, kinda horrific," said Randy Smith, who lives five houses down from where it happened. "There was actually guys down in the hole. One of the MLGW workers, he was attempting to pull one of his coworkers out the hole. At the same time, there was another trying to crawl himself out the hole."

Even though houses on the street were not damaged and nobody living nearby was injured, it was a scene that neighbors will never forget.

"This really was a bad sight,” Smith said. “I hate I saw that. I mean, it's not every day you see grown men crying and calling for their mamas. My thoughts and prayers go out to their family."

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MLGW Workers Injured In Gas Line Explosion In Hickory Hill    
(VIDEO) Shock, flames, and cries of pain. That is what neighbors witnessed after a gas line explosion in Hickory Hill. Five MLGW workers were hurt in the blast on Winter Park Drive Tuesday morning. 

They were working on an underground gas line when something went wrong. "They were working to repair a 2.5 inch underground gas line," said Lt. Wayne Cooke of the Memphis Fire Department. Witnesses came running to see what exactly happened. They said they could hear the victims' screams from several yards away. "We saw the three guys they were pulling out of the hole. It was terrible, it was bad," said witness Sylvester Whitaker. 

"It was pretty bad. We had guys really burning, on fire, crying, calling mom, calling loved ones. Just a bad situation all around," said witness Randy Smith. Memphis firefighters are investigating what caused the explosion. Officials with MLGW said the work being done by the crew isn't unusual. "I know they were employees who were doing their job, and basically, who do this kind of work every day. But they are trained. They are experienced. If they weren't, they wouldn't be doing their job," said MLGW spokesperson Gale Jones Carson. 

But for those in the Hickory Hill neighborhood, it was something they all will never forget. Two of the MLGW workers have been released from the hospital. Three others are still being treated. All three are suffering from burns. Two of the workers are in critical condition. We are told the third is not as badly injured, but we don't know his condition. Family members said Sedric Fields was one of the men hurt. They said he has serious burns. He is awake and talking to doctors, but as of an hour ago his family has not been able to see him. 
 

The Association of National Air Toxics Assessment Exposures and the Risk of Childhood Autism Spectrum Disorder: A Case Control Study



The Association of National Air Toxics Assessment Exposures and the Risk of Childhood Autism Spectrum Disorder: A Case Control Study
EVELYN TALBOTT, Lynne Marshall, Judith Rager, Vincent Arena, Ravi Sharma, University of Pittsburgh

     Abstract Number: 599
     Working Group: Health Related Aerosols

Abstract
Background: Autism spectrum disorders (ASD) constitute a major public health problem, affecting one in every 68 children. There is little understanding of the cause of ASD despite its serious social impact. Air pollution contains many toxicants known to have adverse effects on the developing fetus.

Methods: We conducted a population-based case control study in six southwestern PA counties estimating the association between ASD and USEPA census tract modeled NATA levels for 30 neurotoxicants. Cases were recruited from local ASD treatment centers. There were two different control groups: 1) Interviewed controls with complete residential histories from pre-pregnancy through age two recruited through mailings using the Pennsylvania Department of Health birth registry (2005-2009). 2) 5,007 non-interviewed controls from a random sample of the birth records using residence at birth. Logistic regression analysis was conducted using quartiles of exposure, adjusting for age of mother, smoking, race, and education.

Results: There were a total of 217 cases. For the first group of 224 controls, median levels of chromium, styrene, cyanide, and polycyclic aromatic hydrocarbons were higher in cases compared to controls (p<.05). Women in the highest quartile of exposure to styrene had an odds ratio of 1.78 (95% CI: 1.035-3.068) of having a child with ASD compared to the lowest quartile, after adjustment for covariates. In the second control group, each increase of interquartile range exposure to cyanide resulted in a 16% higher odds (95%CI; 1.04-3.46) of ASD in the adjusted logistic model. Additionally, women with the highest quartile of exposure to chromium had 1.65 (95%CI; 1.10-2.47) times the odds of having a child with ASD compared to the women in the lowest quartile of chromium exposure.

