Category: General
HAZOP Study- A primer for technical professionals
Miami, Jan 29, 2011 – This article will present some information about HAZOP (acronym that stands for Hazard and Operability Study) that is used in process plants such as Oil and Gas facilities, chemical plants, power plants and similar installations, to assess the safety aspects of the plant and related facilities.
If you would like a more detailed coverage and training related to HAZOP, you can download the HAZOP Training Course from here.
HAZOP is a technique that started out circa 1960s as “efficiency” studies in ICI (Imperial Chemical Industries) in the UK. At that time it was the rage to do efficiency and productivity studies on various operations in different kinds of industries (it was the golden era of Industrial Engineering) and some bright spark decided to try it out on a spanking new design of a phenol plant was on the design board.
Well, he opened a can of worms, as it were, because the efficiency improvement study found several holes in operational safety as well and the technique of HAZOP was born. Inititally it was confined only to ICIs internal departments, but later on it spread via conferences and papers to other companies as well and soon became an established safety technique.
The Bhopal incident that happened two decades later was a wake up call to the global chemicals and process industries and HAZOP began to be used not only for new plants at the design stage but also for older plants, modifications, shutdowns and turnarounds and so on. The process not only improved Safety but also operational ease.
In the typical HAZOP methodology, a plant or a subsystem of the plant (called a node) is chosen for study. Then all deviations are studied against the original intentions and permutations and combinations give rise to possibilities that can result in accidents. These are then assessed to modify the design or the workflow, so that the process becomes safer. Of course there is much more to this and it requires training in the technique plus a few real life HAZOP studies to really master the technique.
Today one cannot think of not using HAZOP in a process plant, it has become ubiquitous. However being subjective, the result of the HAZOP study depends greatly on the people that comprise the team carrying it out and a bad HAZOP from a bad team results in the plant being even more unsafe than had there been no HAZOP at all! As we always say, incompetence is worse than malfeasance, because malicious people will behave in certain predictable ways, but incompetent people can be incompetent and stupid in several ways that can never be thought of by the rest of humanity. So it is very important that only trained and competent people are in charge of HAZOPs.
CSB Board Member Mark Griffon Calls on American Society of Mechanical Engineers to Adopt CSB Recommendation Prohibiting Natural Gas Blows at Power Plants
Phoenix, Arizona, September 21, 2010—U.S. Chemical Safety Board (CSB) Member Mark Griffon today called on the American Society of Mechanical Engineers (ASME) to adopt a CSB recommendation calling for natural gas blows to be prohibited during power plant construction.
————-Advt——————
For excellent training programs on Gas Detectors, Hazardous Area Instrumentation and Safety Instrumented Systems please click here
————————————————–
The recommendation was one of 18 urgent recommendations issued in June 2010 following a CSB investigation into a powerful natural gas explosion that killed six workers and injured dozens of others at the Kleen Energy plant in Middletown, Connecticut on February 7, 2010, which was under construction. Workers used hundreds of thousands of cubic feet of natural gas to clean debris from gas pipes used to fuel electricity-producing turbines. The gas accumulated in and around the buildings, was ignited by an unknown ignition source, and exploded.
Speaking to a meeting of ASME members in Phoenix who are considering changes to the ASME Code for Pressure Piping Systems, Mr. Griffon said, “The CSB believes that using natural gas or other flammable gases to clean fuel gas piping is inherently unsafe and should be prohibited.” He cited other accidents to show that explosions resulting from flammable gas blows have the potential of causing death, serious injuries, and costly property damage.
Mr. Griffon noted that the practice of using gas blows, or forcing large volumes of flammable gas through piping to clear out debris, was common in construction of electric generating facilities. The CSB investigation of Kleen Energy, resulting in 18 urgent recommendations, states “From a fire and explosion perspective, releasing large volumes of natural gas in the vicinity of workers or ignition sources is inherently unsafe.”
