Fire Safety for Magnesium Processing and Finishing Operations

Fire Safety for Magnesium Processing and Finishing Operations
NADCA North American Die Casting Association Fire Safety for Magnesium Processing and Finishing Operations Unit 4

Enabling Objectives After completing this section of the course students should be able to: Discuss magnesium melting and casting operations and the precaution for carrying out these operations safely. Explain procedures for fire and explosion prevention for melting and casting, heat treating, machining and finishing, dust collection, cleaning procedures, electrical equipment, personal protective equipment, spark producing operations, grinding wheels, stamping and drawing, fugitive dust, vacuums, storage and fire prevention After completing this section of the course, the students should be able to discuss causes and occurrence of magnesium fires and explosions. They should understand the potential hazards risks associated with magnesium metal operations. They should also understand the precautions and safety requirements needed to control these risks. This problem may affect them because combustible magnesium is used in die casting plants. This unit will explain the types of processes and equipment used in magnesium casting operations and explain the primary procedures for fire and explosion prevention for melting, casting, heat treating, machining and finishing, dust collection, cleaning procedures, electrical equipment, personal protective equipment, spark producing equipment, grinding wheels, stamping and drawing, fugitive dust generation and control, the use of vacuums, storage procedures and fire prevention.

Magnesium!

Magnesium Melting & Casting
Buildings non-combustible Melt rooms access to fire control Floors free of moisture & standing water Storage below magnesium no depressions where H2O could accumulate Pouring magnesium castings Buildings used for casting magnesium must be made of non-combustible materials. Melt rooms must have access to facilitate fire control. Floors must be of noncombustible construction and kept free of the presence or accumulation of water. The storage area beneath magnesium should not have any depression where water could flow or collect.

Solid metals thoroughly dried by pre-heating > 250°F or higher if impurities are present Fuel supply lines to melt pots remote shutoffs Ovens for preheating ingots Solid metal should be thoroughly dried by preheating at least 250°F. A higher temperature could be needed for adequate drying of the solid metal contains impurities such as salts, corrosion or foreign substances. Fuel supply lines to melting pots and pre-heating units must have fuel shutoff locations and combustion safety controls and should comply with the requirements of NFPA 86 ‘Standard for Ovens and Furnaces’.

Turnings, powders etc. can ignite at lower temperatures than the solid metal and should be avoided Keep solid magnesium free of dust, grindings and swarf Turnings, grindings, powders and swarf will auto-ignite at a lower temperature than solid metal and can in turn ignite solid metal. Solid metal should be kept free of this type of material.

Concrete always contains water! Contact with molten magnesium and concrete will cause a violent explosion! Concrete always contains water, therefore the contact of molten metal with concrete can cause an extremely violent explosion.

Keep the furnace and the surrounding area free of moisture and iron oxide in the event of a runout The contact of moisture with molten magnesium can cause an explosion of steam or hydrogen. Ensure documented procedures are in place to ensure all metal is heated to at least 250°F so that all moisture is removed. Higher temperatures may be required if the metal is contaminated with salts, corrosion products or other foreign materials. Areas of and around the furnace that could contact molten magnesium must be kept free of moisture and the presence of iron oxide. Area around the furnace is kept clean and dry

Molten magnesium systems to have 110% secondary containment of largest expected failure Install barriers or shields to prevent contact with incompatible materials Iron scale and magnesium possible thermite reaction Molten magnesium systems must overflow or relieve to secondary containment. Overflow should be designed to handle 110% of maximum expected spill. Barriers shields or other means should be employed to prevent contact with incompatible materials. Iron scale and molten magnesium can create a thermite reaction.

Crucible interiors and covers free of iron oxide scale to avoid thermite reaction Inspect crucibles and melting pots regularly! Use of protective atmospheres can cause formation of iron scale above Melting pots and crucibles must be put on a regular inspection schedule. The interior of the crucible furnace which is also called the ‘setting’ is a critical area of concern. With the use of hexafluoride (SF6) and other protective atmospheres, the problem of iron scale forming above with the potential to fall into the melt becomes a concern.

Crucible Maintenance Repair or discard damaged crucibles
Preheat ladles, skimmers & sludge pans and molds Vigilant for avoiding spilling magnesium Pots and crucibles that show signs of failure or deterioration or that could allow molten metal to contact iron oxide or concrete must either be repaired or discarded. Ladles, skimmers and sludge pans must be pre-heated and thoroughly dried before they are allowed to contact molten metal. Extreme care must be exercised whenever magnesium castings are being poured to prevent any spillage. Molds must be thoroughly preheated and dry before any pouring any magnesium castings.

