The fire protective envelope of any building consists of multiple elements with widely differing properties relating to a fire, such as glass, roof tiles and sheathings, wood cladding, gaps and openings. Where resistance to an exterior fire is required, all elements should be verified to provide a comparable risk of burn-through. Elements are rated by either the material response to fire or fire resistance. In Europe, cladding sheets and wall membranes can be rated by K classes, which effectively include a measure of the time to burn through. A determination of burn-through time of each element of a specific building envelope should be obtained. A design tool to verify the performance of a building's fire protective envelope has been developed. In this paper, a general description of passive elements of the envelope, which should be included in a risk assessment tool such as an index method, is presented. An illustrative approach to visualise the profiles for areas densely spaced structures where an exterior fire may trigger building-to-building fire spread is also included. The research is based on the hypothesis that a relatively subtle and pointed upgrading of an exterior building envelope will severely reduce the speed of building-to-building fire spread, thus allowing firefighting efforts to get on top of the situation. For a burning structure to expose other buildings to fire, the fire has to settle, which leads to a burn-through to the inside. Once inside, an enclosure fire needs to develop and burn through the roof or break one or more large window panes. It is estimated that a 5-10 min delay for a structure to expose other structures to fire can be sufficient to avoid loss of multiple structures. A 10-50 min burn-through time allows for an extended intervention by the fire brigade, which is significant in rural areas. A fire protective envelope may prevent an exterior fire from penetrating the protective envelope at all and the structure can be saved. This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The principal objective of this study was to test the hypothesis that the orientation of the presented map on a navigation display (i.e., north-up vs. track-up) would influence performance in a computer-based navigation task. In addition, it was believed that the user's level of spatial ability would interact with the nature of the display.Results indicated that neither display led to more accurate or faster performance. However, the track-up group reported finding the task more difficult (higher workload) and rated the map display less helpful. The north-up group also reported such a display as potentially being more helpful in real world driving. Results indicated a significant correlation between spatial ability and performance accuracy, with high spatial ability scores associated with better performance on the navigation task. Implications for the design of navigation devices, such as those currently marketed for automobiles, will be discussed as well as areas warranting further research.

Objectives/Scope This case history paper describes the well integrity challenges Spirit Energy was faced with for executing the drilling operations on the Scarecrow wildcat well in the Barents Sea. The expected reservoir depth on Scarecrow was the shallowest reservoir ever drilled in the Barents Sea being only 188 m below mudline with a water depth of 454 m MSL. Several mitigating actions were implemented to improve robustness of the well integrity such as: The focus in this paper is to describe the qualification of a new automated pressure control method (Autochoke system) used on the Scarecrow wildcat well in the Barents Sea for circulating out an influx. Simulations and return of experience indicated that manual conventional well control practices would not provide sufficient pressure control precision to maintain bottomhole pressure within the +/- 4 bar (58 psi) operational window required to circulate out an influx. A new automated pressure control method based on a commercial managed pressure drilling (MPD) control system was developed, tested, and DNV approved to achieve the required pressure control precision for both single- and multi-phase scenarios, and permit safe operations. Methods, Procedures, Process A pressure control method was developed to automate control of well control chokes to maintain a constant standpipe pressure, as required during circulating using Driller's Method. The methodology used is comparable to commercial MPD pressure control systems, in which pressure transducer (PT) measurements are input to a control loop which actuates chokes to attain the pressure demand while minimizing overshoot. Unlike a typical MPD installation, in which PTs are typically located upstream of a choke manifold, this installation utilized PTs installed on the rig standpipe, with chokes installed in the well control manifold. The choke control system was improved to automatically compute and account for pressure wave propagation lag due to the distance between the chokes and the control PTs. Results, Observations, Conclusions The system was tested at a test rig in Norway that permitted the injection of air into the standpipe to simulate a gas kick. In multiple test cases, various quantities of air were injected into the standpipe, circulated into the annulus, and finally circulated out of the wellbore with automated chokes operating to maintain a constant standpipe pressure as the air was circulated out of the wellbore and through the chokes. Testing was repeated with varying quantities of injected air and varying standpipe pressure setpoints to validate the process across a range of operating conditions. The control system demonstrated standpipe pressure control precision of +/- 1 bar (14.5 psi) during all test phases, achieving the required precision. Testing under additional operating conditions was conducted to approximate a real-world well control scenario, in which constant casing pressure is maintained while ramping the pumps, and constant standpipe pressure is maintained while circulating out the kick (i.e. first circulation of driller's method of well control). The maximum observed deviation from the control value was 2 bar (29 psi), again meeting the required control precision. Novel/Additive Information These tests were observed, validated, and approved by DNV. The technology was introduced to the field in July 2018.