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 warn- ing of the hazard.
Signs must be posted at each point of entrance identify- ing 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 techni- cians 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 liq- uid 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 explo- sion 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. Airborne contaminants such as dust and fumes.
Burns and heat stress from exposure to radiant heat.
What Should Melt Deck Workers Wear? Tere 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 expo- sure to hazards is possible. Te 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 mol-
26 | MODERN CASTING August 2012 Proper melting gear can include boots, coats, face masks and hard hats.
Hazard zones must be properly identified, including yellow railing.
ten 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. Te 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
Do:
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.
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