Shields over metatarsals
Crucible Maintenance FR clothing & no pockets or cuffs Foundry boots Safety glasses and faceshields when handling molten magnesium Shields over metatarsals Operators in melting and casting areas must wear FR clothing, high-top foundry boots, safety glasses and faceshields. No exposed pockets or cuffs allowed in the area of molten magnesium.

Practice Quiz 1. Where the melting of magnesium takes place: A. There should be no standing water on the floor. B. There should be no depressions under the magnesium where water could collect. C. Buildings should be non-combustible construction. D. All of the above

Practice Quiz 2. Concrete always contains water, therefore contact with molten magnesium and concrete will likely cause: A. A housekeeping problem B. A violent explosion C. A minor nuisance D. None of the above

Practice Quiz 3. Damaged crucibles can create a safety hazard, crucibles should therefore: A. Be inspected for damage regularly B. If damaged, be discarded or repaired C. Used until there is a definite problem D. Only choices A & B above.

Practice Quiz 1. Where the melting of magnesium takes place: A. There should be no standing water on the floor. B. There should be no depressions under the magnesium where water could collect. C. Buildings should be non-combustible construction. D. All of the above

Practice Quiz 2. Concrete always contains water, therefore contact with molten magnesium and concrete will likely cause: A. A housekeeping problem B. A violent explosion C. A minor nuisance D. None of the above

Practice Quiz 3. Damaged crucibles can create a safety hazard, crucibles should therefore: A. Be inspected for damage regularly B. If damaged, be discarded or repaired C. Used until there is a definite problem D. Only choices A & B above.

Magnesium Heat Treating
Poses fire risks! In furnaces > 750°F use a special atmosphere inside the furnace to retard the ignition of magnesium Procedure needed to check for furnace hot spots, check prior to the heat and at regular intervals sulfur dioxide (SO2) sulfur hexafluoride with carbon dioxide (SF6/CO2) helium (He) argon (Ar) Heat treating magnesium poses potential fire risks. In heat treating furnaces operated above 750°F a mixture of sulfur dioxide (SO2), sulfur hexafluoride with carbon dioxide (SF6/CO2), helium (He) and argon (Ar) should be used with air to retard the ignition of magnesium. Establish a standard procedure for checking and ensuring uniformity of temperature within the heat-treating furnace. Check furnaces prior to the heat and regular periods or intervals to identify undesirable hot spots.

Combustion safety controls One set maintains operating temperature High set control to shut fuel or power if max op temp is exceeded even by a small amount! Gas or oil fired furnaces must have combustion safety controls. All furnaces must have two sets of temperature controls that operate independently. One set of temperature controls is used to maintain the desired operating temperature. The other set of temperature controls operates as a high-level limit control and will automatically cut off fuel or power to the furnace if the furnace rises even slightly above the maximum allowable operating temperature.

Only clean parts free of swarf & turnings placed in furnace! No combustible or aluminum separators or any other Al in furnace load of Mg Furnaces for Mg cleaned as necessary to remove any accumulation of iron oxide scale Only clean parts free of swarf, turnings & chips can be placed into a furnace. Combustible spacers on pallets are not allowed into the heat-treating furnace. Aluminum parts, sheets or separators must never be included in a furnace load of magnesium. Furnaces that are used to heat magnesium or magnesium alloys must be inspected and cleaned as necessary to remove any iron oxide scale.

When heat treating it is critical to identify Al containing Mg alloys Aluminum and magnesium can form a eutectic alloy which can cause furnace fires! Same effect if Al contact Mg at elevated temperatures Use alloy manufacturer heat treating specifications Extreme care must be taken when heat treating aluminum that contains magnesium alloys, since aluminum additions form a eutectic alloy with considerably lower melting and auto-ignition temperatures. Failure to identify the alloy can result in heat treat fire furnaces. Magnesium in physical contact with aluminum at elevated temperatures can also produce the same effect. You must maintain strict adherence to the heat-treating temperature cycle recommended by the alloy manufacturer.

Ensure magnesium alloys are never immersed into salts used for aluminum Mg in nitrate salt baths may cause an explosion! Mg and Al parts easily distinguished Magnesium and aluminum together forms an alloy which has a lower melting and auto-ignition temperature of either parent metal + = Do not use nitrate or nitrite molten salt baths for heat treating magnesium alloys. Heating magnesium in the presence of oxidizers can result in combustion. Special salt fluxes can be safely used for dip brazing of magnesium. Segregate and ensure magnesium and aluminum metals are easily distinguishable from each other to avoid the possibility of accidentally immersing magnesium alloys into salts used for aluminum due to the possibility of creating a eutectic alloy which has a lower melting and auto-ignition temperature than either parent metal.

