The GRID Tab Page
This Tab page provides access to another set of tab pages where a GRID can be entered.
When the design configuration is a rectilinear grid, the input data can be significantly simplified. The standard grid systems that can be modeled are shown on the Select Tab Page.
Because the program automatically numbers pipes and nodes when the GRID commands are used, a considerable amount of time and effort can be saved if the GRID commands are used even for a relatively simple tree system.
Definitions
For the purpose of defining the grid the following definitions apply.
Main Pipes Left and Right (MPL and MPR) are the two sets of main supply pipes for the grid. They can change size at the junction with any range pipe and can contain fittings.
Main pipe Centre (MPC) - is a third main pipe if required similar to the MPR and MPL.
Range pipes (RNG) - are the pipes running between the left, centre and right hand main supply pipes. They are assumed to be all equally spaced. A tee is automatically inserted at each branch from the main pipe and the user can enter additional fittings for each section of pipe in each range pipe, e.g. a straight through tee.
Outrigger pipes left and right are the dead feed pipes to the left and right of a main pipe, referred to as Tree Left (TL) and Tree Right (TR). They are assumed if present, to be equal in number to the range pipes and at the same spacing. A tee is automatically inserted at each branch from the main pipe and the user can enter additional fittings for each section of pipe in each range pipe.
Rows and columns - correspond to nodes on the grid with rows numbering from the bottom left hand corner up the page and columns numbering from the same origin but from left to right across the page.
This concept of rows and columns is used in specifying the elevation of all pipe intersections and sprinklers in the grid (on the Elevations Tab Page) and in nominating the sprinklers that are operating (on the Operating Sprinklers Tab Page).
The Numbering System for Pipes and Nodes in the GRID
The sprinklers and range and tree pipes in the grid are numbered consecutively starting from the bottom left sprinkler. The first sprinkler and pipe are numbered (by default) 2000.
The left hand Main has nodes that are numbered starting, by default with 7000 and increasing by 1. The pipe joining nodes 7000 and 7001 will be numbered 7000, and so on. If the centre main pipe is entered the nodes for these pipes are numbered by default starting at node 8000 and pipe 8000 and if the right hand side Main pipe is included, they are numbered similarly by default, starting at node 9000 and pipe 9000.
When the RMP (Rising Main Pipe) command is used a new set of nodes are created at the junction of the riser pipes with the range and tree pipes. If "j" is the number of ranges or rows (i.e. the number of Main Pipes plus 1), then these nodes are numbered 7000+j, 7001+j, etc. for the left side of the grid, 8000+j, 8001+j, etc., for the centre of the grid and 9000+j, 9001 +j, etc. for the right side.
There will be j risers associated with the left-hand main pipes, and if the centre main pipe exists, another j riser pipes associated with them, and similarly, if the right-hand main pipes exist, another j riser pipes associated with them. Riser pipes on the left side will be numbered 7000+j, 7001+j, etc. with pipe 7000+j connecting node 7000 to 7000+j. Similarly, riser pipes in the centre are numbered 8000+j, 8001+j, etc., and pipes on the right side are numbered 9000+j, 9001+j etc.
Note that if the riser pipes exist, it is most probable that the pipe or pipes feeding water to the grid will connect to a Main Pipe e.g. node 7000 not at the top of the riser (node 7000 + j), however additional pipes outside the grid can be connected to any node in the grid.
The screens for the GRID are:
Select
On this Tab Page the type of GRID is selected before entering the subsequent tab pages that allow the user to enter the details of the selected GRID. The required Main pipe, Ranges, etc, input tables are generated in these screens according to the GRID type selected.