OSHA publishes SHIB on electric arc furnaces
Posted December 14, 2015
On December 4, OSHA released a Safety and Health Information Bulletin (SHIB), Carbon Monoxide Explosion Hazards in Electric Arc Furnace Steelmaking Operations. The text offers details on explosions; causes, prevention, and protecting employees.
Although water explosion hazards in electric arc furnaces (EAFs) are well known in the steelmaking industry, explosions caused by excess carbon monoxide concentrations in the furnace headspace during the reduction of carbon content (decarburization) are an emerging concern, according to OSHA. As the steelmaking industry expands EAF use to melt and refine scrap metal during recycling operations, the potential for explosions increases. Explosions can result in serious injury or death to workers.
OSHA recommends the following in the SHIB to reduce or eliminate explosions from excess carbon monoxide concentrations during decarburization in EAFs:
- Train workers on how to recognize and avoid unsafe EAF operations associated with excess carbon monoxide concentrations during decarburization.
- Verify that the off-gas analyzer system accurately measures off-gas accumulation in the furnace.
- Use off-gas composition analyses to control the oxygen injection rate and ensure that gas mixtures above "the heat" stay well below the lower limit of the carbon monoxide explosive range, between 12.5 to 74.2 percent.
- Ensure that proper furnace ventilation along with off-gas composition analyses are used to help control chemical reactions in the EAF headspace.
- Do not consider smaller explosions as acceptable and immediately investigate their cause to modify furnace process controls to prevent them.
- Control furnace tilting during EAF operations to help avoid creating potentially explosive gas mixtures.
In the SHIB, OSHA recommends the following to protect workers from explosion hazards in EAFs:
- Ensure that engineering controls (e.g., shields or shelters) adequately protect workers from maximum potential blast overpressure, heat gradients, and struck-by hazards from explosions.
- Develop and implement written procedures for workers to stand behind shields or shelters when on the furnace floor or to remain in the control booth, to the maximum extent possible.
- Develop and implement written procedures to detect and control excess carbon monoxide concentrations in the EAF headspace.
- Ensure that procedures for alarms or signals to workers on the furnace floor alert them when potentially hazardous conditions occur (e.g., if off-gas analyses indicate carbon monoxide buildup).
OSHA also requires employers to ensure that workers use PPE that will adequately protect against explosion hazards in EAFs.
The entire SHIB can be viewed at www.osha.gov/dts/shib/shib120415.html.
The SHIB is not a standard or regulation, and it creates no new legal obligations. The Bulletin is advisory in nature, informational in content, and is intended to assist employers in providing a safe and healthful workplace.
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