Practice Quiz 1. Heat treating of magnesium: A. Poses potential fire risks B. Should be done using a special atmosphere that retards ignition of magnesium C. Include procedures to check the furnace for undesirable hot spots. D. All of the above

Practice Quiz 2. A second set of temperature controls on magnesium heat treating furnaces is needed because: A. The first set of controls may fail. B. To shut down the furnace if the maximum operating temperature is exceeded. C. For convenience and to speed heating treating.

Practice Quiz 3. Nitrate salt baths if used for magnesium: A. Will likely cause an explosion. B. Is the preferred solution. C. Is sometimes use to reduce processing time.

Practice Quiz 1. Heat treating of magnesium: A. Poses potential fire risks B. Should be done using a special atmosphere that retards ignition of magnesium C. Include procedures to check the furnace for undesirable hot spots. D. All of the above

Practice Quiz 2. A second set of temperature controls on magnesium heat treating furnaces is needed because: A. The first set of controls may fail. B. To shut down the furnace if the maximum operating temperature is exceeded. C. For convenience and to speed heating treating.

Practice Quiz 3. Nitrate salt baths if used for magnesium: A. Will likely cause an explosion. B. Is the preferred solution. C. Is sometimes use to reduce processing time.

Machining, Finishing & Fabricating Magnesium
Cutting tools must not ride on the metal without cutting – frictional heat can ignite the fines! Back the tool off as soon as the cut is finished Cutting tools kept sharp, ground with sufficient clearance Drilling holes > 5X diameter of drill, use high helix bits (45°) to prevent packing Cutting tools must not be permitted to ride on the metal without cutting, the friction that can be created is capable of igniting any fine metal that is scrapped off. Cutting tools must be kept sharp with sufficient clearance so that rubbing on the end and sides of the tool is minimized. When drilling deep holes in magnesium that are five times greater than the drill diameter or more, use high-helix bits to prevent packing of the chips. Relief maintained on tools used in grooving or parting operations since the tool rubs the side of the groove as it cuts. Side relief 5°; end relief from 10 degrees to 20 degrees.

Use only high flash tapping fluid Don’t use water, water soluble oils and oils > 0.2% fatty acids (hydrogen gas hazard) Use water-oil emulsion fluids that inhibit hydrogen gas formation Use tapping fluid that is approved for use with magnesium. If lubrication is needed, as in tapping or very fine grooving you must use a tapping fluid with a high flash point. Water, water soluble oils and oils that contain greater than 0.2 percent fatty acids must not be used because of the potential to generate hydrogen gas.

Machines provided with pan to catch turnings and chips Pan designed to be pulled out quickly in case of fire Pan arranged so fire can be quickly extinguished Machines use for machining magnesium castings should be equipped with a tray to catch any chips or turnings produced. The pan should be arranged so it can be removed quickly in the event of the turnings or chips catching fire. Arrange the pan so that in the event of a fire an extinguishing agent can be applied quickly and easily.

Machine to keep chip size large Maintain good housekeeping around magnesium machining operations Remove chips regularly Avoid accumulation of more than 3 lbs of chips Chips stored in covered containers Machining of magnesium should be done so that chips generated are larger in size. Maintaining good housekeeping around chip generating operations will minimize damage in a fire. Remove chips regularly or install a system that automatically conveys the chips away from the operation. Limit accumulation of dry chips to no more than three pounds before they are removed. Keep chips in covered containers that are compatible and will not burn.

Magnesium Machining & Finishing
Practice Quiz 1. Machine magnesium so as to keep the size of chips generated: A. A consistent size. B. Large. C. Small to reduce scrap volume.

Practice Quiz 2. Tapping fluids for magnesium must be approved for use with magnesium and: A. Prevent the formation of explosive hydrogen gas. B. Have a very low flash point. C. Have a high concentration of fatty acids.

Practice Quiz 3. Machines that produce chips and turnings should be provided with a catch pan that: A. Will catch the chips and turnings. B. Can be removed quickly in case of fire. C. Is arranged so the fire can be put out quickly. D. All of the above.

Practice Quiz 1. Machine magnesium so as to keep the size of chips generated: A. A consistent size. B. Large. C. Small to reduce scrap volume.

Practice Quiz 2. Tapping fluids for magnesium must be approved for use with magnesium and: A. Prevent the formation of explosive hydrogen gas. B. Have a very low flash point. C. Have a high concentration of fatty acids.

Practice Quiz 3. Machines that produce chips and turnings should be provided with a catch pan that: A. Will catch the chips and turnings. B. Can be removed quickly in case of fire. C. Is arranged so the fire can be put out quickly. D. All of the above.

Dust Collection for Magnesium Operations
Machines fitted with enclosures or hoods to capture dust produced Use wet-type collectors or cyclone collector located outdoors Do not use bag-type collectors for magnesium Make sure that adequate dust collection systems are installed using proper hoods or enclosures. Use wet-type collectors designed for magnesium. Dry collectors should be cyclone type and located outdoors. Do not use dry type media filter collectors for magnesium operations.

