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PHAST™. The Multi Component extension supports the core steady-state discharge models, and dispersion modelling via the UDM, currently limited to clouds. PHAST Tutorial Manual - Download as PDF File .pdf), Text File .txt) or read online. tut. Contact [email protected] for more information. Re: DNV PHAST step by step guide. Good afternoon I have a Phast manual. Pdf, but I have no license Phast , could you help me on.

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Prerequisite: The course is suitable for new users and for more experienced users who have not attended a formal training course or would like a refresher. Training catalogue PHAST, SAFETI AND KFX 03 The course introduces the concepts and models within Phast. . It also introduces methods of manual. We are using Phast , dispersion / explosion modelling with consideration Energy_Model/links/aaebccc4e1apdf?origin.

Reddit Abstract Hydrogen is a critical component in the production of cleaner fuels. Underground pipelines provide a safe, reliable supply of hydrogen to refineries and the petroleum industry. Proper assessment of the risks associated with underground hydrogen pipelines requires an accurate model of the jet fire consequence. This article will describe experimental and modeling work undertaken in order to define the appropriate methodology for utilizing DNV's PHAST software tool to represent the hydrogen jet fire from the rupture of underground hydrogen pipelines. Two experiments were conducted to measure the flow and radiation from an intentionally ignited rupture of a 6 in. Adjustments to PHAST modeling parameters were required in order to obtain agreement between the measured and predicted radiation and flame length values.

Introduction An accidental toxic gas release may have serious consequences on neighbouring population. Concern for public safety has led to the establishment of safety perimeters, within which land use planning is strictly controlled.

Toxic Release Dispersion Modelling with PHAST: Parametric Sensitivity Analysis

It is important that these safety perimeters be established using the best scientific knowledge available, and that the level of uncertainty be minimised.

A significant contribution to the calculation of the safety zones comes from the modelling of atmospheric dispersion, particularly of the accidental release of toxic products. This software application is quite flexible, allowing the user to customize values for a wide range of model parameters. Users of the software have found that simulation results may depend considerably on the values chosen for some of these parameters. While this flexibility is useful, it can lead to disparities in the calculations of effect distances even when studying the same scenario.

Sensitivity Analysis SA is the study of how the variation in the output of a model can be apportioned, quantitatively or qualitatively, to variation in the model input parameters Saltelli et al.

In literature related to atmospheric dispersion modeling, there are essentially sensitivity analysis studies based on OAT method. For example, Bubbico and Mazzarotta have applied an OAT method to a minute accidental toxic release scenario.

The parameters studied are Pasquill stability class, wind speed, ambient temperature and release hole diameter. An OAT method has been employed for various release scenarios, studying parameters such as release height, release velocity, surface roughness, and stability class.

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For this purpose, a methodology is developed and is illustrated through a nitric oxide gas dispersion scenario. The main input parameters involved in the calculation of various model outputs are related to storage, atmospheric, release and orographic conditions. The effect of their variability, within specific intervals and according to their distribution type, on the results has been evaluated.

Phast manual pdf dnv

Software Tools 2. It examines the process of a potential incident from the initial release to far field dispersion, including modelling of pool vaporisation and evaporation, and flammable and toxic effects. An integral-type dispersion model called UDM Unified Dispersion Model calculates several consequence results: i cloud behaviour ii transition through various stages such as jet phase, heavy phase, transition phase and passive dispersion phase, iii distance to hazardous concentration of interest and iv footprint of the cloud at a given time.

Sensitivity studies can be easily carried out using these Spreadsheets, since they allow direct control of input parameters and output results, easy parameter variation and multiple runs simultaneous simulation of various scenarios. PHAST v. The results of these evaluations are used to determine i the uncertainty in model predictions and ii the input variables that give rise to this uncertainty.

SimLab generates a sample of points based on the range and distribution of each input parameter specified by the user. For each element of the sample, a set of model outputs is produced by evaluating an internal or external model. In essence, these model evaluations create a mapping from the space of the inputs to the space of the results.

This mapping is the basis for subsequent uncertainty and sensitivity analysis to calculate various sensitivity indices. Sensitivity Analysis SA The aim of SA is to determine: i the factors that contribute the most to the output variability, ii the model parameters that are negligible since they have little impact on the outputs , iii interaction effects of parameters.

Saltelli et al. Screening methods.

Phast pdf dnv manual

The aim of screening methods is to identify the most important parameters from amongst a large number that affect model outputs. Various strategies and methods have been discussed in several articles with illustrative examples: Campolongo et al. However, local sensitivity analysis can only inspect one point at a time and the sensitivity index of a specific parameter depends on the central values of the other parameters. Global SA methods. Global SA techniques incorporate the whole range of variation and the probability density function of the input parameters to calculate their influence on the output.

A survey of sampling-based methods has been presented by Helton et al. The quantitative measure of sensitivity is represented by Sensitivity Indices. The firstorder sensitivity index, S i of an input factor p i is a measure of the main direct effect of p i on the output variance.

S ij where i j , the second-order sensitivity indices, measures the interaction effect of p i and p j on the output variance. Other higher-order indices are defined in the same manner. The total sensitivity index, S Ti is the sum of all sensitivity indices involving factor p i Homma and Saltelli, The FAST method calculates the first-order and total sensitivity indices, whereas Sobol s method, in addition to these, also provides all higher-order sensitivity indices to determine quantitatively the interaction between parameters.

However, the computational cost implied by Sobol s method increases significantly as the number of indices to be calculated is increases. Our method comprises of six steps, as shown in Figure 1.

