Fire Suppression around HDG Kettles
Are sprinklers needed around a galvanizing kettle?
The short answer is no and the explanation is pretty straight forward. Imagine what happens when there is a little moisture on a steel part when it enters the hot-dip galvanizing (HDG) kettle. You hear some loud pops and see little splashes of zinc popping up from the kettle. If this occurs with just a little moisture on the steel surface, imagine if there was a lot of water sprinkling down on the kettle. The result would be disastrous.
The main purpose to have fire sprinklers is to extinguish or control fires. The use of fire sprinklers in a galvanizing facility would create dangerous situations instead of reducing and eliminating fires. Any type of fire suppression/sprinklers are typically excluded from molten material use areas because of this potential to develop a violent steam explosion.
Hazards with Using Fire Suppression around HDG Kettles
Any water usage should be used with caution around the HDG kettle. The introduction of water or the insertion of wet parts into the HDG kettle can be explosive in nature. The water will instantly vaporize and can cause the molten zinc to erupt in all directions. The larger the volume of water, the more violent the reaction becomes. Due to the possible reaction between water and molten zinc, only dry chemical or carbon dioxide extinguishers should be used in the vicinity of the HDG kettle.
National Fire Protection Association and OSHA
Sprinklers may be required to be installed by building codes or may be recommended by insurance companies to reduce potential property losses or business interruption. There is very little specific federal legislation regarding building codes, which are generally left to local jurisdictions. The National Fire Protection Association (NFPA) provides specifications for fire sprinkler usage and installation of sprinkler systems. HDG facilities are not commercial buildings and do not follow the same fire codes for sprinkler usage. Local building and fire authorities should be contacted regarding their specific codes or permits.
OSHA does not address fire sprinkler installation but adopts the NFPA specifications. OSHA focuses on the requirements of preventing fires in a workplace. OSHA’s regulations discuss the development of fire prevention and emergency action plans. Employees must be made aware of the fire hazards of the materials and processes with which they are exposed to. A written copy of the facility’s fire prevention plan must be kept in the workplace and made available for employees to review. Employers are required to review with each employee the parts of the plan necessary for self-protection.
Communication with Local Fire Authorities
Communication with the local fire department should include information on the existence and location of the HDG kettle. Signs should be posted at the building entrances stating that there is a molten zinc bath in the building. Another sign informing of the danger of explosion if water is used near the kettle should also be displayed.
Some cities may request a variance or exemption for fire sprinklers over the HDG kettle. Local authorities should be contacted to determine the city/state fire suppression requirements.
For more detailed information, the AGA has developed a Galvanizing Guideline on Fire Suppression Around Hot-Dip Galvanizing Kettles. This guideline is available in the Members Only section of the AGA website.
© 2019 American Galvanizers Association. The material provided herein has been developed to provide accurate and authoritative information about after-fabrication hot-dip galvanized steel. This material provides general information only and is not intended as a substitute for competent professional examination and verification as to suitability and applicability. The information provided herein is not intended as a representation or warranty on the part of the AGA. Anyone making use of this information assumes all liability arising from such use.