Examining new PPE guidelines for ferrous melting.
Every day, you, an iron casting facility employee, removes slag off the top of the melt in a furnace. You've worked in the melting operation for years (adding scrap, removing slag, and ladling and pouring iron) without an accident. But one day, a piece of wet scrap falls into the melt. The water immediately becomes steam, expanding to 1,600 times its original volume and produces an explosion in the melt, spraying molten metal everywhere outside the furnace. If you are not wearing the proper protective equipment, you will sustain third-degree burns, or worse--you could be killed!
The induction furnace melting area can provide for a reasonably safe working environment, but the hazards of molten iron and steel still can be dangerous. Therefore, it is essential to be properly fitted with special clothing and personal protective equipment (PPE) to minimize or prevent any injuries from happening if an explosion or runout were to occur.
In June, the AFS Safety and Health Committee (10-Q), Schaumburg, Ill., will finalize an updated version of its document, "A Guide for Selection and Use of Personal Protective Equipment and Special Clothing for Foundry Operations." This guide details the selection and use of PPE in metalcasting operations where there are risks of exposure to hazards. It can be used as a good tool to help facilities complete their job hazard assessments required for the Occupational Safety and Health Administration's (OSHA) PPE Standard 29 Code of Federal Regulations (CFR) 1910.132-139 rules that specify the necessary protective equipment for metalcasters.
Detailed within are various types of clothing and PPE that are essential for as safe a work environment as possible in a ferrous casting facility. Two areas are discussed: primary protective clothing for molten metal exposure; and secondary protective clothing for less-intense environments. Although the guidelines in this article cannot be substituted for the OSHA standards or the required hazard assessment, wearing the proper protective clothing can mean the difference between walking away from a metalcasting catastrophe or being seriously injured or killed.
Primary Protective Clothing
Like any casting environment, ferrous casting facilities are intense when in operation. Conditions that ferrous casters always should be vigilant of are physical contact with molten metal (as a result of splashes and spills) and potential burning from hot metal surfaces.
According to OSHA 29 CFR 1910.132 (d)-Hazard Assessment and Equipment Selection, "The employer shall assess the workplace to determine if hazards are present, or are likely to be present, which necessitate the use of PPE." Improper flammable clothing is the number one cause of severe burns due to molten metal. Because there always is a risk of hazard in a ferrous casting environment, the OSHA rule garners the use of primary protective clothing.
Gear, such as safety glasses, a face shield, hard hat, jacket, apron, gloves, leggings, spats and cape sleeves, all are forms of primary protective clothing (Fig. 1). This equipment can be made of aluminized fabrics, leather and/or special synthetic fabrics of treated wool. Primary protective clothing is necessary when conditions call for exposure to radiant heat, molten metal splashing and flame. It always should be worn over secondary clothing during metalcasting plant activities like charging, slagging, tapping, pouring and casting operations when molten metal is in the vicinity.
Eye and Face Protection--Eye and face injuries can occur from molten metal splash, foreign bodies, and infrared and ultraviolet radiation emitted from high-temperature surfaces and furnaces. Safety goggles or glasses with side shields are a standard requirement and must meet American National Standards Institute (ANSI) Z87.1 specifications. Goggles and glasses with filter lenses should be worn near conditions with high radiant energy. When fitting for tinted lenses, it is best to start with the darkest shade, working toward lighter shades until the employee is most comfortable. For iron casting operations, tinted eye protection levels of shades #3-5 Green are sufficient while shades #8 Green or #6 Cobalt Blue will protect in steel operations. Higher shade numbers are for direct viewing of molten metal for extended periods of time, such as for making quality checks, pouring or slagging. In instances where there is exposure to molten metal, a face shield made of acrylic or #40 wire mesh is needed in addition to eye protection.
Head Protection--Hard helmets are one of the most essential elements for metalcasting PPE as they protect from falling objects and moving equipment. All helmets must meet ANSI Z89.1 standards. In cases where minor metal splatter may come into contact with the head, treated cotton or wool caps worn under the helmet help protect from burns. Further, aluminized hoods provide the most protection when near high-heat and sparking areas. And remember, visitors also should be made to wear appropriate PPE at all times while in the facility.