Wet-Type Collectors Any hydrogen generated from contact with water must be properly vented Remove sludge from the tank if the collector will be inoperable for longer than a day Use a secondary blower to ensure venting of the sludge tank whenever the main exhaust is not on Wet type collectors used for magnesium dust collection must be designed so that any hydrogen that is generated is properly and safely vented. All parts of the collection system must be vented so that hydrogen gas does not accumulate. A secondary blower must be installed to automatically turn on, to ensure adequate venting of any hydrogen in the event that the primary exhaust system is shut down for any reason.

Wet-Type Collectors Use good collector housekeeping!
Sludge build up in the collection tank should not exceed 1/20 of the tank capacity Remove sludge whenever the collector will be shut down for extended periods greater that a day. Wet collectors must be dedicated to the collection of magnesium type materials only Aluminum especially containing copper is incompatible Maintain good housekeeping on wet-type magnesium dust collection systems. Do not allow large amounts of sludge to build up in the tank. Remove sludge from the tank regularly. Limit sludge accumulation to 1/20 of the tank capacity. Do not use dust collectors that serve magnesium dust producing operations for any other types of dust. Aluminum fines especially if they contain copper can create an exothermic reaction with magnesium and also evolve hydrogen gas.

Cyclone Dust Collectors
Locate collectors outdoors! Vent exhaust outside to a safe location Do not recycle air back into the building Make sure that the cyclone dust collector is efficient and high powered. Locate the dust collector outdoors. Make sure that the venting of the collector is directed to a safe location. Do not recycle any air from the collectors back into the building.

All components of the dust collector should be conductive and the system should be bonded and grounded Ensure no water can leak into the collector All parts of the dust collector system should be made of conductive material and the collector should be properly bonded and grounded to guard against the accumulation of static charges. The dust collector should not have any cracks or openings anywhere and should be situated to eliminate the possibility of rain or water entering the system.

Separate the collector from the machines that feed it with duct that is at least 15 feet long Explosion venting can be used on cyclone dust collectors Vent away from personnel and other equipment The length of duct from machines that produce magnesium dust to the dust collector should be at least 15 feet long to allow for an adequate distance to the collector in case of fire or explosion. You need this distance for explosion protection in order to install a ‘quick acting valve’. Dry type collection systems can be fitted with explosion venting to allow for adequate pressure release in the event of an explosion inside the collector.

Cyclone Dust Collection for Magnesium Operations
Air movement should be such to keep the concentration of magnesium dust below ¼ of the minimum explosive concentration for machines feeding a cyclone dust collection system Fast air movement helps keep concentration of dust at safe levels The fan system the arrangement of the ducts for a cyclone collector should provide enough air movement to keep the concentration of dust to not more than ¼ of the minimum explosive concentration for the size particle being generated. For example the minimum explosive concentration of 100 mesh magnesium dust is 0.03 oz/ft³. …FAST!! KEEP AIR MOVEMENT

Cyclone Dust Collection for Magnesium Operations
Keep duct tubes as short as possible Eliminate any unnecessary bends in ductwork No dead end section or unused caps where dust can accumulate Interlocked equipment power supply with exhaust blower Duct runs should be kept as short as possible and they should not contain any unnecessary bends or curves. Make sure that unused portions of duct or dead ends or unused caps are eliminated so dust cannot collect in them. Have the machines feeding the duct collector electrically interlocked so that if the dust collector is not functioning the machines cannot run. Explosion venting in short duct run

Dust Collectors Practice Quiz 1. Wet dust collectors must be.
A. Vented to prevent the accumulation of hydrogen gas. B. Located outdoors. C. Fitted with duct runs that incorporate bends.

Dust Collectors Practice Quiz
2. Insufficient air movement in a dust collection system could cause: A. A high concentration of dust that approaches the minimum explosive concentration. B. Helps keep the concentration of dust below ¼ of the explosive range. C. Will prevent dust from collecting in ducts.

Dust Collectors Practice Quiz 3. For cyclone dust collectors:
A. Keep the duct runs as short as possible. B. Eliminate unnecessary bends in the ductwork. C. Eliminate dead ends and unused caps. D. Interlock the collector to the machines that feed into it. E. All of the above.

Dust Collectors Practice Quiz 1. Wet dust collectors must be.
A. Vented to prevent the accumulation of hydrogen gas. B. Located outdoors. C. Fitted with duct runs that incorporate bends.

Dust Collectors Practice Quiz
2. Insufficient air movement in a dust collection system could cause: A. A high concentration of dust that approaches the minimum explosive concentration. B. Helps keep the concentration of dust below ¼ of the explosive range. C. Will prevent dust from collecting in ducts.

