| UNITS | CFS / GPM / MGD / IMGD / AFD / |
| | LPS / LPM / MLD / CMS / CMH / CMD |
-| PRESSURE | PSI / KPA / METERS |
+| PRESSURE | PSI / KPA / METERS / FEET / BAR |
| HEADLOSS | H-W / D-W / C-M |
| HYDRAULICS | USE / SAVE filename |
| VISCOSITY | value |
@@ -342,9 +342,9 @@ __Definitions:__
- \b CMH = cubic meters per hour
- \b CMD = cubic meters per day
-For CFS, GPM, MGD, IMGD, and AFD other input quantities are expressed in US Customary Units. If flow units are in liters or cubic meters then Metric Units must be used for all other input quantities as well. (See the @ref Units topic). The default flow units are \b GPM.
+For CFS, GPM, MGD, IMGD, and AFD other input quantities are expressed in US Customary Units. If flow units are in liters or cubic meters then Metric Units must be used for all other input quantities as well. (See the @ref Units topic). An exception is pressure which can use either US or SI units. The default flow units are \b GPM.
-\b PRESSURE sets the units in which pressure is expressed, for networks using metric units, as determined by the \b UNITS option, the choices are: \b KPA, or \b METERS. For networks using US Customary Units, you can only use \b PSI.
+\b PRESSURE sets the units in which pressure is expressed, regardless of which unit system is in use. The default pressure unit is \b PSI for US Customary Units and \b METERS for SI Metric Units.
\b HEADLOSS selects a formula to use for computing head loss for flow through a pipe. The choices are the Hazen-Williams (\b H-W ), Darcy-Weisbach (\b D-W ), or Chezy-Manning (\b C-M ) formulas. The default is \b H-W.
@@ -374,7 +374,7 @@ The \b HYDRAULICS option allows you to either SAVE the current hydraulics
\b MINIMUM PRESSURE is the pressure below which no demand can be delivered under a pressure driven analysis. It has no effect on a demand driven analysis. Its default value is 0.
-\b REQUIRED PRESSURE is the pressure required to supply a node's full demand under a pressure driven analysis. It has no effect on a demand driven analysis. It must be at least 0.1 psi or m higher than the MINIMUM PRESSURE, which is also its default value.
+\b REQUIRED PRESSURE is the pressure required to supply a node's full demand under a pressure driven analysis. It has no effect on a demand driven analysis. It must be at least 0.1 pressure units higher than the MINIMUM PRESSURE, which is also its default value.
\b PRESSURE EXPONENT is the power to which pressure is raised when computing the demand delivered to a node under a pressure driven analysis. It has no effect on a demand driven analysis. Its default value is 0.5.
diff --git a/doc/toolkit-units.dox b/doc/toolkit-units.dox
index db30aa2..e5ee997 100644
--- a/doc/toolkit-units.dox
+++ b/doc/toolkit-units.dox
@@ -2,7 +2,7 @@
/**
@page Units Measurement Units
-The toolkit can use data expressed in either US Customary of SI Metric units. A project's unit system depends on the unit system used for its choice of flow units. If the @ref EN_open function is used to supply data to a project from an Input File then its flow units are set in the @ref OptionsPage section of the file. If the @ref EN_init function is used to initialize a project then the choice of flow units is the fourth argument to the function. The following table lists the units used to express the various parameters in an EPANET model.
+The toolkit can use data expressed in either US Customary of SI Metric units. A project's unit system depends on the unit system used for its choice of flow units. If the @ref EN_open function is used to supply data to a project from an Input File then its flow units are set in the @ref OptionsPage section of the file. If the @ref EN_init function is used to initialize a project then the choice of flow units is the fourth argument to the function. An exception to this convention is pressure whose units can be expressed in either US or SI units. The following table lists the units used to express the various parameters in an EPANET model.
| Parameter | US Customary | SI Metric |
|----------------|-------------------------|---------------------------|
@@ -25,7 +25,9 @@ The toolkit can use data expressed in either US Customary of SI Metric units. A
|Length | feet | meters |
|Minor Loss Coeff. | unitless | unitless |
|Power | horsepower | kwatts |
-|Pressure | psi | meters or kPa |
+|Pressure | psi (pounds / sq. in.)| meters |
+| | feet | kPa (kiloPascal) |
+| | | bar |
|Reaction Coeff. (Bulk) | 1/day (1st-order)| 1/day (1st-order) |
|Reaction Coeff. (Wall) | mass/sq-ft/day (0-order) | mass/sq-m/day (0-order) |
| | ft/day (1st-order) | meters/day (1st-order) |
diff --git a/src/input1.c b/src/input1.c
index 5918c4f..a990856 100644
--- a/src/input1.c
+++ b/src/input1.c
@@ -432,7 +432,6 @@ void initunits(Project *pr)
strcpy(rpt->Field[DEMAND].Units, RptFlowUnitsTxt[parser->Flowflag]);
strcpy(rpt->Field[ELEV].Units, u_FEET);
strcpy(rpt->Field[HEAD].Units, u_FEET);
- strcpy(rpt->Field[PRESSURE].Units, u_PSI);
strcpy(rpt->Field[LENGTH].Units, u_FEET);
strcpy(rpt->Field[DIAM].Units, u_INCHES);
strcpy(rpt->Field[FLOW].Units, RptFlowUnitsTxt[parser->Flowflag]);
diff --git a/src/input3.c b/src/input3.c
index 305bf46..ac98d7a 100644
--- a/src/input3.c
+++ b/src/input3.c
@@ -1884,8 +1884,8 @@ int optionchoice(Project *pr, int n)
** those listed below, or -1 otherwise
** Purpose: processes fixed choice [OPTIONS] data
** Formats:
-** UNITS CFS/GPM/MGD/IMGD/AFD/LPS/LPM/MLD/CMH/CMD/CMS/SI
-** PRESSURE PSI/KPA/M
+** UNITS CFS/GPM/MGD/IMGD/AFD/LPS/LPM/MLD/CMH/CMD/CMS
+** PRESSURE PSI/KPA/METERS/BAR/FEET
** HEADLOSS H-W/D-W/C-M
** HYDRAULICS USE/SAVE filename
** QUALITY NONE/AGE/TRACE/CHEMICAL (TraceNode)