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General project properties for the analysis are input in this window





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Stress analysis code

Code used for stress analysis and analysis mode (see "stress analysis code" table). You can't change the code while the project file is already open. To change the code need to close the project file, open it again and change the code

Use Eh for support loads

By default, START-PROF use cold Elastic modulus for pipe and fitting stiffness calculation in all load cases for ASME codes. If this option is checked then START-PROF use hot Elastic modulus for load cases used for support and vessel load calculation. Using this option can reduce the loads on supports and nozzles, pumps etc. More...

We recommend to switch on this option

Consider creep effect

If this option checked, 2 additional load cases considering creep effect in operating and cold mode will be added and add two additional sustained stress checks in operating mode and in cold mode. The creep stress relaxation in operating mode and pipe self-springing effect in cold state is taken into account. More...

We recommend to switch on this option

Consider tee branch flexibility

If this option is checked, the branch flexibility will be considered for all tees with Db/Dh less than 0.5 (Db - branch diameter, Dh - header diameter). Flexibility calculated according to ASME BPV SIII div 1 class 1 NB 3686. This option affect all types of tees including non-standard. More...

Liberal Stress Allowable

For example for ASME B31.3 code:

The same idea is used for all other codes

Stress range from operation to cold

By default START-PROF calculate the stress range between operation and installation state. If this option is checked, then START-PROF calculate the stress range between operation and cold mode. In this case the stress range could be greater. . We recommend to switch on this option

Installation mode is state before the piping first warming up. The cold mode is a state after piping cooling down. The difference is in friction forces behavior. In installation state all friction forces is zero. In cold mode all friction forces is not zero and their direction is opposite to the direction of friction forces in operating mode.

Add axial force and torsion stress

By default, the most of ASME, EN, GB, DLT codes (except ASME B31.3) doesn't consider axial force and torsion moment influence on sustained and expansion stress. For example:

ASME B31.1


ISO 14692:

It's not safe in some situations. For example in case of pipe restrained between two fixed anchors the code stress will be always zero. But in real life this pipe may collapse.

If this option is checked, START-PROF add axial force (F/A) and torsion moment (Mt/2Z) stress to sustained and expansion stress check. For example ASME B31.1 equations will be following:


ISO 14692:

It adds more safety to standard code stress checks. We recommend to switch this option on. More...

Use ASME B31J SIFs and k-factors

If selected, then all SIF factors and k-factors for bends, tees, reducers are calculated according to ASME B31J code, instead of selected pipe stress code

Use Wc factors

If selected, then allowable stress for sustained loads is multiplied by circumferential weld joint efficiency factor Wc for ASME B31.1, ASME B31.3, DL/T 5366More...

Maximum f=1.2

See ASME B31.3 302.3.5 equation (1с). If selected, then maximum value of stress range factor f can be 1.2 for materials with enabled option "Maximum f=1.2" in material database, otherwise maximum value always f=1.0

Maximum f=1.0

See ASME B31.4 403.3.2. If selected, then maximum value of stress range factor f can be 1.0, otherwise maximum f=1.2

Use In-Plane/Out-Plane SIF

If selected, then used table H.3 of EN 13480, else used table H1. See 12.3.8 EN 13480

Liberal Stress Allowable

If selected, then equation 11.6-5 EN 13480 is used, otherwise equation 11.6-4 is used

Consider Corrosion

If selected, corrosion allowance is subtracted from the wall thickness according to 12.3.1 EN 13480

With Surveillance of Creep Exhaustion

If selected, then right two columns of table 5.3.2-1 EN 13480 are used

Use maximum distortion energy

True - used maximum distortion energy equation

False - used maximum shear stress equation (Tresca combined stress)

Maximum - used maximum value of Tresca combined stress and maximum distortion energy equation

See. 402.7 ASME B31.4 and A842.2.2 (c) ASME B31.8


Detailed information on Restrained and Unrestrained pipe sections of buried pipe can be found here.

Specify manually - user should manually specify restrained or unrestrained option for each buried pipe element in the model

Autodetect - start automatically select "restrained" or "unrestrained" option. See details here.

Use START Smart Check - use alternative (non code!) strength check equations suggested by START-PROF authors that can guarantee the strength for booth restrained and unrestrained pipelines. See details here.

Add Thermal Bowing

Consider affect of thermal bowing on horizontal pipes. More...

Use MDMT Allowable Reduction

Take into account the minimum impact test exemption temperature reduction according to 323.2.2 (c) ASME B31.3. Read more...

High pressure

All piping considered as high pressure according to GOST 32388-2013 if checked. If not checked then only the elements with design pressure higher than 10 MPa considered as high pressure

Overload factor

This factor should be entered for high temperature pipelines according to p. 8.1.15 GOST 32388-2013, RD 10-249-98  section

Ambient temperature

Average wall (metal) temperature at the time when pipe segments become a single joined structure. More...

This property can be changed in different operation modes. To see the value of this property in all operating modes push the button

Service life

Service life can be from 1 to 50 years or from 10000 to 300000 hours (for RD 10-249-98). 1 year is considered to be equal to  365*24 hours.

Used for fatigue strength analysis, as well as for determining nominal allowable stress from the materials database (for RD 10-249-98).

Test state analysis

Product with which tests are done (water, gas). Test state analysis need not be run. Product weight is taken into account for determining loads on equipment, expansion joint deformations, displacement, and Stress. Wall thickness analysis for test pressure  Ptest  (set in element properties) is done.

Test temperature, Тtest

Operation temperature in test state. Average wall (metal) temperature along the piping during testing. Testing is usually done without product heating, i.e. at surrounding air temperature. Usually set as Тtest = +200С.





