Section 4 of the HITS report is probably the most important one. This section is really a print—out of the internal data structure that represents the piping network. This data is organized on the basis of topos.
A topo is a construction used to group the data representing the pipeline topology. By definition a topo is a string of piping that starts at a network endpoint or a branch point and ends at a network endpoint or another branch point. A pipeline network may consist of a single topo or dozens of topos depending upon its configuration.
Figure 6-1. Example line consisting of one topo.
The line in Figure 6-1 consists of one topo because it does not contain any branch points. The beginning of the topo is a line endpoint as is the end of the topo.
Figure 6-2. Example line consisting of two topos
The line in Figure 6-2 contains two topos due to the branch component in it (the tee). The first topo consists of the line from endpoint 1 to endpoint 2 (the header of the pipeline). The second topo consists of the piping from the center of the tee to line endpoint 3.
Figure 6-3. Example line consisting of three topos
The line in Figure 6-3 contains three topos because there are two branches in it. The first topo again consists of the line from endpoint 1 to endpoint 4. The second topo consists of the line from connect point 1 of weldolet 1 to endpoint 2. The third topo consists of the line from connect point 1 of weldolet 2 to endpoint 3.
Figure 6-4. Topo’s on a line that contains a loop
The line in Figure 6-4 consists of two topos. One topo is comprised of the line header from endpoint 1 to endpoint 2. The other topo starts at the center of one tee and goes to the center of the other tee.
Interpreting the HITS Report 6 - 17
The data in section 4 of the HITS report is sorted primarily by topo number. At the very beginning there are several lines where the topo number is zero. These are component origins which do not receive topo numbers or node numbers — they should be ignored.
Subsequent to the lines where the topo number is zero are lines for the first, second and subsequent topos.
The secondary sort key for the data in section 4 of the report is node number. Thus, within a topo the data is sorted by node number. This results in connect points with the same node number being adjacent to each other in the report. The result is that section 4 of the HITS report contains a trace of each topo of the line.
Example 1:
The following is an excerpt from a HITS report section 4:
Name cp# node topo
This trace consists of a single topo. The first endpoint is connect point 1 of a 90 degree elbow.
Connect point 2 of the elbow is connected to connect point 1 of a pipe. Following this logic, the sequence of components starting from the top is: elbow -> pipe -> elbow -> pipe -> valve -> pipe.
This same procedure may be followed to sketch out each network topo. Topo sketches are useful if you are interested only in the sequence of components in a particular region of the line. If you are interested in the entire network, connect the topos together.
The topos are connected together by the branch column in section 4 of the report. The branch column is used together with the last column. The last column in section 4 is a report line number. You can see by looking back at Figure 6-1 that the last column starts out at 1 and is incremented for each line in section 4. When the branch column contains a nonzero value then this indicates that the node is a branch point. The value of branch refers you to the line number of the report where the connecting topo begins.
Example 2:
The following is an excerpt from a HITS report section 4:
Name occ# cp# node topo branch
PIPE 10 1 -1 1 0 1
PIPE 10 2 1 1 5 2
PIPE 30001 1 1 1 5 3
PIPE 30001 2 2 1 0 4
WOL 15 1 1 2 -2 5
WOL 15 2 3 2 0 6
PIPE 35 1 3 2 0 7
PIPE 35 2 -1 2 0 8
The network is composed of two topos. Topo 1 is simply two pipes. Topo 2 consists of a weldolet connected to a piece of pipe. Note that the occurrence number of the second pipe in topo 1 indicates the model contains a single pipe which the software split into two at the olet.
Figure 6-5 shows the Network for Example 5.
Figure 6-5. Network for Example 2
The value for branch at node 1 is 5. Looking at line 5 in the report we see that it is the first line of topo 2. Thus topo 2 connects to topo 1 at node 1. This is confirmed by the fact that the node numbers where topo 2 connects to topo 1 match. That is, the WOL cp1, PIPE (occ 10) cp2, and PIPE (occ 30001) cp1 are all node number 1.
The value of branch for cp1 of the WOL is -2. The negative sign indicates that this is a "back pointer". The back pointer is exactly the same as any other branch value except that it (usually) points back to a previous topo rather than forward to a subsequent topo. Note that where two or more topos are connected together the branch numbers must agree. In
Example 5 they do. The back pointer on topo 2 points back to line 2 while the forward pointer on topo 1 points to line 5.
In Example 2, the branch flag pointed to the start point of the connecting topo. It can also happen that the branch flag points to the endpoint of the connecting topo. In this case you traverse the topo in reverse order.
Example 3:
Name occ# cp# node topo branch .
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In Example 3, topo 3 consists of pipe, elbow, pipe, pipe. Topo 7 is a typical drain assembly—
plug, block valve, nipple, sockolet. Topo 7 connects to topo 3 at line 53 in the report (the value of branch on line 25 is 53 and the value of branch of line 53 is -25). In this case, the value of branch on topo 3 points to the bottom of topo 7 and the network structure is obtained by moving up topo 3 rather than down (See Figure 6-6).
Figure 6-6. Network for Example 3
Example 4:
The following data is from section 4 of a HITS report:
Name Occ cp# Node Topo Branch
90E 37 1 -1 1 0 1
T 36 2 6 1 15 12
In Example 4, the tee is slightly different from the olet type components. Branch flags are set on both connect points 1 and 2 of the T and the node numbers do not match where topo 2 connects to topo 1. This is a consequence of the fact that node numbers are not assigned to component origins. See Figure 6-7 which shows the Network for Example 4.
Figure 6-7. Network for example 4
Example 5:
Name Occ cp# Node Topo Branch
PIPE 23 1 -1 1 0 1
In Example 5, topo 1 consists of a pipe connected to an eccentric reducer which in turn is connected to another pipe. Notice, however, that the branch flag is set to two different numbers on the reducer. This indicates that the reducer is tapped twice. The branch flag on the first connect point points to the topo connected at the first tap while the branch flag on the second connect point points to the topo connected to the second tap. A tap is always a branch starting point and thus is always the start point of a new topo. Refer to Figure 6-8, which shows the network for Example 5.
Interpreting the HITS Report 6 - 21
Figure 6-8. Network for Example 5
If you generate some HITS reports and practice sketching out the pipeline networks, you will become familiar with the report contents and better understand the concepts presented in the examples above.
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