In remarks prepared for the ASME, which is considering the CSB recommendation to prohibit gas blows and use inherently safer methodologies to clean piping, Board Member Griffon said, “It has been argued that the gas blow at Kleen Energy was not conducted properly to ensure the dispersion of the released natural gas and to prevent the gas from encountering ignition sources. This point overlooks the simple fact that cleaning piping with flammable gases presents an inherent explosion hazard. Cleaning piping with flammable gases presents an explosion hazard that cannot be wholly eliminated.”
Even if every effort is made to eliminate ignition sources, such as welding, or electrical equipment not rated for a hazardous environment, he noted, the friction of the gas flowing through the piping can cause an accumulation of static electricity and cause ignition; in addition, sparks from impacts of metal debris striking surfaces when the gas exits the piping can also ignite the gas.
Mr. Griffon noted the CSB investigation found ample alternatives to gas blows which are safer. These methods include blowing air or nitrogen through piping, or by “pigging,” in which a cleaning device is propelled through the pipe using air.
Board Member Griffon noted that that some in industry have already eliminated gas blows. He said that a representative of General Electric, a major gas turbine manufacturer, stated at the CSB public meeting in June that his company greatly discourages gas blows and did not know of any situation where using gas to clean pipes was necessary. The company official said GE wants to “make gas blows something that will not happen again under GE’s watch.” GE also expressly prohibits its own employees from being on site if one of its customers chooses to conduct a blow with natural gas.
Since the public meeting, several other major turbine manufacturers also have reported to the CSB that they already have, or intend to soon develop, guidance that strongly advises their clients away from the practice of natural gas blows.
CSB gets a new Chairman Dr. Rafael Moure-Eraso-former Chairman John Bresland to continue as board member
June 25, 2010-Dr. Rafael Moure-Eraso has been confirmed as the new Chairman of the U.S. Chemical Safety Board. Former Chairman Mr. John Bresland will continue on the board as a member until he completes his five year term. Additionally, Mr. Mark Griffon has been also appointed to the board as a member.
A part of the statement from the CSB is given below:
Dr. Rafael Moure-Eraso Confirmed and Appointed as New Chairman and Mark Griffon as Board Member of the U.S. Chemical Safety Board
Washington, DC, June 25, 2010 – Dr. Rafael Moure-Eraso has been confirmed and appointed as the new chairman of the U.S. Chemical Safety Board (CSB), the agency announced today; Mr. Mark Griffon has been appointed as a new board member, filling the other vacancy on the Board.
The new chairman and board member were nominated by President Obama on March 22, 2010. They were discharged from the Senate Environment and Public Works Committee on June 17 and confirmed by the full Senate on June 23. They were appointed and commissioned by the president the following day.
Outgoing Chairman John Bresland said, “I greatly look forward to working with the new appointees; their diverse backgrounds and deep dedication to workplace safety will serve as an invaluable resource for the board as we enter a time of profound challenge and opportunity.”
Mr. Bresland has now stepped down from the chairman position but will continue to serve as a board member for the remainder of his five-year term, which runs through March 2013.
Dr. Moure-Eraso has until now served as Chair and Head of the Department of Work Environment, School of Health and Environment, University of Massachusetts, Lowell. He has 30 years of experience in workplace safety issues and is a certified industrial hygienist. He received a bachelor’s degree in chemical engineering from the University of Pittsburgh and a master’s degree in chemical engineering from Bucknell University. He received a Ph.D. from the University of Cincinnati in Environmental Health-Industrial Hygiene.
Mr. Griffon has been working as a consultant in the environmental and occupational health field for 18 years. Mr. Mark Griffon is also a member of the Federal Advisory Board on Radiation and Worker Health under the Energy Employees Occupational Illness and Compensation Program Act (EEOICPA). Mr. Griffon holds a B.S. in Chemistry from Rensselaer Polytechnic Institute and an M.S. in Radiological Sciences from University of Massachusetts.
Both new appointees will participate in the CSB’s upcoming public meeting to release urgent recommendations from the Kleen Energy investigation on Monday, June 28, 2010, at 6:30 pm in Portland, Connecticut. Dr. Moure will preside at the meeting.
