Fire Water Systems

Explosion shortly after plant turnaround caused impact to incoming power and fire water system 4,500,000 loss... 

Facilities with a maximum foreseeable loss of greater than X shall be protected by a looped fire water system equipped with redundant fire pumps. 

Facilities shall be protected by fire water systems that are designed in accordance with NFPA 20 and NFPA 24. 

Fire protection systems should be maintained until materials that pose a hazard are removed. A fire water system should be the last item removed or deactivated. When necessary, decommissioning plans must be reviewed with the AHJ. Fires have occurred during removal of equipment due to cutting operations, material still in the equipment, and other hazards. A separate fire hazard analysis should be conducted to determine fire hazards that may be present during a decommissioning of a unit or plant. 

Quite often jetties are fitted with their own water pumps, taking suction into the sea or river. The jetty fire water grid is often connected to the main plant fire water system as a backup. Care should be taken to avoid seawater corrosion of the main site fire water system. 

Normally, fire water demands range between 2,000 and 10,000 gpm (7,600 to 38,000 Ipm). The design capacity of the fire water system should be at a minimum four (4) hours of continuous operation of the largest fire water demand. The capacity is based on a number of factors, including ... 

Valves used in a fire water system should be of a type such that their position, open or closed, can be readily determined, e.g., rising stem, post indicator. A post-indicator valve is shown in Figure 7-9. 

If marine facilities are connected to a fire water system, an appropriate connection should be provided for the fireboatthat could be used at the facility. 

On large fire water systems, the location of pumps and storage tanks at various plant areas provides greater reliability of protection and results in less pressure drop between the pump and the area of demand. Net positive suction head (NPSH) requirements and friction loss in the piping should be considered in locating fire water pumps. 

When the fire water system will be routinely used for purposes other than firefighting (e.g., washdown), the pressure maintenance pump, typically 150-300 gpm (570-1,150 Ipm), should have sufficient capacity for such use or a separate service pump should be provided. The service pump need not meet the requirements for fire water pumps. 

VIII Appendices Useful reference materials such as maps, fire water system diagrams, critical utility emergency shut off points, names and contacts for service providers should be Included. 

If trained to do so and confident that you are capable, activate any fire monitors and/or fixed fire water systems in the immediate area and attempt to cool the tank and surrounding equipment. If the tank is receiving material or product, close a valve on the inlet line at a safe location. Stand by to direct the Emergency Response Team (ERT) to scene Use appropriate Personal Protective Equipment (PPE) First Responder... 

Will the gas detection systems, fire-water systems, diking or drainage need... 

Some of the detailed information, such as fire water systems and Personal Protective Equipment that were in the first edition of this book have been moved to the new book, Design and Operation of Process Facilities. 

AEs) - Fire water system - Central Control Room... 

As delineated in the K-Reactor Cold Standby Plan, L-Reactor Cold Shutdown Plan, and the P-Area Standby Plan (BjtC 6-48,6-49,6-62) fire hazards were significantly reduced in Cold Standby of K-Reactor and Cold Shutdown of L- and P-Reactors due to systems being drained of flammable liquids, tranrieot combustibles being removed, and work being reduced inside K-, L-. and P-Reactors. Nonessential batteries were, removed from the areas and nonessentiai systems were de-energized. The fire patrol has been replaced by operators utilizing operator round sheets (Ref 6-63, 6-7, and 6-8). Fire protection is supported by the currently installed fire water system... 

Every industrial plant is protected by a fire water system that provides water to each piece of equipment through hydrants, monitors, or deluge spray systems. Each process unit has its own underground piping loop system, which is adequately valved to protect the system from a failure in any part of the line or isolation because of maintenance. Although each piece. of equipment must be protected by one hydrant or monitor, client specifications often override this rule and require two sources of fire water for each piece of equipment. Basic fire protection equipment consists of fire hydrants, hydrants with monitors, grade-level and elevated monitors, hose reels, and deluge and spray systems. 

Although each plant must conform to local firefighting rules and regulations, client interpretation of tho.se regulations can produce t tly different fire water system layouts. Early consultation with each client is strongly su ested before a complete systems layout is developed. 

To provide a maigin of safety in the fire water system, the fire water loop is fed from opposite ends of the unit—Enough block valves are provided to ensure the overall firefighting capabilities of the system in the event of a rupture in the fire water loop. The number of valves placed in the header is subjective and is submitted to the client for approval. 

The layout of a fire water system in a process unit is usually accomplished in the following way ... 

The safety and risk of facility cannot be assessed solely on the basis of firefighting systems, e.g., we have a plant fire water system, or past loss history, e.g., we never had a fire here for 25 years, so we don t expect any.The overall risk can only be assessed by thorough risk analysis for the facility and the risk philosophy adopted by senior management for the organization. 

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