消防流量和压力限值对供水管网建造成本的影响规律

Influence of fire flows and pressure limits on construction costs of water distribution systems

为探究消防流量和压力限值对供水管网建造成本的影响,建立以最小化建造成本和消防工况欠压为目标的多目标优化模型,并运用NSGA-Ⅱ算法求解该模型。基于ZJ管网的结果表明:建造成本与设计消防流量呈正相关,且基本符合一次函数回归模型。当消防压力限值为10 mH_(2)O时,消防流量每增加100 L/s,管网建造成本增加约16万元。随着消防压力限值的提高,建造成本和消防流量的拟合一次函数斜率也在增加;但消防压力限值从10 mH_(2)O增加到24 mH_(2)O时,拟合一次函数的斜率增幅有限。这表明在建造成本增幅很小的情况下,可以适当提高消防流量和压力限值的设计标准,从而大幅提高供水管网的消防安全性。

In order to explore the influence of fire flows and pressure limits on the construction costs of water distribution systems, a multi-objective optimization model was established, aiming at minimizing both construction costs and pressure deficiencies under firefighting conditions. The model was solved by the NSGA-Ⅱ algorithm. Results of the ZJ network show that the construction costs have a positive correlation with the designed fire flows and generally conform to the linear regression function. When the fire pressure limit is 10 m, the construction cost of the ZJ water distribution system increases by about 160 000 CNY for every 100 L/s increase of fire flows. With higher fire pressure limits, the construction costs and the slopes of the linear regression function of fire flow also increase. However, when the fire pressure limit increases from 10 mH;O to 24 mH;O, the increase in terms of the slope of the linear regression function of fire flows is quite limited. These findings suggest that with a marginal increase in construction costs, the design standard in terms of the fire flow and pressure limit can be improved appropriately to improve the fire safety of water distribution systems.