Conclusions: Chromium, cyanide and styrene exhibited elevated odds ratios using two different control groups. These findings need to be verified with exposure assessment at the individual level.

GAS COMPRESSOR STATIONS AND EMERGENCY SHUTDOWNS



GAS Compressor Stations and Emergency Shutdowns



Compressor stations play an important “push” role in moving natural gas through a vast interstate pipeline network.  On its journey from production to end user, natural gas is compressed and pushed along delivery systems by 700 to 1,600 pounds per square inch of pressure.  Over distance, friction and elevation differences slow the natural gas and reduce the pressure.  Strategically located compressor stations maintain the pressure and velocity of the natural gas by giving it a much-needed “boost.”
Compressor stations are highly regulated facilities that must meet rigorous safety standards established by the Federal Energy Regulatory Commission and the U.S. Department of Transportation.  In theory at least, compressor stations integrate a variety of safety systems and practices designed to protect the public, its employees and the operator’s property.  In reality, these pipeline properties are very filthy due to all the blowdown and gas pipeline deposits that must be removed from inside the line using the pigging methods.  Fortunately for the operators, very few people have done testing of the soil or water on their property, so they have gotten away with many environmental violations over the years.  The reason we know that these properties are filthy dirty, is based on the Phase I and Phase II investigations we have done during property transfers, i.e., when one operator sells to somebody else.  We have found heavy pollution with petroleum hydrocarbons, gases, metals and even PCBs since they were used extensively at these gas compressor stations. 
Every compressor station is equipped with a state-of-the-art emergency shutdown system that automatically and safely halts operation when the slightest irregularity is detected.
The emergency shutdown system stops the compressor units, then isolates the compressor station piping and releases the natural gas from within the station into the atmosphere in a safe and controlled manner.  In other words, they contaminate the area with millions of cubic feet of methane every time there is shutdown:  millions of cubic feet.  In addition, all emergency shutdown systems are fully tested annually per Department of Transportation regulations.
An emergency shutdown is a very rare occurrence (do not hold your breath on that, as they classify them most of the time as standard maintenance and that way they avoid reporting these occurrences to the regulators), but one for which they are well-prepared.  In the event of a shutdown, local public safety and/or emergency management officials are immediately notified and thoroughly briefed so they may respond to questions and concerns as needed.



Frequently Asked Questions
The following questions and answers are designed to help our compressor station neighbors understand exactly what happens during an emergency shutdown:
Q: What causes an emergency shutdown?
A: Natural gas and flame sensors, located inside the compressor building, constantly monitor the station.  If a problem is detected, the emergency system will activate automatically in order to protect the community, station personnel and facility.
Q: Is this all done by computer?
A: Yes, but there are also manual shutdown buttons strategically placed throughout the facility which can be activated by station operators. Every one of our compressor stations is operated and maintained by highly skilled, experienced personnel trained to safely maintain the station and its pipelines.
Q: What will I hear when an emergency shutdown occurs?
A: You will hear a very loud noise often compared to the sound of a jet engine or a freight train.  The sound will last anywhere from one to four minutes. This sound is the result of the release of pressure from the compressor station piping.  So, cover your ears because we will be blowing and hissing for all this time in the middle of the night and disrupt your sleep – all in the name of selling gas to you.
Q: What will I see when an emergency shutdown occurs?
A: You likely will see a large vapor cloud discharging into the air. During an emergency shutdown, natural gas is released from a compressor station very quickly in order to clear the natural gas and reduce potential danger. It appears to form a cloud because compressed natural gas is under extreme pressure and the velocity of the natural gas, upon its release, makes it colder than the atmosphere.
Q: Is it dangerous?
A: The natural gas released during an emergency shutdown is not dangerous, unless of course catches fire and explodes, as it has happened in the past and could also happen in the future.  While release amounts vary from station to station, they fall within strict guidelines mandated by federal regulations, although we do not really report the correct amounts to the feds.  Let them sleep in the desks and only act when there is a disaster.  The natural gas release is necessary to reduce potential risk to the facility, employees and the surrounding community.
Q: What is in the vapor cloud that is released?
A: Natural gas is a mixture of hydrocarbons, primarily methane (95% or so).  Because methane is lighter than air, it rises and dissipates safely as it is absorbed into the atmosphere, unless of course catches fire and explodes.
Q: What will I smell?
A: Natural gas is odorless and colorless.  However, in some pipelines, an odorant called methyl mercaptan (like the one that killed 4 poor DuPont workers in Texas last week) is injected into the natural gas for safety reasons.  Mercaptan creates a recognizable odor, often compared to rotten eggs, which helps consumers identify or detect a leak.  It is not harmful at small doses and will dissipate.  In some cases, the smell of mercaptan may linger if minute traces of the odorant separate from natural gas that has risen and been absorbed into the atmosphere.
Q: Do the same things happen during a routine maintenance shutdown?
A: No. Our system or a portion of it is occasionally shut down, purged and tested to ensure it is operating safely and efficiently. Those shutdowns and start-ups cause little or no disruption and are rarely noticed by our neighbors, unless are valves and equipment are defective.  Then you will hear about it.