Hand Protection--Many ferrous casting facilities operate manually, which furthers the need for adequate hand protection. When working near places where there is heat, heat-resistant/flame-retardant gloves should be worn (if not gloves, then mitts or cover pads of the same caliber should be used). When operating near molten metal, founders' gloves 14-in. (35.5 cm) long--so that they extend above the wrists--are required. Treated cotton and wool gloves will help protect from heat. The same can be said of leather gloves, especially gauntlet-style gloves if there is no chance of metal being spilled onto or into the glove. More durable glove materials include aluminized fabrics, Kevlar, wool-lined Kevlar, Vinex and Oasis. Further, when selecting a glove, consider the need for dexterity and grip when operating equipment.
Foot Protection--Like the head, feet also must be protected from falling or rolling objects. Foot PPE must meet ANSI Z41 requirements. Pourers' or laceless safety boots are recommended for foot protection from molten substance exposures. These can be removed quickly in case molten metal accidentally gets inside. Metatarsal-guard shoes help protect the top of the foot, and, if worn, they should have a built-in tongue area cover design, or spats or leggings that cover areas where molten metal could lodge. If laced boots are worn, they should be covered with spats, especially near the top where there is danger of molten iron entering.
Body, Arm and Leg Protection--Many PPE suppliers suggest that aluminized outerwear, such as a 50-in. (127-cm) aluminized coat, be used for protection against radiant heat and molten iron/ steel splashing. Aluminized outerwear will reflect 90% of the radiant heat away from the body while shedding molten metal splashes and sparks. When melting ferrous metals at high temperatures, suppliers recommend clothing that has undergone phosphorus-base treatment.
For leg protection, leggings of at least 11 in. (28 cm) should be worn with a securing mechanism, such as Velcro, to keep them stabilized on the leg.
A consolidated portion of the Committee 10-Q guide is shown in Table 1.
Secondary Protective Clothing
Secondary protective clothing is worn in areas where there is no exposure to molten metal and is used to prevent ordinary clothing from igniting and burning. One example of this is flame-resistant coveralls. Although secondary clothing is not a ticket to complete safety, it will help to reduce burns significantly. In many cases, serious burns and fatalities have occurred because ordinary clothing caught fire from a small spark or splash, not because of burns caused directly by molten metal.
Along with secondary protective clothing, natural fiber outer clothing, undergarments and socks should be worn. Some synthetic fabrics melt or catch fire increasing the bum hazard. Cotton sateen is frequently recommended as offering good protection without sacrificing comfort or restricting flexibility.
With respect to respiratory and hearing protection, the melt deck must follow the same rules as the other sections of the facility with particular attention given to noise and dust content. Silica dust particles that are diffused throughout the metalcasting plant are considered a health hazard when inhaled. Further, toxic metals, such as lead and beryllium, may have been alloyed with some of the scrap and will emit vapors into the air when melted. Dust also often gathers during the removing and installing of furnace linings. Air-purifying respirators are one method to protect against these hazards. Such respirators should meet the 29 CFR 1910.134 and National Institute for Occupational Safety and Health (NIOSH) certification 42 CFR 84 (part 84) requirements. It should be noted that not all respirators will protect against the same exposures, so operations must be observed before a respirator is selected.
Hearing protection devices commonly used include ear plugs, muffs or caps. Although most earplugs are safe, foam earplugs made of urethane materials may be combustible and should not be used near molten metal.
What to Avoid
While there are many materials to consider for ultimate protection, there are other items that should be avoided.
Nomex materials should not be worn because molten metal tends to stick to the fabric. The same can be said of polyester, nylon and other manmade materials that also can ignite and melt within seconds of exposure to molten metal. Clothing with cuffs, open pockets and loose legging tops can trap molten metal and sparks and should not be worn. Also, pant legs should not be tucked inside of boots in order to prevent metal from falling into the boots.
Clothing also should be in serviceable condition, meaning it does not have any holes, rips or tears. Its flame-retardant properties must be maintained because these properties can be lost over time due to laundering.
