# Medium Problems

## NYT

The NYT is comprised of twenty-one pipes organised in two loops, nineteen demand nodes, and one reservoir with a fixed head of 300 ft (1 ft=0.3048 m). All the existing pipes are considered for duplication in order to meet the projected future demand. The Hazen-Williams roughness coefficient for both new and existing pipes is 100. The minimum pressure of all demand nodes is fixed at 255 ft except for node 16 and 17 that are 260 ft and 272.8 ft, respectively. A selection of fifteen diameter sizes are available as well as a ‘do nothing’ option. Table NYT.1 shows the diameter options and associated unit costs. Figure NYT.1 depicts the layout of NYT.

 Table NYT.1. Diameter options and associated unit costs of NYT
 Figure NYT.1. Layout of NYT (Undetermined pipes are shown in red lines.)

## BLA

Blacksburg Network (BLA) consists of thirty-five pipes of which twelve have fixed diameters, one reservoir with a fixed head of 715.56 m, and thirty demand nodes. A universal Hazen-Williams coefficient of 120 is applied to all the pipes under consideration. The pressure requirement of each node is limited within a specified range under the single loading condition. The minimum pressure head for each node is 30 m, while the maximum pressure head varies from node to node and is provided in Table BLA.1. Table BLA.2 shows commercially available diameters and the corresponding unit costs. Figure 5 depicts the layout of BLA.

 Table BLA.1. Maximum pressure head requirement of each node of BLA ‌
 Table BLA.2. Diameter options and associated unit costs of BLA ‌
 Figure BLA.1. Layout of Blacksburg Network (Undetermined pipes are shown in red lines.) ‌

## HAN

Hanoi network consists of thirty-four pipes organised in three loops, thirty-one demand nodes and one reservoir with a fixed head of 100 m. The Hazen-Williams roughness coefficient for all pipes is 130. The minimum head above the ground elevation of each node is 30 m. There are six commercially available pipe sizes, ranging from 12 in. to 40 in. (1 in.=0.0254 m). Table HAN.1 shows the diameter options and associated unit costs. Figure HAN.1 depicts the layout of HAN.

 Table HAN.1. Diameter options and associated unit costs of HAN ‌
 Figure HAN.1. Layout of HAN ‌

## GOY

GoYang Network includes thirty pipes, twenty-two demand nodes, and one constant pump of 4.52 kW linking to one reservoir with a constant head of 71 m. The Hazen-Williams roughness coefficient for each new pipe is 100. The minimum pressure head above the ground elevation of each node is 15 m. Table GOY.1 shows commercially available diameters and the corresponding unit costs. Figure GOY.1 depicts the layout of GOY..

 Table GOY.1. Diameter options and associated unit costs of GOY ‌
 Figure GOY.1. Layout of GOY ‌