Unit23
补中益气丸的功效与作用 The history of organized fire-fighting dates back to the ancient Romans, who introduced the first public water supply system and organized “Vigiles”(watchmen of the city) to combat fires using methods such as bucket-brigades .Since that time, the planning and design of water systems for fire suppression has evolved significantly to limit loss of life and property. While advanced fire suppression systems in buildings and brave firefighters are responsible for directly combating today’s fires, water system utilities must have the necessary water main and hydrant infrastructure in place to deliver adequate fire flows throughout their systems.
Determining if a water distribution system can provide adequate fire flow throughout a rvicearea can require significant data collection,andthousands of hydraulic calculations to account for the numerous possible fire flow scenarios that could occur. Performing this type of analysis may em like a daunting endeavor; however, there are modern computer software and analysis tools that can be leveraged to make this a very manageable effort. This paper provides an overview of how current hydraulic modeling and GIS technologies can be ud to help utilities effectively and efficiently evaluate the fire suppression capabilities of their water system. A ca study that illustrates how a Florida water utility has recently utilized the technologies to analyze and improve their fire suppression capabilities is also provided.
Overview of fire suppression planning for water utilities
月亮的变化过程
Fire suppression planning for a water utilityshould include the following steps:
1. Define fire suppression requirements and goals;
2. Evaluate water distribution system infrastructure and operations to determine any current or projected future fire flow delivery issues;
3. Evaluate system improvement options to address fire flow delivery issues; and
4. Develop recommended system improvements and/or operational modifications.
淘气的拼音Defining fire suppression requirements and goals
The first step in fire suppression planning for a water distribution system is to define the fire suppression
requirements and goals for the rvice area. The fire suppression goal that are lected can have a significant on the water system infrastructure requirements and operating protocol for the system.
Defining the goals should be a collaborative effort between the water utility departmentand the fire department. City managers and Key
微信请帖
staff from other municipal departments such as land-u planning and building and development should also be included. It is common for a municipality to develop a Fire Prevention and Protection Code by adopting guidelines from
water industry reference manuals such as AWWA manuals M31 (Distribution System Requirements for Fire Protection) and M32 (Computer Modeling of Water Distribution Systems). The AWWA manuals reference information published by the Insurance Services Office (ISO), which is an advisory organization that provides guidelines for property and casualty insurance companies to reat acommunity’s local fire protection capabilities
Examples of the type of distribution system requirements for fire suppression that should be defined include:
西晋王朝Minimum fire flow delivery requirements : The flowrate required for fire suppression in an area will vary significantly bad on the type of structure being rved. A single family residential property will have a significantly lower fire flow requirement than a high-ri condominium building or commercial building. For a duration of 2 hours , whereas the fire flow required for a highri building may be 3500 gpm for a 3 hour duration.
Minimum system pressures to be maintained during a fire flow event : A typical requirement for fire suppression planning is to be able to maintain a minimum of 20 psi pr
essure throughout the distribution system while operating under maximum day demand conditions and also meeting the demand requirements of a fire flow event anywhere in the system where fire rvice is provided by the utility.打雪仗英文
Fire hydrant spacing: The number of fire hydrants that must be located within a specified distance from a structure should be defined. The number of hydrants required and the proximity of the hydrants to the structure can vary depending on the type of structure rved. For example, a low density residential area may only require a single hydrant to be located within 500 feet of each property.
望庐山Minimum water storage capacity maintained for fire flow events: The amount of storage capacity that should be rerved for fire protection is typically defined by multiplying the maximum fire flow needed in the system by a specified maximum duration. For example , a municipality may have a maximum fire flow of 3500 gpm for a duration of 3 hours. This would result in a total fire flow volume requirement of 630000 gallons. The average daily minimum water storage capacity for the system should be grater than the calculated maximum fire flow volume requirement. Evaluating system infrastructure and operations
