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Set maximum velocity constraints and run the fireflow analysis on a specified domain.
Type:
Tutorial
Length:
8 min.
Transcript
00:03
Maximum velocity constraints can be applied to any firef flow analysis
00:08
to ensure the available flow at the hydrant,
00:10
maintains the user specified minimum pressure.
00:12
While the targeted pipes do not exceed the user defined velocity
00:17
results from this additional constraint can help identify pipes
00:20
that are exceeding the maximum velocity or experiencing pipeline restrictions
00:25
to begin.
00:26
Double click the desired project dot APR X file to open RGI
00:30
Pro.
00:31
Once the project starts,
00:33
click the info water pro tab to open the info water pro ribbon
00:37
in the project panel, click initialize,
00:41
you will perform the firef flow analysis
00:43
only on the junctions hydrants in the domain
00:47
on the info water pro ribbon
00:48
in the domain panel, click domain manager
00:52
in the domain manager for the element source select network,
00:57
then expand the drop down, select all pipes and then click add.
01:02
Now the firef flow simulation will be limited to the hydrants in the domain.
01:06
However,
01:07
the maximum velocity constraint will be applied to all pipes in the system.
01:12
Click close to close the domain manager.
01:15
A well defined search range is critical to modeling
01:18
velocity constraints as certain pipes may artificially cap the results
01:22
when identifying search range pipes consider excluding hydrant stubs
01:26
and other tiny lines such as six inch pipes,
01:30
smaller pipes will always have higher velocities.
01:32
So they will artificially limit the fire flow results to smaller amounts.
01:37
For example, based on flow rate calculations, a 10 FPs
01:41
constraint within a six inch pipe will limit flow to 881 GPM.
01:47
Additionally,
01:48
consider leaving out virtual bypass lines as
01:51
they do not actually exist within distribution
01:53
systems and are only digitized in specific
01:55
situations such as modeling combo valves.
01:59
These pipes will often be assigned a small diameter.
02:01
So they will have a similar effect on the results as you
02:04
would get including a six inch pipe within the search range.
02:08
Following these guidelines will help identify
02:10
main lines and realistic pipes where
02:12
the velocity constraint makes sense to apply to your search range.
02:16
Run the simulation
02:18
on the info water pro ribbon
02:20
in the analysis panel, click run
02:23
in the run manager on the firef flow tab.
02:26
Make sure that run firef flow on domain only is enabled,
02:30
then enable max velocity and set the value to 10,
02:39
But be sure to check your local standards criteria and use that value. If it differs.
02:44
Additionally, expand the pipe search range, drop down and select domain pipes,
02:50
then click run
02:52
the Firefly report opens automatically in the report manager.
02:56
If you are prompted to switch to the most recent output data. Click yes.
03:01
Review the report
03:03
sort.
03:03
The hydrant pressure at available flow and
03:05
critical pipe velocity at available flow fields to
03:08
identify which of these two parameters was most
03:10
constraining to the hydrant available flow calculations.
03:15
The results within the hydrant pressure at available flow field that are equal
03:19
to the user defined residual pressure setting or 20 psi in this example,
03:23
indicate that the hydrant available flow was constrained by the residual pressure
03:28
values greater than the user defined residual pressure.
03:31
Mean that the hydrant available flow was recalculated
03:34
and constrained by the critical pipe velocity.
03:38
When you are finished reviewing the results,
03:40
return to the domain manager and click remove to remove all pipes from the domain.
Video transcript
00:03
Maximum velocity constraints can be applied to any firef flow analysis
00:08
to ensure the available flow at the hydrant,
00:10
maintains the user specified minimum pressure.
00:12
While the targeted pipes do not exceed the user defined velocity
00:17
results from this additional constraint can help identify pipes
00:20
that are exceeding the maximum velocity or experiencing pipeline restrictions
00:25
to begin.
00:26
Double click the desired project dot APR X file to open RGI
00:30
Pro.
