http://www.csb.gov/assets/document/CSB_Hot_Work_Safety_Bulletin_EMBARGOED_until_10_a_m__3_4_10.pdf is the document Photo from document
FM Global Data Sheet 10-3, 2006, p. 2-3. OSHA 1910.252 requires moving the hot work or fire hazard to a safe location. This guidance applies to hot work conducted outside of a designated area approved for hot work such as a maintenance shop. If the hot work or hazard cannot be relocated, OSHA requires guards to confine the sources of ignition and the protection of fire hazards. For additional guidance, see NFPA 51B, 2009, p. 51B-6
Job Task – Repair well head Job Step – Weld wellhead Hazard – Buildup of an accumulation of flammable gases, such as Methane or Hydrogen Sulfide, around the wellhead area. Exposure - Welder Control – Require permit to do welding. Verify training in hot works. Monitor the atmosphere with a gas detector continually. Provide H2S badges. If a flammable or combustible gas exceeds 10 percent of the lower explosive level (LEL), the work must be stopped. Provide fire extinguisher with trained fire watch. Identify the source of the gas and repair the leakage. Accident / Incident - Getting burned by a flash fire or explosion
http://www.osha.gov/SLTC/etools/oilandgas/general_safety/hot_work_welding.html has more tips.
What is Combustible Gas Monitoring? Flammable gas and vapor concentrations are generally determined using a portable combustible gas detector, also called an LEL3 meter. Combustible gas detectors are relatively inexpensive and widely available. Training in LEL instrument use is a key component to effective gas testing and is a critical aspect of an effective hot work safety program. MAR Oil La Rue, Ohio, October 19, 2008 2 Workers Killed An explosion killed two contract workers while they were welding above a series of three interconnected crude oil storage tanks at a MAR Oil site. The explosion occurred when the workers attempted to weld a bracket on top of one of the tanks, near an atmospheric vent. Because the tanks were interconnected, oil flowing into an adjacent tank likely displaced flammable vapor into the tank being welded. The vapor escaped through the vent and was ignited by welding sparks. The CSB investigators found that combustible gas monitoring was not performed prior to or during the welding. There is conflicting evidence as to whether or not the welding job was authorized by the host company. MAR Oil lacked a formal hot work program that required the hot work be identified in a written permit and be authorized by a person responsible for hot work management. The company had no formal program to select or oversee contractors, and the two contractors lacked documented training on safe hot work practices
Packaging Corporation of America Tomahawk, Wisconsin, July 29, 2008 3 Workers Killed, 1 Injured Three workers were killed in an explosion at the Packaging Corporation of America (PCA) fiberboard manufacturing facility while they were welding on a temporary metal clamp to stabilize a damaged flange connection. The flange was located on top of an 80-foot tall storage tank that contained recycled water and fiber waste. Facility personnel were unaware of the potential presence of flammable gas from the decomposition of the organic material in the tank, and combustible gas monitoring was not typically required or performed prior to starting work. At the time of the accident, three workers were on a catwalk above the tank; one began welding the flange into place when sparks from the welding ignited flammable vapors inside the tank. The resulting explosion ripped open the tank lid, knocking two of the workers to the ground 80 feet below. All three workers died of traumatic injuries. A fourth worker, who had been observing the work from a distance, survived with minor injuries. The CSB analysis of the tank contents determined that anaerobic bacteria had multiplied inside the tank and water recycle system over time, feeding on organic waste material. The bacteria likely produced hydrogen, a highly flammable gas, which ignited during the welding work. The CSB found that at the time of the incident, PCA supervisors and workers were unaware of the risks of flammable gas production from anaerobic bacteria growth. PCA did not perform a hazard analysis or recognize fiber waste tanks as potentially hazardous. Combustible gas monitoring was not required for the work. TEPPCO Partners, LP Garner, Arkansas, May 12, 2009 3 Workers Killed Three contractors were using a cutting torch on top of the internal floating roof of a 67,000-barrel capacity gasoline storage tank at the TEPPCO Partners McRae Terminal when an internal explosion blew both the top of the floating roof and the secondary dome-shaped lid off the tank. All three were killed. The contractors were preparing to install a gauge pole. The gauge floats within the pole and measures the quantity of product within the tank. Part of the installation process involved cutting an opening into the floating roof for the pole to be inserted. The torch-cutting activity most likely ignited flammable vapor within the tank. Prior to commencing work, the contractors had been issued both a confined space permit to enter the tank and a hot work permit to torch-cut the roof. The hot work permit indicated that gas testing occurred at 7:00 am, the start of the work shift. However, no documentation exists indicating that gas testing was conducted after the workers returned from lunch or when they started the hot work activities just prior to the explosion at approximately 2:30 pm. Work atmospheres can change rapidly; gas monitoring needs to be conducted immediately prior to and during hot work activities to ensure that workers are constantly aware of the potential development of an explosive atmosphere.