Spring selection

Selected if variable spring supports are present. If "run" is selected, automatic variable spring support selection is done and their compression force is calculated according to RTM 24.038.12-72. Code for springs must be input

Spring selection table

Code of standards for springs from the springs database used for their selection. If "other" is selected, allowable load and stiffness must be specified in spring properties

Constant force hanger and support selection

Used if constant spring supports are present. If "run" is selected, automatic selection of constant spring supports and hangers is done. Standard for these supports must be specified. If "other" is chosen, then program will show the load and displacement for manual constant load spring selection for any manufacturer

Restraint selection standard

Constant force restraints code from the constant force restraints database

Spring and constant spring support selection state

Spring flexibility can be selected from  zero displacement from weight load conditions in operation or cold state.

Spring selection in cold mode is for advanced users, who understand the advantages of this method. With selection in cold mode, installation must be done with the "separation method", where support adjustments are less time-consuming than the traditional method. In other cases, selection in operation state is recommended. More...

Analysis mode

There are two options: Single Use Compensator analysis or pre-heating analysis

To use the single use compensator or pre-heating, please switch the "Spec. Analyze" flag in the operation mode editor

Locking temperature, Тweld

Piping locking temperature at which single use compensators are welded. Optimal locking temperature is half of temperature range Тweld = (Тop - Тassembly) / 2.

Pre-heating temperature, Тweld

Piping pre-heating temperature at which the trench is backfilled. Optimal pre-heating temperature is half of temperature range Тweld = (Тop - Тassembly) / 2.





Automatically insert cap in free nodes

After starting analysis, all end nodes will be considered capped

Use minimum thickness

During wall thickness analysis, a value no less than that allowed in standards is given:

If the flag is not checked, minimum wall thickness check for GOST 32569-2013 is not done. For other standards, it is done regardless.

Anchor coefficient by default

Default load factor. From 0.5 to 1.0. Used for  intermediate supports load analysis.

Pipping size specification

Specifies the piping specification standard: ANSI (American National Standard), GOST (Russian), EN (European Union)

PUR Insulation Jacket Code

Select the PUR pre-insulated pipe manufacturer

Anchor coefficient by default

Allowable rotation for various type of hangers. When exceeded, the warning message appears

Number of cycles

Minimum number of cycles used in EN 13941 calculations

*Iteration mode of constant restraints

Constant spring support selection algorithm  type

*Iteration mode of spring restraints

Mode 1 - At LH2 load case single-directional links on/off mode are calculated by iteration, mode 2 - single-directional links are always on

Iteration mode

Pre-defined iteration algorithm selection for non-linear problems with friction and single-directional restraints. Switched in cases of problems with iteration convergence

  • Type 1 - The initial approximation is constant value of friction force. A several restraints can be switched off at each iteration

  • Type 2 - The initial approximation is constant value of friction force. Only one restraint can be switched off at each iteration

  • Type 3 - The initial approximation is zero value of friction force. A several restraints can be switched off at each iteration

  • Type 4 - The initial approximation is zero value of friction force. Only one restraint can be switched off at each iteration

  • Type 5 - The initial approximation is zero value of friction force. Any number of restraints and gaps can be switched on and off at each iteration

It should be borne in mind that nonlinear systems with friction, single-directional restraints and gaps can have many equilibrium states (solutions). And they are all correct. For example, a cubic equation has three solutions. And all three are correct. Therefore, it is quite possible that different types of iterations (1-5) will converge to different solutions for the same system. Different support loads, displacements and stresses can be obtained. This is a normal situation as we do not take into account the history and load application sequence

*Soil model

  • Outdated soil model - soil support placement model, used in START-PROF 4.77 and lower. Soil supports not placed for small-radius bends. Support placement step near concentration points is 7D, and 14D further away.

  • New recommended soil model - soil supports placed at all bends with a step of no less than 1.6D (see "bend splitting step" property below), with no less than one soil support in each bend. Straight pipe splitting step differs in various zones #1, #2, #3. More...

*Consider tee branch flexibility

Consider tee branch flexibility for Russian codes: - on, - off, - by default ("off" for RD 10-249-98 5.2, SNIP 2.05.06-85, SP 36.13330.2012 and "on" for all other codes)

*Accuracy iteration, tf

Parameter has an influence on the iteration process. It is the accuracy of the force in wrong direction. If force is higher than this value the restraint is switched off. if force is lower then restraint is not switched off. It stabilize the iteration process with single-directional links. If the parameter is 0 then the default value 0.001 tf is used

*Accuracy movement

Parameter used for accuracy control after analysis. The error is generated if the displacement along the restricted direction is greater than wall thickness multiplied by this parameter. If the parameter is 0 then the default value 0.15 is used (i.e. movement is greater than 15% of the wall thickness)

*Accuracy force

Parameter used for accuracy control after analysis. The error is generated if the load along the restricted direction is greater than the maximum vertical load multiplied by this parameter. If the parameter is 0 then the default value 0.02 is used (i.e. load is greater than 2% of the maximum vertical load)

*The maximum span between soil springs, D

The maximum span between soil springs in restrained zone. Default value is 100D

*Horizontal Tolerance

Specifies the maximum slope of a straight pipe. The pipe pitch is calculated using formula: |DZ| / ( DX^2 + DY^2 + DZ^2 )^0.5. Used for

  • thermal bowing effect, that is considered only for horizontal pipes

  • checking of sliding and guide support, that is allowed only on horizontal pipes


Hidden property. It should be edited only by professionals at their own risk!

Menu Access

Dialog window opens automatically when creating a new analysis file or opening an existing analysis file. To open this window in an open file, use  File > Project Settings