Dust Collectors Practice Quiz 3. For cyclone dust collectors:
A. Keep the duct runs as short as possible. B. Eliminate unnecessary bends in the ductwork. C. Eliminate dead ends and unused caps. D. Interlock the collector to the machines that feed into it. E. All of the above.

Cleaning Procedures for Magnesium Operations
A thorough cleaning plan must be put in place that includes the entire production area, beams & joists, pipes, etc. Use conductive non-sparking tools for cleaning Vacuums listed for magnesium dust A system must be in place to ensure the entire area around the production and building are thoroughly cleaned on a regular basis. This includes beams, joists, tops of cabinets, pipes, conduit and anywhere dust is accumulating. Use brooms that have soft bristles, use scoops and pans that are non-sparking and also conductive. Vacuums must be listed and approved for use with magnesium dust or not be used. You do not want too much dust up here!

Cleaning Frequency Every effort must be made by management to prevent the accumulation of hazardous levels of dust Perform regular cleaning Turn machines off Clean regularly and as often as necessary to keep accumulations of dust below hazardous levels Cover all portions of the building Cleaning activities must be paid close attention to by both management and personnel. It is everyone’s job to ensure hazardous levels of dust do not accumulate on any part of the building. Include parts of the building and machines that do not normally get cleaned for periodic cleaning and also as needed. When cleaning is performed all machines should be idle and the power should be turned off. Magnesium dust is particularly hazardous so great care must be taken to maintain cleanliness with regard to dust accumulation.

Electrical Equipment for Magnesium Operations
Dust producing equipment and associated areas inspected and cleaned regularly Other portable electrical equipment approved for Classified Location Areas where electrical equipment is used that contain magnesium dust or dust producing operations should comply with Article 500 of NFPA 70, the National Electrical Code. Electrical equipment should be on a regular maintenance schedule to ensure it is inspected and kept clean. Other types of electrical equipment used in these areas also should be listed for the type of environment and level of combustible dust that could be present. All equipment in the area must be securely grounded with permanent ground wires. Class II Approved Flashlight

Electrical Considerations
Electrical equipment and wiring in magnesium production, processing, handling and storage areas comply with the NEC Processing equipment used in magnesium operations grounded and bonded to dissipate static electricity NEC All electrical equipment and wiring in magnesium production, processing, handling and storage areas must comply with NFPA 70 The National Electrical Code. Processing equipment used in magnesium operations must be electrically bonded and grounded to prevent the accumulation of static electricity.

PPE Safety for Magnesium Operations
Clothing flame retardant Clean and dust-free Dust easily brushed off No pockets or cuffs No wool or silk (static electricity) No exposed steel on shoes (spark generating) No pockets or cuffs on clothes for working around magnesium dust. The clothing worn around magnesium dust producing operations must be flame retardant. Clothing should be able to be removed quickly if necessary. Clothing should be kept dust free and clean. Do not wear clothing that can hold a static charge like wool or silk. Exposed steel on shoes could lead to an unwanted spark.

Cleaning Operations Practice Quiz
1. A thorough cleaning plan should be put in place that includes: A. Beams, ducts, and tops of equipment. B. Incorporates the use of conductive non-sparking hand tools. C. Uses only vacuums approved for magnesium dust. D. All of the above.

Electrical Equipment Practice Equipment
2. Portable electrical equipment for operations that produce ignitable magnesium: A. Must only be operated by battery B. Must be safe and approved for use for the hazard class involved. C. Does not require a grounding conductor.

Personal Protective Equipment
Practice Quiz 3. Clothing used around magnesium operations should be: A. Wool or silk. B. Cuffed to prevent tripping. C. Flame retardant.

Cleaning Operations Practice Quiz
1. A thorough cleaning plan should be put in place that includes: A. Beams, ducts, and tops of equipment. B. Incorporates the use of conductive non-sparking hand tools. C. Uses only vacuums approved for magnesium dust. D. All of the above.

Electrical Equipment Practice Equipment
2. Portable electrical equipment for operations that produce ignitable magnesium: A. Must only be operated by battery B. Must be safe and approved for use for the hazard class involved. C. Does not require a grounding conductor.

Personal Protective Equipment
Practice Quiz 3. Clothing used around magnesium operations should be: A. Wool or silk. B. Cuffed to prevent tripping. C. Flame retardant.

Safety for Magnesium Operations
Control spark producing operations where magnesium dust producing equipment is used No flames, cutting or welding in areas where machines that produce magnesium dust are in operation Control spark producing operations where magnesium dust producing equipment is used. When magnesium dust producing equipment is in operation there should be no open sources of ignition, sparks, welding or cutting activities permitted.