Employees need to know when work falls within the scope of this program, and employees involved in hot work need to be trained in the hot work requirements. Employees with fire watch responsibility must be trained to understand the inherent hazards of the work site and of the hot work project, and in the use of their fire extinguishing equipment and alarm notification. 29 CFR 1910.252 (a)(2)(iii) Cutters or welders and their supervisors must be suitably trained in the safe operation of their equipment and the safe use of the process. 29 CFR 1910.252 (a)(2)(xiii)
Philip Services Corporation 14 Kapolei, Hawaii, October 7, 2008 1 Worker Killed, 3 Injured A contract welder was killed while welding on a catwalk located over a 9,300-gallon waste oil storage tank at the Philip Services Corporation (PSC). Following an investigation, the Honolulu Fire Department (HFD) concluded that, during the welding, sparks dropped in and around the vent area of the tank. The contents of the tank ignited, resulting in an explosion and fire. The force of the explosion hurled the contract welder about 120 feet, fatally injuring him. Three others were injured, and the tank was thrown about 30 feet. According to the HFD investigation, a PSC official asserted that the contractors were not authorized to weld within the dike area surrounding the tank, a hot work permit had not been issued for the welding, and combustible gas monitoring was not conducted. Conversely, the contracting company’s personnel asserted that they believed that the work was authorized and that PSC had conducted combustible gas monitoring prior to the welding activity. CSB • Seven Key Lessons to Prevent Worker Deaths During Hot Work In and Around Tanks 5 EMC Used Oil Corporation Miami, Florida, December 2, 2008 1 Worker Killed, 1 Injured An explosion killed a contract welder who was repairing a two-compartment oil tanker and injured another worker at the EMC Used Oil facility. The welder was in the process of welding transfer piping onto the tanker when residual hydrocarbon vapor from the 2,500-gallon rear compartment ignited, causing a powerful explosion. The surviving worker stated that the contractors did not perform combustible gas monitoring and relied upon the host company to assure that tanks were safe for hot work. However, EMC indicated that it relied on contractors to monitor for gas; although the company owned a multiple gas detector, it was used only for confined space entry. EMC did not have a formal hot work permitting or authorization system. Damage to an oil tanker sustained from the December 2, 2008, explosion at EMC Used Oil Corporation.
Eight Killed in Blast at Colombian Power Station <ul><li>CHEC’s director, Bruno Seidel, told the media Thursday that the blast occurred during routine maintenance on a pipe carrying water to the plant. The work consisted of applying rust-coating and other protective treatments to the inside of the pipe, he said. Just as the crew was completing the job, a spark ignited the fumes and triggered an explosion. </li></ul>
CSB <ul><li>The CSB has identified over 60 fatalities since 1990 due to explosions and fires from hot work activities on tanks. </li></ul>
VPP <ul><li>Hot Work Program </li></ul><ul><li>The company’s hot work program consists of an evaluation of whether the work will be open or non-open flame along with the type of location in which the work will be performed, either a hazardous area or a non-hazardous area. After determining those variables, they refer to requirements for issuing the hot work permit in their “Hot Work Permits Requirements Matrix.” For example, the most stringent permit requirements apply in the case of open flame work being performed in a hazardous area, necessitating measures such as a written Risk Assessment Pre-Plan, two management levels of approval, a standby fire watch with fire extinguisher, constant monitoring of the Lower Explosive Limit and/or Oxygen levels, and other appropriate safety measures. </li></ul>
"Hot work" means work involving electric or gas welding, cutting, brazing, or similar flame or spark-producing operations . What is Hot Works?