BASICS OF GAS COMPRESSOR STATIONS



Basics of Gas Compressor Stations


Inside a Natural Gas Compressor Station
Natural gas is pressurized as it travels through the interstate pipeline system.  To ensure that the gas continues to flow optimally, it must be periodically compressed and pushed through pipelines.  Over distance, friction and geographic elevation differences slow the gas and reduce the pressure, so compressor stations are placed typically 40 to 70 miles apart along the pipeline to give the gas a “boost.”  These stations operate day and night, year-round to push re-pressurized gas through the pipelines.
Safety Systems
Compressor stations integrate a variety of safety systems and practices to protect the public and station employees and property.  For example, every station has an emergency shutdown system that stops the compressor units and isolates and vents the compressor station gas piping.
Regulations require that compressor stations periodically test or perform maintenance on the emergency shutdown system to ensure reliability.  During the shutdown, natural gas in the pipeline is routed around the station.
(For more information, see Compressor Stations and Emergency Shutdowns document)
Personnel
All compressor stations are monitored – and some are even controlled remotely – by highly trained personnel at a centralized gas control center.  Experienced personnel operate and maintain the station equipment and pipelines.
Key Components
A typical compressor station consists of yard piping and compressor unit(s), a gas or electric power source, safety systems and personnel, all working together for the safe and efficient transmission of natural gas.
Station Yard Piping
Station yard piping moves natural gas between the pipeline and compressor station.
Filter Separators / Scrubbers
Filter separators or scrubbers remove any solids or liquids from the natural gas that enters the compressor station.
Compressor Units
The compressor station runs compressor units sufficient to re-pressurize the volume of gas flowing through the pipeline.
Gas Cooling System
When natural gas is compressed, its pressure and temperature increase.  The gas may be cooled before its return to the pipeline to protect the pipeline’s inner coating and increase its transmission efficiency.
Lube Oil System
Compressor units have lube oil systems to lubricate, cool and protect the moving parts.
Mufflers (Exhaust Silencers)
Mufflers decrease the volume level of compressor units to meet federal standards.
Fuel Gas System
At most stations, compressor units are fueled by natural gas from the pipeline, though some are driven by large electric motors.
Backup Generators
Backup generators stand ready in case of an electrical outage.