Dressing the wheel is a problem! Do it right….
Grinding Wheels Remove grinding wheels to a safe location for dressing Or, remove hoods Or, clean thoroughly Remove all deposits of dust around wheel before, during and after dressing The grinding wheels that are used for magnesium castings should be taken to a safe location for dressing the wheels. If the grinding wheels cannot be moved where it is safer to dress them then the hoods for the grinding wheels should be removed or thoroughly cleaned before dressing operations are begun. Any deposits of dust on or around the grinding wheel is to be removed before dressing the wheel, during dressing the wheel and after dressing the wheel is complete. Dressing the wheel is a problem! Do it right….

Non-sparking box wrench set
Grinding Wheels Use only non-sparking tools to make repairs dust collectors that contain magnesium dust grinding wheel hoods that serve them Use only non-sparking tools for adjustments or repairs on collector units that contain magnesium dust and on grinding units that contain magnesium dust. Non-sparking box wrench set

Stamping and Drawing Take precautions to prevent overheating magnesium
Collect trimmings and clippings at frequent intervals Place into dry and clean steel or non-combustible receptacles Use reliable means to heat magnesium for drawing or spinning to prevent any overheating of the magnesium. Clippings and trimmings must be collected at frequent intervals and placed into clean and dry non-combustible containers.

Non-sparking tools for cleaning
Fugitive Dust Prevent the accumulation of fugitive dust Use only conductive, non-sparking shovels and scoops Brush bristles must be soft Brushes and brooms natural bristles Never use compressed air for cleaning magnesium dust You must not allow magnesium dust to accumulate anywhere in the plant. Use only conductive non-sparking scoops, shovels, dust pans and brooms and dust brushes that have soft natural fibers. Do not use compressed air for cleaning magnesium dust. Non-sparking tools for cleaning

Fugitive Dust & Vacuums
Use hand cleaning to pick up as must dust as feasible Only vacuum dust that is spread out Scoop up or sweep bigger piles Vacuum used must be bonded and grounded Design, installation and use of vacuum systems for magnesium dust must be properly engineered due to the great potential hazard of fire or explosion Listed, labeled and approved Vacuum cleaners are only to be used for magnesium dust that is too fine, small, or widely dispersed as to make sweeping or scooping impractical. Any vacuum system used must be properly bonded and grounded. Proper engineering considerations are to be undertaken in order to control the hazards associated with designing, installing and using vacuum systems for magnesium dust. The only kind of vacuum that is allowed for magnesium are those that are specifically designed for such purposes and must be listed, labeled and approved for use with magnesium dust. See NFPA 77 for guidance on static electricity. Class II approved vacuum

Vacuums Hoses and attachments conductive and non-sparking
System is to grounded and bonded where necessary Test for continuity to ground Locate fixed collection receptacle outside Class II Div 1 Group EFG HAZ LOC HAZ LOC The hose for the vacuum must be conductive and all the fittings must be made of non-sparking conductive materials. You should test the continuity to ground of the system periodically and on an established interval. Fix vacuum collection containers must be located outside of the building.

Grinding Wheels Practice Quiz
1. When dressing grinding wheels used for grinding magnesium parts, which of the following would be unacceptable: A. Remove the wheel to a safer location for grinding. B. Remove the hood. C. Leave the hood in place and dress the wheel quickly.

Fugitive Dust Practice Quiz
2. A responsible program for the management of fugitive dust would not include: A. Use of conductive non-sparking tools. B. A procedure that prevents excessive accumulation of dust anywhere in the plant. C. Plant air reduced to 30 psi.

Vacuums Practice Quiz 3. Requirements for vacuums used to collect magnesium dust include: A. Vacuums should only be used where dust is too dispersed or too small or spread out to sweep or scoop up. B. Periodically tested for continuity to ground. C. Have only hoses and attachments that are conductive and non-sparking. D. All of the above.

Grinding Wheels Practice Quiz
1. When dressing grinding wheels used for grinding magnesium parts, which of the following would be unacceptable: A. Remove the wheel to a safer location for grinding. B. Remove the hood. C. Leave the hood in place and dress the wheel quickly.

Fugitive Dust Practice Quiz
2. A responsible program for the management of fugitive dust would not include: A. Use of conductive non-sparking tools. B. A procedure that prevents excessive accumulation of dust anywhere in the plant. C. Plant air reduced to 30 psi.

Vacuums Practice Quiz 3. Requirements for vacuums used to collect magnesium dust include: A. Vacuums should only be used where dust is too dispersed or too small or spread out to sweep or scoop up. B. Periodically tested for continuity to ground. C. Have only hoses and attachments that are conductive and non-sparking. D. All of the above.