Seven Hot Works Keys from CSB <ul><li>Use Alternatives </li></ul><ul><li>Analyze the Hazards </li></ul><ul><li>Monitor the Atmosphere </li></ul><ul><li>Test the Area </li></ul><ul><li>Use Written Permits </li></ul><ul><li>Train Thoroughly </li></ul><ul><li>Supervise Contractors </li></ul>
Alternatives <ul><li>Weld in area with no flammable vapors or tanks present. </li></ul><ul><li>Control sparks </li></ul><ul><li>Consider cold cutting (see photo). </li></ul>
Use a Job Hazard Analysis <ul><li>Prior to the initiation of hot work, perform a hazard assessment that identifies the scope of the work, potential hazards, and methods of hazard control. </li></ul><ul><li>Identify each major step of the job task </li></ul><ul><li>List the hazard(s) to each major step </li></ul><ul><li>Determine the control(s) that would prevent an accident for each hazard identified </li></ul>
Job Safety Analysis - Blank form - Copy for use at the workplace Item Work activity Hazard Risk control Persons responsible Completion Number Break the job down into steps What could harm someone? What can be done to make Who will make sure it Date and signoff the job sale? happens?
Analyze for Sources of Ignition <ul><li>Vent pipes </li></ul><ul><li>Where do the sparks go? </li></ul><ul><li>“ Hot work was allowed near tanks that contained flammables including those that had known holes due to corrosion “ </li></ul>
Monitoring <ul><li>Monitor for YOUR hazards </li></ul><ul><li>Gas monitoring needs to be conducted immediately prior to and during hot work activities to ensure that workers are constantly aware of the potential development of an explosive atmosphere </li></ul><ul><li>Monitor continually, record every hour. </li></ul>
Monitoring <ul><li>Calibrate your monitor – ensure the validity of your sensors </li></ul><ul><li>Calibration must occur in clean air </li></ul>
NOTES: Fill out permits! Data must be reentered (minimum) each hour hot work is in progress . Is H2S, CO, or other toxics anticipated? Test the Area RECORD TESTS! Minimum atmospheric entry conditions are: Oxygen - Between 19.5% - 23.0% Combustible - Less than 10% LEL
Sample Permits Part 1 <ul><li>PERMIT APPLIES TO AREA LISTED BELOW: </li></ul><ul><li>Permit Requested By </li></ul><ul><li>Date </li></ul><ul><li>Start Time Stop Time ____________ </li></ul><ul><li>Permit Expires ____________ </li></ul><ul><li>Location </li></ul><ul><li>Description of Work Being Performed </li></ul><ul><li>Before approving any welding and cutting, the Supervisor shall inspect the work area and confirm that the below precautions have been taken to prevent fire. (in accordance with NFPA, No.51B) </li></ul><ul><ul><li>( ) Sprinklers are in service. </li></ul></ul><ul><ul><li>( ) Cutting and welding equipment is in good repair. </li></ul></ul><ul><ul><li>Within 35 Feet of Work </li></ul></ul><ul><ul><li>( ) Floors swept clean of combustibles. </li></ul></ul><ul><ul><li>( ) Combustible floors wet down, covered with damp sand or fire resistive sheets. </li></ul></ul><ul><ul><li>( ) Flammable liquids removed; other combustibles, if not removed, protected with fire resistant tarpaulins or metal shields. </li></ul></ul><ul><ul><li>( ) Explosive atmosphere in area eliminated. </li></ul></ul><ul><ul><li>( ) All wall and floor openings covered. </li></ul></ul><ul><ul><li>( ) Fire resistive tarpaulins suspended beneath work. </li></ul></ul><ul><ul><li>( ) Vent openings for flammable liquid tanks are identified . </li></ul></ul><ul><ul><li>( ) Sources of Combustible dust . </li></ul></ul><ul><ul><li>Work on Walls or Ceilings </li></ul></ul><ul><ul><li>( ) Construction is noncombustible and without combustible covering or insulation. </li></ul></ul><ul><ul><li>( ) Combustibles moved away from other side of wall. </li></ul></ul><ul><ul><li>Work on Enclosed Equipment </li></ul></ul><ul><ul><li>( ) Enclosed equipment clean of all combustibles. </li></ul></ul><ul><ul><li>( ) Containers purged of flammable liquids. </li></ul></ul><ul><ul><li>( ) Organic material in vessels analyzed for potential of generating flammable gas. </li></ul></ul><ul><ul><li>Fire Watch </li></ul></ul><ul><ul><li>( ) Will be provided during and 60 minutes after operation. </li></ul></ul><ul><ul><li>( ) Supplied with extinguisher and small hose. </li></ul></ul><ul><ul><li>( ) Trained in use of equipment and activating fire alarm. </li></ul></ul>
