CFPS - Certified Fire Protection Specialist (CFPS)

In the plastics industry, the four broad areas of processing arepolymerization,conversion,finishing, andrecycling1.Polymerization is the process of creating plastic resins from monomers or pre-polymers, using chemical reactions such as addition, condensation, or ring-opening2.Conversion is the process of transforming plastic resins into plastic products, using various methods such as injection molding, blow molding, extrusion, rotational molding, and thermoforming3.Finishing is the process of adding value to plastic products, such as coating, printing, welding, or assembling4.Recycling is the process of recovering plastic waste and converting it into new plastic products or raw materials, using mechanical, chemical, or biological methods5. Therefore,manufacturingis not one of the four broad areas of processing in the plastics industry, as it is a general term that encompasses all the stages of producing plastic products from raw materials.References:

• Plastics Manufacturing: Types of Plastic and Processes - Deskera
• Plastics industry - Wikipedia
• Methods of Processing Plastic - Plastics Industry
• Plastic recycling - Wikipedia
• Polymerization - an overview | ScienceDirect Topics

The coefficient of discharge of a fire hydrant when the outlet is smooth and well-rounded is 0.90. This is the highest coefficient given by NFPA 291 for fire hydrant outlets, and it means that the stream is almost as large as the outlet diameter. The coefficient of discharge is a factor that accounts for the difference between the actual flow and the theoretical flow from an orifice, based on the shape and condition of the outlet1. A lower coefficient means that the stream is more restricted and has a smaller cross-sectional area than the outlet. NFPA 291 provides three coefficients for fire hydrant outlets, depending on how the outlet projects into the barrel: 0.90 for smooth and well-rounded outlets, 0.80 for outlets with a hexagonal or square projection, and 0.70 for outlets with a long projection or adamaged edge2. The coefficient of discharge is used to calculate the flow rate from the pitot pressure measured at the centerline of the stream3. References:

• Fire Fighting Foams - Chemguard
• Guide to Hydrant Flow Testing | WSRB
• New Fire Hydrant Flow Test Charts (PDF) - MeyerFire

When using water mist as an extinguishing mechanism, the effectiveness of a fine mist depends on the momentum and direction of the spray relative to the fire. The momentum and direction of the spray determine how well the mist can penetrate the fire plume and reach the flame zone, where the mist droplets can evaporate and cool the fire, displace oxygen, and dilute the fuel vapors. The mist spray should have sufficient momentum to overcome the buoyancy and entrainment of the fire plume, and the direction of the spray should be aligned with the fire plume to avoid deflection and dispersion. The ability of the mist to directly spray on the fire, how much mist diverts to the compartment boundaries, and how much conductive heat the mist system will absorb are not the main factors affecting the extinguishing effectiveness of a fine mist.

References:Water Mist Systems Overview | NFPA;Engineering Relations for Water Mist Fire Suppression Systems;Effectiveness of Swirl Water Mist Nozzles for Fire Suppression