Dos and don'ts in melt deck safety: here is a safety list of dos and don'ts to protect you from hazardous situations when working on the melt deck.
To some, handling and melting metal is a normal, everyday part of their job. It may even be easy to forget that the tasks performed present risks and hazards when not carried out using proper safety equipment But, what safety equipment is required in what areas?
For starters, it's important to know what areas are considered hazardous in and around the melt deck. Proper hazard identification needs to be in place to alert users that they have entered a zone where hazards, such as a molten metal, heat, sparks or splash can exist.
Workers must be prepared for possible dangerous situations or hazards when working on the melt deck. After working in that area for an extended time, the situations may seem less dangerous, but workers cannot overlook the potential for danger to arise.
When working melt deck operations, certain personal protective equipment (PPE) is required. Employers must perform a hazard assessment to determine the correct PPE to wear for each operation. Workers must know the correct PPE to wear and how to properly wear it; the equipment is designed to be effective when worn properly.
What Areas Around the Melt Deck Present a Hazard?
According to the American Society for Testing and Materials (ASTM) Standard 2349-12, the hazard zone in melting operations includes areas where there is a possibility of a molten metal splash. ASTM describes the zone as extending from the edge of the induction melting furnace to a distance of either 20 ft. or five times the crucible inner diameter, whichever of the two is greater. Metalcasters know this area as the melt deck.
ASTM requires hazard zones to be identified properly, including the following:
* The employer shall identify the extent of the hazard zone and mark it with color coding or post signs warning of the hazard.
* Signs must be posted at each point of entrance identifying it as a hazardous area.
* The flooring in the hazardous area entrances must be marked with a yellow line spanning the entire entrance.
* Only authorized personnel (supervisors, lab technicians and approved visitors dressed in appropriate PPE) should be allowed within the hazard zone and only to perform authorized tasks and keep their time within the zone to a minimum.
Seeing the above notifications should immediately alert you that PPE is required.
What Hazards Exist on the Melt Deck?
Workers in the identified hazard zone or melt deck area are likely to be affected by the following types of hazards, which would again be considered during the PPE assessment:
* Burns from physical contact with molten metal splashes, run-out, spills, sparks, flames, hot surfaces, cold tools or liquid introduction into the metal (explosion hazard). When molten metal comes into contact with a liquid in such a way that it entraps the liquid/moisture, a violent explosion can occur by the rapid production of steam or vapor. Physical explosions occur through an initiation mechanism whereby hot particles of molten metal are finely dispersed in a small volume of water resulting in rapid heat transfer from the hot particles to the water. This initiating event may cause severe damage to property and life.
* Burns and heat stress from exposure to radiant heat.
* Airborne contaminants such as dust and fumes.
What Should Melt Deck Workers Wear?
There are two types of PPE: primary and secondary. Secondary or basic PPE refers to clothing or PPE designed as basic protection for continuous use in areas where exposure to hazards is possible. The following are all examples of appropriate secondary protection:
* 100% cotton or wool socks.
* 100% cotton undergarments.
* 100% cotton or wool outer garments.
* Safety glasses with side protection.
* Leather safety shoes with toe protection and a smooth toe.
* Hearing and respiratory protection, depending on the degree of exposure.
Workers performing melting operations and working inside the identified hazard zone or melt deck area require primary PPE. Primary PPE is clothing or PPE designed for activities where significant exposure to hazards such as molten metal splash, radiant heat, flame, noise or flying particles are likely to occur. Types of primary PPE include coats, jackets, aprons, cape, sleeve(s) and bib, leggings, chaps and spats. The appropriate PPE may vary from facility to facility as operations are set up and operate differently (i.e., type of metal poured, casting size, position of worker to the pour and the furnace, condition of charge materials, engineering controls, etc.). Appropriate PPE can be determined by a hazard assessment, required by the Occupational Safety and Health Administration (OSHA) standard 1910.132(d).
Now that the types of PPE have been properly identified, let's take a look at how to properly wear the required PPE.
Dos and Don'ts in Melt Deck Basic Protection and PPE
* Wear pants or leggings.
* Wear spats or leggings that cover the lacings of boots (if wearing laced boots). Molten metal or sparks can lodge in the tongue area of the boot.
* Maintain all protective clothing to keep it in serviceable condition.
* Repair fabric in a way that maintains its flame resistant properties.
* Wear types of PPE in any combination as needed to protect exposed body parts to heat or metal splatter, as determined by the hazard assessment for each work activity
* Consider aluminized PPE when exposed to high heat and spark producing operations such as lancing, tapping, slagging or activities where molten metal splash is possible.
* Tuck pant legs inside boots or spats.
* Wear Nomex, as molten metal tends to stick to the fabric.
* Wear polyester, nylon or other man-made materials that can melt and possibly ignite.
* Wear phosphorus-treated cotton (for nonferrous metals) because molten metal sticks to the fabric. Many flame resistant cotton fabrics use a phosphorus-based treatment.
* Wear clothing that may trap molten metal or sparks, such as cuffs, open pockets, loose legging tops, etc.