Sample Permits part 2 <ul><li>The location where this work is to be done has been examined, above necessary precautions taken, and permission is granted for this work. </li></ul><ul><ul><li>Signature ____________ Date ____________ Time ____________ </li></ul></ul><ul><ul><li>Supervisor ____________ </li></ul></ul><ul><ul><li>Permit Approval ____________ </li></ul></ul><ul><ul><li>Final Inspection ____________ </li></ul></ul><ul><li>After work has been completed, work area and adjacent areas where sparks and heat might have spread were inspected for at least 60 minutes, and no signs of fire were found. </li></ul><ul><ul><li>Signature ____________ </li></ul></ul><ul><ul><li>Time ____________ </li></ul></ul><ul><ul><li>Supervisor ____________ </li></ul></ul><ul><li>This Permit should be completely filled out before any welding, cutting or brazing can be performed. </li></ul><ul><li>Permit must be returned to Supervisor/Manager when work is completed </li></ul>
Training <ul><li>Train personnel on hot work policies/procedures, proper use and calibration of combustible gas detectors, safety equipment, fire watch responsibility, and job specific hazards and controls in a language understood by the workforce. </li></ul><ul><li>Cutters or welders and their supervisors must be suitably trained in the safe operation of their equipment and the safe use of the process. </li></ul>
Supervise Contractors <ul><li>Provide safety supervision for outside contractors conducting hot work. </li></ul><ul><li>Inform contractors about site-specific hazards including the presence of flammable materials. </li></ul>
What is the organic material? <ul><li>“ Examination of a sample of the liquid indicated that bacterial decomposition of the organic matter likely produced flammable gas, which was then ignited by the welding activity”. </li></ul>
One Accident and Hot Works Citations Photo from www.CSB.gov
Initial Response <ul><li>Welders with the specialty contractor, were attaching a bracket onto a 10,000-gallon, metal storage tank on the grounds of the plant, officials from the two companies said. </li></ul><ul><li>The tank previously held a slurry form - a solid-liquid mixture - of the chemical polyvinyl fluoride, or PVF, which is used a protective coating for solar panels. </li></ul><ul><li>The tank had been cleaned, inspected and taken out of use, a plant spokesman said, though it's not clear whether some chemical residue remained in the tank. </li></ul><ul><li>"As far as I know right at this point, all safety precautions took place and everything was done to the letter of the law, and that's why we're all kind of mystified [at] what took place" the spokesman said. </li></ul>
1910.252(a)(2)(xiii)(D) <ul><li>Advise all contractors about flammable materials or hazardous conditions of which they may not be aware. </li></ul><ul><li>The employer did not inform the contractor regarding any potential hazards related to hot works on the slurry tank. </li></ul>
1910.252(a)(2)(xiv)(B) <ul><li>The supervisor shall determine the combustible materials and hazardous areas present or likely to be present in the work location. </li></ul><ul><li>The Supervisor made no determination regarding the presence of, or potential presence of, vinyl fluoride in the slurry tank prior to hot work. </li></ul>