Depending on the selected sensitivity analysis method FAST or Sobol , SimLab calculates various sensitivity indices 1 st order, 2 nd order,, Total order. The icon represents an instance of that Model and will have its own set of values for the input data, and you can define any number of instances of a given Model in your Study Folder, each with its own set of input data to represent a particular hazardous event.

The Model icons are organised in a tree structure.

DNV PHAST step by step guide

The top level represents the entire Study Folder, with the name PHAST Example Study, the next level is the Study named example , the third level contains several Folders, and the fourth level contains the Models themselves.

You can create any number of Studies or Folders, depending on how you want to organise your analysis. To add a Model at a particular point in the structure, select the Study or Folder, and then select the appropriate Model from the Insert menu as shown. You can also insert a Model by selecting the Model from the Insert cascade at the top of the right-click menu, or by selecting the icon for the Model from the toolbar.

The program performs a separate run of the consequence calculations for each separate weather conditions, giving a set of results that are specific to that Weather. The Weather tab section also contains a Study icon called Example Cases. In the Model tab section, all of the Models have been placed inside the Example Cases Study, but you create and use any number of Studies in an analysis. You can insert Weathers underneath a Study in the Weather tab section. When the program is processing the consequence calculations for a given Model, it will perform the calculations for every Global Weather and for any Local Weathers under the Study that contains the Model, i.

As with the Weathers, there is a set of Global Parameters, and you can also define Local Parameters that are specific to a given Study. If you define a local set of Explosion Parameters, for example, the values in this set will be used instead of the values for the global Explosion Parameters during the calculations for the Models in that Study. Green border to icon: shows use of default values All of the icons in the Global Parameters folder have green borders. The program uses this border to show that all of the Parameters under that icon are using the default values that are supplied with the program.

If you change the value of any of the Parameters then the green border around the icon will disappear. This allows you to see at a glance which aspects of an analysis are using alldefault values, and which are using changed values. Chapter 1: Introduction The program is supplied with a set of System Materials that contains full property data for more than sixty materials. However, the Materials tab section does not show icons for all of these materials, but only for materials that have been selected in the input data for the various Models in the Study Folder, or for materials that you have added yourself while working in the Material tab section.

You cannot currently define Local Materials to be used only for the Models in a given Study. Each icon has a green border, which shows that all of the input fields for the material have the values set for that material in the System Materials.

You can change the values if you wish - e. The yellow-and-red icon is a Mixture, and in the PHAST Example Study Folder it represents the plume of hydrogen chloride, nitrogen dioxide and sulphur dioxide produced by a fire in a pesticide warehouse which is the situation modelled by the Warehouse Fire Model.

This particular Mixture is generated automatically when you run the Warehouse Fire Model, but you can also define your own Mixtures, using any combination of the materials in PHAST, and select these Mixtures for use in the dispersion, fire and explosion calculations.

Pink Icon: a Pesticide The six pink icons are all Pesticides, and are used to describe the contents of the warehouse for the Warehouse Fire Model. Pesticides are only relevant to the Warehouse Fire Model and cannot be selected for any other type of modelling.

Chapter 1: Introduction The Map Tab Section The Map tab section allows you to set up map image and geographic data so that you can view the regions and features affected by consequence results. The map image is defined by the powerstation raster image, and you view the image by selecting Map from the View menu. The Map Window will open in the area to the right of the Study Tree pane, and you can use the options in the Map menu, the right-click menu and the Map toolbar to zoom in and out, to move around in the Map Window, and to control the display of the features of the window such as the scale bar and the legend.

211576535 PHAST Tutorial Manual

These dots can sometimes be difficult to see and to relate to the individual Models, but there are several options that can make this easier: Changing the Size and Colour of the Dots Select Map from the Preferences cascade of the Options menu to open the Map Preferences dialog, and then move to the Model tab section.

By default the colour is turquoise and the Point Size is 7 pixels, but if you change the colour to blue and the size to 10 pixels as shown, then the dots will be easier to see on the powerstation Map. Displaying the Model Names on the Map If you move to the Models tab section, select any Model, and then select Labels from the View menu, the names of all of the Models will be displayed on the Map. To hide the names, deselect the Labels option.

If there is more than one Model at a given location as with the Chlorine Models and the Butadiene Models then the names will be superimposed and may be difficult to read, although this will make it clear that there are multiple Models at the location.

Chapter 1: Introduction Pinpointing an Individual Model If you select a Model in the Study Tree and then select Pinpoint from the View menu or press the F4 key , the dot for that Model will become centred in the Map window and will also be highlighted i.

Phast manual pdf dnv

This allows you to locate a specific Model, which is useful if you cannot identify the name for that Model on the Map. Viewing Input Data The section above introduced the main types of input data and their organisation, and this section describes how to work on the details of the input data.

The dialog contains a large number of input fields organised over sixteen tab sections, but many of these fields are relevant only to advanced modelling options e. Input Dialog for the Chlorine Rupture Model Chapter 1: Introduction Getting Help on the Input Data This tutorial does not attempt to describe every item on input data, but the program is supplied with comprehensive online Help. Every input dialog contains a Help button at the bottom right.

When you click on this button, the online Help will appear in a separate window, as shown.

Phast pdf dnv manual

The Help Window The Help Window will be displaying a description of the current tab section, but you can use the links inside the topic and the Contents, Index and Search tabs to reach any topic in the Help system and gain a full understanding of the way that the input data will be used in the calculations and the appropriate values that you should set for the hazardous events that you want to model.

Most dialogs also have a Whats This Help button in the form of a question mark at the right of the title bar.