* Wear any sort of metal jewelry.
Eye and Face Protection in Pouring Operations
PPE items are available to protect you from head to toe. Identify the type of equipment that is available and required. For protection of the face and eyes, potential hazards are eye and face injuries from foreign bodies, molten metal splash and chemicals, and damage from infrared and/ or ultraviolet radiation.
Safety glasses with side shields are minimum secondary protection that should be used for all metalcasting operations, especially melting. The following types of additional PPE should be used for the eyes and face:
* Full face shield, thermal/infrared with a gold tint/wire mesh.
* Full face shield, polycarbonate or #40 steel wire mesh.
* Tinted glasses specific to the type of metal (iron--shade #3-#5 green; steel--shade #8 green or #6 cobalt blue; brass/ bronze--shade #3-#5 green or shade #3 green with #3 aluminized face shield or shade #6 cobalt blue (half lenses); aluminum and magnesium--clear, no tint.
Dos and Don'ts in Melting Face and Eye Protection
* Use appropriate darker shades of glasses for intense radiant energy.
* Switch to a lower shade number of untinted lenses when leaving the molten metal area or during extended periods when no molten metal viewing is required.
* Choose a lower shade number for glasses when molten metal viewing is momentary or incidental.
* Use a full face shield (such as polycarbonate or #40 steel mesh) when exposed to a potential hazard of molten metal splash such as furnace charging, tapping or ladle pouring.
* Forget to wear safety glasses with side protection when face protection is worn.
* Choose eye protection that is too dark as it may reduce visibility and create hazards such as tripping.
Protection in Pouring Operations for Head, Hands and Feet
The hazard assessment should consider potential head, hand and foot hazards found on the melt deck, including head injuries from falling objects, 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 and scrapes, cuts and abrasions.
When head protection is needed, workers should utilize a thermal rated hard hat, with a cotton or wool cap or an aluminized hood.
For hand protection, workers should use the following materials for mitts, cover mitts, cover pads or gloves: leather, cotton, wool, Kevlar, wool-lined Kevlar, aluminized fabric or other heat resistant materials.
For primary protection of the feet, workers should use metatarsal safety shoes or shoes with heat resistant soles.
Dos and Don'ts in Head, Hand and Foot Protection
* Use a thermal rated hard hat with a cotton or wool cap to provide protection from minor metal splatter.
* Consider the need for dexterity and grip security while operating equipment when choosing safety gloves.
* Have sleeves that cover the end of gloves, unless reaching overhead.
* Wear smooth toe safety shoes such as metatarsal safety shoes or engineer boots.
* Wear spats or leggings that cover the lacings to prevent molten metal or sparks from lodging in the tongue area of the boot when wearing lace boots.
* Wear pants or leggings that cover the top of the boot to prevent molten metal and sparks from entering the boot.
* Use gauntlet-type gloves unless there is no chance of metal being spilled into the glove.
* Wear Nomex gloves, as molten metal tends to stick to the fabric.
* Wear phosphorus-treated cotton (for nonferrous metals) because molten metal sticks to the fabric. Many flame resistant (FR) cotton fabrics use a phosphorus-based treatment.
* Tuck pant legs inside the boot or spat.
* Use shoes with exposed zippers or elastic materials that can melt or ignite.
Hearing Protection in Melting and Pouring Operations
Potential hazards involving hearing include hearing loss due to noise exposure and an inability to hear warnings. Consider primary protection for hearing, including ear plugs, ear muffs and ear caps.
Dos and Don'ts in Hearing Protection
* Select hearing protection that provides sufficient noise reduction for the exposure.
* Calculate noise reduction and the noise reduction rating for the hazard when selecting proper protection.
* Select hearing protection that does not properly fit.
* Select hearing protection that is not appropriate for the work-place noise level.
Melt Deck Respiratory Protection
Workers in ferrous melting operations risk exposure to toxic metals such as lead, cadmium, arsenic, chromium (either as part of the alloy or as a contaminant of the scrap being melted) and toxic gases such as carbon monoxide. Crystalline silica may be present from handling refractory materials such as furnace and ladle tear-out, relining and from other metalcasting areas. For magnesium, consider acid gases when sludging, and for aluminum, consider chlorine or fluorides used for degassing.
The below respiratory protection can be used when needed:
* Half mask respirator
* Full facepiece respirator
* Filtering or air purifying facepiece respirator
* Powered air-purifying respirator
* Air supplied helmet or hood.
Dos and Don'ts in Respiratory Protection
* Choose a respirator that is part of an effective respiratory protection program.
* Ignore industrial hygiene monitoring of noise, dusts, metal fumes, gases and vapors when performing your hazard assessment.
Visit www.moderncasting.com for additional safety and protective equipment articles.
JILLIAN KNUERR, ASSISTANT EDITOR, FRED KOHLOFF, AFS DIRECTOR OF ENVIRONMENTAL, HEALTH AND SAFETY AND THE AFS SAFETY & HEALTH COMMITTEE (10-Q)