Further, plastic cigarette lighters should be banned from any metalcasting facility to avoid any accidental contamination, or another explosion.
Table 1: Consolidated List of PPE As Suggested By The AFS Safety and Health Committee (10-Q) Potential Hazards and Basic Protection Considerations Evaluate the applicability Recommended minimum special of these items when clothing for all melting performing the hazard and pouring operations. For assessment. employees in a hazardous zone (such as near a furnace or ladle containing molten metal or other known hazards) additional application-specific clothing and PPE is required. Clothing for Hazards: Burns from Socks and Undergarments: Ferrous Melt physical contact with 100% cotton. Outer Deck molten metal splash, Garments: 100% cotton or molten metal runout, wool. spills, sparks, flames and hot surfaces; burns and heat stress from exposure to radiant heat. Considerations: Presence of molten metal in furnace, ladle and/or mold; temperature of metal or hot surface, level of the metal and area of the body that could be impacted by a splash, runout, sparks, flames or hot surfaces; proximity to metal and hot surfaces; material being handled (i.e. additives, chilling blocks). Eye and Face Hazards: Eye and face Safety glasses with Protection injuries from foreign side protection. bodies, molten metal splash and chemicals; damage from infrared and/ or ultraviolet radiation. Considerations: High-temperature surfaces emit infrared radiation; electric arcs emit ultraviolet radiation. Head, Hand Hazards: Head injuries Leather safety shoe, and Foot from falling objects, smooth toe. Protection moving equipment and/or overhead obstructions; burns from physical contact with molten metal splash, sparks, flames and/or hot surfaces; foot injuries from falling or rolling objects; scrapes, cuts and abrasions. Hearing Hazards: Hearing loss due N/A Protection to noise exposure. Respiratory Hazards: Exposure to toxic N/A Protection metals (lead, cadmium, arsenic beryllium, etc.) either as part of the alloy or as a contaminant of the melted scrap; exposure to toxic gases; crystalline silica exposures from other areas in the plant. Application-Specific Protection Appropriate for the severity of the hazard as noted in the hazard assessment; some operations (such as those not involving close proximity to molten metal or other known hazards) may not require specific special clothing beyond the basic requirements. Clothing for Materials: Aluminized Kevlar, aluminized Ferrous Melt cotton, leather, FR cotton, wool, aluminized Deck leather, aluminized wool, other fabrics that are acceptable as determined by ASTM F1002. Types of PPE: Coats; jackets, aprons, cape, sleeves and bib, leggings, chaps and spats. Eye and Face Materials: Goggles; face shield; full face Protection shield (acrylic or #40 wire mesh); Tinted glasses: Iron (shade #3-5 Green), Steel (shade #8 Green or #6 Cobalt Blue). Head, Hand Head protection: Hard hat, treated cotton or and Foot wool cap, aluminized hood. Protection Hand protection: Materials--leather, treated cotton or wool, Kevlar, aluminized fabrics, other heat-resistant materials. Types of PPE--mitts, cover mitts, cover pads, gloves. Foot protection: Metatarsal safety shoe, heat-resistant soles. Hearing Materials: Ear plugs, ear muffs, ear caps. Protection Respiratory Respiratory protection (particulate metal Protection fumes, organic vapor, etc.): Half mask respirator; full facepiece respirator; filtering facepiece air-purifying respirator (APR); powered air-purifying respirator (PAPR).
Information in this article was adapted from the "Inductotherm Founds, Safety Training Kit," Inductotherm Corp.
For More Information
"Inductotherm Foundry Safety Training Kit," Inductotherm Corp., Rancocas, N.J.
"OSHA Standards for General Industry (29 CFR Part 1910)."
"Recommended Clothing and Personal Protective Equipment (PPE) for Metal Melting and Pouring Operations," AFS Safety & Health Committee (10-Q), September 1998, The American Foundry Society, Schaumburg, Ill.
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|Title Annotation:||Personal protective equipment|
|Comment:||Examining new PPE guidelines for ferrous melting.(Personal protective equipment )|
|Date:||Jun 1, 2005|
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