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HomeMy WebLinkAboutIslamorada NFPA 652 DHA DS(1)NFPA 652 Dust Hazard Analysis for Islamorada Brewery North 3200 St. Lucie Boulevard Fort Pierce, FL 34946 Prepared For: Mr. Tyrone Bradley, President, Co-Founder Islamorada Beverages 82229 Overseas Highway Islamorada, FL, 33036 5/27/2021 Page | 2 A) Requirement A Dust Hazard Analysis (DHA) is mandatory per and shall be conducted in accordance with NFPA 652, Standard on the Fundamentals of Combustible Dusts. A DHA is a structured approach to identify, then manage the risks associated with dusts at different locations within the area where it is produced or can accumulate. B) Process, Hazard Identification, and Material Properties The building and silo are used to brew various types of beer. Grain is trucked to the site and off loaded into a silo located outside the building. The grain is then moved into the building by a series of augers and a closed piping system. The augers are intrinsically safe. The full kernel grain piped up and dropped into the mill and cracked into several large pieces. These pieces are then transferred into a vat where they are soaked in water inside the brew house through a closed pipe system by use of a flex auger. This process typically occurs four times per day five days a week. The process entails approximately fifteen (1500) hundred pounds of grain per batch, which equates to six (6000) pounds daily. The hazard becomes present (the creation of dust) when filling the silo, during transfer, and during the milling of the grain. The material properties for the primary grain used is for Barley. Barley becomes a hazardous dust when the particle size of the dust is less than 50 microns. The minimum ignition energy for barley dust is greater than 50 mJ. The minimum ignition temperature is 450° C (842° F) and the minimum explosive concentration is 55 g/m³ (.05oz/ft³.) Pmax is 10 and kst is 152. The Explosion Class is St1. C) Analysis of the Hazard Areas of where the combustible dusts are present include 1. Outside when the grain truck is off loading the truck into the silo. 2. Inside the conveying system when moving the grain from the silo into the building. Note: as stated before this is a closed piping system that use flexible augers and intrinsically safe motors and includes intrinsically safe milling to convey the grain throughout the entire process.) 3. At the hopper, one bag of grain is manually added at each process cycle. This process creates a nominal and insignificant amount of dust. D) Areas of Ignition Sources 1. Electrostatic discharge can occur while the grain truck is off loading into the silo. 2. Electrostatic discharge can occur at the hopper while grain is conveyed. 3. All equipment in the conveying process can be a source of ignition. 4. Electrical equipment and components in the location of combustible dust such as motors. 5. Heat sources such as cutting or welding in the area of combustible dust. 6. Overheating of motors or other mechanical moving parts. E) Classify the Hazard 1. The silo is a possible risk for a dust explosion when the grain truck is off loading into the silo. 2. Dust is present within the closed conveying system, however since the piping system is full of grain and limited dust is present, however the risk is negligible and unlikely to cause an explosion since no dust cloud is present. 3. Dust is present at the hopper/mill machine; however, the risk is negligible and unlikely to cause an explosion Page | 3 since no dust cloud is present. 4. Dust is present where the cracked grain is dumped from the conveyance system unto the vats. This process has a dust collection system, and the risk is negligible and unlikely to cause an explosion since no dust cloud is present. F) Deflagration Hazard Potential To determine if a deflagration hazard exists within the building or within the silo, NFPA 654, Standard for the Prevention of Fire and Dust Explosions from Manufacturing, Processing, and Handling of Combustible Particulate Solids is the governing document recognized as an industry standard. Section 6.1.3 identifies for a potential to exist, more than 1/32” (approximately the thickness of a paperclip) covering at least 5% of the total floor area must be present for a dust flash fire or dust hazard to exist. Neither of these two conditions were present at the facility due to proper housekeeping. The electrical motors used in the conveying and milling process are totally enclosed fan cooled motors. These types of motors are approved for Class II Division 2 Group G per NFPA 70, National Electric Code. Electrical wiring and equipment within thirty (30’) of the dust source must comply with Class II Division 2 requirements. No dust cloud is present during operations and no area was observed with more than 1/32” dust layer anywhere in the facility. G) Management of Hazard 1. Controlling points of ignition – ▪ All existing and future electrical equipment and wiring in the area where dust is created, or the potential dust hazard exists shall be rated for Class II Division 2 per the National Electrical Code. ▪ All existing and future equipment in the area where dust is created, or the potential dust hazard exists shall be properly grounded. ▪ Install or use methods to prevent the buildup of static electricity. ▪ Implement an internal hot work permit program that will regulate the use of open flames such as welding. ▪ Designate the brewery portion of the business as non-smoking. ▪ Isolate heated surfaces from dust exposure. 2. Housekeeping • Minimize dust buildup within the brewery with a proper housekeeping plan. The plan shall designate practices which eliminate the accumulation of dust through good housekeeping practices. The goal is to never allow the buildup of 1/32” of dust in any area of the facility regardless of the previously mentioned five (5%) percent floor area factor which includes floors, vats, electrical equipment, ducts, lights, bar joists, trusses, and any other horizontal surfaces. • Regular cleaning of all areas subject to the buildup of combustible dust shall be implemented. • Tether the grain supply truck to the silo and open the explosion roof hatch prior off-loading the grain. • Create a process to monitor and manage the dust collection system at the vat in the brew room and implement it to ensure proper collection of dust when the vat is filled with grain.