Webinar - Practical Fire and Gas Mapping Using DELOS

Please find below a recording of the webinar on Practical Fire and Gas Mapping Using DELOS.  We have also included a copy of the Questions and Answers session featured at the end of the webinar, including answers to questions we did not have time to get to during the webinar.


 

Questions and Answers

Question What guide do you follow to perform Fire and Gas Mapping ?
Answer

This needs to be considered on a project-by-project basis. However, a larger number of projects follow the BP guide (BP Guidance on Practice for Fire and Gas Detection (GP 30-85), Dec 2009), which uses a geographical gas detector placement and a somewhat complex detection criteria for flame detector mapping. DELOS allows the configuration of grades and detection ranges to complete F&G  mapping project in line with the various standards and internal company guides.

   
Question Does DELOS perform scenario-based Fire and Gas Mapping?
Answer DELOS is a geographical or volumetric based fire and gas mapping tool.

There is an ongoing dialogue in the oil and gas industry about scenario-based mapping, which currently only really applies to gas detection.

There are obviously pros and cons to each approach and there is not really a consensus on the 'best' approach, each needs to be considered individually, which is something the recent British Standard 60080 tried to highlight.

   
Question Does DELOS require a high-end 3D modelling computer?
Answer No, DELOS can run on most modern machines. It does make use of multithreading, so it scales with processing power and with better graphics cards.

It is recommended to have at least 8GB of RAM as 3D models can be large, but DELOS does offer mechanisms to cope with memory issues such as only loading relevant aspects of a geometry.

   
Question Does DELOS contain a detector database?
Answer The current version of DELOS does not have a detector database, but we are constantly seeking ways to streamline the user experience. DELOS does allow the user to modify detectors which should be sufficient to model most detector types, and this can be saved along with the project. Not having a detector database engages the user to obtain up-to-date detector characteristics from manufacturers.
   
Question Does ESR Technology offer training courses?
Answer ESR can offer training courses for fire and gas mapping using DELOS on request. Please contact ESR Technology if this is something you are interested in.
   
Question Does DELOS perform automatic optimisations?
Answer Yes, DELOS has both a simple and genetic optimiser built in.

The simple optimiser is a good choice for finding the best location for a single new detector and keeping existing ones fixed.

The genetic optimiser is a good choice for new or unknown layouts with many variables.

Both optimisers offer benefits to offload the thinking to the computer and leave for a while.

The design philosophy of DELOS is such that these modes are not required. With sufficient insight and ease of use, a human will still beat a machine in a short amount of time.

   
Question You mentioned 3D mapping but performed a 2D result, does DELOS do 3D visual results?
Answer Yes, along with the zero coverage isosurface, there is a single command to perform multiple isosurfaces to display the 3D equivalent of the 2D plot. The 2D plot is good for presenting in a report. The 3D isosurface can be a little complex to interpret printed on a page but you can employ tricks such as using thin slices and ‘exploding’ the view, which provide good insight.
   
Question Can DELOS calculate the percentage of the areas (and volume) that is detected by 2 or more gas detectors?
Answer Yes, there is a lot of generated output which can be interpreted to answer a number of queries. The setting up of grades for flame detectors is a major factor in the way the results are presented, resulting in a more complex outcome with detection at various ranges for different grades. If no graded areas are defined, the coverage results are presented simply for the number of detectors. Coverage by area or volume can be calculated by defining a slice or calculation volume respectively, with the results for a cumulative number of detectors provided on the Statistics tab. The raw data can be used to continue an analysis into other characteristics if required. This can be further broken down by any of the areas defined within the slice or volume. For example, percentage volume of two detectors at any vertical range in area 1 within calculation volume 1.
   
Question How do you map fusible plug using mapping software?
Answer DELOS assigns the appropriate detection level (e.g. control action) and assumes a fire of a given radius would be detected by the fusible plug. A composite image of flame detector and fusible plug coverage will be generated if both fire detector types are being used.
   
Question Any demo for fusible plug and toxic gas detection?
Answer Unfortunately, there wasn’t time to cover all the features and capabilities of DELOS during the webinar. However, we would be happy to set up individual Teams meetings to demonstrate further specific features or a demo version of DELOS can be requested via the website and this functionality can be trialled.
   