00:31
Once the project starts,
00:33
click the info water pro tab to open the info water pro ribbon
00:37
in the project panel, click initialize,
00:41
you will perform the firef flow analysis
00:43
only on the junctions hydrants in the domain
00:47
on the info water pro ribbon
00:48
in the domain panel, click domain manager
00:52
in the domain manager for the element source select network,
00:57
then expand the drop down, select all pipes and then click add.
01:02
Now the firef flow simulation will be limited to the hydrants in the domain.
01:06
However,
01:07
the maximum velocity constraint will be applied to all pipes in the system.
01:12
Click close to close the domain manager.
01:15
A well defined search range is critical to modeling
01:18
velocity constraints as certain pipes may artificially cap the results
01:22
when identifying search range pipes consider excluding hydrant stubs
01:26
and other tiny lines such as six inch pipes,
01:30
smaller pipes will always have higher velocities.
01:32
So they will artificially limit the fire flow results to smaller amounts.
01:37
For example, based on flow rate calculations, a 10 FPs
01:41
constraint within a six inch pipe will limit flow to 881 GPM.
01:47
Additionally,
01:48
consider leaving out virtual bypass lines as
01:51
they do not actually exist within distribution
01:53
systems and are only digitized in specific
01:55
situations such as modeling combo valves.
01:59
These pipes will often be assigned a small diameter.
02:01
So they will have a similar effect on the results as you
02:04
would get including a six inch pipe within the search range.
02:08
Following these guidelines will help identify
02:10
main lines and realistic pipes where
02:12
the velocity constraint makes sense to apply to your search range.
02:16
Run the simulation
02:18
on the info water pro ribbon
02:20
in the analysis panel, click run
02:23
in the run manager on the firef flow tab.
02:26
Make sure that run firef flow on domain only is enabled,
02:30
then enable max velocity and set the value to 10,
02:39
But be sure to check your local standards criteria and use that value. If it differs.
02:44
Additionally, expand the pipe search range, drop down and select domain pipes,
02:50
then click run
02:52
the Firefly report opens automatically in the report manager.
02:56
If you are prompted to switch to the most recent output data. Click yes.
03:01
Review the report
03:03
sort.
03:03
The hydrant pressure at available flow and
03:05
critical pipe velocity at available flow fields to
03:08
identify which of these two parameters was most
03:10
constraining to the hydrant available flow calculations.
03:15
The results within the hydrant pressure at available flow field that are equal
03:19
to the user defined residual pressure setting or 20 psi in this example,
03:23
indicate that the hydrant available flow was constrained by the residual pressure
03:28
values greater than the user defined residual pressure.
03:31
Mean that the hydrant available flow was recalculated
03:34
and constrained by the critical pipe velocity.
03:38
When you are finished reviewing the results,
03:40
return to the domain manager and click remove to remove all pipes from the domain.
Maximum velocity constraints can be applied to any fireflow analysis to ensure the available flow at the hydrant maintains the user-specified minimum pressure while the targeted pipes do not exceed the user-defined velocity. Results from this additional constraint can help identify pipes that are exceeding the maximum velocity or experiencing pipeline restrictions.
To perform the fireflow analysis only on the junctions (hydrants) in the domain:
Note: The fireflow simulation will now be limited to the hydrants in the domain; however, the maximum velocity constraint will be applied to all pipes in the system.
To run the simulation:
Note: Ten feet per second is a common velocity constraint used for these simulations; however, check your local standards criteria and use that value if it differs.
The Fireflow report opens automatically in the Report Manager.
To identify which of these two parameters was most constraining to the hydrant available flow calculations:
The results within the Hydrant Pressure at Available Flow field that are equal to the user-defined Residual Pressure setting, or 20 psi in this example, indicate that the Hydrant Available Flow was constrained by the residual pressure. Values greater than the user-defined Residual Pressure mean that the Hydrant Available Flow was recalculated and constrained by the critical pipe velocity.
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