Storage of Magnesium Limit the size of piles of magnesium stored
Piles should not exceed 20 feet in height Aisles should be at least 10 feet wide Do not store magnesium below grade The size of piles of magnesium ingots or billets or pigs should be limited. Pile height should not exceed 10 feet. Aisle width should be at least 10 feet. Storing magnesium in basements or other area where water may accumulate is not advisable and should be avoided.

Outdoor Storage Store on level and firm ground
Stack to prevent toppling Keep the storage yard free of overgrowth of vegetation Ensure proper drainage is maintained Quantities of stored piles kept to a minimum No combustibles underneath ingots Magnesium for the war effort in WW II Magnesium should be carefully placed on firm level ground and stacked level. Keep good drainage at all times in the yard. Cut back any overgrowth of vegetation as needed. Keep the quantities stored to a minimum.

Outdoor Storage Up to 100,000 pounds of magnesium may be stored if:
Proper drainage moves water away from stored material Aisles at least ½ the pile height plus 10 extra feet Piles kept to less than 10 feet wide Combustible materials not stored closer than 25 feet to ingots Refer to NFPA regarding property lines Storage of up to 100,000 pounds may be allowed if: Proper drainage moves water away from stored material Aisles at least ½ the pile height plus 10 extra feet Piles kept to less than 10 feet wide Combustible material should be no closer than 25 feet to magnesium ingots in storage. An open space equal to the height of the piles plus 10 feet is to be provided between the stored magnesium ingots and adjoining property lines where combustible material or buildings are exposed or where the adjacent occupancy could provide fire exposure to the magnesium.

Castings Storage Magnesium castings must be free of chips and fine particles when stored Floors non-combustible and well drained Buildings non-combustible unless full sprinkler protection Light castings piles < 1000 ft³ Stored away from heat & combustibles Buildings used to store heavy magnesium castings must be noncombustible construction unless there is full fire sprinkler protection. Floors must be non-combustible and well drained so as to prevent the accumulation of puddles of water. In storage, magnesium castings must be free of fine particles and chips. Light castings are not to be stored near combustible materials, sources of heat that could cause ignition and kept in piles whose volume is less than 1000 ft³.

Magnesium Rack Storage
Aisles in front of racks equal in width to the height of the racks All aisle space kept clear and unobstructed Do not lean or stack separators or metal sheets on edge so as to prevent heat from a fire activating a sprinkler system Combustible materials or rubbish not allowed to accumulate in the rack space Racks for the storage of magnesium may extend along wall in lengths as necessary. The allocated aisle space in front of racks of stored magnesium must be equal to the height of the racks. All aisles and aisle spaces kept clear. Do not allow combustible materials or rubbish to be stored in racks that are also storing magnesium. Do not stand separators or metal sheet on side in storage rack areas where they may block the heat generated by a small fire from activating the sprinkler system.

Scrap Magnesium Storage
Buildings of noncombustible construction Dry magnesium kept away from other combustibles Scrap kept in covered containers and managed so they will not become wet. Wet magnesium submerged and stored outside in covered, vented steel containers (check frequently) Do not stack scrap containers Applies to chips, solids, swarf, turnings and fine particles. Buildings used for such storage must be non-combustible construction. Dry magnesium scrap is to be separated well away from any combustible materials. Scrap kept in covered steel or non-combustible containers and kept from becoming wet. Fines are not allowed to be stored outdoors unless precautions are taken to prevent them from becoming wet. Wet magnesium must be stored only outdoors, submerged in covered and vented steel containers. Sources of ignition are to be kept away from drum vents and tops. Do not stack scrap containers.

Storage of Magnesium Practice Quiz
1. Magnesium storage should conform to all of the following except: A. Limit the size of piles of magnesium stored. B. Leave adequate aisle room between piles. C. Store magnesium in basements. D. Pile height should not exceed 20 feet high.

Storage of Magnesium Practice Quiz 2. Storage of castings must be:
A. Free of chips and fines. B. In piles that do not exceed 1000 ft³. C. Well away from heat and combustibles. D. A & C above only. E. A, B & C above.

3. Magnesium stored outdoors must be: A. Stacked to prevent toppling. B. Protected from vegetation overgrowth. C. Not closer that 25 feet to combustibles. D. All of the above.

1. Magnesium storage should conform to all of the following except: A. Limit the size of piles of magnesium stored. B. Leave adequate aisle room between piles. C. Store magnesium in basements. D. Pile height should not exceed 20 feet high.

Storage of Magnesium Practice Quiz 2. Storage of castings must be:
A. Free of chips and fines. B. In piles that do not exceed 1000 ft³. C. Well away from heat and combustibles. D. A & C above only. E. A, B & C above.

3. Magnesium stored outdoors must be: A. Stacked to prevent toppling. B. Protected from vegetation overgrowth. C. Not closer that 25 feet to combustibles. D. All of the above.