Question Are 2D images automatically generated from 3D by DELOS?
Answer Firstly, lets distinguish between a 2D image, being an image in a Word document and 2D result, such as a slice which can be viewed in 3D or exported as a 2D image.

It is possible to export 3D objects or 3D analysis by using the snapshot tool to get a 2D image. Taking a snapshot of a 3D result from requestable camera angles, e.g. from the top, can achieve something which looks like a 2D result.

However, if the user is trying to achieve a 2D result directly from a 3D result, then this is the purpose of the slice tool. The user can request the height the slice maps through a 3D result, or a composite 2D result from multiple heights can be achieved. This can all be calculated within DELOS at the same time if required.

   
Question Do you offer a demo version?
Answer Yes, a demo version can be requested via the website or by contacting ESR Technology by any other means.
   
Question Is this similar to/ from other software on the market?
Answer There are a number of tools commercially available for Fire and Gas Mapping, which, by definition do similar things. The common F&G mapping features such as the 3D CAD operations or modelling of detectors with a well-known shape for the field of view may look similar but DELOS is different and unique, offering clients a cost effective and practical tool.

ESR has a history of both developing software for the oil and gas industry as well as offering consultancy services for fire and gas mapping so it makes sense for us to have our own tools.

   
Question Does DELOS come with viewer version? Can it be used to set coverage targets?
Answer

This is something being assessed for a future release. Ultimately, we would like to be able to offer a free viewer which allows greater interaction with the results for the end client once the study is completed.

   
Question How do you define the gas cloud size for mapping? What kind of offline calculation has to be done for mapping input?
Answer The size of the gas cloud is typically determined by the volume which would produce overpressures at a certain threshold. This is usually governed by the guidance being followed. In geometric modelling the calculation is fairly straightforward – calculate the volume which would generate the overpressure and calculate a radius assuming the volume is spherical.

overpressure of any ignited event is a complex function of a number of factors including the degree of confinement, plant congestion, ratio of gas in air, uniformity of gas / air mixing and the quality of the ignition source.  However, work done by the HSE (Offshore Gas Detector Siting Criterion - Investigation of Detector Spacing, Health & Safety Executive, Offshore Technology Report (OTO 93 002), Apr 1993) gives a qualitative guidance on the stoichiometric gas cloud size that will serve as a threshold for design purposes.  The study found that for low order alkanes (C1 to C4), the size of the smallest stoichiometric gas cloud capable of causing damage to an enclosed plant or semi enclosed plant is 6m.  For a largely unconfined volume, a 6m gas cloud produced an overpressure of less than 150mbar, which is within the acceptable limit. Based on this, the spacing of gas detectors can be selected, depending on the blockage ratios / congestion within the modules.

Specific explosion modelling could be carried out for the installation being assessed to approximate the expected cloud diameter with the potential to lead to a 150 mbar overpressure.

   
Question How many installations have deployed Delos based on an existing 3D model? What is the realistic timescale to completion?
Answer Since 2013, DELOS has been used in-house by ESR Technology for many installations around the world from small normally unmanned platforms to large offshore installations and onshore sites. The time to complete a project depends on a number of factors such as whether both fire and gas mapping is required, the size of the installation, and the number of decks / areas which require mapping. A project could take from around a week for a small platform or onshore site, up to a month if the installation is very large, has multiple jackets or has a very congested layout. These timescales include getting familiar with the project, compiling reports etc., and is not full time DELOS use. Following issue of a draft report, there could be a period of feedback and refinement as other aspects of a project develop.
   
Question How do you perform Fire and Gas mapping for a plant where there is no 3D model?
Answer DELOS does not currently offer a 3D build tool. This is a feature which is easily performed by several free to use packages. During the course of our own work, if no 3D model is provided, ESR Technology has used a free package to generate a 3D model from plot plans and elevation drawings. These models are then exported in OBJ format and imported into DELOS. This is how the demo materials were made.
   
Question How much does DELOS cost? 
Answer

Please contact ESR Technology for an up-to-date brochure on software sales (This email address is being protected from spambots. You need JavaScript enabled to view it.).

 

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