CSB releases report on power plant safety violations after Kleen energy explosion
Pipe Cleaning Practices that Led to Kleen Energy Explosion Are Common Across Gas Energy Industry, Survey Data Show
CSB Public Meeting Planned Next Month in Connecticut to Consider New Safety Recommendations
Washington, DC, May 19, 2010 – The practice of using flammable natural gas to clean power plant piping, which led to the fatal explosion at Connecticut-based Kleen Energy on February 7, has been commonly used across the gas-fired power generating industry, CSB investigators said today.
—————advt—————————————-
For an excellent training course on Hazardous Areas that cover Hazardous Area Instrumentation including Intrinsic Safety and Area Classification, please click here.
——————————————————————-
The explosion, which killed six workers and injured at least 50 others, occurred during a “gas blow” – a plannedExample of a gas blow. Note: this photo was not taken at Kleen Energy effort to clean out new fuel-gas piping leading to combustion turbines by directing high-pressure natural gas through the pipes and out of vents located near ground level, adjacent to the power generation building. The gas accumulated above the lower explosive limit and ignited, causing massive damage to the new billion-dollar facility, which was nearing completion.
The ignition source for the blast has not been determined. CSB investigators said the construction site had many possible ignition sources, and that gas blows could also self-ignite if debris ejected from piping impacted other objects nearby, creating sparks – adding to the risk of the practice.
The plant was designed to use a “combined cycle” to efficiently generate electricity. In this type of facility, natural gas is combusted to drive massive turbines, and then residual heat is recovered from the exhaust gases to produce additional power through the use of steam turbines. Newly constructed pipes frequently have debris and other contaminants that can damage gas turbine blades, necessitating some form of pipe cleaning prior to start-up.
CSB investigators will present the new findings, derived from a survey of 62 representatives from the combined-cycle gas power industry, at professional society meetings in Maryland and Connecticut this week. Thirty-nine survey respondents (63%) indicated their companies had at some time used flammable natural gas to blow out piping. Only one of those 39 respondents said a flare was used to safely combust the gas prior to venting to the atmosphere.
According to the survey, using natural gas to clean pipes remains the most common single practice in industry, employed by 37% of respondents. The other respondents reported using nitrogen, which is nonflammable, or inherently safer alternatives such as air, steam, or cleaning pigs. On February 25, 2010, eighteen days after the explosion at Kleen Energy, the CSB stated that natural gas blows were “inherently unsafe” and urged industry to seek alternatives.
“The industry survey confirms that there are readily available safe alternatives to using flammable natural gas for pipe cleaning,” said CSB Investigator Dan Tillema, P.E. “At the same time, a disturbing number of companies continue to use natural gas which creates the serious risk of a fire or explosion.”
“Venting any significant amount of natural gas into a workplace is an open invitation to disaster,” said CSB Chairman John Bresland. “With more than 120 new gas power plants slated for completion in the next five years, there is an urgent need to ensure safety during the construction and maintenance of gas piping. The CSB will be considering recommendations to promote safer practices in industries that use natural gas as fuel.”
In February 2010, the CSB issued urgent safety recommendations to the National Fire Protection Association (NFPA) to prohibit indoor venting of natural gas during purging operations within the national fuel gas code, known as NFPA 54. However, the explosion at Kleen Energy occurred during outdoor venting of a massive quantity of gas. Power plants are in any case exempt from the national fuel gas code, which is developed and maintained by nongovernmental consensus committees administered by the NFPA and the American Gas Association, an industry group.
Chairman Bresland said he anticipated the CSB would convene a public hearing in Connecticut in late June to consider further recommendations to prevent accidents involving the planned venting of natural gas at workplaces.
The CSB is an independent federal agency charged with investigating serious chemical accidents. The agency’s board members are appointed by the president and confirmed by the Senate. CSB investigations look into all aspects of chemical accidents, including physical causes such as equipment failure as well as inadequacies in regulations, industry standards, and safety management systems.