Fire Prevention – Hot Work
Permits required in areas that contain exposed magnesium chips, dust or sponge All areas requiring a Hot Work Permit are to be thoroughly cleaned of magnesium chips, dust or sponge prior to work Hot work permits are required in areas that contain magnesium chips, powder, or sponge. Hot work areas must be thoroughly cleaned prior to any hot work being done in the area and chips, dust and sponge removed. Hot work cannot proceed under these conditions

Fire Prevention – Hot Work
Containers to receive molten magnesium thoroughly cleaned and dried Good housekeeping mandatory Supplies stored orderly, with separation of incompatible materials and aisles maintained Supplies of magnesium limited to those needed for normal operations All containers used to receive magnesium must be cleaned and dried before use. Good housekeeping must be maintained at all tomes. Supplies are to be stored in an organized fashion and adequate aisle space is to be provided to allow for inspections. Supplies of magnesium materials processing kept limited to those amounts needed for normal operations.

Fire Prevention – Other Materials
Regular combustibles like paper and wood are not allowed to accumulate in magnesium processing areas What is necessary to be in the area for production is allowed but they must be stored in designated areas Clean chips and dust from buildings whenever necessary and as frequently as conditions require Chips and dust are to be removed to safe storage or disposal areas Ordinary combustible materials such as paper, wood or packaging are not to be allowed to accumulate in magnesium processing areas. Materials that are necessary for production are allowed in production areas but they must be stored in designated areas. Periodic cleaning of magnesium chips and powder is to be done as often as necessary according to the housekeeping conditions. Chips and dust are to be removed safely to safe storage or disposal areas.

Fire Prevention - Inspections
Documented inspections detect build up of magnesium dust on all parts of buildings equipment not cleaned during daily operations No ordinary combustibles commingled with magnesium dust, chips or sponge No smoking and signs posted where chips or dust is present Regular inspections will be done as operations dictate for the purpose of detecting accumulation of excessive amounts of magnesium dust or chips on portions of the building or equipment that is not get cleaned as part of normal operations. Records of these inspections are to be on file. Containers for magnesium waste are not to have other types of waste place into them such as combustibles. If flammable liquids are used their use must comply with NFPA 30 Flammable and Combustible Liquids. No smoking allowed where ignitable magnesium is present. Post NO SMOKING signs where magnesium chips or dust is present.

Fire Prevention - Inspections
Where smoking is prohibited in the entire plant no smoking signs are optional Consider the risks of using tools and utensils in areas where magnesium dust is handled that could generate static electricity or impact sparks Where magnesium is collected or stored in containers material handling equipment able to remove any container from the area is readily available If smoking is not allowed in the entire plant then posting ‘No Smoking’ signs are at the discretion of management. Where tools and utensils are used in areas that handle magnesium dust, consideration is to be given to the effects of static electricity and impact sparks that could be generated from tools and equipment used in those areas. Where magnesium is collected or stored in containers, material handling equipment capable to remove any container from the immediate area is to be readily available.

Fire Prevention Practice Quiz
1. Hot work around ignitable magnesium requires: A. A permit. B. That the area be thoroughly cleaned. C. Chips, dust and sponge removed. D. All of the above.

2. Inspections for fire prevention must be: A. Mandatory only if a fire occurs. B. At the discretion of management. C. Documented. D. None of the above.

1. Hot work around ignitable magnesium requires: A. A permit. B. That the area be thoroughly cleaned. C. Chips, dust and sponge removed. D. All of the above.

2. Inspections for fire prevention must be: A. Mandatory only if a fire occurs. B. At the discretion of management. C. Documented. D. None of the above.

Summary In this section we covered the potential hazards and risks associated with: Melting and Casting Heat Treating Machining and Finishing Dust Collection Cleaning Procedures Electrical Equipment Personal Protective Eq. Spark Producing Operations Stamping and Drawing Fugitive Dust Use of Vacuums Storage of Magnesium Fire Prevention In this section of the program we discussed some of the primary hazards and risks for magnesium operations as they relate to the casting industry. We covered the potential hazards and risks associated with melting and casting, heat treating, machining, finishing and fabricating, dust collection, cleaning procedures and cleaning frequency, electrical equipment, personal protective equipment, spark producing operations, grinding wheels, stamping and drawing operations, fugitive dust, the use of vacuums, storage of magnesium and fire prevention and the procedures and precautions necessary to control these potential hazards and risks. Students should now have a better understanding of the importance of recognizing the potential risks associated with magnesium casting operations and the importance of establishing and following procedures and developing processes to control those hazards in order to prevent the occurrence of fires and explosions. And the controls needed for these potential hazards and risks

Fire Safety for Magnesium Processing and Finishing Operations

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Fire Safety for Magnesium Processing and Finishing Operations

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