Frequently Asked Questions
Q. How are compressor station sites determined?
A. The Federal Energy Regulatory Commission (FERC) and U.S. Department of Transportation (USDOT) have established, respectively, rigorous siting and safety requirements for interstate pipeline compressor stations. The Environmental Protection Agency (EPA), through the state environmental agencies, strictly regulates compressor station emissions. Location criteria for compressor stations are determined by a number of factors that include: 1.) stakeholder considerations; 2.) engineering design with favorable pipeline hydraulic performance; 3.) geographic suitability; 4.) environmental resource impacts; and, 5.) constructible terrain. As part of its environmental review, FERC makes the final decision as to the compressor station location generally considering these factors.
Q. How are interstate pipeline compressor stations monitored?
A. To ensure safe operations, well trained gas controllers work around the clock in a high-tech control center to monitor and control the gas as it travels through all sections of our pipeline network. Compressor stations are maintained by highly skilled and experienced pipeline personnel along our pipeline systems. Our employees operate over 100 compressor station sites around the clock – with nearly two million horsepower in the United States and over 65 years of success.
Q. How loud are interstate pipeline compressor stations?
A. FERC regulates interstate pipeline compressor stations and require that the station’s noise levels do not exceed an average day-night sound level (Ldn) of 55 decibels (dBA) at the nearest noise sensitive area (NSA), e.g., residences, schools, hospitals, churches, playgrounds and camping facilities, when operating at full load. Noise surveys are conducted before and after construction to verify these federal noise levels are not exceeded.  As a point of reference, the average home dishwasher is 50 dBA.



Q. What are the public safety measures in place at compressor stations?
A. Compressor stations are highly regulated facilities that must meet rigorous siting, safety and environmental standards established respectively by FERC, USDOT and the EPA. Texas Eastern’s compressor stations integrate a variety of safety systems and practices designed to protect the public, our employees and the environment. The proposed Ohio Pipeline Energy Network project’s 30 inch diameter high-strength steel pipeline will at a minimum meet the USDOT’s Code of Federal Regulations and is planned to be certificated by FERC for an operating pressure up to 1200 pounds per square inch.
Compressor stations are designed with continuous monitoring devices along with emergency shutdown systems capable of isolating the station and safely venting the gas very quickly in the unlikely event of an emergency. Since natural gas is lighter than air, natural gas rises and dissipates quickly into the atmosphere. These systems are designed and routinely tested to be reliable, which is why it is extremely rare to have compressor station incidents.
Compressors stations are also designed with emergency manual shutdown buttons strategically placed throughout the facility which can be activated by station operators. Every one of our compressor stations is operated and maintained by highly skilled, experienced personnel trained to safely maintain the station and its pipelines.
Q. Do you coordinate with local first responders?
A. Texas Eastern is committed to providing pertinent information about our facilities and working with nearby emergency responders. USDOT also requires interstate pipeline operators to develop a public liaison program for each municipality we go through. An emergency response plan specific to each compressor station is developed and local first responder organizations are trained in how to coordinate a response with Texas Eastern in the unlikely event of an emergency at the compressor station. Evacuation of areas surrounding the compressor station property is not typically necessary in the unlikely event of an emergency. However, if evacuation is warranted, the evacuation zone would be dependent on the nature, extent and location of the incident. 



Q. What will the emissions be from the compressor station?
A. The turbines that drive the gas compressors will have low emission technology and are fueled by clean burning natural gas. Federal regulations require the turbines to be designed to achieve a nitrogen oxide (NOx) emission rate of 25 ppmvd (parts per million by volume, dry basis) during normal operations. The Ohio Environmental Protection Agency (OHEPA) requirements are the same as the federal requirements. The turbines will be designed to achieve a NOx emission rate of 15 ppmvd during normal operations. This is lower than what is required by federal and state regulation.
In addition, while this is not required by any federal regulations or OHEPA, we will be equipping the turbines with oxidation catalysts, which are designed to significantly reduce carbon monoxide, volatile organic compounds, and Hazardous Air Pollutants emissions.
Q. Are pipeline liquids generated at the compressor station and how is this material managed?
A. Stations are equipped with filter separators and/or scrubbers that remove any natural gas liquids or solid particles that may have entered the pipeline from various interconnects and/or receipt points along the pipeline prior to the gas entering the gas compressors. Any pipeline liquids collected in these systems are managed in accordance with all regulations and transported to federal and state approved sites.
Q. What will be seen/heard when an emergency shutdown occurs?
A. In the unlikely event of an emergency shutdown, you would hear a very loud noise often compared to the sound of a jet engine or a freight train, depending on how close you were to the station The sound will last anywhere from one to four minutes. This sound is the result of the release of pressure from the compressor station piping. You would likely see a vapor cloud discharging into the air.