1910.252(a)(2)(xiv)(C)(3) <ul><li>The supervisor shall see that cutting and welding are so scheduled that plant operations that might expose combustibles to ignition are not started during cutting or welding. </li></ul><ul><li>Electric Arc Welding was permitted on slurry tank while the tank was interconnected to the polyvinyl fluoride process which was in normal production operation. </li></ul>
1910.252(a)(3)(i) <ul><li>Used containers. No welding, cutting, or other hot work shall be performed on used drums, barrels, tanks or other containers until they have been cleaned so thoroughly as to make absolutely certain that there are no flammable materials present or any substances such as greases, tars, acids, or other materials which when subjected to heat, might produce flammable or toxic vapors. </li></ul><ul><li>Any pipe lines or connections to the drum or vessel shall be disconnected or blanked. </li></ul><ul><li>After the slurry tank was cleaning during shutdown, the tank was reconnected to the polymer process through the common overflow line allowing an explosive concentration of vinyl fluoride to accumulate in the tank prior to welding on the tank. </li></ul><ul><li>The Slurry tank was interconnected to other slurry tanks by the common slurry tank overflow lines. </li></ul>
1910.252(a)(2)(vi)(B) <ul><li>In the presence of explosive atmospheres (mixtures of flammable gases, vapors, liquids, or dusts with air), or explosive atmospheres that may develop inside uncleaned or improperly prepared tanks or equipment which have previously contained such materials, or that may develop in areas with an accumulation of combustible dusts </li></ul><ul><li>The slurry tank had developed an atmosphere of vinyl fluoride vapor via piping, that was interconnected to the ongoing polymer process. The tank was improperly prepared. </li></ul>
1910.252(a)(3)(ii) <ul><li>Venting and purging. All hollow spaces, cavities or containers shall be vented to permit the escape of air or gases before preheating, cutting or welding. Purging with inert gas is recommended. </li></ul><ul><li>Flammable vapors were not vented from the slurry tank prior to welding. </li></ul>
Aftermath <ul><li>"This death and injury graphically underscore how vitally important it is that employers anticipate the hazards associated with welding in potentially explosive atmospheres and institute all protective measures before allowing such work to begin," said OSHA </li></ul><ul><li>Case is in contest </li></ul>
Resources <ul><li>NFPA 51B Standard for Fire Prevention During Welding, Cutting, and Other Hot Work 2009 Edition </li></ul><ul><li>FM Global, Property Loss Prevention Data Sheet 10-3, Hot Work Management, 2006 </li></ul><ul><li>U.S. Chemical Safety and Hazard Investigation Board, Safety Bulletin, Seven Key Lessons to Prevent Worker Deaths During Hot Work In and Around Tanks, February 2010 </li></ul><ul><li>American Petroleum Institute (API). Safe Welding, Cutting and Hot Work Practices in the Petroleum and Petrochemical Industries , Recommended Practice (RP) 2009, Washington, DC, 2002. </li></ul><ul><li>Kletz, Trevor. What Went Wrong? Case Histories of Process Plant Disasters , 4th Ed., Woburn, MA, 1999. </li></ul>
Further <ul><li>This was prepared as a collaborative effort with several friends as a preliminary aid for anyone involved in hot works. </li></ul><ul><li>These are just some the issues. A comprehensive job hazard analysis should be conducted for any task where someone can get hurt. </li></ul><ul><li>This is not an official OSHA publication. Those will be on the OSHA.gov website. </li></ul><ul><li>If you see any errors my email is [email_address] or firstname.lastname@example.org </li></ul><ul><li>312-353-5977 </li></ul><ul><li>I want to thank Janet S. and Mark K. for her assistance in reviewing the hazards in this sector. </li></ul>