This rule ensures that a pipe slopes appropriately and warns when a pipe is placed too close to a ground surface.
For gravity-based systems, this is perhaps the most useful rule. It ensures that a pipe slopes in the desired direction under various conditions, while ensuring that minimum cover is not exceeded. In addition, it manages conditions when a pipe drop across structure rule conflicts with the pipe’s gradient and cover rules.
When drawing a pipe, the pipe attempts to stay within minimum and maximum cover values, unless the minimum or maximum gradient is reached. At that point, maximum cover distance is exceeded to satisfy the minimum gradient requirement, if it is violated.
This rule ensures the following:
- The connections to structures are at a location as specified by the structure rules, if any are specified.
- The pipe always slopes in the proper direction, with the minimum gradient being honoured, unless this is in conflict with a connected structure.
- The minimum cover is maintained unless this is in conflict with a connected structure.
Note: The Cover and Gradient Pipe rule applies to pipes starting from upstream to downstream. A front pipe may cover a back pipe, though the rule applied to a back pipe may cover the front pipe. It is important to make sure that all pipes to which the rules are applied have same flow direction.
Parameters
The following parameters govern the behaviour of the pipe Cover And Gradient rule.
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Maximum Cover. Specifies the maximum cover of soil over the length of the pipe, based on the surface being referenced by that pipe. If the maximum cover is exceeded, a rule violation occurs. Note that this parameter provides validation only; it does not alter (move or resize) the part in the drawing in any way. It simply produces a rule violation on the part if the specified value is exceeded.
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Maximum Gradient. Specifies the maximum gradient of the pipe, expressed in percent. If the pipe gradient is greater than the maximum, a rule violation occurs for that object.
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Minimum Cover. Specifies the minimum cover of soil over the pipe, based on the surface being referenced by that pipe. If no surface is referenced, then the surface level is 0. During layout, a pipe will be created that attempts to maintain the minimum cover. This is also used to determine the initial levels of the pipe. If the pipe is edited so that its cover is less than the minimum cover value, a rule violation occurs for that object.
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Minimum Gradient. Specifies the minimum gradient of the pipe, expressed in percent. If no surface is referenced, then the surface level is 0. During layout, a pipe will be created according to its minimum gradient rule value. If the pipe is edited so that its gradient is less than the minimum, you can still edit the pipe as desired, breaking the minimum gradient rule, but a rule violation occurs for that object.